Did you know that a healthy gut microbiome is an essential part of your weight management journey? We have a mutualistic relationship with our gut whereby our health can benefit from a diverse gut microbiome. Food is the main source of fuel for gut microbes; both food and our gut microbes therefore have a role to play in our unique metabolism and overall state of health.

Is there an ‘overweight’ gut microbiome?

Through gene sequencing, it has been found that the gut microbiota in individuals at a healthy weight differ from that of individuals who are overweight or obese. For example, a higher Firmicutes to Bacteroidetes ratio is commonly found to be more common in individuals with an increased BMI, as compared to people with moderate weight. Elevated levels of Firmicutes are thus a potential marker of obesity. Overweight individuals are also associated with having a less diverse gut microbiome, which increases the risk of gut dysbiosis and low-level intestinal inflammation.

How can I manage my weight with my gut microbiome?

Given the close relationship between food and the gut microbiome, certain dietary choices may promote reduced weight gain in the long term via alterations to the gut microbiome.

Increase your fibre intake‍

A high fibre diet with foods such as whole grains, fresh fruit and vegetables have been linked to increased levels of Short Chain Fatty Acids (SCFAs) such as butyrate, acetate, propionate. SCFAs are mainly produced by the gut microbiota in the large intestine by bacterial fermentation of resistant starch and dietary fiber. SCFAs aid in the regulation of the gut microbiome and stabilisation of the intestinal barrier, suppressing intestinal inflammation, and improving insulin sensitivity. Research has found that anthocyanins in purple sweet potato induced growth of Bifidobacterium and Lactobacillus/Enterococcus spp. The SCFAs produced by these bacteria had a prebiotic-like effect on the gut.

An apple a day

Non-absorbable procyanidins in apples have been shown to increase the proportion of beneficial gut bacteria – specifically A.Muciniphila, and decrease the ratio of Firmicutes to Bacteroidetes in mice. A.Muciniphila is associated with improved lipid regulation and SCFA production, which lowers the risk of fat accumulation in the body and obesity. Similar procyanidins can be found in grapes and cranberries.

Healthy fats

‍No, that isn’t an oxymoron. The type of fat we consume in our diet has an impact on our gut microbiome as well! In particular, foods rich in omega-3 fatty acids have shown to positively impact the gut microbiome by boosting levels of SCFA producing A.Muciniphila.

In preliminary studies, a higher omega-3 polyunsaturated fatty acid (n-3 PUFA) content in muscle tissue has also been shown to decrease E.coli and increase growth of beneficial Bifidobacteria and Lactobacilli. Evidence suggests that intake of dietary PUFAs decreases risk of weight gain and cardiovascular heart disease, through modification of components of the intestinal wall.  Examples of foods rich in omega 3 fatty acids include oily fish (salmon, mackerel), walnuts and flaxseeds. In comparison, consuming a diet high in saturated fats lowers the abundance of Bifidobacteria and Lactobacilli and leads to an increase in Bilophila and risk of intestinal barrier dysfunction and inflammation.

Fermented foods

Fermented foods such as tempeh may help you maintain a healthy weight! Tempeh is a traditional Indonesian fermented soybean cake that has been shown to increase the gut healthy bifidobacterium, enhance lipid metabolism, and decrease total cholesterol levels. Tempeh is also rich in soluble fibers. Current research suggests that consumption of tempeh over a prolonged period of time boosts levels of Bifidobacterium and A.Muciniphila. This may be due to the presence of polyphenols in tempeh.

Can enterotypes be changed?

It is possible for an individual’s enterotype to move along the scale from one to another depending on how they change their long-term diet. Short-term dietary changes cannot change one’s enterotype. Geographic relocation, if long-term, will have an impact on an individual’s enterotype due to the major changes in diet (if the individual changes their diet). In this way, geography does in fact have an impact on the microbiome.

Glossary

Gut dysbiosis is an imbalance in the gut microbial community associated with disease, driven by genetics, environmental factors (such as diet) & chronic inflammation.

Non-absorbable procyanidins are a type of flavonoid which are associated with a reduced risk of obesity and metabolic syndrome.

Bifidobacterium, Lactobacilli, A.Muciniphila, and Enterococcus spp are Short Chain Fatty Acid (SCFA) producing bacteria and are beneficial for the gut.

Bilophia and Firmicutes are bacteria that may be associated with increased risk of metabolic syndrome and gut dysbiosis.

References

1. Costantini, L., Molinari, R., Farinon, B., & Merendino, N. (2017). Impact of omega-3 fatty acids on the gut microbiota. In International Journal of Molecular Sciences (Vol. 18, Issue 12). MDPI AG. https://doi.org/10.3390/ijms18122645
2. Masumoto, S., Terao, A., Yamamoto, Y., Mukai, T., Miura, T., & Shoji, T. (2016). Non-absorbable apple procyanidins prevent obesity associated with gut microbial and metabolomic changes. Scientific Reports, 6(1), 1–10. https://doi.org/10.1038/srep31208
3. Holmes, Z. C., Silverman, J. D., Dressman, H. K., Wei, Z., Dallow, E. P., Armstrong, S. C., Seed, P. C., Rawls, J. F., & David, L. A. (2020). Short-chain fatty acid production by gut microbiota from children with obesity differs according to prebiotic choice and bacterial community composition. MBio, 11(4), 1–15. https://doi.org/10.1128/mBio.00914-20
4. Stephanie, Kartawidjajaputra, F., Silo, W., Yogiara, Y., & Suwanto, A. (2019). Tempeh consumption enhanced beneficial bacteria in the human gut. Food Research, 3(1), 57–63. https://doi.org/10.26656/fr.2017.3(1).230
5. Zhang, N., Ju, Z., & Zuo, T. (2018). Time for food: The impact of diet on gut microbiota and human health. In Nutrition (Vols. 51–52, pp. 80–85). Elsevier Inc. https://doi.org/10.1016/j.nut.2017.12.005

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