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Nutrigenomics: How Genes Should Dictate Your Diet

Nutrigenomics

We all want to know what to put in our bodies so that we can improve our health, reduce our risk of disease, solve some nutritional problem, or become better, faster, stronger. No two people respond to diet and exercise the same way, but for decades health professionals have been relegated to answering some very specific health questions with the same general advice—less fat, less sugar, more water, more exercise. It has been well established in studies that compare the performance of different diets that people can react very differently to the same diets. Some people react well when consuming a good percentage of their calories in the form of carbs, whereas others do better with a higher concentration of protein. Until recently, we lacked the technology to provide individualized nutritional advice, but not anymore. The future is finally here in an emerging science called nutrigenomics.

The Gene-Food Interaction

Nutritional genomics (also called nutrigenomics) combines molecular genetics with nutrition science. First emerging as a field of study in 2001, nutrigenomics examines the interaction between the food we eat and our genes. With a nutrigenomic test, the need for one-size-fits-all nutrition counseling is over. Healthcare practitioners can now objectively give us more personalized instructions on how to take better care of our health, answering the age-old question—“what should (and shouldn’t) I be eating?”

At its most fundamental level, nutrigenomics examines the protein products (e.g., enzymes, transport molecules, receptor molecules) produced by our genes and how these products interact with the food we eat to influence our nutritional status (e,g how well are we metabolizing vitamins), as well as our risk for certain chronic diseases like diabetes and heart disease. 

Genetic Variations

Each of us has 46 chromosomes that contain all of our genes. Genes tell our bodies how to make the proteins essential for us to live and are coded by four nucleotides:

  1. Adenine 
  2. Guanine
  3. Cytosine
  4. Thymine 

Most genes have small variations in the sequence of these four nucleotides, resulting in genetic variation (the difference in DNA among individuals). Because of this variation, more than one version of a gene (called a variant) can be expressed from person to person. Variants can cause changes in the proteins produced from our DNA (i.e., increasing or decreasing production or changing how the proteins function). 

There are many different types of mutations that can cause variation in our DNA, but the majority of nutrigenomic tests examine the two most common types

1. Single nucleotide polymorphisms (SNPs)—Change in a single nucleotide in the sequence 

Single Nucleotide Polymorphisms (SNPs)

Source: Yourgenome.org 

 

2. Insertions and deletions (INDELs)—Addition or deletion of single nucleotide in the sequence

Insertions and deletions

Source: Yourgenome.org 


While most variants don’t cause clinically significant changes in our health status, some can change the way our bodies respond to our environment and even our diet. For example, we all have a gene that codes for the lactase enzyme that breaks down the lactose present in milk; however, because of genetic variation—namely a SNP that replaces thymine with cytosine in the DNA sequence—some of us have a version of the gene that makes enough lactase to digest lactose while others do not, resulting in lactose intolerance. 

A Developing Field

With the extraordinary advances in genetic sequencing technology over the past two decades, starting with the Human Genome Project, nutrigenomics has been making its way to consumers faster than anticipated, and while some researchers and practitioners are excited to make use of individualized nutrition protocols, others still hold their reservations. 

To date nutrigenomics has been used in research on heart disease, insulin resistance, diabetes, and obesity, identifying genetic variants that could potentially be used to alter disease risk in certain individuals. Other research in nutrigenomics has identified variants for irritable bowel disease as targets for potential therapeutic interventions. 

With regards to application, additional studies have looked to nutrigenomics to provide information on conversion efficiency for certain vitamins and minerals (e.g., vitamin A), the likelihood of developing food intolerance (e.g., lactose intolerance), and even our preference for sugary foods

As far as where the science is today, it appears that we’re still in the early stages. One quote that captured this sentiment for us is from Dr. Ahmed El-Sohem, the research chair of Nutrigenomics at the University of Toronto: 

“If you ask five different experts in the field to define nutrigenetics vs nutrigenomics, you'll get five different answers. There really is no technical official definition of one over the other. I've moved to using nutrigenomics as the umbrella term to cover gene-diet interactions. 'How does my diet affect my genes?' is what most people want to know." 

Potential Applications

While there are many potential applications for nutrigenomic information, the whole infrastructure around it is still being developed. The most obvious area or need is in the interpretation of the actual information. Health practitioners must be trained in interpreting nutrigenomic information and translating it into individualized plans. 

Additionally, new relationships between variants and food are being discovered and studied all the time. This is another instance of information and the consumer market jumping ahead of the medical establishment and creating a gap on how new practices can be implemented on a larger scale.

