Food intolerances, sensitivities, and allergies are increasingly common issues that affect how our bodies process and respond to certain foods. While these terms are often used interchangeably, they refer to different biological responses. A food intolerance is the body’s inability to digest a particular food properly, often due to enzyme deficiencies, such as lactose intolerance. Food allergies, on the other hand, involve the immune system, where the body mistakenly identifies certain food proteins as harmful, leading to potentially severe reactions like anaphylaxis. Food sensitivity lies between these two, involving reactions that may not trigger the immune system but still cause discomfort or inflammation.

What many people may not know is that genetics play a crucial role in influencing how our bodies react to food. Your genetic makeup can determine how well you digest certain foods, whether you're prone to developing sensitivities, and even how likely you are to experience food allergies. This blog explores the genetic basis of these dietary sensitivities, helping you understand the connection between your genes and your food responses.

How genes influence food intolerances, sensitivities, and allergies

Our genes carry instructions for various biological processes, including how our body processes food. Specific genes can influence enzyme production, immune responses, and even how our digestive system functions. In cases of food intolerance, a genetic variation can result in the absence or malfunction of an enzyme necessary for breaking down certain nutrients, such as lactase deficiency in lactose intolerance. With food allergies, genetic variants can affect immune system genes, making certain individuals more likely to have an overactive immune response to harmless food proteins.

Food sensitivity is more complex, as it may involve multiple systems, including the digestive and immune systems, as well as inflammation markers. While the genetic links to sensitivities are not as well studied as intolerances and allergies, several genes have been implicated in influencing individual food sensitivities.

Key genes involved in different intolerances and allergies

Lactose intolerance

  • Gene: LCT (Lactase).

  • Variants in the LCT gene affect the production of lactase, the enzyme responsible for digesting lactose in dairy products. Individuals with certain variants are unable to produce enough lactase, leading to lactose intolerance.

Gluten intolerance (Celiac Disease)

  • Gene: HLA-DQ2/DQ8 (Human Leukocyte Antigen Complex).

  • These genetic markers are strongly associated with celiac disease, a serious autoimmune condition triggered by gluten in wheat, barley, and rye. Individuals carrying these genes are at a significantly higher risk of developing celiac disease.

Fructose intolerance

  • Gene: ALDOB (Aldolase B).

  • Variants in the ALDOB gene can cause hereditary fructose intolerance, a condition where the body cannot properly metabolize fructose, leading to digestive issues and liver damage.

Peanut allergy

  • Gene: FLG (Filaggrin).

  • Mutations in the FLG gene, which is important for skin barrier function, have been associated with a higher risk of developing peanut allergies. Impaired skin barriers may increase exposure to allergens, sensitizing the immune system.

Histamine intolerance

  • Gene: DAO (Diamine Oxidase).

  • The DAO gene encodes an enzyme responsible for breaking down histamine, a compound found in many foods. Variants in this gene can lead to a reduced ability to metabolize histamine, causing symptoms of histamine intolerance.

Galactose intolerance (Galactosemia)

  • Gene: GALT (Galactose-1-Phosphate Uridylyltransferase).

  • Mutations in the GALT gene impair the body's ability to metabolize galactose, leading to galactosemia, a condition that can cause serious health issues if untreated.

Conclusion

Understanding the genetic influences on food intolerances, sensitivities, and allergies provides valuable insight into managing your diet and health. Genetic testing can identify specific variants that contribute to these conditions, empowering you to make informed decisions about what to eat and what to avoid. By knowing your genetic predispositions, you can tailor your nutrition to prevent adverse reactions and improve your overall well-being.

References

Ingram, C. J., et al. (2009). Lactose digestion and the evolutionary genetics of lactase persistence. Human Genetics, 124(6), 579-591.
Sollid, L. M., & Lie, B. A. (2005). Celiac disease genetics: current concepts and practical applications. Clinical Gastroenterology and Hepatology, 3(9), 843-851.
Geller, F., et al. (2013). Genomics and peanut allergy: current understanding and future directions. The Journal of Allergy and Clinical Immunology, 132(2), 298-304.
Swain, A. R., et al. (1985). Histamine in foods and its role in histamine intolerance. International Journal of Food Science and Technology, 20(4), 507-519.