What is the best diet for me? Nutritional genetics may be the missing part of the puzzle

This is a guest post by Helen Phadnis, The Brighton Dietitian

What is the best diet to follow?

That is the million-dollar question that science has floundered with but is the silver bullet many of us want. 

We were recommended a low-fat diet in the 80’s and 90’s, low carbs and high protein in the noughties, and now it’s veganism that tops the list.

What is the best diet for me? Nutritional genetics may be the missing part of the puzzle by Sarah Almond Bushell - the Children’s Nutritionist
What is the best diet for me? Nutritional genetics may be the missing part of the puzzle by Sarah Almond Bushell - the Children’s Nutritionist

As a Freelance Dietitian, clients come to me time and time again who have studied every book, followed them to the letter, and still not achieved the results they were striving for. 

In many cases, their health and well-being are worse off, after cycles of yo-yo dieting and restrictive eating. They’ve become confused by the conflicting advice and frustrated by the fact that the myriad of diets have worked for other people, just not them. 

“Just tell me what to eat!” Does this sound familiar?

The fact is, there is no one size fits all diet. We are all unique, and once we understand this, we can then harness our individuality to create a tailor-made solution. 

One of the most powerful tools in my opinion, and the missing piece of the diet puzzle, is called nutritional genomics, the future of nutritional therapy and diet counselling.

What is nutritional genomics?

We are all unique, and it is our DNA, or “genetics”, that determines all aspects of who we are. With further understanding of genetics, we now know that our genetic make-up is as fundamental to our nutritional needs as it is to our eye colour.

It all boils down to which proteins are made in our body, which are completely unrelated to the proteins we get from food. These proteins take the form of enzymes, transporters, receptors, and hormones, all of which influence how we crave, taste, absorb and digest food. This has huge implications for how we optimise our own health and prevent and manage disease.

Once we understand that our genetic make-up influences all these things, it becomes clear that the traditional one size fits all dietary recommendations are inappropriate. Standard NHS messages promoting “healthy eating” will not suit everyone, and the reckless pursuit of a dietary solution could even be damaging to some.

So where has all this new information come from?

The complete set of human DNA, known as the human genome, was published in 2001. Nutritional genomics, or nutrigenomics, focuses on the genes that affect our nutritional health. The main focus of scientific studies in this area has been around which genes put us at greater risk of disease, and how we can prevent that disease risk by changing our diets.

What is the best diet for me? Nutritional genetics may be the missing part of the puzzle by Sarah Almond Bushell - the Children’s Nutritionist
What is the best diet for me? Nutritional genetics may be the missing part of the puzzle by Sarah Almond Bushell - the Children’s Nutritionist

Where are we now?

Having matured over several years, the technology has now reached a point where it has become affordable, convenient, and reliable enough to test your own genetics. What’s more, this can now be taken to the next level, and your genetic information can be paired with your age, weight and health information using artificial intelligence to form bespoke meal plans, exercise regimens, and recipes.

Furthermore, there is robust scientific evidence (which has often lacked with fad diets) that shows that genetic testing when combined with seeing a specialist dietitian leads to improved success and dietary outcomes.

How well does it work?

Randomised Controlled Trials (which are the gold-standard of scientific research), show that using DNA testing improves client compliance with diet therapy and improves success with diet outcomes such as weight loss, over and above traditional diet counselling. Most importantly, this has been shown to be successful and sustainable in the long-term – which is fantastic. This has the potential to end ‘yo-yo’ dieting and rebound weight gain and break the cycle of battling with your weight and health.

Genetics – Understanding how it works

Let’s take a moment to look at the science. Each gene is made up of a series of four nucleotides. The most common form of genetic variation are single nucleotide polymorphisms (SNPs, or ‘snip’s), where two nucleotides in the sequence are swapped. This means the same dietary advice can have either a positive or a negative effect on a person’s health, or even no effect at all, due to their personal genetic differences and therefore their differences in metabolism – how our bodies process nutrients. These differences are known as genetic variants.

