Think leisure is a waste? That may not bode well for your mental health
August 23, 2021
Science Daily/Ohio State University
Feeling like leisure is wasteful and unproductive may lead to less happiness and higher levels of stress and depression, new research suggests.
In a series of studies, researchers examined the effects of a common belief in modern society: that productivity is the ultimate goal and time's a-wasting if you're just having fun.
People who most strongly agreed with this belief not only enjoyed leisure less, but also reported poorer mental health outcomes, said Selin Malkoc, co-author of the study and associate professor of marketing at Ohio State University's Fisher College of Business.
"There is plenty of research which suggests that leisure has mental health benefits and that it can make us more productive and less stressed," Malkoc said.
"But we find that if people start to believe that leisure is wasteful, they may end up being more depressed and more stressed."
One bright side: Some skeptical people could enjoy fun activities if leisure was part of a larger goal, and not an end in itself.
"If leisure can be framed as having some kind of productive goal, that helps people who think leisure is wasteful get some of the same benefits," said study co-author Rebecca Reczek, professor of marketing at Ohio State.
The study was published online Aug. 21, 2021 in the Journal of Experimental Social Psychology.
In one study, 199 college students rated how much they enjoyed a variety of leisure activities and completed assessments that measured their levels of happiness, depression, anxiety and stress.
They were also asked how much they agreed with five statements assessing the degree to which they believed leisure is wasteful (such as "Time spent on leisure activities is often wasted time.")
Results showed that the more the participants believed leisure to be wasteful, the less they enjoyed leisure activities.
That was true whether the leisure activity was active (exercising) or passive (watching TV), social (hanging out with friends) or solitary (meditating).
In addition, the more they thought leisure was wasteful, the lower their levels of happiness and the higher their levels of depression, anxiety and stress.
In one study, 302 online participants were asked what they did to celebrate Halloween a few days after the holiday in 2019. Some of the activities they could choose from were fun for their own sake, like going to a party. Others served a larger goal, such as taking your kids out trick or treating.
The participants were asked to rate how much they enjoyed their Halloween experience.
Results showed that those who thought leisure was more wasteful reported less enjoyment of activities, like parties, that were only about the fun.
"But those who participated in fun activities that fulfilled responsibilities, like trick or treating with your kids, didn't see such a reduction in how much they enjoyed their Halloween," said study co-author Gabriela Tonietto, an assistant professor of marketing at the Rutgers Business School.
The negative view of leisure is not just an American issue. One study, which compared people in the United States, India and France, found that the French were less likely than those in the U.S. and India to believe leisure was wasteful - as is consistent with cultural stereotypes. But for those in France who did disdain leisure, the bad effects were the same.
"We live in a global society and there are people everywhere that hear the same messages about how important it is to be busy and productive," Reczek said.
"And once you believe that, and internalize the message that leisure is a waste, our results suggest you're going to be more depressed and less happy, no matter where you live."
The researchers were struck by how the negative views of leisure affected enjoyment of anything fun, no matter the situation or how short the leisure activity was.
In one study, college student participants were asked to watch a short funny cat video in the middle of other parts of an experiment. Some read articles beforehand that touted leisure as a way to manage stress and increase energy. Even then, the same effects persisted.
"These are students who are coming into the lab to answer surveys, which can be boring. In the middle of that we give them a funny video to watch, which you would expect would be a nice break - and even then, some participants didn't enjoy it as much," Malkoc said.
"They had no way to use the time more productively. We were giving them a break from other, more boring activities. And still, those who believe leisure is wasteful didn't think watching the videos was as fun as others did."
The study showed it is not easy to change people's beliefs about the value of leisure. So a different approach may be needed, the researchers said.
For those who believe leisure is wasteful, "it may be helpful to think about the productive ways that individual leisure activities can serve their long-term goals," Tonietto said.
In other words, connect each leisure activity to something you want to accomplish, she said.
"Find ways to make fun activities part of a larger goal in your life," Malkoc added. "Think about how it is productive, instrumental and useful."
https://www.sciencedaily.com/releases/2021/08/210823104334.htm
Too much time on a computer, watching TV or other sedentary activities raises stroke risk
August 19, 2021
Science Daily/American Heart Association
Adults younger than age 60 who spent eight or more hours a day during their free time using a computer, watching TV or reading and participated in little physical activity had an increased risk of stroke. Boosting physical activity may reduce or eliminate the increased stroke risk from prolonged sedentary time. Public health efforts to increase physical activity and reduce sedentary time in adults younger than age 60 could help to lower their long-term stroke risk.
