Green tea extract combined with exercise reduces fatty liver disease in mice

Although untested in human trials, results suggest a potential health strategy

February 14, 2020

Science Daily/Penn State

The combination of green tea extract and exercise reduced the severity of obesity-related fatty liver disease by 75% in mice fed a high-fat diet, according to researchers, whose recent study may point to a potential health strategy for people.

The outcome is important, explained Joshua Lambert, associate professor of food science, because nonalcoholic fatty liver disease is a significant global health problem that is expected to worsen. Because of the high prevalence of risk factors such as obesity and type 2 diabetes, fatty liver disease is forecast to afflict more than 100 million people by 2030. And there are currently no validated therapies for the disease.

In the study, mice fed a high-fat diet for 16 weeks that consumed green tea extract and exercised regularly by running on a wheel were found to have just a quarter of the lipid deposits in their livers compared to those seen in the livers of a control group of mice. Mice that were treated with green tea extract alone or exercise alone had roughly half as much fat in their livers as the control group.

In addition to analyzing the liver tissues of mice in the study, which was published recently in the Journal of Nutritional Biochemistry, researchers also measured the protein and fat content in their feces. They found that the mice that consumed green tea extract and exercised had higher fecal lipid and protein levels.

"By examining the livers of these mice after the study concluded and by screening their feces during the research, we saw that the mice that consumed green tea extract and exercised actually were processing nutrients differently -- their bodies were handling food differently," Lambert said.

"We think the polyphenols in green tea interact with digestive enzymes secreted in the small intestine and partially inhibit the breakdown of carbohydrates, fat and protein in food," he added. "So, if a mouse doesn't digest the fat in its diet, that fat and the calories associated with it pass through the mouse's digestive system, and a certain amount of it ends up coming out in its feces."

It may be significant, Lambert explained, that mice treated with both green tea extract and exercise had higher expression of genes related to the formation of new mitochondria. That gene expression is important, he said, because it provides markers that will help researchers understand the mechanism by which green tea polyphenols and exercise might work together to mitigate fatty liver deposits.

"We measured the expression of genes that we know are related to energy metabolism and play an important role in energy utilization," Lambert said. "In the mice that had the combination treatment, we saw an increase in the expression of genes that wasn't there before they consumed green tea extract and exercised."

More research is needed to see if there is a synergy created by green tea extract and exercise working together to reduce fat deposited in the liver, or if the effects are simply additive, Lambert pointed out. His research group in the College of Agricultural Sciences for 12 years has studied the health benefits of polyphenols -- often called antioxidants -- from green tea, cocoa, avocados and other sources.

In previous related research, Lambert and colleagues demonstrated that green tea extract and exercise together sharply reduced body mass and improved cardiovascular health of high-fat-fed mice. But because no human trials assessing the health benefits and risks of green tea combined with exercise have been conducted, he urges caution for people who decide to experiment with the health strategy on their own.

"I believe people should engage in more physical activity, and replacing high-calorie beverages with decaffeinated, diet green tea -- which has no calories -- is a smart move," he said. "Combining the two might have health benefits for people, but we don't have the clinical data yet."

https://www.sciencedaily.com/releases/2020/02/200214134655.htm

Natural compound in vegetables helps fight fatty liver disease

New research shows how indole can reduce inflammation, fatty deposits

February 7, 2020

Science Daily/Texas A&M AgriLife Communications

A new study led by Texas A&M AgriLife Research scientists shows how a natural compound found in many well-known and widely consumed vegetables can also be used to fight fatty liver disease.

The study demonstrates how non-alcoholic fatty liver disease, or NAFLD, can be controlled by indole, a natural compound found in gut bacteria -- and in cruciferous vegetables such as cabbage, kale, cauliflower and Brussels sprouts. It also addresses how this natural compound may lead to new treatments or preventive measures for NAFLD.

The study was recently published in Hepatology.

"Based on this research, we believe healthy foods with high capacity for indole production are essential for preventing NAFLD and are beneficial for improving the health of those with it," said Chaodong Wu, M.D., Ph.D., a Texas A&M AgriLife Research Faculty Fellow and principal investigator for the study. "This is another example where altering the diet can help prevent or treat disease and improve the well-being of the individual."

About NAFLD and indole

NAFLD occurs when the liver becomes "marbled" with fat, sometimes due to unhealthy nutrition, such as excessive intake of saturated fats. If not properly addressed, this condition can lead to life-threatening liver disease, including cirrhosis or liver cancer.

Many diverse factors contribute to NAFLD. Fatty liver is seven to 10 times more common in people with obesity than in the general population. In addition, obesity causes inflammation in the body. Driving this inflammation are macrophages, types of white blood cells that normally battle infection. This inflammation exacerbates liver damage in those with liver disease.

Gut bacteria can also have an effect -- either positive or negative -- on the progression of fatty liver disease. These bacteria produce many different compounds, one of which is indole. This product of the amino acid tryptophan has been identified by clinical nutritionists and nutrition scientists as likely having preventive and therapeutic benefits to people with NAFLD.

The National Cancer Institute also notes the benefits of indole-3-carbinol found in cruciferous vegetables, including their anti-inflammatory and cancer-fighting properties.

A comprehensive and multi-level study on fatty liver disease

The present study examined the effect of indole concentrations on people, animal models and individual cells to help determine indole's effect on liver inflammation and its potential benefits to people with NAFLD. It investigated the extent to which indole alleviates non-alcoholic fatty liver disease, incorporating previous findings on gut bacteria, intestinal inflammation and liver inflammation. It also incorporated investigation into how indole improves fatty liver in animal models.

For the study, researchers investigated the effects of indole on individuals with fatty livers. As research collaborator Qifu Li, M.D., was also a physician at Chongqing Medical University in China, the team decided he should lead the clinical research using Chinese participants.

In 137 subjects, the research team discovered people with a higher body mass index tended to have lower levels of indole in their blood. Additionally, the indole levels in those who were clinically obese were significantly lower than those who were considered lean. And in those with lower indole levels, there was also a higher amount of fat deposition in the liver.

This result will likely extend to other ethnicities, Li noted, though ethnic background may have some influence on gut bacteria populations and the exact levels of metabolites.

To further determine the impact of indole, the research team used animal models fed a low-fat diet as a control and high-fat diet to simulate the effects of NAFLD.

"The comparisons of animal models fed a low-fat diet and high-fat diet gave us a better understanding of how indole is relevant to NAFLD," said Gianfranco Alpini, M.D., a study collaborator and former distinguished professor of Texas A&M Health Science Center, now the director of the Indiana Center for Liver Research.

Alpini said treatment of NAFLD-mimicking animal models with indole significantly decreased fat accumulation and inflammation in the liver.

The research team also studied how indole affected individual cells.

Shannon Glaser, M.D., a professor of Texas A&M Health Science Center, said that in addition to reducing the amount of fat in liver cells, indole also acts on cells in the intestine, which send out molecular signals that dampen inflammation.

"The link between the gut and the liver adds another layer of complexity to studies on non-alcoholic fatty liver disease, and future studies are very much needed to fully understand the role of indole," Glaser said.

Additional nutrition research needed

"Foods with a high capacity of indole production or medicines that mimic its effects may be new therapies for treatment of NAFLD," Wu said, adding prevention is another important aspect to consider.

"Preventing NAFLD's development and progression may depend on nutritional approaches to ensure that gut microbes allow indole and other metabolites to function effectively," he said. "Future research is needed to investigate how certain diets may be able to achieve this."

Wu said in future research he hopes to collaborate with food scientists and clinical nutritionists to examine what healthy foods can alter gut microbiota and increase indole production.

https://www.sciencedaily.com/releases/2020/02/200207123746.htm

Lower protein diet may lessen risk for cardiovascular disease

February 3, 2020

Science Daily/Penn State

A plant-based diet may be key to lowering risk for heart disease. Penn State researchers determined that diets with reduced sulfur amino acids -- which occur in protein-rich foods, such as meats, dairy, nuts and soy -- were associated with a decreased risk for cardiovascular disease. The team also found that the average American consumes almost two and a half times more sulfur amino acids than the estimated average requirement.

