Absence of these microbes harms the immune system, causing asthma, eczema and other allergies in children.
They found that African children who were eating food similar to the diet of the earliest farmers thousands of years ago had a far lower proportion of microbes associated with obesity in adults and far more fatty acids known to protect against inflammation.
"The diet of Burkina Faso children is low in fat and animal protein and rich in starch, fibre and plant polysaccharides, and predominantly vegetarian," The Daily Mail quoted Dr Paolo Lionetti as saying.
"All food resources are completely produced locally, cultivated and harvested nearby the village by women.
Although the intake of animal protein is very low, sometimes they eat a small amount of chicken and termites," he added.indsey McManus, of Allergy UK, said, "There is some evidence that probiotics in the gut are effective at boosting the immune system, especially in children with eczema and that they can protect against allergies."