The main determinants of health and disease onset in humans are food intake, genetics and the environment. Technological advances into the human genome and the understanding of nutrigenomics means clinicians now have the ability to account for each of these factors in their case-taking process and provide personalised nutritional protocols for all clients.
Nutrigenomics is the term used for establishing how the nutrients in our food affect gene activity, either through the expression of genes or changes in their activity. It focuses on the effect of nutrients on the genome, proteome and metabolome.
Nutrigenomics is the influence of genetic variability between individuals accounting for the variations in health status and disease risk despite similarities in dietary intake.
This new frontier in science emerged after the Human Genome Project (HGP) mapped the full sequence of the human genome in 2003. The project that spanned over 20 years provided the possibility for personalised nutrition programmes, utilising specific bioactive compounds based upon an individual’s genetic profile.
The bioactive compounds found in foods and supplements can affect genes in many ways, including binding to transcription factors, influencing molecular signalling pathways and limiting or increasing enzymatic processes.
Vitamin A, D and fatty acids are examples of nutrients that are able to induce gene transcription by directly activating transcription factors. Resveratrol and soy genistein may indirectly influence the factor kappa B signalling pathway.
Single nucleotide polymorphisms (SNPs) are the most common variations in DNA sequences or chromosomes. They are natural variations in genes, occur in the general population and provide the individual differences in humans and potential influence on disease risk. Genetic profiles document an individual’s SNPs.
A well-known and nutritionally relevant SNP that affects folate and homocysteine status is the C677T polymorphism. This SNP affects methylation processes, reducing the activity of the 5,10-MTHFR enzyme required for folate and homocysteine metabolism. The presence of this SNP highlights a greater need for folate in that individual.
The use of nutrigenomics is already present in some clinical practices with the availability of genetic testing for practitioners beyond the medical setting increasing rapidly. However, the Academy of Nutrition and Dietetics recommends an evidence-based approach to validating personalised recommendations, due to the complexity of understanding, interpreting and communicating genomic profile results. Additionally, these results should be aligned with the individual’s family history, presence of disease risk and environmental factors, and their current symptoms and disease status.
- Sales NM, Pelegrini PB, Goersch MC. Nutrigenomics: definitions and advances of this new science. J Nutr Metab 2014. doi 10.1155/2014/202759 [Full Text]
- Camp KM, Trujillo E. Position of the Academy of Nutrition and Dietetics: nutritional genomics. J Acad Nutr Diet 2014;114(2):299-312. [Abstract]