Allergies or intolerances to common foods such as peanuts, gluten, or milk, can severely impact quality of life and may even be life-threatening in some cases. But how do allergies arise? Some claim that the increase in allergies over the past few decades is due to kids not being exposed to enough different foods and environments, but this is likely an oversimplification that ignores a role for genetics and an interplay between genetics and the environment.
Peanut allergies can result in severe or even fatal reactions to eating peanuts, and numerous studies have indicated that an individuals genetics may predispose them to peanut allergies . The SNP rs7192 is the most strongly associated genetic variant. Having a single T at this position increases the risk of peanut allergy by approximately 1.7 times, while having two T’s increases the risk by more than 3 times.
The studies identifying this relationship have been predominately in European populations - as a result, it is still not clear whether this genetic risk factor applies for all people and research into more diverse groups of people.
Gluten intolerance can range from mild to very severe, and the causes underpinning these differences are not fully understood. As of this writing, more then 160 different genetic variants have been associated with risk for Celiac Disease, a severe form of gluten intolerance. Many of these genetic variants confer a very small increased risk, but some are large. For example, individuals with the ‘T’ allele at rs2187668 have a much greater chance (approximately 7 times higher) of developing Celiac Disease than individuals carrying the C allele .
The role that genetics plays in gluten intolerance in the general population is still unclear, and a subject of ongoing study.
More than 68% of the world’s population is lactose intolerant, and drinking milk may cause a stomach ache or other discomfort. See our full report on lactose intolerance for a more detailed breakdown on why this is...
How can this information be used?
There is still much to learn about the role of genetics in common food allergies, as well as how an individuals environment may interact with their genetics to increase or decrease risk. In the future, genetic predisposition to food allergies or intolerances may be useful to identify children at a high risk of developing allergies, and design therapies or other approaches to prevent a life-threatening event and allow earlier treatment. Furthermore, while allergies are often identified in a standardised way using a skin-prick test, the cause for the allergy may be different amongst individuals, and a better understanding of how each individual differs genetically may pave the way for more personalised therapies.