Gut Health as We Age – Dietary Support
The gut microbiome is a community of microorganisms that live in the gastrointestinal tract. This microbiome is unique to each of us, even in the case of genetically identical twins. Throughout our lives, the gut microbiome fluctuates. Read Part 1 of ‘Gut Health as We Age’ to learn more about how our microbiome (and gut health) changes from birth to old age.
Nutrition and Gut health6
Diet and lifestyle has an effect on the composition of our microbiota. The Western diet is a good example: the Western diet is characterised by food that is ultra-processed and typically contains much less vegetables and fibre than the diets in developing countries. The Western diet has been implicated in disease from cancer and obesity to dementia and Alzheimer’s due to its pro-inflammatory effect on the body.
We know that the microbiome composition is vastly affected by long-term as well as short term dietary patterns. We now know from animal models as well as human studies that the Western diet leads to dysbiosis (alteration in the microbiota that is associated with disease) (Fig. 3). Not only does the diversity and dominance change, some microbes also alter their metabolism in response to unhealthy diets. For example, some members of the microbiome increase their expression of virulence factors in the presence of some emulsifiers increasing the pro-inflammatory activity of the microbiome.
On the other hand, diets high in dietary fibre intake, such as the Mediterranean diet, are associated with a wide range of health benefits including reductions in risk of CVD, type 2 Diabetes, blood pressure and LDL cholesterol (and some cancers). There are of course many reasons for this, with one of them being the promotion of symbiosis in the gut (Fig 3.).
Fig 3. Graph taken from Touhy et al. (2014) on PubMed “A schematic representation of how diet shapes the human gut microbiota and impacts on chronic disease risk”.6
Dietary factors to promote gut health
The 2014-2016 NDNS report showed that fibre intake in all age/sex groups was below government recommendations, with only 4% of women meeting the guidelines. Enhancing dietary fibre consumption and thus fermentation by gut microbes is advised as “this will strengthen the intestinal barrier against pathogens, increasing the intestinal motility and helping to reduce the underlying pro-inflammatory status (immunosenescence), thus contributing to the general well-being”.8 Having a variety of fibre sources is also important with greatest microbial diversity shown when consuming 30 different plant foods a week. From hypertension to Alzheimer’s, many illnesses are associated with poor diversity of gut microbiome. If your biome is poor, you are more likely to be infected. Whilst highly processed foods have an effect of reducing microbial diversity in our guts, dietary fibre and the consumption of many different fruits and veg improves gut health. So if you were to start “biohacking”, meeting your dietary guidelines for dietary fibre and consuming 30 different plant foods a week should be your first step.
Probiotics are live microorganisms, which when consumed in adequate amounts bring health benefits to the host. Several intervention studies in healthy elders have shown probiotics to improve the gut microflora and protect against opportunistic pathogens like Clostridium difficile. C.difficile is normally harmless, however it is a toxin-producer that can cause infection when the host’s resistance is low. This is especially dangerous to those exposed to antibiotics and over 65 y. Therefore, the use of probiotics may be a good strategy for elders. Consider supplements and natural probiotic foods like yoghurt, kefir and sauerkraut.
Most prebiotics are complex carbohydrates that pass undigested into the colon where they are utilized by resident bacteria. Bacteria, like any other microorganism, have nutrient requirements. By meeting the needs of beneficial bacteria, prebiotics selectively promote symbiosis (a microbial composition that brings beneficial physiologic effect on the host). Prebiotics can be found in wholegrains and plant foods; chicory, asparagus, onions and leeks all contain inulin and fructooligosaccharides, which have shown to increase Bifidobacteria and Lactobacilli bacteria and decreases in pathogenic bacteria populations in clinical trials. Lactulose is an isolated prebiotic that can also be found in pharmacies and is used as a laxative.
In summary, we change, grow and age. So does our gut microbiome. Whilst aging exhibits a natural shift towards dysbiosis, this phenomena occurs in all of us at different rates. Eating a balanced and varied diet, meeting your dietary recommendations, consuming pro- and pre-biotic foods are all great ways to nurture your gut family and and your health.
- Bode, L. 2012. Human milk oligosaccharides: every baby needs a sugar mama. 22(9), pp.1147-1162.
- Zapata, H.J. and Quagliarello, V.J. 2015. The microbiota and microbiome in aging: potential implications in health and age-related diseases. Journal of the American Geriatrics Society. 63(4), pp.776-781.
- Dogra, S., Sakwinska, O., Soh, S.-E., Ngom-Bru, C., Brück, W.M., Berger, B., Brüssow, H., Karnani, N., Lee, Y.S., Yap, F., Chong, Y.-S., Godfrey, K.M. and Holbrook, J.D. 2015. Rate of establishing the gut microbiota in infancy has consequences for future health. Gut microbes. 6(5), pp.321-325.
- British Nutrition Foundation. 2020. Personalised Nutrition: Listen to your gut.[Online]. [Accessed 4April 2020]. Available from: https://www.nutrition.org.uk/component/rseventspro/event/60-free-bnf-webinar-personalised-nutrition-is-it-all-in-the-gut.html
- Nagpal, R., Mainali, R., Ahmadi, S., Wang, S., Singh, R., Kavanagh, K., Kitzman, D.W., Kushugulova, A., Marotta, F. and Yadav, H. 2018. Gut microbiome and aging: Physiological and mechanistic insights. Nutrition and healthy aging. 4(4), pp.267-285.
- Tuohy, K.M., Fava, F. and Viola, R. 2014. ‘The way to a man’s heart is through his gut microbiota’ – dietary pro- and prebiotics for the management of cardiovascular risk. Proceedings of the Nutrition Society. 73(2), pp.172-185.
- Childs, C. 2020. Immunity Webinar Series, Part 2: Gut Health & Immunity through the Lifecourse. [Online]. [Accessed 20 May 2020] Available from: https://mynutriweb.com/immunity-series-part-2-gut-health-immunity-through-the-lifecourse/
- Salazar, N., Valdés-Varela, L., González, S., Gueimonde, M. and de Los Reyes-Gavilán, C.G. 2017. Nutrition and the gut microbiome in the elderly. Gut microbes. 8(2), pp.82-97.
- Askarova, S., Umbayev, B., Masoud, A.-R., Kaiyrlykyzy, A., Safarova, Y., Tsoy, A., Olzhayev, F. and Kushugulova, A. 2020. The Links Between the Gut Microbiome, Aging, Modern Lifestyle and Alzheimer’s Disease. Frontiers in cellular and infection microbiology. 10, pp.104-104.
- Xu, C., Zhu, H. and Qiu, P. 2019. Aging progression of human gut microbiota. BMC Microbiology. 19(1), p236.
- Goycoolea, F.M. 2020. Carbohydrates. FOOD3330 Functional Foods. 4 March, University of Leeds.
Rusne is a United Kingdom-based writer passionate about nutrition as treatment and prevention of illness. She is currently completing her Bachelor in Food Science and Nutrition at the University of Leeds, and has Research & Development experience in the reformulation of sugary soft drinks.
Apart from her studies, Rusne particularly enjoys cooking, travelling and exploring independent coffee shops.