Amino acids are the building blocks of proteins. A subcategory, called sulfur amino acids, including methionine and cysteine, play various roles in metabolism and health.

"For decades it has been understood that diets restricting sulfur amino acids were beneficial for longevity in animals," said John Richie, a professor of public health sciences at Penn State College of Medicine. "This study provides the first epidemiologic evidence that excessive dietary intake of sulfur amino acids may be related to chronic disease outcomes in humans."

Richie led a team that examined the diets and blood biomarkers of more than 11,000 participants from a national study and found that participants who ate foods containing fewer sulfur amino acids tended to have a decreased risk for cardiometabolic disease based on their bloodwork.

The team evaluated data from the Third National Examination and Nutritional Health Survey. They compiled a composite cardiometabolic disease risk score based on the levels of certain biomarkers in participants' blood after a 10-16 hour fast including cholesterol, triglycerides, glucose and insulin.

"These biomarkers are indicative of an individual's risk for disease, just as high cholesterol levels are a risk factor for cardiovascular disease," Richie said. "Many of these levels can be impacted by a person's longer-term dietary habits leading up to the test."

Participants were excluded from the study if they reported having either congestive heart failure, heart attack or a reported change in diet due to a heart disease diagnosis. Individuals were also omitted if they reported a dietary intake of sulfur amino acids below the estimated average requirement of 15 mg/kg/day recommended by the Food and Nutrition Board of the National Academy of Medicine.

For a person weighing 132 pounds, food choices for a day that meet the requirement might include a medium slice of bread, a half an avocado, an egg, a half cup of raw cabbage, six cherry tomatoes, two ounces of chicken breast, a cup of brown rice, three quarters of a cup of zucchini, three tablespoons of butter, a cup of spinach, a medium apple, an eight inch diameter pizza and a tablespoon of almonds. Nutritionists collected information about participants' diets by doing in-person 24-hour recalls. Nutrient intakes were then calculated using the U.S. Department of Agriculture Survey Nutrient Database.

After accounting for body weight, the researchers found that average sulfur amino acid intake was almost two and a half times higher than the estimated average requirement. Xiang Gao, associate professor and director of the nutritional epidemiology lab at the Penn State University and co-author of the study, published today (Feb. 3) in Lancet EClinical Medicine, suggested this may be due to trends in the average diet of a person living in the United States.

"Many people in the United States consume a diet rich in meat and dairy products and the estimated average requirement is only expected to meet the needs of half of healthy individuals," Gao said. "Therefore, it is not surprising that many are surpassing the average requirement when considering these foods contain higher amounts of sulfur amino acids."

The researchers found that higher sulfur amino acid intake was associated with a higher composite cardiometabolic risk score after accounting for potential confounders like age, sex and history of diabetes and hypertension. They also found that high sulfur amino acid intake was associated with every type of food except grains, vegetables and fruit.

"Meats and other high-protein foods are generally higher in sulfur amino acid content," said Zhen Dong, lead author on the study and College of Medicine graduate. "People who eat lots of plant-based products like fruits and vegetables will consume lower amounts of sulfur amino acids. These results support some of the beneficial health effects observed in those who eat vegan or other plant-based diets."

Dong said that while this study only evaluated dietary intake and cardiometabolic disease risk factors at one point in time, the association between increased sulfur amino acid intake and risk for cardiometabolic disease was strong. She said the data supports the formation of a prospective, longitudinal study evaluating sulfur amino acid intake and health outcomes over time.

"Here we saw an observed association between certain dietary habits and higher levels of blood biomarkers that put a person at risk for cardiometabolic diseases," Richie said. "A longitudinal study would allow us to analyze whether people who eat a certain way do end up developing the diseases these biomarkers indicate a risk for."

https://www.sciencedaily.com/releases/2020/02/200203141501.htm

Eating red meat and processed meat hikes heart disease and death risk

Eating red meat and processed meat hikes heart disease and death risk

February 3, 2020

Science Daily/Northwestern University

A large study links red and processed meat with higher risk of heart disease and death. Eating two servings of red meat, processed meat or poultry -- but not fish -- per week was linked to a 3 to 7 percent higher risk of cardiovascular disease. Eating two servings of red meat or processed meat -- but not poultry or fish -- per week was associated with a 3 percent higher risk of all causes of death.

After a controversial study last fall recommending that it was not necessary for people to change their diet in terms of red meat and processed meat, a large, carefully analyzed new study links red and processed meat consumption with slightly higher risk of heart disease and death, according to a new study from Northwestern Medicine and Cornell University.

Eating two servings of red meat, processed meat or poultry -- but not fish -- per week was linked to a 3 to 7% higher risk of cardiovascular disease, the study found. Eating two servings of red meat or processed meat -- but not poultry or fish -- per week was associated with a 3% higher risk of all causes of death.

"It's a small difference, but it's worth trying to reduce red meat and processed meat like pepperoni, bologna and deli meats," said senior study author Norrina Allen, associate professor of preventive medicine at Northwestern University Feinberg School of Medicine. "Red meat consumption also is consistently linked to other health problems like cancer."

"Modifying intake of these animal protein foods may be an important strategy to help reduce the risk of cardiovascular disease and premature death at a population level," said lead study author Victor Zhong, assistant professor of nutritional sciences at Cornell, who did the research when he was a postdoctoral fellow in Allen's lab.

The paper will be published Feb. 3 in JAMA Internal Medicine.

The new findings come on the heels of a controversial meta-analysis published last November that recommended people not reduce the amount of red meat and processed meat they eat. "Everyone interpreted that it was OK to eat red meat, but I don't think that is what the science supports," Allen said.

"Our study shows the link to cardiovascular disease and mortality was robust," Zhong said.

What should we eat?

"Fish, seafood and plant-based sources of protein such as nuts and legumes, including beans and peas, are excellent alternatives to meat and are under-consumed in the U.S.," said study coauthor Linda Van Horn, professor of preventive medicine at Feinberg who also is a member of the 2020 U.S. Dietary Guidelines Advisory committee.

The study found a positive association between poultry intake and cardiovascular disease, but the evidence so far isn't sufficient to make a clear recommendation about poultry intake, Zhong said. Still, fried chicken is not recommended.

The new study pooled together a large diverse sample from six cohorts, included long follow-up data up to three decades, harmonized diet data to reduce heterogeneity, adjusted a comprehensive set of confounders and conducted multiple sensitivity analyses. The study included 29,682 participants (mean age of 53.7 years at baseline, 44.4% men and 30.7% non-white). Diet data were self-reported by participants, who were asked a long list of what they ate for the previous year or month.

Key findings:

• A 3 to 7% higher risk of cardiovascular disease and premature death for people who ate red meat and processed meat two servings a week.

• A 4% higher risk of cardiovascular disease for people who ate two servings per week of poultry, but the evidence so far is not sufficient to make a clear recommendation about poultry intake. And the relationship may be related to the method of cooking the chicken and consumption of the skin rather than the chicken meat itself.

• No association between eating fish and cardiovascular disease or mortality.

Limitations of the study are participants' dietary intake was assessed once, and dietary behaviors may have changed over time. In addition, cooking methods were not considered. Fried chicken, especially deep fat-fried sources that contribute trans-fatty acids, and fried fish intake have been positively linked to chronic diseases, Zhong said.

https://www.sciencedaily.com/releases/2020/02/200203114328.htm

Fermented soy products linked to lower risk of death

January 29, 2020

Science Daily/BMJ

A higher intake of fermented soy products, such as miso and natto, is associated with a lower risk of death, finds a study from Japan published by The BMJ today.

