Food Allergies: Nature or Nurture?

Reading time: 3 – 4 minutes

The emerging field of epigenetics has added a new dimension to the “nature versus nurture” debate, by which researchers have historically attempted to determine whether a characteristic was influenced by genes or environment. Increasingly, it appears that environmental influences can affect gene expression, meaning that “nature” and “nurture” are inextricable from one another to an even greater extent than previously understood.

DNA structureImage credit: DNA structure via Shutterstock

A recent article published in Clinical and Experimental Allergy notes that epigenetic factors can help explain the significant increase in food allergy prevalence in developed nations [1]. The mechanism by which the rate of food allergy has increased so rapidly has been puzzling to researchers; it’s happened too quickly to be accounted for purely in genetic terms. However, food allergies appear to have a strong genetic component, since they run in families and co-occur with a number of other related disorders, including eczema and asthma. In fact, it appears that there are two influences that increase the likelihood of an individual having a food allergy: genetic predisposition (family members with allergies), and a “modern lifestyle” [2].

How does the environment influence genetics? Simply put, an individual’s characteristics are encoded in genetic material — DNA — but not everything encoded in DNA is actually expressed.

Gene Expression: production of the protein sequence that a gene codes for; a gene must be “expressed” for it to have any effect upon an individual’s appearance, health or behavior.

Some genes remain “silent,” and researchers are increasingly realizing that environmental factors may cause the expression of genes that, in the absence of that environmental trigger, would have remained inactive. In a very real sense, the environment can turn genes on and off, changing physical characteristics, influencing health, and affecting behavior. Furthermore, it seems that the prenatal period — the time during which a fetus is developing in utero — is particularly important with regard to epigenetic influences [3].

While the scientific understanding of food allergies (and of epigenetics in general) is still in its infancy, it appears that researchers will increasingly focus on the effects of environmental triggers on gene sequences that predispose individuals to develop allergies. In so doing, it might someday be possible for those individuals from families with high risk of allergies to avoid the environmental triggers that turn allergy-related genes on in the first place.


  1. Tan et al. The role of genetics and environment in the rise of childhood food allergy. Clin Exp Allergy. 2012 Jan;42(1):20-9. doi: 10.1111/j.1365-2222.2011.03823.x. Epub 2011 Jul 19.
    View abstract
  2. Jackson, M. Allergy: the making of a modern plague. Clin Exp Allergy. 2001 Nov;31(11):1665-71.
    View abstract
  3. Bird, A. Perceptions of epigenetics. Nature. 2007 May 24;447(7143):396-8.
    View abstract
About the Author

Kirstin Hendrickson, Ph.D., is a science journalist and faculty in the Department of Chemistry and Biochemistry at Arizona State University. She has a PhD in Chemistry, and studied mechanisms of damage to DNA during her graduate career. Kirstin also holds degrees in Zoology and Psychology. Currently, both in her teaching and in her writing, she’s interested in methods of communicating about science, and in the reciprocal relationship between science and society. She has written a textbook called Chemistry In The World, which focuses on the ways in which chemistry affects everyday life, and the ways in which humans affect each other and the environment through chemistry.