According to American Heart Association statistics, U.S. adults spend an average of 10.5 hours a day connected to media such as smartphones, computers or television watching, and adults ages 50 to 64 spend the most time of any age group connected to media. Data also indicate that stroke-related deaths decreased in 2010 among adults 65 years and older. However, death from stroke appears to be on the rise among younger adults, ages 35 to 64 years -- increasing from 14.7 in every 100,000 adults in 2010 to 15.4 per 100,000 in 2016. Previous research suggests the more time adults spend sedentary, the greater their risk of cardiovascular disease including stroke, and nearly 9 in 10 strokes could be attributed to modifiable risk factors such as sedentary behaviors.
"Sedentary time is increasing in the United States and Canada," said study author Raed A. Joundi, M.D., D.Phil., a stroke fellow in the department of clinical neurosciences at the Cumming School of Medicine at the University of Calgary in Canada. "Sedentary time is the duration of awake activities that are done sitting or lying down. Leisure sedentary time is specific to the sedentary activities done while not at work. It is important to understand whether high amounts of sedentary time can lead to stroke in young individuals, as a stroke can cause premature death or significantly impair function and quality of life."
In this study, researchers reviewed health and lifestyle information for 143,000 adults with no prior stroke, heart disease or cancer who participated in the Canadian Community Health Survey in years 2000, 2003, 2005, 2007-2012. Researchers followed the participants for an average of 9.4 years (until Dec. 31, 2017) and identified strokes through linkages with hospital records.
They reviewed the amount of time spent each day in leisure sedentary activities (hours spent on computer, reading and watching TV) and divided them into categories of less than four hours per day; four to less than six hours per day; six to less than eight hours per day; and eight hours or more a day. They also divided physical activity into quartiles, or four equal categories, where the lowest quartile was the least physically active and equivalent to going for a walk for 10 minutes or less daily. "A walk of 10 minutes or less per day is lower than half of what the American Heart Association's physical activity guidelines recommend," Joundi said.
The American Heart Association recommends adults get at least 150 minutes, or 2.5 hours, of moderate-intensity physical activity per week.
Analysis of study participants found:
During the follow-up period, an average of 9.4 years, 2,965 strokes occurred. Nearly 90% of those were ischemic strokes, the most common stroke type, which occurs when a vessel supplying blood to the brain is obstructed.
The average daily leisure sedentary time among all participants was 4.08 hours. Individuals aged 60 and younger had an average leisure sedentary time of 3.9 hours per day. Average daily leisure sedentary time was 4.4 hours for adults aged 60 to 79, and 4.3 hours for those 80 years and older.
Adults 60 years and younger who had low physical activity and reported eight or more hours of leisure sedentary time a day had a 4.2 times higher risk of stroke compared to those reporting less than four hours of daily leisure sedentary time.
The most inactive group -- those reporting eight or more hours of sedentary time and low physical activity -- had 7 times higher risk of stroke compared to those reporting less than four hours of sedentary time a day and higher levels of physical activity.
"Adults 60 years and younger should be aware that very high sedentary time with little time spent on physical activity can have adverse effects on health, including increased risk of stroke," Joundi said. "Physical activity has a very important role in that it reduces the actual time spent sedentary, and it also seems to diminish the negative impact of excess sedentary time. Physician recommendations and public health policies should emphasize increased physical activity and lower sedentary time among young adults in combination with other healthy habits to lower the risks of cardiovascular events and stroke."
A significant limitation of the study's results was that the survey did not ask participants about occupation-related sedentary time; this could mean sedentary time is underreported among people who have desk jobs, for example.
https://www.sciencedaily.com/releases/2021/08/210819081501.htm
Lonely flies, like many humans, eat more and sleep less
August 18, 2021
Science Daily/Rockefeller University
Single fruit flies quarantined in test tubes sleep too little and eat too much after only about one week of social isolation, according to a new study.
COVID-19 lockdowns scrambled sleep schedules and stretched waistlines. One culprit may be social isolation itself. Scientists have found that lone fruit flies quarantined in test tubes sleep too little and eat too much after only about one week of social isolation, according to a new study published in Nature. The findings, which describe how chronic separation from the group leads to changes in gene expression, neural activity, and behavior in flies, provide one of the first robust animal models for studying the body's biological reaction to loneliness.
"Flies are wired to have a specific response to social isolation," says Michael W. Young, the Richard and Jeanne Fisher Professor and head of the Laboratory of Genetics at Rockefeller. "We found that loneliness has pathological consequences, connected to changes in a small group of neurons, and we've begun to understand what those neurons are doing."