A good example is the ‘salt gene’ ACE. The blanket health promotion message is to restrict salt in your diet to under 6g daily in order to keep blood pressure under control. There are 3 possible genotypes for the ACE gene: AA, CA, and CC. When people are put on a strict low salt diet those with an:

AA genotype have raised blood pressure,

CA genotype have no change in blood pressure,

CC genotype have a decrease in blood pressure.

Therefore, the whole concept that we should all be following a low salt diet is flawed, as only those with the CC genotype will have success in lowering their blood pressure. Those with the CA genotype will frustratingly have no affect at all on their blood pressure, but even worse those with the AA genotype will worsen their high blood pressure readings by restricting salt intake.

Personalized Nutrition

Using the example of salt, I know from testing my own nutritional genetics that I have the CC genotype of the salt gene, and therefore would benefit from a low salt diet if my blood pressure were raised. However, I do not focus on a low salt diet and still eat salted nuts and other salty foods like cheese and olives.

Why is this? Because my blood pressure is not high. This could be because I exercise frequently, have very salty sweat, a low stress lifestyle, and eat lots of fruit and vegetables. This is an example of how diet related conditions such as high blood pressure can be influenced by a multitude of factors. Therefore, we need to look at current health parameters (blood tests, weight, blood pressure etc), as well as genetics, and then form a plan, prioritising only what is relevant to you and your health needs.

This whole process is called personalized nutrition.

What is the best diet for me? Nutritional genetics may be the missing part of the puzzle by Sarah Almond Bushell - the Children’s Nutritionist
What is the best diet for me? Nutritional genetics may be the missing part of the puzzle by Sarah Almond Bushell - the Children’s Nutritionist

How do you do the genetic testing?

It’s not scary! A DNA test is taken using a mouth swab – which looks like a large cotton bud, rubbed on your inside cheek for a minute. Several companies provide testing although the processing and analysis of your DNA is the same. 

I work with a DNA testing company called DNAfit and I chose them because they have been rigorously vetted and assessed by the same standards of data protection and confidentiality applied to hospitals. 

The testing kits are sent through the post, which makes it really easy to receive a kit through your letterbox, and to post it back for testing. It’s quick, easy, completely pain-free and can be done from home. I’d love you to watch a video of me on my YouTube Channel taking my own test as an example. (Video below).

It takes around 10 working days to receive your full DNA report back. Your results are then available via a secure online portal.

What happens when you come to see me for nutritional genetic testing?

In my clinics, genetic testing is only part of a nutritional assessment and consultation, it’s a ‘piece of the puzzle’. The 1 hour consultation also includes:

  • A full dietary analysis comparing how your current food intake compares to that recommended for someone of your age, gender, weight and activity level

  • DNAfit test including nutrition, exercise, obesity, bone health, stress and sleep genetic reports, a bespoke meal planner, exercise planner, and access to personalised cook book and blood testing

  • Bespoke nutrition plan taking all of the above into account

  • A summary of your dietary advice

  • Example meal plan

The DNA genetic test includes the following elements:

Optimal Diet Type

The best diet for you to manage your weight: low fat, low carb, or Mediterranean.

Lactose tolerance

Do you have the gene to code for the enzyme lactose dehydrogenase, that breaks down the lactose sugar found within milk?

Coeliac disease predisposition 

We have genes that show if you are predisposed to coeliac disease or not. What we know is that if you don’t have genes predisposing you to this disease then there is zero chance of you developing it at any point in your life.

Alcohol response

How quickly you metabolise alcohol is assessed, and therefore if alcohol can benefit your HDL healthy cholesterol levels.

Salt sensitivity

Would your blood pressure be lowered by cutting down on salt?

Caffeine sensitivity

Does caffeine intake increase your risk of cardiovascular disease or lower it?

Obesity Risk

If you struggle with your weight is this down to genetics, and in what way? Obesity is a polygenic disease – many genes are tested within this report.

Bone Mineral Density

Risk of low bone density and therefore need to focus on dietary calcium and vitamin D intake.

Micronutrient needs

Specific requirements of each vitamins A, B2, B6, Folate, B12, C, D, E, Omega 3 fatty acid needs, and mineral requirements for Iron, Calcium and Selenium.

