What is nutrigenetics and why is it important?
Nutrigenetics is the rapidly growing field of science that seeks to understand how we metabolise and process different nutrients, based on variations found within our DNA (these are called genetic polymorphisms). The ultimate goal of nutrigenetics is to enable an individual to achieve optimal levels of physical and mental health, by using the insights provided by their genetic polymorphisms to personalise nutrient intake.
It has been well-established that there is great diversity and variability in the human genome (the sum total of all DNA in the body) which affects how we metabolise nutrients. However dietary reference values or recommended daily allowance (RDA) guidelines that are established for the general population to prevent deficiencies in micronutrients do not consider our genetic differences. They are therefore not optimized for genetic subgroups that may differ markedly in nutrient requirements.
Nutrigenetics aims to match nutrient intake with the current generic makeup, so that metabolism and functions of the cells can perform optimally. Scientific studies have demonstrated that we can achieve better health outcomes if nutritional requirements are tailored for each individual taking into consideration their genetic differences and characteristics.
Biological effects of nutrients and bioactive food compounds (nonessential biomolecules that are present in foods and exhibit the capacity to modulate one or more metabolic processes) depend on many physiological processes which include absorption, transport, biotransformation, uptake, storage and excretion and cellular mechanisms such as binding to a receptor on the cell to elicit an action. Every single one of these processes is dependent and regulated by several genes. If there is a single variation present in a gene (known as single nucleotide polymorphism or SNP for short), it can change their function and ultimately our physiological response to a nutrient.
Some common polymorphisms can occur in 40 to 50% of the population. The polymorphism can either have no affect or have significant consequences on the structure or function of the gene product/function.
Some common polymorphisms can occur in 40 to 50% of the population and can have significant consequences on the structure or function of the gene and it’s product or function, such as producing proteins required for effective digestion and metabolism.
For example, there are two types of vitamin A: carotenes, which come from fruits and vegetables and retinoids that come from animal sources. Beta -carotene can be converted into biologically active retinoids by BCMO1 gene. Genetic variation in this gene can reduce a person’s ability to convert beta-carotene into retinoid by as much as 60%. Retinoids are very important for the health of our skin, immune system, thyroid gland, connective tissues and eye health/healthy vision. If a person has T variant of the gene, they convert beta carotene 69% less efficiently than people without this variant, and consequently it is best to get the preformed Vitamin A (retinoid form) from animal sources and not fruit and vegetables. This would be a serious consideration for vegan diets.
- Michael Fenech et al., (2011) Nutrigenetics and Nutrigenomics: Viewpoints on the Current Status and Applications in Nutrition Research and Practice. J Nutrigenet Nutrigenomics. 2011 Jul; 4(2): 69–89.
- Hendrickson SJ1, Hazra A, Chen C, Eliassen AH, Kraft P, Rosner BA, Willett WC. β-Carotene 15,15'-monooxygenase 1 single nucleotide polymorphisms in relation to plasma carotenoid and retinol concentrations in women of European descent.
Am J Clin Nutr. 2012 Dec;96(6):1379-89. doi: 10.3945/ajcn.112.034934. Epub 2012 Nov 7.