Vitamin A, high-fibre diet may help prevent food allergies: study

Melbourne: Eating a diet rich in fibre such as bran and dried apricots and vitamin A may shape the immune system to reduce allergies to substances such as peanuts, a new study has claimed.

Scientists led by researchers from Monash University in Australia showed how the immune system works with the good bacteria in the gut to help protect against life threatening allergic responses.

According to researchers, it may be a lack of fibre in our diets that is causing this deadly rise in allergies.

By determining how this happens, researchers have suggested potential treatments to prevent, or possibly even reverse food allergies.

They suggest that allergy treatments could use probiotics (beneficial bacteria) that recolonise the gut, or prebiotics (healthy foodstuffs) that could work together to prevent or reverse allergies.

The research, performed largely by Jian Tan from Monash University found that mice allergic to peanuts were protected against the allergy when fed a high-fibre diet. In particular, the fibre appears to act by reshaping the gut and colon
microbiota.

The study found that eating a high-fibre diet such as bran and dried apricots actually changes the gut microbiota, the bacteria in the gut, to protect against food allergies.

The transfer of these 'good bacteria' to mice without these bacteria could reduce the symptoms of food allergies.

The microbiota in the gut assist the immune system in resisting allergies through the breaking down of fibre into short-chain fatty acids, researchers said.

This opens up a potential route for drug therapy for allergies by delivering short-chain fatty acids as a treatment, they said.

Scientists found that short-chain fatty acids boosted a particular subset of the immune system called dendritic cells, which control whether an allergic response against a food allergen happens or not.

Effectively, increased levels of short-chain fatty acids switch these cells to stop the allergic response, while a lack of fibre may have an opposite effect, researchers said.

These specialised dendritic cells require vitamin A, another factor which can only be obtained through the diet, and is high in vegetables and fruits, they said.

While deficiency of vitamin A in adults is unusual, researchers suggest that less than ideal levels of vitamin A in addition to short-chain fatty acids, could promote food allergies in infants.

The findings were published in the journal Cell Reports.