The science of loneliness
Drosophila are social creatures. The fruit flies forage and feed in groups, serenade one another through complex mating rituals, tussle in miniature boxing matches. And then they conk out: flies sleep 16 hours each day, split between a languorous midday nap and a full night's rest.
So when Wanhe Li, a research associate in Young's lab, began investigating the biological underpinnings of chronic social isolation, she turned to the gregarious and well-studied fruit fly. "Over and over again, Drosophila have put us on the right track," says Young. "Evolution packed a great deal of complexity into these insects long ago and, when we dig into their systems, we often find the rudiments of something that is also manifest in mammals and humans."
"When we have no roadmap, the fruit fly becomes our roadmap," Li adds.
For the study, Wanhe Li first compared how flies fare under various lockdown conditions. After seven days, flies housed together in groups of varying sizes produced no anomalous behaviors. Even two flies cut off from the crowd were content with one another. But when a single fly was entirely isolated, the lonely insect began eating more and sleeping less.
Further investigation revealed that a group of genes linked to starvation were expressed differently in the brains of lonely flies -- a tempting genetic basis for the observed connection between isolation and overeating.
Li then found that a small group of brain cells known as P2 neurons were involved in the observed changes to sleep and feeding behavior. Shutting down the P2 neurons of chronically-isolated flies suppressed overeating and restored sleep; boosting P2 in flies isolated from the group for only one day caused them to eat and sleep as if they had been alone for a full week.
"We managed to trick the fly into thinking that it had been chronically isolated," says Wanhe Li. "The P2 neurons seem to be linked to the perception of the duration of social isolation, or the intensiveness of loneliness, like a timer counting down how long the fly has been alone."
The Young lab painstakingly confirmed these observations. They engineered insomniac flies, to make sure that lack of sleep alone did not cause overeating (it didn't). They tested group-reared flies to find out whether manipulating P2 neurons would cause overeating and sleep loss in socialized flies (it doesn't). Ultimately, they concluded that only a perfect storm of both P2 neuron activity and social isolation will cause flies to begin to losing sleep and overeating.
Explaining the "Quarantine 15"
Scientists have observed that many social animals -- from fruit flies to humans -- eat more and sleep less when isolated. The reason for this is unclear. One possibility, Young says, is that social isolation signals a degree of uncertainty about the future. Preparation for tough times may include being alert and awake as often as possible and eating whenever food is available.
This study can hardly confirm that humans in COVID-19 lockdowns ate more and slept less due to the same biological mechanisms that keep lonely flies hungry and sleep deprived. But now that Li and Young have identified the neurons and genes responding to chronic isolation in fruit flies, future researchers can search for corresponding connections between loneliness, overeating, and insomnia in laboratory animals and, eventually, humans.
"Clinically-oriented studies suggest that a large number of adults in the United States experienced significant weight gains and loss of sleep throughout the past year of isolation precautions due to COVID-19," Young says. "It may well be that our little flies are mimicking the behaviors of humans living under pandemic conditions for shared biological reasons."
https://www.sciencedaily.com/releases/2021/08/210818130604.htm
Histamine could be a key player in depression, according to study in mice
August 17, 2021
Science Daily/Imperial College London
Bodily inflammation dampens levels of a 'feel-good molecule' and antidepressants' ability to boost them, according to new research in mice.
The findings, from researchers at Imperial College London and University of South Carolina, add to mounting evidence that inflammation, and the accompanying release of the molecule histamine, affects a key molecule responsible for mood in the brain -- serotonin.
If replicated in humans, the findings -- which identify histamine as a 'new molecule of interest' in depression -- could open new avenues for treating depression, which is the most common mental health problem worldwide.
Inflammation -- a blanket term describing an immune response -- triggers the release of histamine in the body. This increases blood flow to affected areas to flood them with immune cells. While these effects help the body fight infections, both long-term and acute inflammation is increasingly linked to depression. Inflammation accompanies infections but can also be caused by stress, allergic responses and a host of chronic diseases such as diabetes, obesity, cancer and neurodegenerative diseases.
Lead author Dr Parastoo Hashemi, from Imperial's Department of Bioengineering, said: "Inflammation could play a huge role in depression, and there is already strong evidence that patients with both depression and severe inflammation are the ones most likely not to respond to antidepressants.
"Our work shines a spotlight on histamine as a potential key player in depression. This, and its interactions with the 'feel-good molecule' serotonin, may thus be a crucial new avenue in improving serotonin-based treatments for depression."
Chemical messengers
Serotonin, often referred to as the 'feel-good molecule', is a key target for depression-tackling drugs. Commonly prescribed selective serotonin reuptake inhibitors (SSRIs) inhibit the re-absorption of serotonin in the brain, allowing it to circulate for longer and improve mood.
