Personalised nutrition is relevant to many areas – nutrition, genetics, health care and public health. The consumer has a major impact on the importance and future of personalised nutrition. At present personalised nutrition is very unregulated. Personalised nutrition needs to be based on scientific evidence. This evidence needs to be communicated clearly to the consumer so that the consumer can make an informed choice.

The aim of personalised nutrition is to maintain and or improve health of individuals by using genetic, clinical and dietary information to provide healthy eating advice and implement the necessary dietary changes. Personalised nutrition is not new. It has been used in the treatment of rare genetic disorders i.e. phenylketonuria and also more common disorders i.e. lactose intolerance. Personalised nutrition is based on the concept that individual nutrition advice will be more effective than generic advice. Personalised nutrition can be based on 1) evidence of different responses to foods and nutrients due to genotypic/phenotypic characteristics. 2) examination of current preferences, behaviour and delivering interventions which enable each individual to make the required changes to their eating patterns. An individual’s genotype is the set of genes that they have. Their phenotype are their observable characteristics which are influenced by their phenotype and their environment i.e. height, weight, plasma cholesterol, blood pressure, behaviour.

Personalised nutrition involves the use of both nutrigenomics and nutrigenetics. Nutrigenomics refers to applying principles of genomics in nutrition research. It enables the formation of associations between specific nutrients and genetic factors i.e. how foods/food ingredients influence expression of genes. Diets that are unbalanced can change nutrient-gene interactions, increasing the risk of chronic diseases. Nutrient imbalances are considered as factors in cancer, diabetes, cardiovascular disease, aging, immune disorders, stroke, neurological disorders. Genetic makeup variations are considered as factors in digestive diseases, gastrointestinal cancers, osteoporosis, inflammatory conditions.

Nutrigenetics examines the effect of individual differences at the genetic level that influence the individual’s response to diet. The individual differences can be at the single nucleotide polymorphism (SNP) level rather than at gene level. SNPs change individuals dietary metabolic responses. SNPs can have an effect on the production of risks for the onset of disease. A good example is the relationship between folate and MTHFR. Folate is required for the efficient functioning of MTHFR. MTHFR has a role in supplying 5-MTHF. This is necessary for the remethylation of homocysteine for methionine production. The 677C→T polymorphism in MTHFR results in a significant decreased activity. Individuals with TT unstable copies who also have low folic acid intake, will have increased plasma homocysteine. This increases their risk of cardiovascular disease. When these individuals increase their folic acid intake, they can restore their normal levels of methionine (through metabolization of homocysteine).

Consumers do have concerns about personalised nutrition. Consumers have questioned the evidence that nutrigenomics (and nutrigenetics) can make a difference to an individual’s health. Consumers are especially concerned about what happens to the genetic information that is given to a company to examine and test. Consumers need to know who has access to this information. They also need to know if insurers or employers could access this information. Consumers have concerns about the security of personal data in public databases. Consumers have also expressed concern regarding the regulation of nutrigenomics (and nutrigenetics).

It must be stressed that the majority of the evidence supporting personalised nutrition has only involved observational studies. There is a need for more randomised controlled trials where clinical endpoints can be measured. At present, there is a limited ability to implement current research. There is a need for a framework and clear guidelines for the assessment of diet-gene interactions. There is also a need for more educational resources for personalised nutrition. Evidence based personalised nutrition research should be used for the provision of dietary advice to decrease disease risk and promote long-term health. Ultimately, it is consumers who will decide the relevance and importance of personalised nutrition, for the future.

References:

Garg, R., Sharma, N. & Jain, S. 2014, “Nutrigenomics and nutrigenetics: Concepts and applications in nutrition research and practice”, Acta Medica International, vol. 1, no. 2, pp. 124.

Grimaldi, K.A., van Ommen, B., Ordovas, J.M., Parnell, L.D., Mathers, J.C., Bendik, I., Brennan, L., Celis-Morales, C., Cirillo, E., Daniel, H., de Kok, B., El-Sohemy, A., Fairweather-Tait, S.J., Fallaize, R., Fenech, M., Ferguson, L.R., Gibney, E.R., Gibney, M., Gjelstad, I.M.F., Kaput, J., Karlsen, A.S., Kolossa, S., Lovegrove, J., Macready, A.L., Marsaux, C.F.M., Alfredo Martinez, J., Milagro, F., Navas-Carretero, S., Roche, H.M., Saris, W.H.M., Traczyk, I., van Kranen, H., Verschuren, L., Virgili, F., Weber, P. & Bouwman, J. 2017, “Proposed guidelines to evaluate scientific validity and evidence for genotype-based dietary advice”, Genes & nutrition, vol. 12, no. 1, pp. 35.

Institute of Medicine, 2007. Nutrigenomics and Beyond: Informing the Future: Workshop Summary. Washington, DC, The National Academies Press.

Ordovas, J.M., Ferguson, L.R., Tai, E.S. & Mathers, J.C. 2018, “Personalised nutrition and health”, BMJ (Clinical research ed.), vol. 361, pp. bmj.k2173.