This may partially explain why the Academy of Nutrition and Dietetics (AND) has adopted a more conservative, “too-soon-to-tell”, approach to the use of nutrigenomics in practice. According to their official position statement, AND acknowledges the potential of this fast-evolving field by stating that “nutritional genomics provides insight into how diet and genotype interactions affect phenotype.” 

However, their statement falls short of a full endorsement, stating that “the practical application of nutritional genomics for complex chronic disease is an emerging science and the use of nutrigenetic testing to provide dietary advice is not ready for routine dietetics practice”. 

In a meta-analysis of 38 nutrigenomic studies, the authors suggest that a direct and definitive association between the examined genes and diet-related diseases is not yet strong enough to put nutrigenomics into wide-scale practice. Others researchers, like Dr. El-Sohem, disagree: 

“Many skeptics say that using single SNPs to make nutrition recommendations is useless and that researchers need to wait until the less-robust science on genetic risk scores (GRSs)—which aggregate information from multiple risk-related SNPs—further evolves… [But] we're not trying to predict obesity, we're trying to look at what is a marker that's actionable. You can do that, with even a single gene."

Regardless of the debate around the current applicability of nutrigenomics on a large scale, one thing is clear: the genie is already out of the bottle. It is widely expected that continued advances in this field will lead to customized diets according to genotype, better treatments for chronic and genetic conditions, and possibly even disease prevention

Others suggest that nutrigenomics will pave the way for improvements to public health by facilitating new and more accurate measures of dietary intakes, and by helping reduce health and nutritional inequality. It will certainly be an important tool for the “food as medicine” initiatives that are part of a growing trend we are observing.

The fact is that once consumers can get their hands on actionable information, it’s hard to reverse the process. So, while the health establishment catches up, many nutrigenomics experts and health practitioners are appearing in the landscape as resources for anyone interested in discovering what nutrition-related predispositions they may have and what can be done to best improve their life and healthspan. 

Benefits of Nutrigenomic Testing

Nutrigenomic testing is an exciting frontier for healthcare professionals, but the major share of the benefits accrue to us, the consumers. Most tests currently on the market will include markers that give insights into some, if not all, of these domains:

Weight Loss/Energy Metabolism

Weight loss is a billion-dollar industry. The diet world is full of fads, cleanses, pills, and pre-packaged eating plans all designed to help you lose those extra pounds. The thing is when it comes to nutrition, the one-size fit all approach doesn’t really work. Nutrigenomics is exciting precisely because it can help us create an individualized approach to diet that is sustainable and thus more likely to help us reach our goals. 

A genetic test can help you by letting you know more about your own mechanisms of energy balance (how your body uses the food you eat) and the type of diet that works best for your body. For example, the general advice tells us that if a person cuts 500 calories from their intake through diet and exercise every day they can lose a pound every week; however, there is a segment of the population that has to do more work to lose a pound and it’s in their genes! If you have been following the usual advice but can’t seem to get the scale to move, you might be one of the few who has to do more work to see a result. 

Genetic tests also give us clues into what type of diet works best per individual. Some people respond better to low fat, some to high protein-low carb, some to neither. If you have cycled through diet trends and can’t seem to settle on an eating pattern, a nutrigenomic test may help.

Chronic Disease Risk

Treatment and rehabilitation for chronic diseases like diabetes and heart disease costs billions every year. A genetic test can give you clues about what foods to consume, reduce, or omit from your diet. Gene markers vary between testing brands, but most tests should provide information on caffeine and similar additives as well as nutrient metabolism and whether you may be at risk for disease if you don’t change your habits. 

For example, tests that examine caffeine can provide information on how you metabolize the stimulant and if you are at an increased risk for heart problems because of it. Other tests that examine nutrients like sodium can give you insights into whether or not you have a salt sensitivity, and thus allow you and your doctor to reduce your salt intake to a level that reduces your risk of high blood pressure and stroke. 

It’s important to note that nutrigenomic tests can’t provide an estimation of your specific disease risk, they can only provide more specialized dietary guidance for reducing your risk for common chronic diseases.

Food Allergy/Sensitivities

Food allergies and sensitivities can have varying effects on an individual from mild gastrointestinal discomfort to life-threatening anaphylaxis. A genetic test may help you determine if your allergy symptoms have origins in what you’re eating. 

Test markers vary by brand, but common markers include those for celiac disease and non-specific gluten sensitivity, histamine intolerance, and lactose intolerance. Information on possible food intolerance can help your healthcare provider narrow down probable dietary culprits of gastrointestinal distress, rashes, and other allergy symptoms that cannot be attributed to other causes.

