Healthy Aging: The Role of the Gut Microbiome and How Diet Can Help

The World Health Organisation (WHO) celebrates the International Day of Older Persons every year in October. This year, the theme is ‘Ageing with Dignity: The Importance of Strengthening Care and Support Systems for Older Persons Worldwide’. As we age, maintaining good health becomes increasingly important. One key player in this process is the gut microbiome, a complex community of trillions of microorganisms living in our digestive system. These tiny organisms play an important role in our overall health, influencing all our body functions. Understanding the changes in the gut microbiome as we age and how diet can support a healthy balance is essential for promoting healthy aging.

Some changes that take place in the Gut Microbiome as we age

The gut microbiome is a dynamic ecosystem that changes throughout our lives. In our youth, it is typically diverse and robust, contributing to efficient digestion, strong immune responses, and overall well-being. However, as we age, several changes occur. Age-related changes such as loss of teeth, difficulty in chewing and swallowing (leading to reduced intake of fibre-rich foods), loss of smell and taste, decrease in physical activity can affect the ideal composition of the gut microbiome.

1. Decreased Diversity: As we grow older, the variety of microbial species in the gut tends to decrease with age. This reduction in diversity can lead to an imbalance, a state which is associated with various health issues. For example, emerging research suggests that an imbalanced microbiome may contribute to cognitive decline and conditions like dementia and Alzheimer’s disease.
2. Shift in Composition: When we age, there is often a shift in the gut microbiome towards more pro-inflammatory (harmful) bacteria and a decrease in beneficial bacteria. This shift can contribute to increased inflammation and consequently a higher risk of infections and chronic diseases such as heart diseases and diabetes.
3. Changes in function: As the types of bacteria in the gut change, the overall function of the gut is also altered. For example, the gut microbiome is involved in the metabolism of various nutrients, including vitamins and amino acids. Age-related changes can affect the microbiome’s ability to produce essential nutrients like vitamins K and B. A good example is a decrease in Bifidobacteria, a strain of beneficial bacteria which are important for the production of certain B vitamins. B vitamins help to convert the food we eat into energy that the body can use. Hence, any decrease in the numbers of Bifidobacteria can lead to deficiencies in B vitamins and this in turn could impact overall health and lead to reduced energy levels.

How Diet Can Support a Healthy Gut Microbiome

Diet plays an important role in shaping the gut microbiome. As we age, we need to make a conscious effort to regularly include foods that have been shown to be beneficial for the gut and avoid or eliminate foods that are harmful to the gut. Some dietary strategies to support a healthy gut as we age are outlined below.

Fibre-Rich Foods: Consuming plenty of fibre from fruits, vegetables, cereals and beans of all kinds, helps feed beneficial bacteria in the gut. For people whose ability to chew is reduced, due to aging, tough foods can be pureed to make them easier to eat.

Probiotics and Prebiotics: Probiotics are live beneficial bacteria found in fermented foods like yogurt. Fermented cereal and root local food products such as kenkey, banku, millet or corn porridges and gari have been shown to contain some probiotics. Prebiotics on the other hand are non-digestible fibres that feed these beneficial bacteria, found in foods like garlic, onions, bananas and beans.

Limit Processed Foods: Most processed foods are high in salt (e.g. packaged chips and snacks), sugar (e.g. soft drinks and sugar sweetened beverages) and unhealthy fats (e.g. deep-fried foods, fast foods and baked goods). They are not particularly healthy choices for people who are aging. Avoiding or limiting intake of these foods can help maintain a healthy balance of gut bacteria.

Stay Hydrated: Adequate water intake supports digestion and helps maintain a healthy gut environment. Generally, as we grow older the thirst mechanism diminishes, and we can get easily dehydrated. Thus, drinking water regularly must thus be prioritized.

Diverse Diet: Eating a wide variety of foods can promote a diverse microbiome, which is beneficial for overall health. On the other hand, a monotonous diet, which means eating the same types of food repeatedly, can have several adverse effects on the gut microbiome.

In summary

Healthy aging is closely linked to the health of our gut microbiome. Diet interventions have been shown to significantly improve the gut microbiome by increasing the population of the beneficial bacteria, reducing inflammatory microbes and maintaining the integrity of the gut barrier.  As we age, we all wish to stay healthy and be able to function independently as long as possible and avoid becoming a burden to our loved ones. Research has indicated that healthy aging could be achieved by regulating the gut microbiome which promotes a healthy life and longer life expectancy. Simple dietary changes, such as increasing fibre intake, drinking more water, consuming probiotic and prebiotic foods, and reducing intake of processed foods, among others, can make a significant difference in maintaining a balanced and healthy gut microbiome and enable us to age with dignity.

References

Yue Xiao, Yingxuan Feng, Jianxin Zhao, Wei Chen, Wenwei Lu (2024). Achieving healthy aging through gut microbiota-directed dietary intervention: Focusing on microbial biomarkers and host mechanisms. Journal of Advanced Research. https://doi.org/10.1016/j.are.2024.03.005

Franz, C. M., Huch, M., Mathara, J. M., Abriouel, H., Benomar, N., Reid, G., … & Holzapfel, W. H. (2014). African fermented foods and probiotics. International Journal of Food Microbiology, 190, 84-96.

Written by Dr. Laurene Boateng (PhD, RD) and Ama Afrakoma Amoah (MPhil, RD)

Laurene Boateng (PhD, RD) is a Registered Dietitian and Senior Lecturer in the Department of Dietetics, University of Ghana. She is the founder and editor-in-chief of www.fullproofnutrition.com , a website committed to providing reliable, evidence-based, and practical healthy eating advice.

Ama Afrakoma Amoah (MPhi, RD) is a Registered Dietitian and contributing writer for www.fullproofnutrition.com

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