There might be a new dietary cure for allergies, according to recent research published in the journal Cell Reports. Mice that were given a high-fiber diet had a much lower occurrence of allergies. Specifically, the scientists tested peanut allergies but their findings suggest that fiber can help with other allergies.
The researchers tested mice that had peanut allergies (induced artificially). One group was given a high-fiber diet while the control group was given a diet that was identical except for containing less fiber. In the experimental group, bacteria in the gut released a fatty acid in response to the high amount of fiber. This fatty acid binds to receptors found on immune system cells called regulatory T cells. This reaction helps reduce inflammation in the gut and tones down the allergic response.
Charles Mackay and Laurence Macia, two of the lead authors of this study, found further evidence that the fatty acid release was responsible for the reduced allergic reactions. They transplanted gut bacteria from the mice who had been given the high-fiber diet. The recipients of this transplant, the control group, no longer showed symptoms of a peanut allergy. The researchers then tried giving another control group the same fatty acids released in the guts of the high-fiber mice. Predictably, this group also showed reduced allergic responses. This shows that the fatty acid byproduct itself, released when large amounts of fiber are consumed, is responsible for the anti-inflammatory properties.
Macia and Mackay do caution that this effect may not translate to human allergies. More studies need to be conducted and different sources of fiber need to be analyzed. Currently, it’s hard to say if all fiber would have these effects. Importantly, these studies were done on mice and it’s unknown if human guts respond the same way to fiber intake. A high fiber diet isn’t a bad idea, though, and most people don’t get enough in their diet. Now there’s one more reason to consider increasing fiber consumption—it might help with allergies and other sources of inflammation.
Tan et al. Dietary fiber and bacterial SCFA enhance oral tolerance and protect against food allergy through diverse cellular pathways. Cell Reports (2016).