Entry #: 11
Date: 18 September 2017
Section: Mediterranean diet
Topic: Gut microbiota Type: Human volunteer trial
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D. Elizabeth McCord, Nancy B. Ray and Tom C. Karagiannis
Adherence to the Mediterranean diet is associated with the gut microbiota pattern and gastrointestinal characteristics in an adult population
Mitsou E et al
Citation / Year
(1) / 2017
Mediterranean diet, gut microbiota, gastrointestinal symptoms, short-chain fatty acids, butyrate
This is an important cross-sectional human volunteer trial aimed at investigating the association between adherence to the Mediterranean diet and anthropometric parameters, gut microbiota and gastrointestinal symptoms in healthy individuals. A total of 120 people were recruited (18-65 years), with a 116 individuals (61 M, 55 F and mean age of 42 years completing the study). Results were presented for 100 individuals who were classified according to their MedDietScore(2), which, albeit limited, is an accepted measure of adherence to the Mediterranean diet. By analysis of food group and stimulant (coffee, tea, soda, alcohol) consumption and careful classification the participants were grouped into three MedDietScore tertiles: low (score 19.0-30.0, n=31), medium (score 31.0-33.0, n=29) and high (score 34.0-41.0, n=40). Apart from anthropometric parameters and somewhat subjective gastrointestinal symptom analysis, the authors provide detailed analyses of levels of 1) short-chain fatty acids including (acetate, propionate and butyrate) and 2) culture-dependent and independent levels of gut microbiota (bacteria, yeasts and fungi). Overall, unremarkable differences were observed for general anthropometric features, physical activity and sleeping patterns between the three groups. However, significant differences with a positive correlation with adherence to the Mediterranean diet, were observed for gastrointestinal symptoms including stool composition and evacuation frequency and gut microbiome composition.
Key points and implications
The complex composition and diversity of the gut microbiome is beginning to be better understood (3, 4). It is now becoming clear that there is a correlation between the gut microbiome and various human pathologies including inflammatory conditions, a range of metabolic diseases, cancer and chronic degenerative disorders. The key findings of this work indicated 1) significantly lower levels of Escherichia coli in the high tertile
MedDietScore group compared to the low group, 2) higher levels of bifidobacteria and Candida albicans which also correlated with adherence to the Mediterranean diet and 3) consumption of junk and snack foods correlated negatively with features of the gut microbiome. An important aspect of this work is the analysis of direct levels of faecal short-chain fatty acids and short-chain fatty acid producing microbes. Although the findings were not as compelling, these experiments extend previous findings which have indicated a strong correlation between adherence to the Mediterranean diet and levels of short-chain fatty acids (5, 6). Short-chain fatty acids, particularly, acetate, propionate and butyrate are important intestinal metabolic regulators and well known epigenetic modifiers with established effects on chromatin remodelling and histone hyperacetylation.
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