You may have heard about DNA testing but have you heard about DNA testing regarding your diet?
I recently wrote an article for Dietitians on this topic (in the NHD magazine, I actually wrote 2 articles! the other was about cancer immunotherapy) and had a lot of interest on Instagram for some more info. This wasn’t a surprise, as there is a growing market for home genetic testing so what are the facts…
So, let’s start at the top, what actually is nutrigenomics?
Nutrigenomics is also called nutritional genomics; which is the study of how your genes and nutrition/diet can interact. To explain a bit further we need to understand a few science terms:
Geeky science bit..
DNA: (Deoxyribonucleic acid) is the instructions or generic information that is inside every cell in our body. These instructions are used to make each and every aspect of us. A common image you see of DNA is a twisted ladder or the ‘double helix’.
Nucleotide: These are the building blocks of DNA. Between the double helix or ladder of DNA there are 4 different chemicals also called ‘bases’ these are called adenine (A), guanine (G), cytosine (C) and thymine (T). These groups of nucleotides make up our genes and determine our specific unique characteristics e.g. our hair or eye colour.
Chromosome: DNA is stored in chromosomes that are inside the cell of the body. We inherit one set of 23 chromosomes from our mother and one set of 23 chromosomes from our father. So, we have two sets of 23 chromosomes or 23 pairs.
Gene Expression: This is the process where the instructions in our DNA is converted into a protein. These proteins will then determine how that cell will work.
Right so after the geeky science part how does that relate to nutrigenomics?
The foods you eat or nutrients (vitamins, fats, carbohydrates, proteins etc) and how they can affect your gene expression (i.e. how your different cells work).
How can looking at your dietary DNA help you?
Your own unique genetic differences in your DNA can affect the way the body responds to food and nutrition which is the core of nutrigenomics.
We all have slight differences in our genetic makeup which is due to single nucleotide polymorphisms (SNPs). These SNPs are changes in one nucleotide (the building blocks of DNA) bases e.g. you may have a ‘A’ base where someone else has a ‘G’ base. This tiny variation may influence the effect nutrients has on the body and how we use them. These differences may explain why some people may respond to differently to dietary changes like how we respond to exercise, maintain our weight or our risk of diseases.
What can nutrigenomics help you with?
Testing your DNA may help you understand your genetic responses to:
Lactose intolerance
Developing high blood pressure or cholesterol
Your tolerance to caffeine
How your body responds to carbohydrate, fat and protein
How your body uses vitamin and minerals
How does nutrigenomics testing work?
Testing involves taking a swap of the inside of your mouth which is then sent off to a lab for testing. This information is then used to generate a report about any variations in your genes and your response to the above (e.g. lactose intolerance etc).
Word of warning: There are lots of DNA tests available online and they are very expensive! Unfortunately, it is very difficult to be 100% sure of the quality of these tests as there is very limited regulation in this area. So, you must be really careful before taking this route.
What are the disadvantages to nutrigenomics?
It is too simple to think that a single gene or a few generic changes could explain your reaction to one single thing like how you respond to fat in your diet. Humans are complex, we are also affected by our environment and everything else in our lives. If you have a variant for say high pressure, this doesn’t necessarily mean you will develop high blood pressure. This is why it is really key that you have dietitian support to explain the results and put these into practice depending on your own circumstances.
This area is area still relevantly new and doesn’t replace detailed dietitian assessment and support. During all my programmes you receive detailed nutritional assessment that includes dietary analysis based on what you are actually eating so we can develop a plan together (you learn more here) that has actionable steps you can really achieve.
Finally, I think it is important to remember that genetic predisposition is not destiny, and our environment and the choices we make can influence our risks of disease too.
Useful reading:
https://geneticalliance.org.uk/information/learn-about-genetics/dna-genes-chromosomes-and-mutations/
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