However, although SSRIs bring relief to many who take them, a growing number of individuals are resistant to their effects. Researchers think one reason for this could lie in the specific interactions between chemical messengers, or neurotransmitters, including serotonin and histamine.
With this in mind, researchers set out to investigate the relationship between histamine, serotonin, and SSRIs.
They created serotonin-measuring microelectrodes and put them into the hippocampus of the brains of live mice, an area known to regulate mood. The technique, known as fast scan cyclic voltammetry (FSCV), allowed them to measure brain serotonin levels in real time without harming the brain, as they are biocompatible and only five micrometers wide.
After placing the microelectrodes, they injected half the mice with lipopolysaccharide (LPS), an inflammation-causing toxin found in some bacteria, and half the mice with a saline solution as a control.
Brain serotonin levels dropped within minutes of LPS injection, whereas they remained the same in control mice, demonstrating how quickly inflammatory responses in the body translate to the brain and affect serotonin. LPS is unable to cross the protective blood-brain barrier and could therefore not have caused this drop directly.
On further examination they found that the histamine in the brain was triggered by the inflammatory response and directly inhibited the release of serotonin, by attaching to inhibitory receptors on the serotonin neurons. These inhibitory receptors are also present on human serotonin neurons, so this effect might translate to people.
To counter this, the researchers administered SSRIs to the mice, but they were much less able to boost serotonin levels than in control mice. They posited that this is because the SSRIs directly increased the amount of histamine in the brain, cancelling out its serotonin boosting action.
The researchers then administered histamine reducing drugs alongside the SSRIs to counter histamine's inhibitory effects, and saw serotonin levels rise back to control levels. This appears to confirm the theory that histamine directly dampens serotonin release in the mouse brain. These histamine reducing drugs cause a whole-body reduction in histamine and are distinct from antihistamines taken for allergies, which block histamine's effects on neurons.
A new molecule of interest
The researchers say that if their work translates to humans it could help us towards eventually diagnosing depression by measuring chemicals like serotonin and histamine in human brains.
They also say the findings open new avenues to explore histamine as a causative agent of depression, including potentially developing novel drugs that reduce histamine in the brain.
Because the work was done in animals, more research will be needed to know if the concepts translate to humans. However, it is not currently feasible to use microelectrodes to make similar measurements in human brains, so the researchers are now looking at other ways to get a snapshot of the brain by looking at other organs which use serotonin and histamine, like the gut.
Pain, which accompanies inflammation, can also change neurotransmitter levels -- but previous research shows that in similar models, these changes last a few minutes, whereas the serotonin drop shown in this research lasted much longer, ruling out pain as a reason for the serotonin decrease.
Dr Hashemi added: "Inflammation is a whole-body response and is therefore hugely complex. Depression is similarly complex, and the chemicals involved are affected in myriad ways by both genetic and environmental factors. Thus we need to look at more complex models of depression behaviours in both mice and humans to get a fuller picture of both histamine and serotonin's roles in depression."
https://www.sciencedaily.com/releases/2021/08/210817111404.htm
Scrap the nap: Study shows short naps don’t relieve sleep deprivation
August 12, 2021
Science Daily/Michigan State University
A nap during the day won't restore a sleepless night, says the latest study from Michigan State University's Sleep and Learning Lab.
"We are interested in understanding cognitive deficits associated with sleep deprivation. In this study, we wanted to know if a short nap during the deprivation period would mitigate these deficits," said Kimberly Fenn, associate professor of MSU, study author and director of MSU's Sleep and Learning Lab. "We found that short naps of 30 or 60 minutes did not show any measurable effects."
The study was published in the journal Sleep and is among the first to measure the effectiveness of shorter naps -- which are often all people have time to fit into their busy schedules.
"While short naps didn't show measurable effects on relieving the effects of sleep deprivation, we found that the amount of slow-wave sleep that participants obtained during the nap was related to reduced impairments associated with sleep deprivation," Fenn said.
Slow-wave sleep, or SWS, is the deepest and most restorative stage of sleep. It is marked by high amplitude, low frequency brain waves and is the sleep stage when your body is most relaxed; your muscles are at ease, and your heart rate and respiration are at their slowest.
"SWS is the most important stage of sleep," Fenn said. "When someone goes without sleep for a period of time, even just during the day, they build up a need for sleep; in particular, they build up a need for SWS. When individuals go to sleep each night, they will soon enter into SWS and spend a substantial amount of time in this stage."
Fenn's research team -- including MSU colleague Erik Altmann, professor of psychology, and Michelle Stepan, a recent MSU alumna currently working at the University of Pittsburgh -- recruited 275 college-aged participants for the study.