Nutritional Needs and/or Deficiency

Vitamins and minerals are organic compounds that are essential for life. We get these micronutrients through our diets. Micronutrient deficiencies can cause serious, and sometimes irreversible, symptoms and even death in severe cases. A genetic test can give you insight into how you metabolize different vitamins and minerals (e.g., Vitamins A, B12, C, D, iron, calcium) and whether or not you are at increased risk of vitamin deficiency based on your genes. 

For example, vitamin A comes in different forms, the majority of which we consume as the plant pigment beta-carotene found in red and orange fruits and vegetables. In order for our bodies to use this plant form, we have to convert it to its active form with the help of an enzyme; however, some people are unable to convert the plant form effectively and are at an increased risk of vitamin A deficiency. 

Genetic tests that examine vitamin A metabolism can give you information on whether you are someone who has trouble metabolizing beta-carotene to its active form and thus need to consume preformed sources of active vitamin A in order to prevent deficiency.

Athletic Performance 

Nutrigenomic tests can be helpful for gym enthusiasts and athletes who are interested in optimizing their diets to improve training response, athletic performance, and recovery. Some tests may even give insights into whether you respond better than normal to endurance (aerobic) training and resistance (strength) training. With this information, you and your healthcare provider or personal trainer can agree on a training program that will provide optimal results.

Another important benefit worth considering, is the power of knowledge. Some studies suggest that having knowledge of our genetics can influence how well we comply with dietary recommendations given to us by our healthcare providers, which makes a lot of sense. Being able to examine and monitor our own data is a powerful tool for sustaining healthy habits, which is likely the most fundamental skill to achieving a better life and healthspan.

Whenever we speak about genetics, one thing worth remembering is that genes aren’t destiny. In the case of nutrigenomics, a person could have obesity-related variants and never become overweight, or have low efficiency for vitamin A conversion and never have a vitamin deficiency. Lifestyle behaviors matter and nutrigenomic data is just a tool, not a solution.

So, should you get a test?

We think that Dr. Richard Bland, an accomplished nutrition expert and proponent of nutrigenomics captures the spirit of this question well with these words: 

“Does a person want to be an early adopter of this rapidly emerging new concept? Or, do they want to wait until stuff is more crystallized and we have done more boundary analysis to know what the strengths and weaknesses [exist].” 

For us, the decision to invest in nutrigenomic testing or not is a personal one. These tests can be used for a broad range of purposes, from troubleshooting diet-related health problems to simply satisfying your own curiosity in the hope of acquiring helpful bits of information to optimize your approach to food.

There also isn’t any shame in not adopting the technology now; your DNA doesn't change, and because nutrigenomics is a growing field, we’ll undoubtedly have greater access to resources and better answers to some of our most pressing health questions as the research expands. 

Choosing A Test

When it comes to choosing a nutrigenomic test, there are many options out there. To get oriented around the breadth of options, we examined 10 popular companies that provide the service, although this is far from an exhaustive list: 

  1. DNAfit
  2. Genomelink
  3. Genomic Express
  4. Genomlink
  5. Genopalate
  6. Living DNA
  7. myDNA
  8. Nutrigenomix
  9. Nutrition Genome
  10. Orig3n

Next, we identified the most important attributes you want to consider when choosing a test. We narrowed them down tho these: 

  • Comprehensiveness—How many markers are examined, how is the data explained in the report
  • Accuracy—How accurate is the information generated in the report, is it subject to change over time, is a retest required
  • Data Security—Where are the samples stored, how is the genetic information kept safe over time, is the data sold to third-party entities.
  • Price—How much does the test cost, does the company upsell consumers
  • Interpretation/Actionable Advice—Does the company provide actionable information and advice for the consumer based on their results
  • Timeframe—How long does it take to get the results

Of all these attributes, we found the most determinant in choosing a test are likely to be:

Price 

Nutrigenomic tests vary in price depending on the number of variants that are screened and how the results are delivered. Cheaper tests will not cover as many markers and the results are likely to be presented in a standardized manner, leaving the consumer with the need to do some additional research to fully contextualize the findings.

Conversely, more expensive tests cover a greater variety of markers and often involve a consultation with a qualified health professional to help the consumer make sense of the results and translate them into a specific action plan. 

Ultimately, choosing a price point depends on your objectives: are you troubleshooting a health issue or are you dabbling in a bit of health-data tourism? 

