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How does the gut microbiota affect metabolic response to foods?
It is well understood that consumption of different foods can elicit different metabolic effects, including the degree to which they increase blood glucose and lipid levels. However, in more recent years, research has also shown that individuals’ metabolic response to the same food or meal can be different. In a group of healthy subjects, who consumed four different test meals and had their glycaemic response measured for 2-hours, glucose response (area under the curve) was widely variable, in some cases there was a 4-fold difference, between participants when the same foods were consumed.1
This has important consequences because hyperglycaemia and hyperlipidaemia are risk factors for obesity and many non-communicable diseases.2-3 Understanding what factors influence an individual’s response to food is vital and could help reduce the burden of non-communicable diseases through the use of personalised nutrition approaches.
Researchers at King’s College London are running the PREDICT study which aims to identify the contribution of different factors on an individuals’ metabolic response to foods. One factor that the researchers are keen to explore is the role of the gut microbiota.4
In their study, during a 1-day clinic visit, over 1000 individuals (including twins and un-related healthy adults in the UK) consumed two test meals and were monitored for six hours for postprandial metabolic responses. During their clinic visit, participants also provided a stool sample for microbiome profiling. For the following 13 days, whilst at home, participants consumed multiple test meals and wore a continuous glucose monitor (CGM).
In line with previous research1, it was observed that there was high variability between individuals’ postprandial metabolic responses following consumption of the same test meals. The variation was highest for postprandial triglyceride (103%), followed by postprandial glucose (68%) and postprandial insulin (59%).
Although individuals respond differently to one another, additional findings showed that an individual generally responds in a similar way to different meals when they have the same macronutrient profile.
To understand why there is variability in response between individuals, the researchers accounted for several modifiable and non-modifiable traits to determine their contribution to the variation. Gut microbiota bacterial abundance, diversity and richness, as measured from stool samples, explained between 5.8 – 7.5% variance for postprandial C-peptide, glucose and triglyceride.
Although genetic factors had a far greater contribution to the variance in postprandial glucose compared to the gut microbiota (48% vs 6.4% respectively), their contribution to other postprandial responses was in fact lower – accounting only for 9% variance in insulin and 0% variance in triglyceride responses.
Although its contribution may be small, the gut microbiota does appear to influence our metabolic response to food and will likely be an important factor to consider in personalised nutrition approaches in the future.
References
1. Whelan et al. (2010) Life 62(8):637-641.
2. Blaak et al. (2012) Obesity Reviews 13(10):923-984.
3. Kolovou et al. (2011) Current Vascular Pharmacology 9(3):258-270.
4. Berry et al. (2020) Nature Medicine 26:964-973.