The participants completed cognitive tasks when arriving at MSU's Sleep and Learning Lab in the evening and were then randomly assigned to three groups: The first was sent home to sleep; the second stayed at the lab overnight and had the opportunity to take either a 30 or a 60 minute nap; and the third did not nap at all in the deprivation condition.
The next morning, participants reconvened in the lab to repeat the cognitive tasks, which measured attention and placekeeping, or the ability to complete a series of steps in a specific order without skipping or repeating them -- even after being interrupted.
"The group that stayed overnight and took short naps still suffered from the effects of sleep deprivation and made significantly more errors on the tasks than their counterparts who went home and obtained a full night of sleep," Fenn said. "However, every 10-minute increase in SWS reduced errors after interruptions by about 4%."
These numbers may seem small but when considering the types of errors that are likely to occur in sleep-deprived operators -- like those of surgeons, police officers or truck drivers -- a 4% decrease in errors could potentially save lives, Fenn said.
"Individuals who obtained more SWS tended to show reduced errors on both tasks. However, they still showed worse performance than the participants who slept," she said.
Fenn hopes that the findings underscore the importance of prioritizing sleep and that naps -- even if they include SWS -- cannot replace a full night of sleep.
https://www.sciencedaily.com/releases/2021/08/210812123122.htm
Adult children with college degrees influence parents' health in later life
July 14, 2021
Science Daily/University at Buffalo
Having no children who completed college is negatively associated with parents' self-rated health and positively associated with depressive symptoms. Additionally, among parents with the highest propensity for having no children who complete college, the consequences on depressive symptoms are greatest.
Write down the benefits of obtaining a college degree and, more than likely, all the items on the completed list will relate to graduates: higher salaries, autonomous jobs and better access to health care, for instance. All of those factors, supported by extensive research, help draw a direct line connecting higher education and health. Similar research suggests how the education of parents affects their children.
Now, two University at Buffalo sociologists have used a new wave of data from a survey launched in 1994 to further extend the geometry linking educational attainment and health that demonstrates another dimension of the intergenerational effects of completing college. Their findings published recently in the Journal of Gerontology: Social Sciences suggest that adult children's educational attainment has an impact on their parents' mental and physical health.
"By analyzing these data we arrived at the conclusion that it was detrimental to parents' self-reported health and depressive symptoms if none of their children completed college," says Christopher Dennison, PhD, assistant professor of sociology in UB's College of Arts and Sciences, and a co-author of the paper with UB colleague Kristen Schultz Lee, PhD, an associate professor in the Department of Sociology. "The negative mental health outcome of the parents was in fact our strongest finding."
Dennison and Lee have both used the National Longitudinal Study of Adolescent to Adult Health (Add Health) in their previous research. Add Health is a nationally representative longitudinal study of over 20,000 adolescents. It is the largest such survey of its kind. There was an initial wave of data on the parents (ages 30-60) when the survey began and another wave of data from roughly 2,000 of those original participants (now ages 50-80) gathered from 2015-17.
It's this latter data set that provided the researchers an opportunity to look at the intergenerational relationship between parents and children over time, while statistically balancing factors that could influence an aging parent's health.
"These results are particularly important in light of growing educational inequalities in the U.S. in the last several decades," says Lee. "We know how our own education impacts our own health; we know how parents' education impacts their children in many different ways; now we're trying to add to that understanding by explaining how children's education can have an impact on their parents.
"One thing I thought particularly interesting about these findings is that those parents who are the least likely to have a child attain a college education (low socioeconomic status) seem to benefit the most from a child having a college degree."
Dennison and Lee speculate on a number of elements that might be driving this association, including anxiety, assistance and lifestyle.
"Parents whose children have lower levels of education might spend more time worrying about their children. That has negative implications for their mental health and their self-rated health," says Lee. "Kids without a degree might need more help from their parents and are also less able to provide help if needed in return.
"Another possibility is that educated children might be doing a better job of helping their parents live healthier lives by encouraging exercise and a sensible diet."
What's clear is the evidence pointing to how the benefits of a college degree show up in the parents' health later in life.
"In this era when a college degree is of ever-growing importance, we see how the long-term investment in education is advantageous to the adult child's health, but also has benefits down the road for their parents too," says Dennison.
And it's this idea of an investment that speaks to how educational attainment reaches across generations from a policy perspective.
"Historically, there has been a debate over whether or not different generations are at odds with one another, with one generation taking resources away from another older or younger generation," says Lee. "But our findings point to the fundamentally inter-related nature of the interests and needs of different generations.