However, the researchers stress that the findings should be interpreted with caution as they may have been affected by unmeasured (confounding) factors.

In Asian countries, especially Japan, several types of soy products are widely consumed, such as natto (soybeans fermented with Bacillus subtilis), miso (soybeans fermented with Aspergillus oryzae), and tofu (soybean curd).

It is, however, still unclear whether different soy products, especially fermented soy products, are associated with specific health effects.

So a team of researchers in Japan set out to investigate the association between several types of soy products and death from any cause ("all cause mortality") and from cancer, total cardiovascular disease (heart disease and cerebrovascular disease), respiratory disease, and injury.

They base their findings on 42,750 men and 50,165 women aged 45-74 years who were taking part in a study based in 11 of Japan's public health centre areas.

Participants filled in detailed questionnaires about their dietary habits, lifestyle, and health status. Deaths were identified from residential registries and death certificates over a follow-up period of nearly 15 years.

The researchers found that a higher intake of fermented soy (natto and miso) was associated with a significantly lower (10%) risk of all cause mortality, but total soy product intake was not associated with all cause mortality.

Men and women who ate natto also had a lower risk of cardiovascular mortality than those who did not eat natto, but there was no association between soy intake and cancer related mortality.

These results persisted even after further adjusting for intake of vegetables, which was higher among those consuming larger portions of natto.

The authors point out that fermented soy products are richer in fibre, potassium and bioactive components than their non-fermented counterparts, which may help to explain their associations.

However, this is an observational study, so can't establish cause, and the researchers cannot rule out the possibility that some of the observed risk may be due to other unmeasured factors.

They conclude: "In this large prospective study conducted in Japan with a high rate of soy consumption, no significant association was found between intake of total soy products and all cause mortality. In contrast, a higher intake of fermented soy products (natto and miso) was associated with a lower risk of mortality."

Increasing evidence has suggested that fermented soy products are associated with health benefits, write researchers in a linked editorial. Whether people eat those products depends on their food culture, they say, but some countries already include soy and fermented soy products in their dietary guidelines.

Further studies are still required, however, "to refine our understanding of the health effects of fermented soy, and perhaps to inform the development of healthier and more palatable products," they conclude. "These efforts should be collaborative, including not only researchers but also policy makers and the food industry."

https://www.sciencedaily.com/releases/2020/01/200129212303.htm

Eating disorders linked to exercise addiction

New study is first to calculate risk factor

January 28, 2020

Science Daily/Anglia Ruskin University

New research shows that exercise addiction is nearly four times more common amongst people with an eating disorder.

The study, led by Mike Trott of Anglia Ruskin University (ARU), was published this month in the journal Eating and Weight Disorders -- Studies on Anorexia, Bulimia and Obesity.

The research is the first to measure rates of exercise addiction in groups of people with and without the characteristics of an eating disorder, The meta-analysis examined data from 2,140 participants across nine different studies, including from the UK, the US, Australia and Italy.

It found that people displaying characteristics of an eating disorder are 3.7 times more likely to suffer from addiction to exercise than people displaying no indication of an eating disorder.

Trott, a PhD researcher in Sport Science at Anglia Ruskin University (ARU), said: "It is known that those with eating disorders are more likely to display addictive personality and obsessive-compulsive behaviours. We are also aware that having an unhealthy relationship with food often means an increased amount of exercising, but this is the first time that a risk factor has been calculated.

"It is not uncommon to want to improve our lifestyles by eating healthier and doing more exercise, particularly at the start of the year. However, it is important to moderate this behaviour and not fall victim to 'crash diets' or anything that eliminates certain foods entirely, as these can easily lead to eating disorders.

"Our study shows that displaying signs of an eating disorder significantly increases the chance of an unhealthy relationship with exercise, and this can have negative consequences, including mental health issues and injury.

"Health professionals working with people with eating disorders should consider monitoring exercise levels as a priority, as this group have been shown to suffer from serious medical conditions as a result of excessive exercise, such as fractures, increased rates of cardiovascular disease in younger patients, and increased overall mortality."

https://www.sciencedaily.com/releases/2020/01/200128114642.htm

Weight loss and health improvements with Mediterranean, fasting & Paleo diets

January 23, 2020

Science Daily/University of Otago

There were some weight loss and health benefits for overweight adults who followed the Mediterranean, Intermittent Fasting and Paleo diets, though adherence to the diets dropped off considerably during the one-year study, new University of Otago research shows.

Intermittent fasting -- whereby participants limit their energy intake to about 25 per cent of their usual diet (500kcal for women and 600kcal for men) on two self-selected days per week, led to slightly more weight loss than the other diets. The Mediterranean diet also improved blood sugar levels.

Co-lead author Dr Melyssa Roy, a Research Fellow in the Department of Medicine, says the amount of weight loss was modest -- on average two to four kilograms for the 250 participants, but for those choosing the fasting or Mediterranean diets, clinically significant improvements in blood pressure were also seen.

The aim of the research was to examine how effective all three diets were in a "real world" setting, where participants self-selected which diet they wished to follow, without any ongoing support from a dietitian.

Dr Roy says the evidence shows that for some people the Mediterranean, fasting or paleo (Paleolithic) diets can be "healthful, beneficial ways to eat."

"This work supports the idea that there isn't a single 'right' diet -- there are a range of options that may suit different people and be effective. In this study, people were given dietary guidelines at the start and then continued with their diets in the real world while living normally. About half of the participants were still following their diets after a year and had experienced improvements in markers of health.

"Like the Mediterranean diet, intermittent fasting and paleo diets can also be valid healthy eating approaches -- the best diet is the one that includes healthy foods and suits the individual."

The Mediterranean diet encouraged consumption of fruit, vegetables, whole-grain breads and cereals, legumes, nuts, seeds and olive oil with moderate amounts of fish, chicken, eggs and diary and red meat once a week or less.

The paleo diet consists of mostly less-processed foods with an emphasis on eating fruit and vegetables, animal proteins, nuts, coconut products and extra-virgin olive oil. While "original" Paleo diets strictly exclude all legumes, dairy and grains, this study used a modified version including some dairy as well as up to one serving daily of legumes and grain-based food.

Co-lead author Dr Michelle Jospe, a Postdoctoral Fellow in the Department of Medicine, says the results showed people found the Mediterranean diet to be the easiest to adhere to.

"Our participants could follow the diet's guidelines more closely than the fasting and paleo diets and were more likely to stay with it after the year, as our retention rates showed."

Most of the 250 participants (54 per cent) chose the fasting diet, while 27 per cent chose the Mediterranean and 18 per cent the paleo. After 12 months, the Mediterranean diet had the best retention rate with 57 per cent of participants continuing, with 54 per cent still fasting and 35 per cent still on the paleo diet.

After 12 months, the average weight loss was 4.0kg for those choosing the fasting diet, 2.8kg on the Mediterranean diet and 1.8kg on the paleo diet.

Reduced systolic blood pressure was observed among those participating in the fasting and Mediterranean diets, together with reduced blood sugar levels in the Mediterranean diet.

Dr Jospe explains participants who said they were still following their diet at 12 months lost even more weight, showing the importance of choosing a diet that is sustainable.

She believes the results of this study are relevant to the thousands of people following self-chosen diets with little supervision and indicates more realistic outcomes.

https://www.sciencedaily.com/releases/2020/01/200123170721.htm

Teens with obesity and PCOS have more 'unhealthy' bacteria

Gut microbiome may play a role in PCOS and its related metabolic complications

January 23, 2020

Science Daily/The Endocrine Society

Teens with obesity and polycystic ovary syndrome (PCOS) have more "unhealthy" gut bacteria suggesting the microbiome may play a role in the disorder, according to new research published in the Endocrine Society's Journal of Clinical Endocrinology & Metabolism.

