Mediterranean diet for one year promotes gut bacteria linked to 'healthy aging'
It may help curb advance of frailty and cognitive decline, suggest researchers
February 17, 2020
Science Daily/BMJ
Eating a Mediterranean diet for a year boosts the types of gut bacteria linked to 'healthy' ageing, while reducing those associated with harmful inflammation in older people, indicates a five-country study, published online in the journal Gut.
As ageing is associated with deteriorating bodily functions and increasing inflammation, both of which herald the onset of frailty, this diet might act on gut bacteria in such a way as to help curb the advance of physical frailty and cognitive decline in older age, suggest the researchers.
Previous research suggests that a poor/restrictive diet, which is common among older people, particularly those in long term residential care, reduces the range and types of bacteria (microbiome) found in the gut and helps to speed up the onset of frailty.
The researchers therefore wanted to see if a Mediterranean diet might maintain the microbiome in older people's guts, and promote the retention or even proliferation of bacteria associated with 'healthy' ageing.
They analysed the gut microbiome of 612 people aged 65 to 79, before and after 12 months of either eating their usual diet (n = 289) or a Mediterranean diet (n = 323), rich in fruits, vegetables, nuts, legumes, olive oil and fish and low in red meat and saturated fats, and specially tailored to older people (NU-AGE diet).
The participants, who were either frail (n=28), on the verge of frailty (n=151), or not frail (n=433) at the beginning of the study, lived in five different countries: France, Italy, Netherlands, Poland, and the UK.
Sticking to the Mediterranean diet for 12 months was associated with beneficial changes to the gut microbiome.
It was associated with stemming the loss of bacterial diversity; an increase in the types of bacteria previously associated with several indicators of reduced frailty, such as walking speed and hand grip strength, and improved brain function, such as memory; and with reduced production of potentially harmful inflammatory chemicals.
More detailed analysis revealed that the microbiome changes were associated with an increase in bacteria known to produce beneficial short chain fatty acids and a decrease in bacteria involved in producing particular bile acids, overproduction of which are linked to a heightened risk of bowel cancer, insulin resistance, fatty liver and cell damage.
What's more, the bacteria that proliferated in response to the Mediterranean diet acted as 'keystone' species, meaning they were critical for a stable 'gut ecosystem,' pushing out those microbes associated with indicators of frailty.
The changes were largely driven by an increase in dietary fibre and associated vitamins and minerals -- specifically, C, B6, B9, copper, potassium, iron, manganese, and magnesium.
The findings were independent of the person's age or weight (body mass index), both of which influence the make-up of the microbiome.
And while there were some differences in the make-up of a person's gut microbiome, depending on country of origin to start with, the response to the Mediterranean diet after 12 months was similar and consistent, irrespective of nationality.
The study findings can't establish a causative role for the microbiome in health, added to which some of the implications are inferred rather than directly measured, say the researchers.
"The interplay of diet, microbiome and host health is a complex phenomenon influenced by several factors," they emphasise.
"While the results of this study shed light on some of the rules of this three-way interplay, several factors such as age, body mass index, disease status and initial dietary patterns may play a key role in determining the extent of success of these interactions," they explain.
Older people may have dental problems and/or difficulty swallowing, so it may be impractical for them to eat a Mediterranean diet, they add. But the beneficial bacteria implicated in healthy ageing found in this study might yet prove useful therapeutic agents to ward off frailty, they suggest.
https://www.sciencedaily.com/releases/2020/02/200217192025.htm
Childhood antibiotics and antacids may be linked to heightened obesity risk
These drugs may alter gut microbes associated with weight gain, say researchers
October 30, 2018
Science Daily/BMJ
Young children prescribed antibiotics and, to a lesser extent, drugs to curb excess stomach acid, may be at heightened risk of obesity, new research suggests.
These drugs, particularly if taken for lengthy periods, may alter gut microbes that have been associated with weight gain, explain the researchers.
The composition of gut bacteria (the microbiome) has been linked to various aspects of human health, including obesity. And certain drugs, such as antibiotics and acid suppressants-histamine 2 receptor antagonists (H2RA) and proton pump inhibitors (PPIs)-can alter the type and volume of bacteria in the gut.
To try and find out if exposure to these drugs in early childhood might increase the risk of obesity, the researchers looked at the medicines prescribed to 333,353 infants, whose medical records had been input into the US Military Health System database between 2006 and 2013, in the first two years of their lives.
In all, 241, 502 (72.5%) had been prescribed an antibiotic; 39,488 (just under 12%) an H2RA; and 11,089 (just over 3%) a PPI during this period. Some 5868 children were prescribed all three types of drug.
Some 46,993 (just over 14%) children became obese, of whom 9628 (11%) had not been prescribed any antibiotics or acid suppressants.
Boys, those born after a caesarean section, and those whose parents were below officer rank were more likely to become obese.
But after taking account of potentially influential factors, a prescription for antibiotics or acid suppressants was associated with a heightened risk of obesity by the age of 3 -- the average age at which obesity was first identified in these children.
A prescription for antibiotics was associated with a 26 per cent heightened risk of obesity. This association persisted, irrespective of antibiotic type, and strengthened with each additional class of antibiotic prescribed.
Acid suppressants were also associated with a heightened obesity risk, although to a lesser extent, and this association strengthened for each 30-day supply prescribed.
Although the largest study of its kind, it is nevertheless observational, and as such, can't establish cause. And potentially influential information on how much the children's mothers weighed, and whether they smoked or had other underlying conditions wasn't available.
And the researchers emphasise that the links between the individual, the environment, and obesity are complex, highlighting the "current difficulty of drawing clear conclusions about the interplay between exposure history, gut microbiota and propensity to develop obesity."
They add: "There is an important therapeutic role for microbiota-altering medications. The long term risks to health must be weighed against the short-term benefits."
But they also point out that over prescription of both antibiotics and acid suppressants, including in young children, is "a significant problem."
https://www.sciencedaily.com/releases/2018/10/181030184507.htm