Stress and sleep

Find out if you are genetically a night owl, or an early bird. Discover your susceptibility to stress and how you can manage this.

Fitness markers

What is your optimal training type, power or endurance? Do you require long recovery times, quick, and what is your susceptibility to injury?

How do I know that the diet has been effective?

To get the most out of this technology it’s important to monitor your health before testing and after making the suggested changes.

This will tell us your baseline status, which interventions are necessary, and then if the interventions have had a positive impact on your health.

Some genes put us at higher risk of certain diseases. For example, 30% of the population carry genes that put them at risk of coeliac disease but only 1% of the UK population have coeliac disease due to an (unknown) trigger that has caused gene expression. In other words, just because you are genetically predisposed to a certain disease, it does not mean you will develop it.

Here are the usual parameters I recommend keeping an eye on:

1.      Blood tests. Important blood results to monitor will be individual to you but may include cholesterol, blood glucose, serum vitamin levels, and hormone levels such as Thyroxine. These can be obtained from your GP, or if you’re over the age of 40 you will be eligible for a free health screen including cholesterol, blood glucose and blood pressure at your local Boots branch. There are also some great health screening programmes out there, such as Bluecrest Health Screening, for a more thorough screen. Finger prick blood testing is a fantastic development in recent years which means you can get your bloods tested quickly and easily through the post. Thriva offers a comprehensive service, as do DNAfit with their Snapshot product, which uses a ‘tap’ for those who are not keen on finger prick tests – here’s a photo of me testing my blood cholesterol and glucose levels in a break at my clinic.

2.      Home anthropometrics. Try to avoid the temptation to weigh yourself as an indicator of how you’re doing nutritionally. Weight is a measure of how much fat, fluid, bone mass and muscle are in our bodies, whereas most of us are interested only in fat. Instead use a tape measure to take your waist circumference, at around the level of your belly button. Reduction in waist circumference indicates fat loss, and visceral fat loss in particular – the fat that surrounds your internal organs, which is the most important for health.

3.      Overall symptoms. Remember that diet intake relates to many aspects of health, so keep an eye on your:

·         digestive health (toilet habits, heartburn etc),

·         emotional health (mood, sleep, anxiety levels), and

·         hormonal health (energy levels, periods). Bowelle is a great app for monitoring such symptoms.  

How is nutritional genomics being used to improve health?

I have had many successes in helping clients unpick their personal diet needs to achieve their own nutritional goals. Here are some examples of the practical application of nutrigenomic testing with clients I have seen in my own private dietetic clinic.


Coeliac predisposition – to test or not to test for Coeliac disease?

A young woman with diarrhoea and tiredness came to see me to investigate the possibility of food intolerance. Her diet was low in typical gastric irritants such as caffeine, alcohol and spicy foods, and was well balanced in terms of fibre and other key nutrients. She had been tested for coeliac disease as a child – the test had come back negative, and so she had continued to include gluten in her diet. Coeliac predisposition was very high on her nutrigenetic report, and I, therefore, encouraged her to get retested for coeliac disease as this is a disease that may develop at any time in your life if you are pre-disposed to it. She tested positive, and her symptoms are now coming under control with a gluten free diet and she has reduced the risk of certain cancers and nutrient malabsorption.

Low carb diets – faddy and unhealthy?

A couple came to see me looking to optimise their diets. They were both healthy but found their diets monotonous. Their diets were both low in carbohydrates, and from a traditional dietitian’s perspective appeared faddy and unbalanced. However, their optimal diet type for both came back as low carbohydrate. This is often seen in my clinics that by trial and error people see what their bodies are sensitive to and figure out for themselves what is healthy for them. The testing then confirmed this – this couple were right to continue to ignore blanket health recommendations recommending a Mediterranean style diet and to instead follow a low carb diet instead. Meal plans provided within the testing enabled them to follow this way of eating but with far more variety through the provision of low carbohydrate meal plans and recipes.

Lactose intolerance – an end to a lifetime of stomach woes.