"Investing in one generation, in this case, positively benefits another generation."
https://www.sciencedaily.com/releases/2021/07/210714151205.htm
Growing evidence of vitamin K benefits for heart health
August 9, 2021
Science Daily/Edith Cowan University
New Edith Cowan University (ECU) research has found that people who eat a diet rich in vitamin K have up to a 34 percent lower risk of atherosclerosis-related cardiovascular disease (conditions affecting the heart or blood vessels).
Researchers examined data from more than 50,000 people taking part in the Danish Diet, Cancer, and Health study over a 23-year period. They investigated whether people who ate more foods containing vitamin K had a lower risk of cardiovascular disease related to atherosclerosis (plaque build-up in the arteries).
There are two types of vitamin K found in foods we eat: vitamin K1 comes primarily from green leafy vegetables and vegetable oils while vitamin K2 is found in meat, eggs and fermented foods such as cheese.
The study found that people with the highest intakes of vitamin K1 were 21 percent less likely to be hospitalised with cardiovascular disease related to atherosclerosis.
For vitamin K2, the risk of being hospitalised was 14 percent lower.
This lower risk was seen for all types of heart disease related to atherosclerosis, particularly for peripheral artery disease at 34 percent.
ECU researcher and senior author on the study Dr Nicola Bondonno said the findings suggest that consuming more vitamin K may be important for protection against atherosclerosis and subsequent cardiovascular disease.
"Current dietary guidelines for the consumption of vitamin K are generally only based on the amount of vitamin K1 a person should consume to ensure that their blood can coagulate," she said.
"However, there is growing evidence that intakes of vitamin K above the current guidelines can afford further protection against the development of other diseases, such as atherosclerosis.
"Although more research is needed to fully understand the process, we believe that vitamin K works by protecting against the calcium build-up in the major arteries of the body leading to vascular calcification."
University of Western Australia researcher Dr Jamie Bellinge, the first author on the study, said the role of vitamin K in cardiovascular health and particularly in vascular calcification is an area of research offering promising hope for the future.
"Cardiovascular disease remains a leading cause of death in Australia and there's still a limited understanding of the importance of different vitamins found in food and their effect on heart attacks, strokes and peripheral artery disease," Dr Bellinge said.
"These findings shed light on the potentially important effect that vitamin K has on the killer disease and reinforces the importance of a healthy diet in preventing it."
Next steps in the research
Dr Bondonno said that while databases on the vitamin K1 content of foods are very comprehensive, there is currently much less data on the vitamin K2 content of foods. Furthermore, there are 10 forms of vitamin K2 found in our diet and each of these may be absorbed and act differently within our bodies.
"The next phase of the research will involve developing and improving databases on the vitamin K2 content of foods.
"More research into the different dietary sources and effects of different types of vitamin K2 is a priority," Dr Bondonno said.
Additionally, there is a need for an Australian database on the vitamin K content of Australian foods (e.g. vegemite and kangaroo).
To address this need, Dr Marc Sim, a collaborator on the study, has just finished developing an Australian database on the vitamin K content of foods which will be published soon.
The paper 'Vitamin K intake and atherosclerotic cardiovascular disease in the Danish Diet Cancer and Health Study' was published in the Journal of the American Heart Association. The research is part of ECU's Institute of Nutrition Research.
https://www.sciencedaily.com/releases/2021/08/210809144115.htm
Tracking circadian rhythms from your smartwatch
August 3, 2021
Science Daily/University of Michigan
Smartwatches are handy devices for people to keep track of the number of steps they take per day or to track their mile time during a run. But they are also opportunities for scientists to understand people's physiological processes while they are going about their everyday lives.
In particular, scientists have been interested in tracking people's circadian rhythms through the biological data gathered by their smartwatches -- specifically, their heart rate. Doing so would allow individuals to know the best times of day to sleep, eat, exercise or take their medications.
At night, a person's heart rate lowers in order to conserve energy. During a person's waking period, their heart rate speeds up in anticipation of activity. But the challenge has been figuring out a way to find the throughline of a person's heart rate among all of the ways it varies throughout the day, says Daniel Forger, a professor of mathematics at the University of Michigan.
Now, Forger and his colleagues have developed a statistical method that accounts for all of the "noise" that might affect a person's heart rate and extracts a person's circadian rhythm based on heart rate data provided by their smart watch.
The circadian rhythm is an internal clock that synchronizes all of the physiological functions in the body. The master clock, located in the brain's hypothalamus, oversees all of the millions of other internal clocks in your body: Each cell has an internal clock, as does your heart, the liver and the brain. In healthy individuals, these clocks are all in synchrony. But studying this master clock is difficult -- especially outside of a lab setting.
