Personalised Nutrition Based On Your DNA – Part 1 – The Best Diet For Your Genes

Advancements in nutrition science have the potential to lead us into an era of completely personalised diets.

Nutritional genomics, the study of how food and genes interact, is a critical piece of this puzzle. One of the ultimate outcomes of this science is the ability to personalise and tailor health and nutrition advice to the individual.

Such diets will take into account how you process specific vitamins, minerals and nutrients, any food intolerances you may have, and how your body stores fat and builds muscle. The resulting advice and recommendations will make it easier to identify a sustainable healthy eating plan, make weight management achievable and be tailored to reduce disease risk.

The question being asked, is all this really possible?

This article series will explore the science and evidence behind nutritional genomics. Try to answer a few questions surrounding the legitimacy of DNA tests and compare some DNA tests available in Australia.

What Is Nutrigenomics

The key understanding individual nutrition needs lies within two specific areas of nutrition science.

One, which won’t be covered in this article is the gut microbiome; the study of the bacterial composition within your digestive system.

The other is nutritional genomics.

With nutrigenomics, scientists are trying to unravel the complex relationship between the food we eat and our genetic makeup.

Like height, hair colour and shoe size, our genetics can also determine how we process certain vitamins, how we metabolise fat, protein and carbohydrates and even if we prefer sweet over salty foods. All of this impacts our mental and physical responses to food and ultimately our food choices. And of course, what we end up eating can determine our body weight, health status and risk of disease.

Not only can our genes influence what we choose to eat, but what we choose to eat can influence our genes.

Diet and lifestyle can act as a catalyst to turn on, or off, certain genes. Somewhat like a light switch dimmer turning the lights up or down. This is called gene expression. A slightly confusing concept, but the emphasis here is the very real and important interaction between dietary choices and our genes.

In 2003 The Human Genome Project, the first mapping of the entire human genome, was completed. Since then, genetic science has been continually progressing. Hundreds of nutritional genomics research studies have been conducted to determine which genes are associated with nutrient metabolism and disease risk.

Nutritional genomics is however a relatively new stream of science. It’s incredibly complex, because your environment (diet and lifestyle) can affect gene expression (whether a gene is turned on or off) and vice versa. This makes pinpointing a cause (gene variation) and effect (health outcome) relationship quite difficult.
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How Does Nutrigenomics Work?

You may have a basic understanding of how genes determine your individual characteristics and how certain diseases and conditions can be inherited. However, to fully understand how nutrigenomics work some more detail will help.

Every cell in your body contains your DNA, this massive stand of DNA is broken down into smaller sections called genes. Your specific collection of genes is called your genome.

Over 99% of your genome is the same as the next person. The less than 1% difference determines how you respond differently to certain foods.

Each gene is essentially a set of instructions, or a code, to produce a specific protein. The proteins made are either structural for example, making up part of your liver. Or functional, making the various chemicals and hormones that regulate everything from blood pressure to feelings of hunger.

These codes are made using a combination of four nucleotide bases A, T, C and G.

This DNA code is replicated from both your mother and father, half from each, and passed on to you. However, when the DNA code is being replicated to create the little baby you, some mistakes are made.

Imagine If you were to write out a sequence of A, T, C, G millions and millions of times in a non-repetitive order, you are bound to make some mistakes. This is exactly what happens as your DNA is being replicated to make you, in fact it happens nearly 3 million times. These mistakes are referred to as mutations or gene variations (also referred to as polymorphisms, but technically a polymorphism is only a mutation that occurs frequently within the population)

The result is that some of your codes get messed up, so now they actually code for something else, or perhaps nothing at all. Keep in mind not all gene variations have an effect.

There are many ways gene variations can manifest, the type that most people are familiar with is referred to as a single gene mutation these result in a very specific disease, for example iron overload disorder (haemochromatosis) or cystic fibrosis.

Another is what we are looking at in nutritional genomics.

When only one single base (nucleotide) is changed, this is called a SNP pronounced snip, it stands for single nucleotide polymorphism. When a SNP occurs in a specific gene it can alter the way you metabolise food, store and process fats and increase your risk of certain diseases.

A SNP is more subtle, yet this subtle difference may have a significant impact on the way you process nutrients. For example it may only result in slightly more or less insulin being secreted than needed, however this small change could potential increase your risk of diabetes.

A SNP (mistake or mutation in a gene) can mean you produce too much of the hunger hormone ghrelin, or have a higher risk of developing a certain disease, such as diabetes. SNPs can also have no effect at all.

