How nutrigenomics impacts equine health - A case study of vitamin E.

Nutrigenomics defines the interaction between the nutrients in our food and the genes in our body. Examples from human medicine of diseases and associated genes include lactose intolerance (genetic variants in LCT lactase), hypercholesteremia (low density lipoprotein receptor, LDLR) and caffeine sensitivity (adenosine A2A receptor, ADORA2A). In horses, examples include Hyperkalemic Periodic Paralysis (HYPP), where clinical signs of disease are managed through maintaining a diet low in potassium and Polysaccharide Storage Myopathy Type 1 (PSSM1), where low starch and high fat diets are recommended to prevent episodes of rhabdomyolysis. Personalized nutrition tailors nutrition advice for an individual based on their genetic makeup. In humans and in horses, there is a wide range of individual response to vitamin E supplementation. Some horses obtain very high serum vitamin E concentrations with minimal intake, whereas others require high doses of supplementation to remain in the normal range. In humans, the efficiency of vitamin E absorption is widely variable and is affected by dietary factors, such as food matrix, and genetic polymorphisms in genes related to vitamin E intake, distribution and metabolism. In horses, the efficiency of vitamin E absorption is also related to diet; however, genetic variation has not been yet evaluated. With over 200 genetic variants identified in and surrounding vitamin E candidate genes in horses, future genetic profiling of vitamin E response in horses should be performed.