PCOS is complicated endocrine disorder affecting 6 percent to 18 percent of women of reproductive age and work in adult women indicates that changes in bacteria be involved. The. The hormone disorder is characterized by elevated testosterone levels in the blood that cause acne, excess hair growth and irregular periods. Teens with PCOS often also struggle with obesity and have a higher risk for type 2 diabetes, infertility, and depression.

"We found that in adolescents with PCOS and obesity, the bacterial profile (microbiome) from stool has more "unhealthy" bacteria compared to teens without PCOS," said the study's corresponding author, Melanie Cree Green, M.D., Ph.D., of Children's Hospital Colorado in Aurora, Colo. "The unhealthy bacteria related to higher testosterone concentrations and markers of metabolic complications."

The researchers studied 58 teens with obesity and found that girls with PCOS have an altered gut microbiome compared to those without the condition. These girls had more "unhealthy" bacteria in their stool which was related to higher testosterone levels and other markers of metabolic syndrome, such as higher blood pressure, liver inflammation and plasma triglycerides

"The gut microbiome may play a role in PCOS and its related metabolic complications, and these changes can be found in teenagers who are early in the course of the condition," Green said.

https://www.sciencedaily.com/releases/2020/01/200123090342.htm

Walnuts may be good for the gut and help promote heart health

January 16, 2020

Science Daily/Penn State

Researchers found that eating walnuts daily as part of a healthy diet was associated with increases in certain bacteria that can help promote health. Additionally, those changes in gut bacteria were associated with improvements in some risk factors for heart disease.

Walnuts may not just be a tasty snack, they may also promote good-for-your-gut bacteria. New research suggests that these "good" bacteria could be contributing to the heart-health benefits of walnuts.

In a randomized, controlled trial, researchers found that eating walnuts daily as part of a healthy diet was associated with increases in certain bacteria that can help promote health. Additionally, those changes in gut bacteria were associated with improvements in some risk factors for heart disease.

Kristina Petersen, assistant research professor at Penn State, said the study -- recently published in the Journal of Nutrition -- suggests walnuts may be a heart- and gut-healthy snack.

"Replacing your usual snack -- especially if it's an unhealthy snack -- with walnuts is a small change you can make to improve your diet," Petersen said. "Substantial evidence shows that small improvements in diet greatly benefit health. Eating two to three ounces of walnuts a day as part of a healthy diet could be a good way to improve gut health and reduce the risk of heart disease."

Previous research has shown that walnuts, when combined with a diet low in saturated fats, may have heart-healthy benefits. For example, previous work demonstrated that eating whole walnuts daily lowers cholesterol levels and blood pressure.

According to the researchers, other research has found that changes to the bacteria in the gastrointestinal tract -- also known as the gut microbiome -- may help explain the cardiovascular benefits of walnuts.

"There's a lot of work being done on gut health and how it affects overall health," said Penny Kris-Etherton, distinguished professor of nutrition at Penn State. "So, in addition to looking at factors like lipids and lipoproteins, we wanted to look at gut health. We also wanted to see if changes in gut health with walnut consumption were related to improvements in risk factors for heart disease."

For the study, the researchers recruited 42 participants with overweight or obesity who were between the ages of 30 and 65. Before the study began, participants were placed on an average American diet for two weeks.

After this "run-in" diet, the participants were randomly assigned to one of three study diets, all of which included less saturated fat than the run-in diet. The diets included one that incorporated whole walnuts, one that included the same amount of alpha-linolenic acid (ALA) and polyunsaturated fatty acids without walnuts, and one that partially substituted oleic acid (another fatty acid) for the same amount of ALA found in walnuts, without any walnuts.

In all three diets, walnuts or vegetable oils replaced saturated fat, and all participants followed each diet for six weeks with a break between diet periods.

To analyze the bacteria in the gastrointestinal tract, the researchers collected fecal samples 72 hours before the participants finished the run-in diet and each of the three study diet periods.

"The walnut diet enriched a number of gut bacteria that have been associated with health benefits in the past," Petersen said. "One of those is Roseburia, which has been associated with protection of the gut lining. We also saw enrichment in Eubacteria eligens and Butyricicoccus."

The researchers also found that after the walnut diet, there were significant associations between changes in gut bacteria and risk factors for heart disease. Eubacterium eligens was inversely associated with changes in several different measures of blood pressure, suggesting that greater numbers of Eubacterium eligens was associated with greater reductions in those risk factors.

Additionally, greater numbers of Lachnospiraceae were associated with greater reductions in blood pressure, total cholesterol, and non-HDL cholesterol. There were no significant correlations between enriched bacteria and heart-disease risk factors after the other two diets.

Regina Lamendella, associate professor of biology at Juniata College, said the findings are an example of how people can feed the gut microbiome in a positive way.

"Foods like whole walnuts provide a diverse array of substrates -- like fatty acids, fiber and bioactive compounds -- for our gut microbiomes to feed on," Lamendella said. "In turn, this can help generate beneficial metabolites and other products for our bodies."

Kris-Etherton added that future research can continue to investigate how walnuts affect the microbiome and other elements of health.

"The findings add to what we know about the health benefits of walnuts, this time moving toward their effects on gut health," Kris-Etherton said. "The study gives us clues that nuts may change gut health, and now we're interested in expanding that and looking into how it may affect blood sugar levels."

https://www.sciencedaily.com/releases/2020/01/200116112542.htm

Obesity crisis blamed for a rise in fatty liver disease amongst young adults

January 15, 2020

Science Daily/University of Bristol

One in five young people have fatty liver disease (steatosis), with one in 40 having already developed liver scarring (fibrosis), research published today [15 January] has found. The study, published in The Lancet Gastroenterology & Hepatology, is the first to attempt to determine the prevalence of fatty liver disease and fibrosis in young healthy adults in the UK.

Fatty liver disease is a condition in which fats build up in the cells of the liver. It is broadly split into non-alcoholic fatty liver disease (NAFLD), which is usually seen in people who are overweight or obese, and alcohol related fatty liver disease, which is associated with harmful levels of drinking. If left untreated both can lead to fibrosis (scarring of the liver) and in severe cases eventually cirrhosis of the liver, which is irreversible. Worldwide NAFLD affects approximately a quarter of adults in developed countries.

The research, conducted by Dr Kushala Abeysekera and researchers from the University of Bristol, looked at data collected from 4,021 participants of the Children of the 90s study also known as Avon Longitudinal Study of Parents and Children (ALSPAC). Based in Bristol, participants from the health study -- who had previously been assessed for NAFLD as teenagers using ultrasound -- were invited for assessment using transient elastography with FibroScan as part of the Focus @24 clinic.

Researchers first looked at those participants who did not report harmful alcohol consumption and found that one in five had non-alcoholic fatty liver disease. On widening the data to include all participants, they again found that over 20 per cent displayed evidence of fatty liver and one in 40 had already developed fibrosis, with those participants who had both fatty liver and harmful alcohol use at greatest risk of liver scarring. As a comparison, at 17 years of age, 2.5 per cent of participants had moderate to severe levels of fatty liver, whilst at the age of 24 this number had increased to 13 per cent.

Dr Abeysekera, Honorary Lecturer in the Bristol Medical School: Population Health Sciences, explained: "Children of the 90s data has highlighted the potential importance of liver health amongst young adults. This age group remains a blind spot for clinicians, as they are typically considered a "healthy" age group that are rarely studied. If the obesity epidemic and culture of alcohol abuse aren't tackled nationally, we may see increasing numbers of patients presenting with end-stage liver disease, and at earlier ages.

"It is important to note that whilst we identified that 20 per cent of the cohort had fatty liver -- only a small percentage of the individuals will go on to develop cirrhosis (irreversible liver scarring), and the vast majority of participants should be fine if they manage their diet and exercise appropriately."