A lady came to see me with daily bloating and wind when eating dairy, which she has always suffered from. She had already completely cut out any trace of dairy, however as a result of years of a dairy free diet in lieu of diet counselling, she had developed low thyroid hormone levels because of a low iodine intake (iodine is found mainly in dairy foods), and brittle bones (due to chronic low calcium intake). Genetic testing confirmed lactose intolerance due to lack of her body’s ability to produce the enzyme lactose dehydrogenase. This helped my client understand her condition more clearly than she had done in the past. Rather than eliminating all dairy, it was just the lactose sugar that was causing her symptoms. She was now free to drink lactose-free milk, and eat lactose free yoghurts. She could eat dairy products with naturally very low lactose content such as butter. She could tolerate dairy in meals eaten out by taking the enzyme lactose dehydrogenase at these times. Her diet was suddenly less restricted, her energy levels improved, and she found it easy to meet her daily calcium requirements to protect her bone health.

This sounds great; how can I get my family tested?

At present, testing is only licenced for adults over the age of 18. However, if both parents are tested, your dietitian can extrapolate the combined results and advise on how best to apply the information to your family.

The cost of testing has come down over recent years, but a good quality test containing the most important nutritional genomic markers still comes to about £150. Add this to the fee for a private dietitian to talk you through your report and help you implement it and you are looking at a cost of around £250 per person.

Why is nutritional genetic testing not available on the NHS?

If bespoke nutrition improves health outcomes and the overall cost in terms of healthcare is reduced, should nutritional genomics be integrated into standard practice within the NHS? Yes, I believe so. There is an onus for those of us involved in carrying out this work to collect data and disseminate information to help the NHS achieve this ultimate goal. 

What is the best diet for me? Nutritional genetics may be the missing part of the puzzle by Sarah Almond Bushell - the Children’s Nutritionist
What is the best diet for me? Nutritional genetics may be the missing part of the puzzle by Sarah Almond Bushell - the Children’s Nutritionist

Genome testing could become as routine as going for a blood test. This accessibility means that personalized nutrition could benefit everyone in the future, and help us live longer, healthier lives.

Written by Helen Phadnis, The Brighton Dietitian

Helen lives in Hove with her husband and two small children. Her passions in life are her family, her Thermomix, and, of course, personalized nutrition. You can find her at www.nomnomnerd.com and @nomnomnerd

What is the best diet for me? Nutritional genetics may be the missing part of the puzzle by Sarah Almond Bushell - the Children’s Nutritionist
What is the best diet for me? Nutritional genetics may be the missing part of the puzzle by Sarah Almond Bushell - the Children’s Nutritionist

want 1:1 support?

book a consultation

Leave a Reply

Your email address will not be published. Required fields are marked *

The reCAPTCHA verification period has expired. Please reload the page.

meet Sarah

I’m Sarah, a Registered Dietitian, Children’s Nutritionist and mummy from East Sussex. My blog is to guide & inspire you with information about weaning, nutrition, food and toddler feeding. Learn more about me here.

happy healthy eaters club

The Happy Healthy Eaters Club
Dreaming of family mealtimes without drama?

free quiz

Fussy Eater Or Problem Feeder Quiz
When your child wont eat. Are they a fussy eater or problem feeder? Take the free quiz to find out.

weaning free mini course

Get Ready For Weaning FREE Mini Course
Weaning soon? Take my free mini course to help you get ready.

free fussy eating guide

Unlock the secrets and grab the 5 essential steps now!

I am an affiliate for these products which means that I receive a small commission which goes towards the running of this blog.

nature and nurture vitamin product
NATURE & NURTURE baby vitamins A, C and D providing the exact NHS recommended dose in just 0.5ml. £9.99
baby eating on high chair
NIBBLE & REST Footsie adjustable foot rest for your baby’s highchair. Use the code TCN10 to get 10% off.
baby sitting on high chair and smiling
TIDY TOT’S tray and bib kit £29.99 - get 10% off your order at the link below.

Pin It on Pinterest

Share This

Enrolling Now

Follow our FEASTS Formula & fix fussy eating fast