"I think a big question has been, can we measure circadian rhythms with wearables, and how can we do that?" said Forger, also a research professor of computational medicine and bioinformatics at Michigan Medicine. "Heart rate itself has a circadian rhythm, but it's complicated by a lot of different things: You lie down and go to sleep, and your heart rate drops. You go running and your heart rate goes way up.
"The hard question was, how do we pull out that internal timekeeping signal to know what time of day your body thinks it is from all of those other signals out there?"
The group's algorithm works by discarding data collected during sleep and focusing on data collected during a person's waking period. Then, the algorithm, developed by study co-author and former U-M postdoctoral researcher Clark Bowman, takes into account whether a person's heart rate is affected by the person's activity or cortisol because of exercise, posture or meals. The result is the underlying daily timekeeping signal controlling heart rate.
To test whether this statistical method worked, the group used a dataset from an ongoing study of medical interns, called the Intern Health Study. The study provides more than 130,000 days of data from 900 interns who continuously wore wrist-based sleep-tracking devices collecting motion and heart rate data. Medical interns are good subjects to use in this kind of research because they are shift workers, which means sometimes their work shifts change from day to night from week to week.
"Smart watches collect heart rate data using optical sensors, which aren't very accurate, and there are so many things affecting heart rate throughout the day that measurements tend to be all over the place, so it's a big result to be able to identify a circadian rhythm in that kind of data at all," said Bowman, now a professor of mathematics and statistics at Hamilton College.
"It's only possible since smart watches take measurements so frequently and provide information about activity to help account for cardiac demand. The sheer amount of data is just enough to see the background trend of heart rate subtly rising and falling in time with a circadian clock."
In one example in the study, a person's sleeping and waking patterns, as demonstrated by their heart rate, adjust quickly to their changing work schedule. This means their circadian rhythm was able to quickly adjust to a bedtime and waking time that was almost opposite of what they had previously been experiencing.
Another individual's data, however, showed a different story. Their circadian rhythm lagged behind their adjusted sleep schedule, which likely means they were feeling pretty sluggish during the time they were adjusting to their new waking schedule.
This sluggishness is the same effect that those with jet lag experience. Jet lag can occur when a person's heart rate isn't in sync with their waking period. A slower heart rate can make a person feel sleepy or sluggish.
Forger says the strength of using data from wearables means scientists, as well as the person wearing the watch, can study a person's circadian rhythm based on real-world influences, which has certain advantages over measuring circadian rhythm in a lab. The gold standard clinical study to study circadian rhythm would be to measure a person's melatonin levels over a period of six to 40 hours in a dark lab.
"We've shown that you can take a wearable signal and directly measure circadian rhythms in the real world, and the real world has so many things that affect circadian rhythms that you aren't going to measure in the lab," Forger said, explaining that some of the data the team has had to account for are extended periods of intense activity (a semiprofessional cyclist, for example). The method also does not account for effects on heart rate such as caffeine, psychological stress, pharmaceuticals and disease.
"There are some scenarios that you have to always be a little more careful with, using real world data," he said. "But again we're going to pick up other things you may not experience in a lab."
The researchers also developed the Social Rhythms app, available for iPhone and Android devices, where you can upload your wearable data and receive a report on how your internal circadian clock has changed recently.
"Measuring that signal not only provides information about the body's circadian timing, but also characterizes how each individual's heart rate behaves," Bowman said. "We can use this information to track how the body adjusts to new schedules, study how physical activity affects each individual's heart rate slightly differently, and even quantify the effect of being active at different times of day on the body's internal clock.
"Smart watch users could have real-time information on their circadian clock to help adjust to jet lag or shift work, manage circadian disorders or identify abnormalities in heart rate which might present health risks."
https://www.sciencedaily.com/releases/2021/08/210803121327.htm
Excess coffee: A bitter brew for brain health
July 22, 2021
Science Daily/University of South Australi
It's a favourite first-order for the day, but while a quick coffee may perk us up, new research from the University of South Australia shows that too much could be dragging us down, especially when it comes to brain health.
In the largest study of its kind, researchers have found that high coffee consumption is associated with smaller total brain volumes and an increased risk of dementia.
Conducted at UniSA's Australian Centre for Precision Health at SAHMRI and a team of international researchers*, the study assessed the effects of coffee on the brain among 17,702 UK Biobank participants (aged 37-73), finding that those who drank more than six cups of coffee a day had a 53 per cent increased risk of dementia.
Lead researcher and UniSA PhD candidate, Kitty Pham, says the research delivers important insights for public health.