The next steps will be to take a closer look at how environmental and genetic factors may lead to individuals developing non-alcoholic fatty liver disease earlier in life.

https://www.sciencedaily.com/releases/2020/01/200115191527.htm

Drinking 1% rather than 2% milk accounts for 4.5 years of less aging in adults

High-fat milk consumption is connected to significantly shorter telomeres

January 15, 2020

Science Daily/Brigham Young University

A new study shows drinking low-fat milk -- both nonfat and 1% milk -- is significantly associated with less aging in adults.

Research on 5,834 U.S. adults by Brigham Young University exercise science professor Larry Tucker, Ph.D., found people who drink low-fat milk experience several years less biological aging than those who drink high-fat (2% and whole) milk.

"It was surprising how strong the difference was," Tucker said. "If you're going to drink high-fat milk, you should be aware that doing so is predictive of or related to some significant consequences."

Tucker investigated the relationship between telomere length and both milk intake frequency (daily drinkers vs. weekly drinkers or less) and milk fat content consumed (whole vs. 2% vs. 1% vs. skim). Telomeres are the nucleotide endcaps of human chromosomes. They act like a biological clock and they're extremely correlated with age; each time a cell replicates, humans lose a tiny bit of the endcaps. Therefore, the older people get, the shorter their telomeres.

And, apparently, the more high-fat milk people drink, the shorter their telomeres are, according to the new BYU study, published in Oxidative Medicine and Cellular Longevity. The study revealed that for every 1% increase in milk fat consumed (drinking 2% vs. 1% milk), telomeres were 69 base pairs shorter in the adults studied, which translated into more than four years in additional biological aging. When Tucker analyzed the extremes of milk drinkers, adults who consumed whole milk had telomeres that were a striking 145 base pairs shorter than non-fat milk drinkers.

Nearly half of the people in the study consumed milk daily and another quarter consumed milk at least weekly. Just under a third of the adults reported consuming full-fat (whole) milk and another 30 percent reported drinking 2% milk. Meanwhile, 10% consumed 1% milk and another 17% drank nonfat milk. About 13% did not drink any cow milk.

"Milk is probably the most controversial food in our country," Tucker said. "If someone asked me to put together a presentation on the value of drinking milk, I could put together a 1-hour presentation that would knock your socks off. You'd think, 'Whoa, everybody should be drinking more milk.' If someone said do the opposite, I could also do that. At the very least, the findings of this study are definitely worth pondering. Maybe there's something here that requires a little more attention."

Somewhat surprisingly, he also found that milk abstainers had shorter telomeres than adults who consumed low-fat milk.

Tucker said the study findings provide support for the current Dietary Guidelines for Americans (2015-2020), which encourage adults to consume low-fat milk, both nonfat and 1% milk, and not high-fat milk, as part of a healthy diet.

"It's not a bad thing to drink milk," Tucker said. "You should just be more aware of what type of milk you are drinking."

https://www.sciencedaily.com/releases/2020/01/200115120634.htm

Complexity around childhood obesity

January 6, 2020

Science Daily/University of Notre Dame

In a new study, researchers examined how various psychological characteristics of children struggling with their weight, such as loneliness, anxiety and shyness, combined with similar characteristics of their parents or guardians and family dynamics affect outcomes of nutritional intervention.

The World Health Organization has estimated more than 340 million children and adolescents ages 5-19 are overweight or obese, and the epidemic has been linked to more deaths worldwide than those caused by being underweight.

The Centers for Disease Control recently reported an estimated 1 in 5 children in the United States, ages 12-18, are living with prediabetes -- increasing their risk of developing type 2 diabetes as well as chronic kidney disease, heart disease and stroke.

Efforts to stem the crisis have led clinicians and health professionals to examine both the nutritional and psychological factors of childhood obesity. In a new study led by the University of Notre Dame, researchers examined how various psychological characteristics of children struggling with their weight, such as loneliness, anxiety and shyness, combined with similar characteristics of their parents or guardians and family dynamics affect outcomes of nutritional intervention.

What they found was a "network effect," suggesting a personalized, comprehensive approach to treatment could improve results of nutritional interventions.

"Psychological characteristics clearly have interactional effects," said Nitesh Chawla, the Frank M. Freimann Professor of Computer Science and Engineering at Notre Dame, director of the Center for Network and Data Science and a lead author of the study. "We can no longer simply view them as individualized risk factors to be assessed. We need to account for the specific characteristics for each child, viewing them as a holistic set for which to plan treatment."

The Notre Dame team collaborated with the Centre for Nutritional Recovery and Education (CREN), a not-for-profit, nongovernmental nutritional clinic in São Paulo, Brazil, where patients participate in a two-year interdisciplinary treatment program including family counseling, nutritional workshops and various physical activities. Researchers analyzed the medical records and psychological assessments of 1,541 children who participated in the program.

The study's key takeaway points to the significant impact parents and guardians have on their child's health when it comes to nutrition. Strong family dynamics, such as concern for behavior and treatment and a sense of protectiveness for the child, led to improved outcomes of nutritional interventions. A lack of authority, however, led to minimal changes in results.

"This is quantitative evidence of the success and failure of interactions as they relate to the characteristics and interactions between the child and the parent or guardian," Chawla said.

The study also highlights the need for clinics to expand their views on patient populations. For example, while treatment programs that incorporate development of interpersonal relationship -- familial and otherwise -- may improve outcomes of nutritional interventions, the same treatment plan may not have the same result for children experiencing loneliness coupled with anxiety.

"For the group without anxiety, this makes sense when you consider a treatment plan focused on strengthening a child's social circle and address issues stemming from loneliness, such as poor social network, bullying or self-imposed isolation," said Gisela M.B. Solymos, co-author of the study, former general manager of CREN and former guest scholar at the Kellogg Institute for International Studies at Notre Dame and at the Center for Network and Data Science. "But patients feeling loneliness and anxiety actually showed minimal changes to nutritional interventions, and may be more likely to benefit from additional services at clinics like CREN."

https://www.sciencedaily.com/releases/2020/01/200106161935.htm

Research identifies changes in neural circuits underlying self-control during adolescence

Research identifies changes in neural circuits underlying self-control during adolescence

Study shows developing brain networks support cognition in youth

January 3, 2020

Science Daily/University of Pennsylvania School of Medicine

Researchers applied tools from network science to identify how anatomical connections in the brain develop to support neural activity underlying executive function.

The human brain is organized into circuits that develop from childhood through adulthood to support executive function -- critical behaviors like self-control, decision making, and complex thought. These circuits are anchored by white matter pathways which coordinate the brain activity necessary for cognition. However, little research exists to explain how white matter matures to support activity that allows for improved executive function during adolescence -- a period of rapid brain development.

Researchers from the Lifespan Brain Institute of the Perelman School of Medicine at the University of Pennsylvania and Children's Hospital of Philadelphia applied tools from network science to identify how anatomical connections in the brain develop to support neural activity underlying these key areas. The findings were published in the Proceedings of the National Academy of Sciences.

"By charting brain development across childhood and adolescence, we can better understand how the brain supports executive function and self-control in both healthy kids and those with different mental health experiences," said the study's senior author Theodore Satterthwaite, MD, an assistant professor of Psychiatry at Penn. "Since abnormalities in developing brain connectivity and deficits in executive function are often linked to the emergence of mental illness during youth, our findings may help identify biomarkers of brain development that predict cognitive and clinical outcomes later in life."

In this study, the researchers mapped structure-function coupling -- the degree to which a brain region's pattern of anatomical connections supports synchronized neural activity. This could be thought of like a highway, where the anatomical connections are the road and the functional connections are the traffic flowing along those roads. Researchers mapped and analyzed multi-modal neuroimaging data from 727 participants ages 8 to 23 years, and three major findings emerged.

