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Understanding Your Genes and Athletic Potential: Q&A with Nanci Guest, PhD, RD, CSCS, Nutrigenomix

The world watched in amazement as Olympians took the stage for three weeks in Tokyo, displaying skill, grit, determination, and outright amazing athleticism. Many of us stared with mouths agape wondering, how do they do it?  Of course we know it takes years of dedication, practice, and natural ability, but when the difference in a race can be less than a few hundredths of a second, is there something that can give an athlete an edge? Perhaps the answer lies in our genes. Last March, we introduced you to Paige McDonald, MScFN, RD, Manager of Clinician Services for Nutrigenomix to learn more about the emerging field of nutritional genomics. This month we had the pleasure to speak with Nanci Guest, PhD, RD, CSCS, Director of Dietetic Training & Education for Nutrigenomix, about how their sports report can be used to make personalized nutrition and exercise recommendations for everyone from the weekend warrior to the next gold medalist. 

FLIK: Dr. Guest, we are so excited to have you here with us. Our team of dietitians have unique stories about what brought them to nutrition. Can you tell us a little about your nutrition story. What got you into the field? 

Dr. Guest:  Like many dietitians I found my way into nutrition after pursuing other interests. I originally went to school for animal science, as I wanted to be a veterinarian, but when I realized how taxing that would be emotionally, I completely switched gears and went into the fitness and nutrition field. I loved nutrition so much, I obtained my designation as a Registered Dietitian, followed by a master’s in nutrition with several higher-level fitness certifications so I could start working with athletes. As my practice grew, I began working with high level athletes and I went on to get my PhD in nutrition focusing on nutritional genomics and sport, trying to help athletes improve their performance based on their unique DNA profile. This was a new and exciting field that could help me dial in to exactly what each of my athletes needed and prescribe them with a customized diet.

FLIK:  Nutritional genomics is such an interesting field. Can you explain a little bit more about how you gravitated toward that instead of a more traditional approach such as sports medicine or exercise science?

Dr. Guest:  I was at an annual meeting for the Dietitians of Canada and a professor of mine was doing a presentation and launching his business, Nutrigenomix. I had been contemplating getting a PhD, but I hadn’t yet found something that gave me the spark to do it. It was during that presentation that I became fascinated with the field and that is what pushed me to want to get my PhD. Since many people didn’t have knowledge in nutritional genomics at the time, I thought this could be a unique opportunity to research a new, novel field that was beginning to surge in the athletics community and, at the same time, be able to use the knowledge practically with my own athletic clients.  

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FLIK: We have had our 70 gene test done and we are starting to work with clients to provide individualized counseling based on their genetic profiles. Can you tell us a more about the test and how it relates specifically to performance?

Dr. Guest: Everybody knows the sporting world is very competitive and everyone wants a competitive edge.  So, what we are trying to get away from is a generic one size fits all, whole team approach where everyone is given the same recommendations and instead, we are moving toward optimization of the individual. Whether these athletes are competing in an individual sport or a team sport, I want to serve those individuals individually and provide them with nutrition and supplement strategies that are unique to what their DNA is telling us they need. If you take a look at the normalized bell curve below, we know most of us will fit into the blue area, but what we are looking to do is uncover those who are outliers, perhaps someone who needs more vitamin D, less saturated fat, or more omega-3 fats, for example. And this is all due to genetic variance.

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FLIK: This is fascinating! Can you dive into the science behind this? 

Dr. Guest: Sure. Identifying genetic variants is a way to look at each athlete’s DNA and the corresponding nutrients or foods that it may impact. By aligning our recommendations with what their genes are telling us, we know that we are helping an athlete reach their genetic potential. The science of this lies in looking beyond complex traits that take thousands of genes to determine--like overall strength, muscle mass, VO2 max, obesity--and instead look at how single genes or a small number of genes encode all of our functional endogenous proteins. Endogenous proteins are receptors, transporters, binding proteins, etc. that have an impact on our nutritional biochemistry. If there is a variant in the gene that controls the activity of one of these proteins, this will potentially change our nutritional biochemistry and therefore, change our nutrition requirements. In a nutshell, we are trying to identity individuals who will have a different nutritional requirement based on differences in one of their genes. So, two athletes may have different versions of the gene responsible for vitamin C metabolism. Athlete A may be able to metabolize Vitamin C more efficiently than athlete B and therefore, athlete B would require more vitamin C in their diet or through supplementation. This then allows us to fine tune specific dietary recommendations rather than prescribe a standard 75mg recommendation to everyone. We know these broad recommendations don’t make sense because we know how different we all are in every aspect of health and fitness--some gain muscle mass quickly, others take longer and may need more time to recover, etc.

FLIK:  Are you able to share a practical example of Nutrigenomix at work?  How have you been able to use this report to help an athlete better their performance?

FLIK:  We’ve been talking a lot about athletics, but it sounds like this can be beneficial for all people, not just people looking to better athletic performance. Would you agree?

Dr. Guest:  Yes, anybody looking for better health would benefit from the test. I find Nutrigenomix to be incredibly helpful for people who might be getting frustrated when they are not getting the results they are looking for. Someone who is making lifestyle changes and being very diligent about sleeping better, eating well, exercising more, but perhaps, as an individual, they might need something a little more precise to get the results they are looking for... rather than the more generic approach of everyone should ‘eat more fruits and vegetables, everyone should eat less carbohydrates, or everyone should eat less sodium.’ Those aren't all true for everyone! Whether we are talking about health, gaining muscle, getting leaner, or an Olympic level pursuit, in any walk of life, being able to personalize your health information, primarily your nutrition, will result in a better you. We all need to perform in life – as athletes, busy parents, executives, students and so on. Nutritional genomics can help you optimize your lifestyle for your best you.

Overall, Nutrigenomix testing is a way to help all clients achieve the personalized dietary recommendations they are looking for. Clients can be assured that their individualized prescribed diet is unique to them, based on their specific DNA profile, and won’t be the same diet prescribed to client B, C, D, and E which is a huge motivating factor for anyone looking to make a lifestyle change.  


At FLIK Hospitality Group we believe in great food, great service, and great people. Our wellness first approach ensures our food supports healthy and delicious choices, specially curated by our team of culinary experts and registered dietitians. At FLIK, we believe in seasonality in sourcing our ingredients and providing a customized approach to the culinary and hospitality needs of each client. Our dedication to providing quality hospitality service is unparalleled in the industry.

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