Is there a link between what we eat and how our immune system performs? A growing body of research says yes. According to a recent international study, diet plays a direct role in shaping both immune and metabolic functions. Shifts in eating habits can make individuals more vulnerable to infections and chronic diseases
Diet and health: an inseparable connection
Can our diet influence our immune response? And if so, how? These questions are at the heart of a clinical trial that included contributions from the University of Florence and the Meyer University Hospital in Italy.
The cause-effect relationship between diet and immunity
Published in Nature, the study titled Immune and metabolic effects of African heritage diets versus Western diets in men: a randomized controlled trial was led by Radboud University in the Netherlands and Kilimanjaro Christian Medical University College in Tanzania. It stemmed from an idea developed by researchers in Florence as part of the Horizon 2020-funded Transmic project. The initiative aims to examine how diet and gut microbiota influence human health by comparing traditional African and globalized eating patterns.
A study involving 77 men from urban and rural areas
Researchers tested the immune response of 77 healthy men living in both rural and urban Tanzania.
The two dietary models evaluated were the traditional African diet and the calorie-dense Western diet.
This specific research focus stems from the fact that traditional African diets are increasingly being replaced by calorie-dense Western dietary patterns.
The shift toward Western dietary patterns is growing in African countries, driven by urbanization, economic development, increased access to processed foods, and broader social changes.
Participants’ immune function, inflammatory blood markers, and metabolic processes were monitored at the start of the study, after two weeks, and again at the four-week mark.
Western diets linked to rise in non-communicable diseases
The findings reveal a concerning trend: a sharp rise in non-communicable diseases (NCDs) – including cardiovascular issues, obesity, diabetes, and chronic inflammation – associated with Western dietary habits. Urban populations now face higher mortality rates than rural communities.
In contrast, the traditional African diet consists primarily of vegetables, fruits, legumes, whole grains, and fermented foods.
During the intervention, one group shifted from the African diet to a Western-style diet for two weeks, while another group did the opposite.
A third group consumed a traditional fermented millet and banana beverage known as Mbege, rich in yeast and lactobacilli.
A control group of ten participants maintained their usual diet.
A negative impact on immunity and metabolism
The results were striking. Even short-term dietary changes triggered lasting effects on both the immune and metabolic systems.
Participants completed detailed surveys covering lifestyle, health status, daily activities, medication use, and vaccinations. Physical activity levels were also factored in.
After four weeks, the study found that those who had adopted a Western-style diet showed weakened immune responses and impaired metabolic markers, increasing their susceptibility to infections and chronic illnesses.
“The data we helped collect and analyze point to the significant health risks tied to abandoning traditional diets – a trend that’s rapidly growing in Africa,” said researchers Duccio Cavalieri and Paolo Lionetti from the University of Florence. “At the same time, the findings are a warning for Western societies, where diets rich in processed, high-calorie foods are doing real harm.”