First, the team found that regional variability in structure-function coupling was inversely related to the complexity of the function a given brain area is responsible for. Higher structure-function coupling was found in parts of the brain that are specialized for processing simple sensory information, like the visual system. In contrast, there was lower structure-function coupling in complex parts of the brain that are responsible for executive function and self-control, which require more abstract and flexible processing.

Results showed that structure-function coupling also aligned with known patterns of brain expansion over the course of primate evolution. Previous work comparing human, ape, and monkey brains has showed that sensory areas like the visual system are highly conserved across primate species and have not expanded much during recent evolution. In contrast, association areas of the brain, such as the prefrontal cortex, have expanded dramatically over the course of primate evolution. This expansion may have allowed for the emergence of uniquely complex human cognitive abilities. The team found that the brain areas which expanded rapidly during evolution had lower structure-function coupling, while simple sensory areas that have been conserved in recent evolution had higher structure-function coupling.

Researchers also found that structure-function coupling increased throughout childhood and adolescence in complex frontal brain regions. These are the same regions that tend to have lower baseline structure-function coupling, are expanded compared to monkeys, and are responsible for self-control. The prolonged development of structure-function coupling in these regions may allow for improved executive function and self-control that develops into adulthood. Indeed, the team found that higher structure-function coupling in the lateral prefrontal cortex -- a complex brain area which plays important roles in self-control -- was associated with better executive function.

"These results suggest that executive functions like impulse control -- which can be particularly challenging for children and adolescents -- rely in part on the prolonged development of structure-function coupling in complex brain areas like the prefrontal cortex," explained lead author Graham Baum, PhD, a postdoctoral fellow at Harvard University, who was a Penn neuroscience PhD student during the time of the research. "This has important implications for understanding how brain circuits become specialized during development to support flexible and appropriate goal-oriented behavior."

https://www.sciencedaily.com/releases/2020/01/200103111723.htm

Study finds dopamine, biological clock link to snacking, overeating and obesity

Study finds dopamine, biological clock link to snacking, overeating and obesity

January 3, 2020

Science Daily/University of Virginia

A new study finds that the pleasure center of the brain and the brain's biological clock are linked, and that high-calorie foods -- which bring pleasure -- disrupt normal feeding schedules, resulting in overconsumption.

During the years 1976 through 1980, 15% of U.S. adults were obese. Today, about 40% of adults are obese. Another 33% are overweight.

Coinciding with this increase in weight are ever-rising rates of heart disease, diabetes, cancer and health complications caused by obesity, such as hypertension. Even Alzheimer's disease may be partly attributable to obesity and physical inactivity.

"The diet in the U.S. and other nations has changed dramatically in the last 50 years or so, with highly processed foods readily and cheaply available at any time of the day or night," Ali Güler, a professor of biology at the University of Virginia, said. "Many of these foods are high in sugars, carbohydrates and calories, which makes for an unhealthy diet when consumed regularly over many years."

In a study published Thursday in the journal Current Biology, Güler and his colleagues demonstrate that the pleasure center of the brain that produces the chemical dopamine, and the brain's separate biological clock that regulates daily physiological rhythms, are linked, and that high-calorie foods -- which bring pleasure -- disrupt normal feeding schedules, resulting in overconsumption. Using mice as study models, the researchers mimicked the 24/7 availability of a high-fat diet, and showed that anytime snacking eventually results in obesity and related health problems.

Güler's team found that mice fed a diet comparable to a wild diet in calories and fats maintained normal eating and exercise schedules and proper weight. But mice fed high-calorie diets laden with fats and sugars began "snacking" at all hours and became obese.

Additionally, so-called "knockout" mice that had their dopamine signaling disrupted -- meaning they didn't seek the rewarding pleasure of the high-fat diet -- maintained a normal eating schedule and did not become obese, even when presented with the 24/7 availability of high-calorie feeds.

"We've shown that dopamine signaling in the brain governs circadian biology and leads to consumption of energy-dense foods between meals and during odd hours," Güler said.

Other studies have shown, Güler said, that when mice feed on high-fat foods between meals or during what should be normal resting hours, the excess calories are stored as fat much more readily than the same number of calories consumed only during normal feeding periods. This eventually results in obesity and obesity-related diseases, such as diabetes.

Speaking of the modern human diet, Güler said, "The calories of a full meal may now be packed into a small volume, such as a brownie or a super-size soda. It is very easy for people to over-consume calories and gain excessive weight, often resulting in obesity and a lifetime of related health problems.

"Half of the diseases that affect humans are worsened by obesity. And this results in the need for more medical care and higher health care costs for individuals, and society."

Güler said the human body, through thousands of years of evolution, is hard-wired to consume as much food as possible as long as it's available. He said this comes from a long earlier history when people hunted or gathered food and had brief periods of plenty, such as after a kill, and then potentially lengthy periods of famine. Humans also were potential prey to large animals and so actively sought food during the day, and sheltered and rested at night.

"We evolved under pressures we no longer have," Güler said. "It is natural for our bodies as organisms to want to consume as much as possible, to store fat, because the body doesn't know when the next meal is coming.

"But, of course, food is now abundant, and our next meal is as close as the kitchen, or the nearest fast-food drive-through, or right here on our desk. Often, these foods are high in fats, sugars, and therefore calories, and that's why they taste good. It's easy to overconsume, and, over time, this takes a toll on our health."

Additionally, Güler said, prior to the advent of our electricity-powered society, people started the day at dawn, worked all day, often doing manual labor, and then went to sleep with the setting of the sun. Human activity, therefore, was synchronized to day and night. Today, we are working, playing, staying connected -- and eating -- day and night. This, Guler said, affects our body clocks, which were evolved to operate on a sleep-wake cycle timed to daytime activity, moderate eating and nighttime rest.

"This lights-on-all-the-time, eat-at-any-time lifestyle recasts eating patterns and affects how the body utilizes energy," he said. "It alters metabolism -- as our study shows -- and leads to obesity, which causes disease. We're learning that when we eat is just as important as how much we eat. A calorie is not just a calorie. Calories consumed between meals or at odd hours become stored as fat, and that is the recipe for poor health."

The National Institute of General Medical Sciences and University of Virginia Brain Institute funded the research.

https://www.sciencedaily.com/releases/2020/01/200103111717.htm

Researchers discover brain circuit linked to food impulsivity

This creates the possibility scientists can someday develop therapeutics to address overeating

December 11, 2019

Science Daily/University of Georgia

A team of researchers has now identified a specific circuit in the brain that alters food impulsivity.

You're on a diet, but the aroma of popcorn in the movie theater lobby triggers a seemingly irresistible craving.

Within seconds, you've ordered a tub of the stuff and have eaten several handfuls.

Impulsivity, or responding without thinking about the consequences of an action, has been linked to excessive food intake, binge eating, weight gain and obesity, along with several psychiatric disorders including drug addiction and excessive gambling.

A team of researchers that includes a faculty member at the University of Georgia has now identified a specific circuit in the brain that alters food impulsivity, creating the possibility scientists can someday develop therapeutics to address overeating.

The team's findings were published recently in the journal Nature Communications.

"There's underlying physiology in your brain that is regulating your capacity to say no to (impulsive eating)," said Emily Noble, an assistant professor in the UGA College of Family and Consumer Sciences who served as lead author on the paper. "In experimental models, you can activate that circuitry and get a specific behavioral response."

Using a rat model, researchers focused on a subset of brain cells that produce a type of transmitter in the hypothalamus called melanin concentrating hormone (MCH).

While previous research has shown that elevating MCH levels in the brain can increase food intake, this study is the first to show that MCH also plays a role in impulsive behavior, Noble said.

"We found that when we activate the cells in the brain that produce MCH, animals become more impulsive in their behavior around food," Noble said.

To test impulsivity, researchers trained rats to press a lever to receive a "delicious, high-fat, high-sugar" pellet, Noble said. However, the rat had to wait 20 seconds between lever presses. If the rat pressed the lever too soon, it had to wait an additional 20 seconds.