This is where things get tricky.

Even though a mutation in a gene can put you at higher risk of certain health outcomes, this doesn’t automatically mean this will be the case.

Why is this? It has to do with your environment and lifestyle.

For example, somebody who has a SNP in the FTO gene, otherwise known as the ‘fat gene’ probably has an increased appetite and an increased desire for high-fat, high-energy foods. However, if they exercise frequently and eat a balanced diet they will likely maintain a healthy body weight. Perhaps it requires more effort compared to those who do not possess this gene variation, but it is possible. The same can apply to other gene variations such as those that increase the risk of high cholesterol or type 2 diabetes.

Summary: Your genes can dictate certain physiological processes in your body, this can lead to an increased risk of certain health outcomes. However, in most cases it is entirely possible to overcome these risks with healthy lifestyle habits.

DNA Tests: Scam or Legitimate Science

For the small fee of roughly six thousand dollars you can have your entire genome sequenced.

This means you will be able to see every gene variation (mutation) you have. The problem is not all variations can to be interpreted into actionable advice. While most genes are known to be associated with certain health outcomes, some are less understood.(1, 2)

Other DNA testing methods are now available to the public. These test for mutations in specific genes. So instead of looking at every single gene in your body, they pinpoint useful genes and test for those. These are the SNPs we discussed earlier.

Unfortunately, some people and companies are making misleading claims and inappropriately using DNA tests. This has given rise to some scepticism regarding commercial DNA tests.

A few things to look out for when deciding on a DNA test:

• A Reputable company: Does the company use an accredited lab? Are they promoting other questionable advice or tests?
• Quality over quantity: The higher the number of genes tested doesn’t necessarily equate to a better test. Make sure each gene being tested has good evidence to support the interpretation of the SNP.
• Evidence for diet recommendations: Is there evidence to support the dietary recommendations they are making? Without this the results of your tests will not be very useful.
• Scientific advisory board: Does the company have both genetic and nutrition scientists to advise on diet recommendations?

Summary:

Yes, nutrigenomic DNA tests are legitimate. However, as with everything in the wellness sphere there is the possibility some companies are trying to capitalise by taking things too far. If you decide to get a DNA test make sure you go with a reputable company.

Nutrigenomics and Personalised Diets

Is it possible to create a designer diet based on genetics tests right now? Probably not.

It can however be a useful tool to help guide people towards choosing a sustainable way of eating for health and weight management. In its current state genetic testing can be seen as resource, rather than a definitive pathology test.(2)

When you consider other tools used in nutrition such as BMI (body mass index) and calculations to determine energy requirements, none are absolutes. Yet when they are used appropriately and with guidance, they are essential tools to individualising diets. Nutrigenomics has huge potential to be incorporated as one of these tools.

By recognising and understanding how your body metabolises certain nutrients, it will be easier to implement diet and lifestyle changes that you can stick to.

Knowing your genetic predisposition to certain behaviours, such as increased appetite or a preference for sweet food can help you make choices to control desires. Let’s go back to the person with a SNP at the FTO gene as an example again. This person, who has an increased appetite and preference for high fat food, might do better on a high protein diet to increase satiety (feelings of fullness) and by keeping trigger foods out of the home. These are all actionable behaviours that can be modified with appropriate advice.

Some studies have suggested that genetic testing can also increase motivation to adopt healthy lifestyle habits such as increasing fruit and vegetable intake and exercise. This appears to be more prominent in people who were found to have the risk variant of a specific gene. (3-5)

Summary:

Nutrigenomic testing has huge potential to be used as a tool to help create sustainable diets and lifestyles for individuals. However, it should be used with direction from a dietitian or qualified nutritionist. It is not yet at the point where it can dictate definitively what and what not to eat.

Available DNA Tests and Cost (For Australia)

There are multiple companies and health care providers offering nutritional genomic testing within Australia. Many of them outsource the testing to bigger companies.

Here are a few currently offering testing within Australia.

Easy DNA: NutriFit test

Cost: $399

Test and Report: Easy DNA claim to test for 110 genetic variations. It is uncertain which genes are tested as it is not stated on the website. Also, no clear information on their scientific advisory board.

Verdict: This company lacks transparency and no visible scientific advisory board. For the price, I think it would be wise to choose another company.

Nutrigenomix

Cost: $465 – $525 depending on where you purchase it and what kind of consultation you get with it.

