New research has indicated that eating a Mediterranean diet for a year can help boost gut bacteria which are linked to healthy aging. The five country study also indicates this diet can help reduce bacteria that is associated with harmful inflammation in older people.
Aging is associated with the deterioration of bodily functions and an increase in inflammation. Both are also associated with the onset of frailty. The Mediterranean Diet may act on gut bacteria in a way that helps curb the advance of cognitive decline and physical frailty in advancing years.
Previous studies have suggested that a restrictive/poor diet which is typical among older people and particularly those in long term residential care, reduces the types and range of bacteria or microbiome that is found in the gut and helps accelerate the onset of frailty.
The researchers in the current study wanted to see if the Mediterranean Diet might help maintain the microbiome in the gut of older people and help promote the retention and possibly proliferation of bacteria that are associated with healthy aging.
The team analyzed the gut microbiome of 612 participants aged 65 to 79 before and following 12 months of either consuming their usual diet or a Mediterranean diet. The Mediterranean diet was rich in vegetables, fruits, olive oil, fish and legumes and low in saturated fats and red meat.
The participants who were either on the verge of frailty or were already considered frail or not frail at the start of the study resided in five different countries – France, Netherlands, Italy, the UK and Poland. Those who stuck with the Mediterranean diet for the period of 12 months were associated with beneficial changes to the gut microbiome.
The results were associated with stemming the loss of bacterial diversity; an increase in bacteria types previously linked with several indicators of diminished frailty such as hand grip strength and walking speed, and improved brain function; and with reduced production of potentially harmful inflammatory chemicals.
Additional detailed analysis indicated that the microbiome changes were linked with an increase in bacteria types known to produce beneficial short chain fatty acids and a decrease in bacteria involved in the production of particular bile acids. An over production of these bile acids is linked to increased risk of bowel cancer, fatty liver, insulin resistance, and cell damage.
The bacteria that proliferated in response to the Mediterranean diet acted as keystone species which meant they were critical to a stable gut ecosystem and the pushing out of microbes linked with indicators of frailty.
The changes were mainly driven by an increase in fiber and associated minerals and vitamins. The vitamins and minerals noted were B6, B9, C, potassium, copper, manganese, iron, and magnesium. The findings were independent of the participant’s weight or age both of which influence the make up of microbiome.
There were some differences in the gut microbiome of participants depending on country of origin to start with, however the response to the Mediterranean diet after the 12 month period was consistent and similar irrespective of nationality.
The research team does note that their findings cannot establish a causative role for the microbiome in health and some of the implications are inferred rather than directly measured. The interplay of diet, host health, and microbiome is a complex phenomenon which is influenced by a variety of factors.
The results of the study shed light on some of the rules of this three way interplay. A variety of factors such as body mass index, age, initial dietary patterns, and disease status may play a significant role in determining the extent of the success of these interactions.
The Mediterranean diet may be a challenge for some older adults, particularly those with dental problems and/or difficulty swallowing. However, the beneficial bacteria implicated in health aging found in this study may potentially prove useful therapeutic agents to help ward off frailty.
To view the original scientific study click below