Researchers then used advanced techniques to activate a specific MCH neural pathway from the hypothalamus to the hippocampus, a part of the brain involved with learning and memory function.

Results indicated MCH doesn't affect how much the animals liked the food or how hard they were willing to work for the food. Rather, the circuit acted on the animals' inhibitory control, or their ability to stop themselves from trying to get the food. "Activating this specific pathway of MCH neurons increased impulsive behavior without affecting normal eating for caloric need or motivation to consume delicious food," Noble said. "Understanding that this circuit, which selectively affects food impulsivity, exists opens the door to the possibility that one day we might be able to develop therapeutics for overeating that help people stick to a diet without reducing normal appetite or making delicious foods less delicious."

https://www.sciencedaily.com/releases/2019/12/191211145630.htm

Obesity could affect brain development in children

December 18, 2019

Science Daily/University of Vermont

New research found that obese children had a thinner pre-frontal cortex than normal weight children. The thinner cortex could be factor in the decreased executive function earlier studies observed among children with higher BMI. The new study confirmed that the obese subjects in the study had poorer working memory compared with normal weight children.

Published studies have long found a correlation between obesity in children and decreased executive function. New research published in JAMA Pediatrics, based on data mined from a massive national research study, suggests that a change in brain structure -- a thinner prefrontal cortex -- may help explain that interrelationship.

"Our results show an important connection; that kids with higher BMI tend to have a thinner cerebral cortex, especially in the prefrontal area," said Jennifer Laurent, an associate professor in the Department of Nursing at the University of Vermont and lead author of the study.

The findings are based on data retrieved from a National Institutes of Health-funded research project, the Adolescent Brain Cognitive Development study, or ABCD, which is following 10,000 teens over a 10 year period. Every two years, study subjects are interviewed, take a battery of tests, give blood samples and undergo brain scans.

The study analyzed results from 3,190 nine- and 10-year-olds recruited at 21 ABCD sites in 2017.

The robust study confirmed the findings of its predecessors; that subjects with higher BMI tended to have lower working memory, as measured by a list sorting test.

But it added an important component to that insight -- a physiological correlate in the brain that might help explain the connection.

"Our hypothesis going into the study was that the thickness of the cerebral cortex would 'mediate' -- or serve as an explanatory link for -- the relationship between BMI and executive function," Laurent said.

The findings did confirm the relationship, according to the study's senior author, Scott Mackey, an assistant professor of Psychiatry in the University of Vermont's Larner College of Medicine.

"We found widespread thinning of cerebral cortex" among research subjects with higher BMI, Mackey said, but especially so in the prefontal area.

"That's significant because we know that executive function, things like memory and the ability to plan, are controlled in that area of the brain," he said.

More research is needed to determine the nature of the link between the three variables.

"It could be that a thinner prefrontal cortex is affecting decision-making in some children, and they make unhealthy dietary choices as a result, which could lead to obesity," Laurent said.

Or the causal relationship could work in the opposite direction.

"We know from rodent models and adult studies that obesity can induce low grade inflammatory effects, which actually do alter cellular structure" and can lead to cardiovascular disease, Laurent said.

"With prolonged exposure to obesity, it is possible that children have chronic inflammation, and that may actually be affecting their brain in the long term," she said.

If that were the case, there would be significant public health implications, Laurent said. "We would want to proactively encourage changes in kids' diets and exercise levels at a young age with the understanding that it's not only the heart that is being affected by obesity, it is perhaps also the brain."

The decrease in working memory was a statistical observation, Laurent said, not a clinical one.

"We did not look at behavior. It's very important that this work not further stigmatize people who are obese or overweight," she said.

"What we're saying is that, according to our measures, we are seeing something that bears watching. How and if it translates to behavior is for future research to determine."

Data analysis for the study was done at the University of Vermont and Yale University. Richard Watts, director at the FAS Brain Imaging Center and research associate professor of radiology at Yale, was a co-author of the study.

https://www.sciencedaily.com/releases/2019/12/191218153444.htm

Algae shown to improve gastrointestinal health

Project is the first to test green algae on symptoms related to human digestion

January 27, 2020

Science Daily/University of California - San Diego

A green, single-celled organism called Chlamydomonas reinhardtii has served as a model species for topics spanning algae-based biofuels to plant evolution. While algae have been used as dietary nutraceuticals that provide beneficial oils, vitamins, proteins, carbohydrates and antioxidants, the benefits of consuming C. reinhardtii were previously unexplored. Researchers have now completed the first study in humans demonstrating that C. reinhardtii helps improve human gastrointestinal problems related to irritable bowel syndrome, including diarrhea, gas and bloating.

A widespread, fast-growing plant called Chlamydomonas reinhardtii is famous in scientific laboratories due to its position as the world's most exhaustively studied algae.

For decades, the green, single-celled organism, which primarily grows in wet soil, has served as a model species for research topics spanning from algae-based biofuels to plant evolution. While other species of algae have been used as dietary nutraceuticals that provide beneficial oils, vitamins, proteins, carbohydrates, antioxidants and fiber, the benefits of consuming C. reinhardtii were previously unexplored.

Researchers at the University of California San Diego recently completed the first study examining the effects of consuming C. reinhardtii and demonstrated that the algae improves human gastrointestinal issues associated with irritable bowel syndrome (IBS) such as diarrhea, gas and bloating. Results of the project are published in the Journal of Functional Foods.

"People have been looking at this algae for decades, but this is the first study to show what many of us have suspected -- it's good for you," said principal investigator and algae expert Stephen Mayfield, a distinguished professor in UC San Diego's Division of Biological Sciences and co-director of the Food and Fuel for the 21st Century Program (FF21). "This is exciting because it demonstrates a clear benefit: If you have IBS-like symptoms, this is good for you."

For years researchers in Mayfield's laboratory have been exploring C. reinhardtii as a cost-competitive and sustainable source of valuable plant-based products, specifically pharmaceuticals and biofuels. Now, working with several collaborators, including UC San Diego's John Chang (School of Medicine), Rob Knight (School of Medicine, Jacobs School of Engineering and Center for Microbiome Innovation) and the San Diego-based startup Triton Algae Innovations, they turned their attention towards investigating the algae as a nutritious food additive for improving human health.

The C. reinhardtii biomass used in the study, which was grown by Triton Algae Innovations, was subject to rigorous safety testing and designated as "Generally Recognized As Safe" by the U.S. Food and Drug Administration, green-lighting the use of the organism in a human study.

Preliminary data in mouse studies demonstrated that consuming C. reinhardtii significantly reduced the rate of weight loss in mice with acute colitis, which is generally linked to inflammation of the digestive tract. Building off these results, the researchers set out to test for a similar effect when the algae was consumed by human volunteers, including those with and without symptoms associated with IBS. Volunteers consumed daily spoonfuls of powdered C. reinhardtii biomass and reported their gastrointestinal health for one month. Of the hundreds of interested participants in the project, data from 51 volunteers met the study's requirements for inclusion in the final data analyses.

Results showed that participants who suffered from a history of frequent gastrointestinal symptoms reported significantly less bowel discomfort and diarrhea, significantly less gas or bloating and more regular bowel movements.

"The benefits of consuming this species of algae were immediately obvious when examining the data from both mice and humans who suffered from gastrointestinal symptoms," said Frank Fields, a research scientist in Mayfield's lab and lead author of the paper. "I hope that this study helps destigmatize the thought of incorporating algae and algae-based products into your diet -- it is a fantastic source of nutrition and we have now shown that this species of algae has additional benefits to animal and human health."

Volunteers also were provided with stool sampling kits and sent samples to the American Gut Project, a citizen science effort led by Knight and his lab, to assess any changes in their microbiomes. The results indicated that the gut microbiome composition remained diverse, which is typical of healthier individuals, and that no significant changes to the composition of their gut microbiome occurred during the study as a result of consuming the algae.