Test and Report: They provide a panel of 45 genes. Some of which may be irrelevant if you are only interested in diet and weight management. A few things that stood out were an impressive scientific advisory board, including prominent Canadian dietitian Nanci Guest. As well as the fact that you can only order these tests through a qualified healthcare professional.

On the down side, they do not provide any readily available information on the website regarding which specific genes they test for. The sample report is fairly comprehensive, and they provide a specific recommendation for each of the 45 genes tested. However, no insight to what an overall diet would look like. You will definitely require a dietitian or qualified nutritionist to help you with the interpretation of results.

Verdict: A reputable company with a good scientific board and links to prominent university research projects. A thorough report of the genes tested. Down side can be quite costly, you may not need all of these genes tested.

23 and Me

One of the more well-known DNA testing companies is 23 and Me, they generally focus on ancestry testing however in the UK they also provide health and nutrition reports. They cite regulatory reasons for not supplying these reports in countries outside of the UK. However, you can still get the raw genetic data and then take it to a health care provider to interpret

MyDNA – The Top Pick

The top pick for current DNA tests available in Australia would have to be myDNA (disclosure affiliate link).

MyDNA tick all the boxes for a reputable and well-priced DNA test.

Cost: $99 Nutrition and Diet report

$119 Nutrition, Diet and Fitness report

Test and Report: myDNA are a Melbourne based company and lab co-founded by Professor Les Sheffield a well-regarded geneticist. They also employ an impressive scientific advisory board.

The Wellness and Nutrition test looks at 7 specific genes, all related to weight management and cardiovascular health. The website clearly states which genes are tested. Provided as part of the report (also in the health care provider information) are references to supporting evidence for both the function of the gene and the dietary recommendations. The report provides specific recommendations for each gene. In addition to this, they also include an overall recommendation for the type of dietary pattern would be best suited to you.

The 6 dietary patterns you may be recommended include:

• Higher protein
• Lower Fat – Omega 3 rich
• Higher protein and lower fats
• Higher protein and lower fats – Omega 3 rich
• Lower Fats
• Mediterranean

All of the macronutrient ratios, that is the amount of fat, carbohydrate and protein recommended in each diet adheres to the Australian Dietary Guidelines. They also provide sample meal plans, although fairly basic. If going solely on the information in the report it may leave some consumers slightly confused. Additionally, they give very specific recommendations on calorie intakes without attaining the appropriate background information from the client regarding height, weight and physical activity levels. The recommended calorie intake is only a very rough guide and will need to be calculated separately.

This test would be most beneficial if used in conjunction with a consultation from a qualified nutritionist or dietitian. myDNA do encourage consulting a dietitian and provide a list of dietitians who specialise in nutrigenomics.

Overall the cost and ease of use, coupled with their ability to provide supporting evidence makes myDNA the winner in terms of credibility and accessibility.

The Verdict

Nutritional genomics is such an exciting and promising area of research. Without a doubt, it will eventually change the way we recommend diet and lifestyle changes.

Right now, there are some practical and useful ways we can begin using DNA testing to implement change. Although, there is still a way to go until the full potential of this technology is realised.

If you want to explore your genetic make-up find a dietitian who specialises in nutrigenomics, check out one of the companies mentioned above or give the myDNA test a go.

If you want to delve deeper into the evidence behind these diet and gene interactions, read on in the second part of this nutrigenomic series.

Online retailer foodexercise.com offers $20 off voucher (voucher code: foodcomau20) on your next purchase to myDNA products.

Order online now by clicking the link below:

https://www.mydna.life/order-online/

References

1. Ferguson LR, De Caterina R, Görman U, Allayee H, Kohlmeier M, Prasad C, et al. Guide and position of the international society of nutrigenetics/nutrigenomics on personalised nutrition: part 1-fields of precision nutrition. Journal of Nutrigenetics and Nutrigenomics. 2016;9(1):12-27.
2. Biesecker LG. Opportunities and challenges for the integration of massively parallel genomic sequencing into clinical practice: lessons from the ClinSeq project. Genetics in Medicine. 2012;14(4):393.
3. Nielsen DE, El-Sohemy A. Disclosure of genetic information and change in dietary intake: a randomized controlled trial. PloS one. 2014;9(11):e112665.
4. Nielsen DE, Carere DA, Wang C, Roberts JS, Green RC. Diet and exercise changes following direct-to-consumer personal genomic testing. BMC Medical Genomics. 2017;10(1):24.
5. Nielsen DE, El-Sohemy A. Applying genomics to nutrition and lifestyle modification. Personalized Medicine. 2012;9(7):739-49.