Nutrigenetics & Nutrigenomics
In 460 BCE, long before the discovery of DNA, the Greek physician Hippocrates (often referred to as “The father of medicine”) believed that health was affected by diet and lifestyle, and was known to use diet as part of his treatment plans (Kalish, n.d.). Fast forward to the 21st century, and the fields of nutrigenetics and nutrigenomics now study how our nutrition affects the way in which our individual genes are expressed, and how individualised nutrition and nutritional supplementation can be proactively used to support health and wellbeing by upregulating or downregulating the expression of certain genes.
Understanding our DNA
Nutrigenetics and Nutrigenomics are founded on the science of DNA mapping and incorporate the concepts of bio-individuality and epigenetics.
All species on earth are made up of deoxyribonucleic acid (DNA), which provides the recipe for how proteins, cells and tissues are formed (Culp & Hanaway, 2013). In 1953 James Watson and Francis Crick at Cambridge University were able to describe the structure of DNA and, towards the end of the 20th century, The Human Genome Project was launched. In 2004 the completed human genome was published, showing that within each human cell there is a cell nucleus containing 23 pairs of chromosomes, which are made up of DNA strands. The DNA strands are divided into sections, referred to as genes, and the genes themselves are made up of varying sequences of five nucleotide bases (thymine, uracil, cytosine, adenine and guanine). In humans, there are around 3 billion nucleotides in total. The order of these nucleotide bases on the nucleic acid strands determines the function of the gene (Culp & Hanaway, 2013) (International Human Genome Sequencing Consortium, 2004).
Bio-individuality & Epigenetics
Bio-individuality is a term coined by Joshua Rosenthal, founder of the Institute for Integrative Nutrition in the United States. In essence, it means that everyone has completely unique dietary and lifestyle needs in order to maintain health and wellbeing (Rosenthal, 2015). The concept of bio-individuality can be explained, in part, by our genetic differences. The sequence of nucleotides, that make up our genes, is not the same from person to person. These variations are called polymorphisms with the most common type of polymorphism referred to as a single-nucleotide polymorphism (SNP); where only a single nucleotide in a section of DNA has been changed. Polymorphisms are responsible for our uniqueness, on biological and biochemical levels. They allow us to evolve as a species and, in some cases, also make us more susceptible to certain diseases (Culp & Hanaway, 2013).
The good news is that our gene expression is not set in stone. Health and wellbeing are related to an interaction between both genetic and environmental factors. Regardless of what genes we were born with, it is readily accepted that gene expression is not fixed and is significantly affected by our environment, our lifestyle, what we eat, and the supplements we take (Culp & Hanaway, 2013) (Mateljan, 2015). Whether or not we develop certain diseases is also very strongly affected by the interaction between genes and factors such as diet, nutritional supplementation, exercise, behaviour, belief changes, and a reduction in toxin and microbe exposures (Culp & Hanaway, 2013). For example, in the 1930s Clive McCay discovered that simulating famine conditions (calorie restriction) resulted in increased life expectancy in rats. With a new understanding of genetics, we now know that calorie restriction activates sirtuin genes, causing increased mitochondrial production in skeletal muscle and liver cells, leading to a number of anti-ageing effects (Culp & Hanaway, 2013).
Nutrigenetics and Nutrigenomics are able to put the concepts of bio-individuality and epigenetics into practice through the use of customised nutritional recommendations based on individual genomic profiling.
- Nutrigenetics is the science of personalised nutrition; using specific nutrients to influence specific polymorphisms (Culp & Hanaway, 2013).
- Nutrigenomics is the science of how specific nutrients influence the whole genome (Culp & Hanaway, 2013).
Genomic profiling and SNP identification is now affordable and readily available to the general public, through companies such as 23andMe, AncestryDNA and, more locally, Fitgenes. Nevertheless, the science for interpreting this genetic information is still in its infancy, and further research is required to establish the efficacy of specific treatment regimes for specific genomic profiles. Genomic profiling cannot yet be used as a stand-alone assessment. Instead it should be used holistically as part of a broader assessment process, with the clinician measuring physiological functions, before, during and after a therapeutic intervention, to determine if a particular nutritional programme has been of benefit to the client (Culp & Hanaway, 2013).
In 2018, Dr Ben Lynch, a thought leader in the fields of nutrigenetics and nutrigenomics, published his new book “Dirty Genes”. In it he provides details of seven key SNPs (MTHFR, COMPT, DAO, MAOA, GST/GPX, NOS3 and PEMT) which may have a significant impact on health and wellbeing (Lynch, 2018). On his website, Dr Lynch makes use of a programme called StrateGene to analyse genetic data from 23andMe or AncestryDNA, in order to identify key SNPs and provide both general and individualised dietary and nutritional advice to help regulate the activity of these specific SNPs. This advice is also contained in Dr Lynch’s book. For example, the MTHFR SNP is responsible for methylation and can be supported through specific targeted dietary and supplement recommendations including Riboflavin (B2), Methylfolate (B9), Methylcobalamin (B12), protein, magnesium, leafy greens and beans (Lynch, 2018).
The Fitgenes Health and Wellbeing Genetic Profile Report, available through certified health practitioners in New Zealand (including myself), provides similar personalised supplement, dietary and lifestyle advice, based on SNP data.
There are hundreds of dietary theories and books about diet and supplementation, all claiming to have “the answer”. It can be very confusing for individuals to identify which diet or lifestyle strategy is going to work best for them at any given time. The fields of nutrigenetics and nutrigenomics, although still in their infancy, provide another important tool for beginning to understand our unique dietary needs and to provide personalised nutritional therapy to both prevent and support chronic health conditions.
The phrase “You are what you eat” takes on a whole new meaning when considered through the lenses of nutrigenetics and nutrigenomics (Mateljan, 2015).
- Culp, T. M., & Hanaway, P. (2013). Genomics, nutrigenomics, nutrigenetics, and the path of personalized medicine. In J. E. Pizzorno & M. T. Murray (Eds.), Textbook of Natural Medicine (Fourth edi, pp. 140–149). St. Louis, Missouri. https://doi.org/10.1016/b978-1-4377-2333-5.00016-x
- International Human Genome Sequencing Consortium. (2004). Finishing the euchromatic sequence of the human genome. Nature, International Journal of Science, 431, 931–945. Retrieved from https://www.nature.com/articles/nature03001
- Kalish, N. (n.d.). Hippocrates’ diet and health rules everyone should follow. Retrieved from https://www.rd.com/health/wellness/hippocrates-diet/
- Lynch, B. (2018). Dirty genes: a breakthrough program to treat the root cause of illness and optimize your health (First Edit). New York, NY: HarperOne.
- Mateljan, G. (2015). The world’s healthiest foods, optimize you health with health-promoting superfoods and nutrient-rich cooking (Second Edi). Seattle, Washington: George Mateljan Foundation.
- R, D. (n.d.). What are genes made of? Retrieved from https://www.melixgx.com/blogs/news/what-are-genes-made-of
- Rosenthal, J. (2015). Joshua Rosenthal’s bio-individuality is scientifically proven. Retrieved from https://www.integrativenutrition.com/blog/2015/07/joshua-rosenthal-s-bio-individuality-is-scientifically-proven