Western diet linked to heightened inflammatory response

A small change on your plate can have a significant impact on the immune system. This was shown in a randomized study by researchers from Radboudumc and KCMC University, published in Nature Medicine. The team examined how switching diets for just two weeks — from an African heritage diet (AHD) to a Western diet (WD) and vice versa — affected inflammation markers, metabolites, and gene expression in young Tanzanian men.

Western diet increases inflammatory activity

Participants who moved from AHD to WD showed marked changes. Levels of white blood cells, neutrophils, and reactive monocytes increased. Activation markers such as NEUT-RI and NEUT-GI remained elevated even four weeks after the intervention. Protein analysis revealed increased concentrations of 26 proteins — 19 linked to cardiometabolic processes and seven to inflammation. These included THBS4 and TWEAK, both associated with atherogenesis and apoptosis. At the same time, production of TNF and IFNγ in response to Candida albicans was reduced.

Heritage-based diet lowers inflammation

Switching from WD to AHD had the opposite effect. Levels of inflammation-related proteins dropped, including chemokines such as CXCL1, CXCL5, and CXCL6, and cytokines like IL-6 and IL-17C. These effects were still present four weeks later. In addition, plant-associated metabolites like dodecanoic acid and trans-piceid — both known for their cardiovascular benefits — increased.

Fermentation as immune modulator

The group consuming the traditional fermented banana beer Mbege showed a distinct response. This drink, made from fermented banana and millet, led to reduced neutrophil activity and an increase in anti-inflammatory IL-10 production. Plasma analysis revealed higher levels of polyphenols such as tyrosol and hydrocinnamic acid. Although the alcohol content of 1–3% and potential mycotoxin contamination are points of concern, the results point to the immune-modulating potential of traditional fermented products.

Read the full study: ‘Immune and metabolic effects of African heritage diets versus Western diets in men: a randomized controlled trial’

Nature.com