The results of a randomized and controlled dietary trial, including a multi-omics analysis of immune and metabolic changes associated with switching between a Western-style dietary pattern and a Kilimanjaro heritage-style pattern, were recently published in Nature Medicine. Male non-overweight participants between the ages of 20 to 40 were recruited from one of two cohorts in Northern Tanzania. The first group of men was from a rural area and followed a traditional dietary pattern while the second group was from an urban area where a Western-style diet was more common, with a nutritionist ensuring these respective diets were adhered to prior to the intervention.
There were 3 arms in this open-label study in which 3 meals were provided each day. In the first, 22 men following the heritage-style diet switched to a Western-style diet for 2 weeks (with 5 controls maintaining their diets), in the second arm 22 men switched from the Western to the heritage diet (also with 5 controls), and in the 3rd arm, 22 men following a Western diet began consuming a traditional fermented banana-based beverage (Mbege) for 1 week (no controls).
Among the many outcomes documented in this short-term trial, switching to the largely plant-based heritage-style pattern (as well as the fermented beverage) produced anti-inflammatory effects, while the switch to a Western diet promoted a pro-inflammatory state, marked by changes in the plasma proteome and metabolome, cytokine production, and the whole blood transcriptome, with some changes persisting for 4 weeks following the switch. There were several limitations of the study; food was consumed ad libitum, and weight gain associated with the Western diet may have played a role in the generally unfavorable immunomodulatory effects observed. Despite this, the study provides additional support for this traditional dietary pattern, as well as highlighting the harms of a Western pattern.