How Heritage and Traditional Diets Influence Immunity, Metabolism and Health. New Insights from Tanzania.

Alastair Hunt
1 day ago
5 min read

As Western-style diets continue to spread across the globe, displacing traditional eating patterns, researchers are beginning to examine the toll this shift takes on our health. A new randomised controlled trial, published in Nature Medicine, explored the immune and metabolic impacts of African heritage diets compared with Western diets among young men in Tanzania.

The results were compelling: switching from a traditional diet to a Western one spurred inflammation and metabolic changes linked to chronic disease. In contrast, returning to a traditional diet or consuming a fermented banana beverage known as "Mbege" yielded largely anti-inflammatory effects.

As ever, please talk to your doctor or medical practitioner most familiar with your medical history before implementing any changes in diet, exercise or lifestyle, especially if you are under treatment. Links to all studies at bottom of page.

A Controlled Look at Dietary Change

The study focused on 77 healthy men from Tanzania, all aged between 21 and 27. Participants were divided into three groups:

Men living in rural areas who typically consumed a Kilimanjaro heritage-style diet and switched to a Western-style diet for two weeks.
Men from urban settings, habitually eating a Western-style diet, who switched to the heritage-style diet.
A third group, also urban and consuming a Western diet, who continued their usual eating habits but drank one litre of Mbege daily for a week.

Researchers collected blood samples at three stages: before the intervention, immediately after, and four weeks later. They assessed inflammation, metabolism, immune function and gene expression using a range of high-tech methods.

What Changed with the Western Diet?

Participants who switched from the heritage diet to a Western one showed significant increases in inflammatory and metabolic proteins. Their levels of key immune system markers rose, including proteins linked to cell damage and early stages of diseases like atherosclerosis. Cytokine responses—which help the body respond to infections - dropped sharply. In particular, immune responses to Candida, a common yeast, were notably suppressed.

Moreover, these participants gained an average of 2.6 kg in just two weeks. Their white blood cell counts rose, and markers of immune cell activation remained high even four weeks later, pointing to sustained immune system changes. Gene expression also shifted dramatically, with increased activity in genes linked to inflammation and oxidative stress, and reduced activity in genes involved in adaptive immunity.

Returning to a Traditional Diet: A Calming Effect

Men who moved from a Western-style diet to the heritage-style eating pattern showed the opposite trend. Inflammatory proteins dropped significantly. Metabolites tied to cardiovascular risk, such as indoxyl sulfate and p-cresol sulfate - both produced by gut bacteria and linked to red meat and processed food consumption - also decreased.

Interestingly, this group also showed increases in health-promoting metabolites like DHA, EPA (omega-3 fatty acids), and trans-piceid, a form of resveratrol known for its heart benefits. The changes were largely sustained at the four-week follow-up.

Cytokine responses stayed largely stable, with some increases in immune responsiveness. Unlike the Western diet group, these participants did not experience weight gain or major shifts in white blood cell activity.

The Role of Fermented Banana Beer

In the third group, who drank Mbege daily for one week while continuing their Western-style diet, researchers observed a fascinating pattern. While the metabolic protein changes reverted to baseline after four weeks, the anti-inflammatory effects on immune proteins persisted.

Mbege consumption increased the body’s production of IL-10, a key anti-inflammatory cytokine. It also improved immune responses to Candida and reduced neutrophil activation. Metabolites associated with the gut-friendly flavan-3-ol pathway, known for promoting vascular health, were also elevated.

This suggests that even modest additions of traditional fermented products may provide measurable immune benefits, though researchers caution against excessive alcohol intake.

Why This Matters

Chronic inflammation plays a role in the development of noncommunicable diseases (NCDs) like cardiovascular disease, type 2 diabetes and some cancers. As African countries urbanise and adopt more Western eating habits, rates of obesity and NCDs are rising sharply.

This study shows that even a short-term shift to Western eating habits can trigger persistent immune and metabolic dysfunctions. Conversely, even brief exposure to heritage diets or fermented foods can help restore balance. The traditional Kilimanjaro diet, featuring green vegetables, legumes, root crops like cassava and whole grains such as millet and sorghum, appears to support beneficial gut microbiota and reduce systemic inflammation.

Practical Recommendations

If you live in an area where traditional foods are available, consider incorporating more of these into your daily meals:

Increase your intake of vegetables, legumes and whole grains. These are fibre-rich and help modulate inflammation.
Include fermented foods like naturally brewed drinks or yogurt, which support a healthy gut microbiome. Enjoy our recipes for pineapple tepache and yogurt.
Limit processed foods high in sugars, refined grains and saturated fats, as these contribute to immune imbalance and weight gain.
Aim for diversity in plant-based foods, which can provide a range of beneficial compounds including polyphenols.

While this study focused on young men in Tanzania, the underlying biology likely applies broadly. The heritage diet's benefits mirror those of the Mediterranean diet, known for reducing inflammation and improving metabolic health. Read more here on the Hadza tribe and modern hunter-gatherer type diets.

Final Thoughts

The rise of Western dietary habits in Africa and across the globe is more than a cultural shift - it's a personal public health challenge. This research underscores the value of preserving indigenous diets not only for cultural heritage but also for immune and metabolic resilience. Even short-term changes can have lasting impacts, both good and bad. The Kilimanjaro heritage diet, rich in plant foods and traditional fermentation, offers a powerful example of how food can shape health at a molecular level.

As more regions, even our home in Singapore, grapple with the health effects of dietary westernisation, studies like this offer a hopeful reminder: going back to one's roots might be one of the best health decisions you can make.

Whether your interest is in diet, longevity, to beat chronic illness or to enhance your mental health and well-being, our consultations and programs deliver results that are tailored to your needs.

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