Nutrigenomics and DNA Testing

Now that you’re bringing a new set of DNA into the world you’re probably thinking more about what you’re putting into your body. You should be as your diet can have a major impact on your baby’s health. And perhaps we don’t realise the extent of the impact – it can go as far as influencing their gene expression.

We can now have our genes tested to find out what nutritional plan will best suit our DNA. It may sound more like sci-fi than actual science but it’s absolutely true. And no, it’s not like the blood type diet!

Recent advances have now made genetic testing available to the public. It helps us understand how some people on a high fat diet have no problem with their cholesterol, in contrast with others going through the roof.

It’s nutrigenetics. Scientifically-researched genetic testing, showing us why individuals respond differently to the same nutrients.

“Let food be thy medicine” has never been more undeniable. Our bodies extract certain nutrients from food these are functional in silencing or activating genes. This process is able to impact your gene expression through nutrition this is known as nutrigenomics.  Although you can never alter your genes, you can have an impact on how they’re expressed, which ultimately has a beneficial affect on processes in the body. Simply put, what you eat directly influences the genetic message your body receives.

There have been numerous studies that show how macronutrients, micronutrients, and natural bioactive components (eg phytochemicals such as flavonoids, carotenoids) regulate gene expression. Your genes are responsible for every cellular process within the body, which means that gene expression influences our cellular defense processes. These are methylation (DNA repair process), detoxification, energy production, redox status (of which oxidation is a part) and inflammation.

During pregnancy, focus is given to familiar nutrients like folic acid and B vitamins, which play a vital role in the DNA repair process (methylation). It’s been found that if your diet is high in these nutrients, it can positively change gene expression during your child’s early development. Your diet during pregnancy and your baby’s diet as an infant can affect how their genes are expressed and this impact can continue into their adulthood.  It’s been shown in animal studies that a diet low in methyl rich foods (eg dark green leafy vegetables) before or just after birth can negatively impact DNA repair processes for life.

This means that adults are affected too – but luckily for us it’s something we have complete control over and alter through nutrition and lifestyle changes.

This is an interesting experiment done on mice showing how mom’s diet can play such an important role in affecting the gene expression of their offspring. It’s also a great example of nutrigenomics – how nutrition can influence our gene expression. “All mammals have a gene called agouti. When a mouse’s agouti gene is completely unmethylated (meaning that they would have eaten no food that contain this methyl group), its coat is yellow and it is obese and prone to diabetes and cancer. When the agouti gene is methylated (as it is in normal mice – they would have a diet rich in methyl groups), the coat colour is brown and the mouse has a low disease risk. Fat yellow mice and skinny brown mice are genetically identical. The fat yellow mice are different because they have an epigenetic “mutation.” When researchers fed pregnant yellow mice a methyl-rich diet, most of her pups were brown and stayed healthy for life. These results show that the environment in the womb influences adult health. In other words, our health is not only determined by what we eat, but also what our parents ate.”

So let’s take a step back – what are they actually testing? Your DNA is made up of a double strand helix joined by complimentary base pairs. You receive 50% of your genes from each parent and when your DNA is replicated, variants occur. This means that there is a different single base pair than there was originally. These are called Single Nucleotide Polymorphisms (SNPs) or also known as gene variants.

So how do I get this DNA test? A quick cheek swab sample is sent to a genetic laboratory where your genes are analysed. These genes are low penetrance genes, which means you can have an effect on their outcome. For example, some of your genetic results might indicate that you’re at higher risk for certain cancers. It doesn’t mean you’re going to get cancer, but rather that you’re at higher risk.

Once you receive the report you’ll have some valuable knowledge about how you can improve your health and ultimately improve the health of your baby. Make sure that whoever is doing the DNA test and interpretation of the results for you is reputable.  This will ensure you get a valuable individualised treatment plan.

The key is to implement this intelligent science – as it gives us the advantage of personalising dietary interventions and lifestyle. Nutrigenomics is an exciting and dynamic new tool that can be used to prevent disease and optimise your health!


Rochez is a registered dietitian and has a holistic approach to helping individuals on the journey to health. She has a passion for approaching every person that comes to see her as unique.  Along with Sarah Gouws, Rochez is the founder of MunchWize in Cape Town, focusing on Nutrigenomics and Mindful Eating Practices.  These are amongst the tools that assist her in helping individuals to achieve optimal health and behaviour change. “I value keeping a balance in my life. When helping others to do the same it’s really rewarding. I love healthy food and coming up with great new recipes. I enjoy being outdoors and keeping a routine with exercise really works. All this together with having great friends and having fun keeps me happy.”

BSc Dietetics Hons

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