In a new study, researchers found that urban Tanzanians have a more activated immune system compared to their rural counterparts.
The difference in the diet appears to explain this difference: in the cities, people eat a more western-style diet, while in rural areas a traditional diet is more common.
The traditional rural Tanzanian diet, which is rich in whole grains, fiber, fruits, and vegetables, contains high amounts of these substances.
This increased activity of the immune system could contribute to the rapid increase in non-communicable diseases.
The research was conducted by a team at the University of Bonn and elsewhere.
In the study, the team surveyed more than 300 Tanzanians, some of whom live in the city of Moshi and some in the countryside.
The researchers found that immune cells from participants from Moshi produced more inflammatory proteins.
The people surveyed had no health problems and were not ill, but an activated immune system may increase the risk for lifestyle diseases, such as heart disease.
The researchers used new techniques to test the function of the immune system and the factors that influence its activity.
They looked at active RNA molecules in the blood—known as the transcriptome—and the composition of metabolic products in the blood.
These analyses showed that metabolites derived from food had an effect on the immune system.
Participants from rural areas had higher levels of flavonoids and other anti-inflammatory substances in their blood.
The traditional rural Tanzanian diet, which is rich in whole grains, fiber, fruits, and vegetables, contains high amounts of these substances.
In people with an urban diet, which contains more saturated fats and processed foods, increased levels of metabolites that are involved in cholesterol metabolism were found.
The team also found a seasonal change in the activity of the immune system. In the dry season, which is the time of harvest in the study area, the urban people had a less activated immune system.
It has been known for some time that a Western lifestyle and eating habits lead to chronic diseases.
The study showed that a traditional Tanzanian diet has a beneficial effect on inflammation and the functioning of the immune system.
Additionally, urbanization took place a long time ago in most western countries.
By studying populations at different stages of urbanization, researchers therefore have unique opportunities to improve their understanding of how diet and lifestyle affect the human immune system.
One author of the study is Prof. Mihai Netea.
The study is published in Nature Immunology.
Copyright © 2021 Knowridge Science Report. All rights reserved.