Interpretation/Actionable Advice

Given the depth of science involved in delivering these tests and the need for background knowledge and training in genetics and nutrition, this aspect is likely the most critical. As expected, the more expensive tests are likely to come with the opportunity for a 1:1 consultation or can only be administered under the guidance of a trained healthcare professional. 

Aside from markers covered, we believe there is no technological advantage of using one type of test over another. As a complement to these election criteria, we also found these basic guidelines on picking a DTC genetic testing company from the US National Library of Medicine.

Most Interesting Options

Based on the aforementioned evaluation criteria, here are three nutrigenomic tests that we would pick for ourselves at different price points (no affiliations): 

Living DNA Nutrition DNA Testing ($99)

Living DNA is a personal genomics company that provides direct-to-consumer DNA testing kits. This is one of the cheapest options if you’re up for a little health-data tourism and not quite ready to take the full plunge and spend a few hundred dollars on a more comprehensive nutrigenomic test. 

You can purchase your DNA-based nutrition test to get your feet wet right from their website. In your kit you will receive a mouth swab to collect your sample and in 6-8 weeks you’ll be armed with potentially valuable information about the way your body metabolizes vitamins and minerals as well as your risk for food intolerances. 

Living DNA does not sell your genetic data to third-party entities and ensures the safety of your personal and genetic information by issuing your sample a barcode. View their privacy policy here.

Nutrition Genome DNA Nutrition Test Kit & Health Report ($299)

Nutrition Genome also provides direct-to-consumer DNA testing kits with the added benefit of being able to schedule a consultation with a medical professional. For us, this seems like a nice middle-of-the-road test in the field. It’s a little more robust than Living DNA, examining 95 clinically relevant genes to generate an in-depth analysis of digestion, methylation, hormone health, mental health, inflammation, drug and toxin sensitivity, DNA protection and repair, heart health, and athletic performance.

You also get a personalized grocery list and recommendations for blood work you may find helpful. Test results are generally delivered in 5 weeks and according to their website, Nutrition Genome stores your DNA data on HIPAA compliant servers. View their privacy statement here.

Nutrigenomix General Health ($500+) 

This is our top pick for high-level nutrigenomic testing. This genomics company was founded about 10 years ago by Dr. El-Sohemy (quoted above) and their tests can only be obtained through a qualified healthcare professional, ensuring you get the maximum benefit from your test.

Nurtigenomix offers three specialized tests for consumers: General Health, Sport/Athletic, and Fertility. Each of the tests examines the same 70 genetic markers and provides results based on what area the consumer is concerned with improving. 

For the purpose of this writeup, we found that the general health test provides enough information for any person wanting to improve their health using nutrigenomic testing. For athletes, the sport test can provide more specific sports nutrition advice and for couples looking to conceive, the fertility test can provide specific information on improving nutritional status before becoming parents. 

A test from Nurtigenomix will cost you more than the others, but the expert consultation allows you to ask questions and gain clarity on some of the more complicated results. As with Living DNA and Nutrition Genome, Nurtigenomix does not sell your data to third parties and according to their website, DNA samples are stored in secure, controlled-access facilities with a unique barcode. 

Additionally, Nutrigenomix sends your data report to your healthcare provider through encrypted servers. The time it takes to get test results back from the lab varies, though generally you can expect to receive your results from your healthcare provider within 4 weeks.

Learn More — some excellent nutrigenomic resources we enjoyed: 

How to Personalize Your Nutrition Based On Genetics: The always excellent Rhonda Patrick gives us a nutrigenomics crash course in 14 minutes

Genomic Kitchen: Great for quickly understanding the growth trajectory of this young practice of using nutrigenomic information as a tool to fine-tune your diet & metabolism. Their blog has a good “introduction to nutrigenomics” article. It explains the uses of nutrigenomics and describes specific scenarios where your nutrigenomic profile might be a relevant input for optimizing your nutrition. 

Our favorite “lightbulb” quote: “Nutrition is the principal source of information genes work with.” In this sense, nutrigenomics is the method by which you identify the right information to provide your genes using food

We also like their approach of bridging nutrigenomic information into actual recipes you can prepare, what they call Culinary Genomics. One intriguing resource is their Ingredient Matching Tool, that shows you which ingredients to pair to maximize the nutrition information for your genes

The Future of Nutrigenomics: This article is written for dietitians and practitioners and does a good job capturing the benefits and open questions about nutrigenomics, though it is almost 3-years old.

One parting thought:

Obtaining your nutrigenomic information is only one step in a longer journey. After you identify potential areas for improvement or further analysis, it’s important to follow-up with nutritional blood panels that can tell you the adjustments you’re making have your heading in the right direction. 

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