A groundbreaking study conducted in Tanzania has unveiled the profound impact that traditional plant-based diets and fermented drinks, such as Mbege, can have on reversing the inflammatory effects associated with Western eating habits. Published in Nature Medicine, this research provides new insights into the relationship between food, immunity, and disease prevention. The trial involved 77 healthy African men from both rural and urban areas who were divided into three groups: those consuming a heritage diet, others following a Western diet, and a third cohort maintaining a Western diet supplemented with Mbege. Findings revealed that transitioning from traditional meals to Western options increased biomarkers linked to non-communicable diseases (NCDs) and weakened immune responses. Conversely, reverting to heritage diets or incorporating fermented beverages promoted anti-inflammatory reactions.

Non-communicable diseases are currently at an all-time high globally, with the World Health Organization estimating they account for 43 million deaths annually—approximately 75% of all non-infection-related fatalities. Low- and middle-income nations, particularly in Asia and sub-Saharan Africa, bear the brunt of these deaths, underscoring the urgent need to identify their causes. Urbanization across sub-Saharan Africa has led to alarming trends where adult mortality rates in cities now surpass those in rural areas due to rising incidences of cardiovascular diseases, diabetes, and other conditions placing immense pressure on healthcare systems.

The study took place in the Moshi district of Tanzania between April and August 2021. It focused on young, healthy men aged 20–40 years with normal body mass indices (BMI). Participants were recruited from Uru Shimbwe Juu village, representing rural heritage dietary practices, and Moshi town, symbolizing urban Westernized eating patterns. Researchers provided specific diets thrice daily over two weeks, during which participants adhered strictly to either a traditional or Western regimen. Notably, rural individuals consuming Western diets experienced reduced gut bacterial diversity crucial for digesting fibrous vegetables central to their original meals. Urban dwellers shifting back to heritage diets showed enhanced immune functions alongside anti-inflammatory properties.

Urban men exposed solely to Western diets exhibited what researchers termed "immune confusion"—their cells overreacted to harmless stimuli yet performed poorly against genuine pathogens after just two weeks. Meanwhile, those reintroducing heritage foods demonstrated significantly higher daily fiber intake levels compared to their urban peers, largely sourced from unprocessed millet, sorghum, and leafy greens absent in typical Western meal plans. These dietary adjustments not only influenced inflammatory proteins but also altered gene expressions tied to chronic inflammation—a major risk factor for NCDs—and diminished immune responses towards microbial challenges.

Mbege drinkers experienced rapid increases in short-chain fatty acids within 72 hours, substances known to fortify gut barriers and diminish systemic inflammation. This suggests potential reductions in NCD risks through safe preparation and consumption of traditional fermented beverages alongside adopting healthier eating habits rooted in cultural heritage.

This pioneering investigation underscores the critical role dietary choices play in shaping health outcomes, advocating strongly for policies promoting ancestral eating patterns amidst growing concerns about escalating NCD-related mortality rates in sub-Saharan regions. Despite its promising results, the study acknowledges certain limitations like the relatively short intervention period and exclusive focus on male participants, calling for further exploration into long-term impacts and broader applicability across diverse populations.