The researchers say much more testing with larger groups of participants across longer time periods is needed. At this point, they are unclear about how the algae works to improve gastrointestinal health. The scientists believe the benefits could be traced to a bioactive molecule in algae or perhaps a change in gene expression of gut bacteria caused by algae consumption.

Still, the observed results in human volunteers led them to conclude in the paper that "the addition of C. reinhardtii into the diet will not only add nutritional value but may also function to relieve some gastrointestinal symptoms of certain individuals."

https://www.sciencedaily.com/releases/2020/01/200127134813.htm

An egg a day not tied to risk of heart disease

 

January 27, 2020

Science Daily/McMaster University

The controversy about whether eggs are good or bad for your heart health may be solved, and about one a day is fine. A team of researchers found the answer by analyzing data from three large, long-term multinational studies.

A team of researchers from the Population Health Research Institute (PHRI) of McMaster University and Hamilton Health Sciences found the answer by analyzing data from three large, long-term multinational studies.

The results suggest there is no harm from consuming eggs. Given that the majority of individuals in the study consumed one or fewer eggs per day, it would be safe to consume this level, says Mahshid Dehghan, first author and a PHRI investigator.

"Moderate egg intake, which is about one egg per day in most people, does not increase the risk of cardiovascular disease or mortality even if people have a history of cardiovascular disease or diabetes," she said.

"Also, no association was found between egg intake and blood cholesterol, its components or other risk factors. These results are robust and widely applicable to both healthy individuals and those with vascular disease."

The details are published in The American Journal of Clinical Nutrition.

Although eggs are an inexpensive source of essential nutrients, some guidelines have recommended limiting consumption to fewer than three eggs a week due to concerns they increase the risk of cardiovascular disease.

Previous studies on egg consumption and diseases have been contradictory, said Salim Yusuf, principal investigator of the study and director of PHRI.

"This is because most of these studies were relatively small or moderate in size and did not include individuals from a large number of countries," he said.

The researchers analyzed three international studies conducted by the PHRI. Egg consumption of 146,011 individuals from 21 countries was recorded in the PURE study and in 31,544 patients with vascular disease from the ONTARGET and the TRANSEND studies.

The data from these three studies involved populations from 50 countries spanning six continents at different income levels, so the results are widely applicable, said Yusuf.

https://www.sciencedaily.com/releases/2020/01/200127134727.htm

Increase health benefits of exercise by working out before breakfast

October 18, 2019

Science Daily/University of Bath

Exercising before eating breakfast burns more fat, improves how the body responds to insulin and lowers people's risk of type 2 diabetes and cardiovascular disease.

According to a new study, published in the Journal of Clinical Endocrinology and Metabolism, health scientists at the Universities of Bath and Birmingham found that by changing the timing of when you eat and exercise, people can better control their blood sugar levels.

The six-week study, which involved thirty men classified as obese or overweight and compared results from two intervention groups (who ate breakfast before / after exercise) and a control group (who made no lifestyle changes), found that people who performed exercise before breakfast burned double the amount of fat than the group who exercised after breakfast.

They found that increased fat use is mainly due to lower insulin levels during exercise when people have fasted overnight, which means that they can use more of the fat from their fat tissue and the fat within their muscles as a fuel. To test proof-of-principle the initial study involved only men, but future studies will look to translate these findings for different groups including women.

Whilst this did not lead to any differences for weight loss over six weeks, it did have 'profound and positive' effects on their health because their bodies were better able to respond to insulin, keeping blood sugar levels under control and potentially lowering the risk of diabetes and heart disease.

Building on emerging evidence that the timing of meals in relation to exercise can shift how effective exercise is, the team behind this study wanted to focus on the impact on the fat stores in muscles for individuals who either worked out before or after eating and the effect this had on insulin response to feeding.

Dr Javier Gonzalez of the Department for Health at the University of Bath explained: "Our results suggest that changing the timing of when you eat in relation to when you exercise can bring about profound and positive changes to your overall health.

"We found that the men in the study who exercised before breakfast burned double the amount of fat than the group who exercised after. Importantly, whilst this didn't have any effect on weight loss, it did dramatically improve their overall health.

"The group who exercised before breakfast increased their ability to respond to insulin, which is all the more remarkable given that both exercise groups lost a similar amount of weight and both gained a similar amount of fitness. The only difference was the timing of the food intake."

Over the six-week trial, the scientists found that the muscles from the group who exercised before breakfast were more responsive to insulin compared to the group who exercised after breakfast, in spite of identical training sessions and matched food intake. The muscles from those who exercised before breakfast also showed greater increases in key proteins, specifically those involved in transporting glucose from the bloodstream to the muscles.

For the insulin response to feeding after the 6-week study, remarkably, the group who exercised after breakfast were in fact no better than the control group.

Co-author Dr Gareth Wallis of the University of Birmingham added: "This work suggests that performing exercise in the overnight-fasted state can increase the health benefits of exercise for individuals, without changing the intensity, duration or perception of their effort. We now need to explore the longer-term effects of this type of exercise and whether women benefit in the same way as men."

https://www.sciencedaily.com/releases/2019/10/191018080619.htm

Evening exercise will not ruin sleep and might even reduce appetite

February 21, 2019

Science Daily/The Physiological Society

With growing time demands, many middle-aged adults are finding time to engage in exercise increasingly difficult. For many, even the thought of fitting exercise in after a busy day at work can be as tiring as it is unappetizing. The standing belief that high-intensity exercise should be avoided in the early evening due to its effect on sleep only serves to act as another barrier to exercise at this time.

Must cook dinner. Need to pick the kids up from school. Have to catch up on my favourite TV series. Live too far from the gym. Any of these sound familiar? With growing time demands, many middle-aged adults are finding time to engage in exercise increasingly difficult. For many, even the thought of fitting exercise in after a busy day at work can be as tiring as it is unappetising. The standing belief that high-intensity exercise should be avoided in the early evening due to its effect on sleep only serves to act as another barrier to exercise at this time.

However, encouraging new research published in Experimental Physiology has suggested that 30 minutes of high-intensity exercise performed in the early evening does not negatively affect subsequent sleep, and may also reduce feelings of hunger.

Researchers at Charles Sturt University in Australia recruited eleven middle-aged men to complete three experimental trials to investigate sleep and appetite responses to exercise performed in the morning (6 -- 7 am), afternoon (2 -- 4 pm) and evening (7 -- 9 pm). Participants were required to perform high-intensity cycling involving six one-minute, maximal intensity sprints interspersed by four minutes of rest. Blood collections were taken prior to exercise and following exercise to examine appetite-related hormones, and multiple tests were performed during sleep to assess sleep stages.

The results not only showed that evening exercise did not have a detrimental impact on subsequent sleep, but also that afternoon and evening high-intensity exercise were associated with greater reductions of the hunger stimulating hormone, ghrelin. It is important to note that a single bout of exercise was not linked to reduced hunger, but nevertheless, the observations from this study support high-intensity exercise early in the evening as a viable time-of day for exercise.

As this study's sample size was relatively small, the findings extrapolated to other population groups beyond middle-aged men may be limited, given that sleep and appetite regulation are influenced by sex and age.

Penelope Larsen, lead author of the study, commented said:

"In the future, we hope to conduct similar studies recruiting women, to determine whether sleep and appetite responses may be different depending on sex. Also, this study only considered a single bout of exercise; therefore, it would be beneficial to investigate long-term sleep and appetite adaptations to high-intensity exercise training performed either in the morning, afternoon or evening."

Interestingly, power output during the sprint efforts was higher for the afternoon and evening trials compared to the morning trial, indicating that participants were able to perform better during latter parts of the day. Therefore, time-of-day may also need to be considered when planning training schedules."

https://www.sciencedaily.com/releases/2019/02/190221083411.htm