"Coffee is among the most popular drinks in the world. Yet with global consumption being more than nine billion kilograms a year, it's critical that we understand any potential health implications," Pham says.
"This is the most extensive investigation into the connections between coffee, brain volume measurements, the risks of dementia, and the risks of stroke -- it's also the largest study to consider volumetric brain imaging data and a wide range of confounding factors.
"Accounting for all possible permutations, we consistently found that higher coffee consumption was significantly associated with reduced brain volume -- essentially, drinking more than six cups of coffee a day may be putting you at risk of brain diseases such as dementia and stroke."
Dementia is a degenerative brain condition that affects memory, thinking, behaviour and the ability to perform everyday tasks. About 50 million people are diagnosed with the syndrome worldwide. In Australia, dementia is the second leading cause of death, with an estimated 250 people diagnosed each day.
Stroke is a condition where the blood supply to the brain is disrupted, resulting in oxygen starvation, brain damage and loss of function. Globally, one in four adults over the age of 25 will have a stroke in their lifetime. Data suggests that 13.7 million people will have a stroke this year with 5.5 million dying as a result.
Senior investigator and Director of UniSA's Australian Centre for Precision Health, Professor Elina Hyppönen, says while the news may be a bitter brew for coffee lovers, it's all about finding a balance between what you drink and what's good for your health.
"This research provides vital insights about heavy coffee consumption and brain health, but as with many things in life, moderation is the key," Prof Hyppönen says.
"Together with other genetic evidence and a randomised controlled trial, these data strongly suggest that high coffee consumption can adversely affect brain health. While the exact mechanisms are not known, one simple thing we can do is to keep hydrated and remember to drink a bit of water alongside that cup of coffee.
"Typical daily coffee consumption is somewhere between one and two standard cups of coffee. Of course, while unit measures can vary, a couple of cups of coffee a day is generally fine.
"However, if you're finding that your coffee consumption is heading up toward more than six cups a day, it's about time you rethink your next drink."
https://www.sciencedaily.com/releases/2021/07/210722120624.htm
Higher levels of omega-3 acids in the blood increases life expectancy by almost five years
A 1% increase in this substance in the blood is associated with a change in mortality risk similar to that of quitting smoking.
July 22, 2021
Science Daily/IMIM (Hospital del Mar Medical Research Institute)
Levels of omega-3 fatty acids in the blood are as good a predictor of mortality from any cause as smoking, according to a study involving the Hospital del Mar Medical Research Institute (IMIM), in collaboration with The Fatty Acid Research Institute in the United States and several universities in the United States and Canada. The study, published in The American Journal of Clinical Nutrition, used data from a long-term study group, the Framingham Offspring Cohort, which has been monitoring residents of this Massachusetts town, in the United States, since 1971.
Researchers have found that omega-3 levels in blood erythrocytes (the so-called red blood cells) are very good mortality risk predictors. The study concludes that "Having higher levels of these acids in the blood, as a result of regularly including oily fish in the diet, increases life expectancy by almost five years," as Dr. Aleix Sala-Vila, a postdoctoral researcher in the IMIM's Cardiovascular Risk and Nutrition Research Group and author of the study, points out. In contrast, "Being a regular smoker takes 4.7 years off your life expectancy, the same as you gain if you have high levels of omega-3 acids in your blood," he adds.
2,200 people monitored over eleven years
The study analysed data on blood fatty acid levels in 2,240 people over the age of 65, who were monitored for an average of eleven years. The aim was to validate which fatty acids function as good predictors of mortality, beyond the already known factors. The results indicate that four types of fatty acids, including omega-3, fulfil this role. It is interesting that two of them are saturated fatty acids, traditionally associated with cardiovascular risk, but which, in this case, indicate longer life expectancy. "This reaffirms what we have been seeing lately," says Dr Sala-Vila, "not all saturated fatty acids are necessarily bad." Indeed, their levels in the blood cannot be modified by diet, as happens with omega-3 fatty acids.
These results may contribute to the personalisation of dietary recommendations for food intake, based on the blood concentrations of the different types of fatty acids. "What we have found is not insignificant. It reinforces the idea that small changes in diet in the right direction can have a much more powerful effect than we think, and it is never too late or too early to make these changes," remarks Dr Sala-Vila.
The researchers will now try to analyse the same indicators in similar population groups, but of European origin, to find out if the results obtained can also be applied outside the United States. The American Heart Association recommends eating oily fish such as salmon, anchovies or sardines twice a week because of the health benefits of omega-3 acids.
https://www.sciencedaily.com/releases/2021/07/210722113004.htm