Healthy babies' gut bacteria prevent common food allergy
15 January, 2019
Gut bacteria have a crucial role in protecting against food allergies, according to recent research.
When scientists transplanted gut microbes, or microbiota, from healthy human babies into mice with no bacteria of their own, the animals did not have an allergic reaction on exposure to cow's milk.
In contrast, germ-free mice that received gut bacteria from human babies with cow's milk allergy did experience allergic reactions to cow's milk.
Allergy to cow's milk is the most common childhood food allergy.
The researchers, who report their findings in the journal Nature Medicine, also identified a bacterium that, when present in the gut, prevents allergic responses to food.
"This study," says senior study author Cathryn R. Nagler, Ph.D., a professor in food allergy at the University of Chicago in Illinois, "allows us to define a causal relationship and shows that the microbiota itself can dictate whether or not you get an allergic response."
She adds that the results "strongly suggest" that treatments that work by altering gut bacteria could help to reduce the "food allergy disease burden."
Food allergy and prevalence
Allergic reactions happen when the immune system responds in an extreme way to foreign substances, or allergens, that usually cause no harm in most people.
Some common substances that produce allergic reactions include pollen and certain types of food.
Although most reactions are not severe, when they are, they can be life-threatening because of the enormous stress that they place on circulation and breathing.
Cow's milk, eggs, peanuts, soy, wheat, and tree nuts are some of the foods that most often provoke allergic responses in children.
The foods that are most likely to cause allergic responses in adults include fish, shellfish, peanuts, and tree nuts.
In childhood, most food allergies develop in the first 2 years of life.
The prevalence of food allergy in those aged 0–17 years has been rising slowly in the United States. During 1997–1999 it was 3.4 percent, and it rose to 5.1 percent during 2009–2011.
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