Wouldn’t it be great if runners and triathletes could be genetically tested to tell them exactly what they should eat to improve their performance? Of course, the answer is yes! Personalized (or precise) nutrition is currently an area of ​​increasing interest for endurance athletes. However, the field is still in its infancy. So far, precise nutrition has not been enough to tell runners what they can eat to perform better. In addition, many factors affect performance and health, including sleep and eating patterns. In any case, runners and triathletes are buying (expensive) genetic testing kits.

At the Annual Meeting of the Society for Nutrition and Dietetics (October 2021, www.eatright.org), Dr. David Nieman, director of the Human Performance Laboratory at Appalachian State University and an exercise physiologist, said that we can’t just eat What makes a statement is based on genetic testing because the results vary too much. More research is needed before athletes can obtain effective personalized nutritional advice.

There is no doubt that sports scientists are getting better and better at analyzing genetics and the metabolites (the end products of sports metabolism) of each athlete. This may improve our understanding of how genes, diet, and exercise interact. But the diversity of responses left a big gap in knowledge.

For example: genes related to caffeine metabolism. According to reports, 3 to 13 mg of caffeine per kilogram of body weight can improve athletic performance. But why only some runners perform better after ingesting caffeine? Is the difference due to genes? Genetic testing can determine which runners have the ability to metabolize caffeine quickly or slowly. But Dr. Nieman reports that the data show that there is no model that can reliably link caffeine metabolism genes with improved athletic performance.

This is an example of how personalized nutrition can potentially help athletes. During the 100-mile endurance race in the Western State, Dr. Nieman measured inflammation (cytokines) in 154 super runners. The degree of inflammation varies greatly. Some runners have very high levels of cytokines, while others have very few. Is this genetic? Unknown; genetic testing cannot explain these differences.

Neiman has discovered that "fasting" exercise can cause inflammation. In other words, the inflammatory cytokines in athletes who exercise first in the morning without eating will immediately soar. Regardless of their genes, athletes can reduce this inflammation by about 40% as long as they consume carbohydrates before and during exercise for a long time.

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Is there a difference in the type of carbohydrates you eat? Compared with drinking sports drinks, will eating bananas or blueberries cause inflammation? The following are studies that tell us about the effects of carbohydrates before and during exercise:

Dr. Nieman’s preliminary research looked at the polyphenol quercetin (found in apples). He learned that very high doses of quercetin did not help. Nieman then tested the polyphenols that athletes can easily ingest. He saw better results.

For example, when the athlete ate (or did not eat) 1 cup of blueberries a day for two consecutive weeks before the 75-mile hard bike test, the inflammatory response was generally much lower. But having said that, the response of blueberry eaters was 14 times different. Eight cyclists had severe inflammation, 13 had moderate inflammation, and 10 had much less inflammation. Can genetic testing help identify athletes with high inflammation? If so, can sports nutritionists encourage these athletes to eat more blueberries for a stronger anti-inflammatory response? We don’t know yet...

Inflammation can cause recovery problems for runners and triathletes. What if runners with severe inflammation can undergo genetic testing to determine whether the inflammation caused by their exercise is genetically related? So is it possible to suggest that they participate in swimming instead of super running? (Will they do it? Ha!)

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Is inflammation mainly related to genetics, diet, or some other factors (such as the microbiome)? (The microbiome refers to the billions of bacteria that live in your gut. They have a strong influence on your immune system.) Dr. Neiman suspects that athletes with a strong microbiome are more Exercise has less inflammation. How much influence does genetics have on the microbiome?

We do know that athletes who eat a diet rich in polyphenols (fruits, vegetables) do a good job of feeding gut microbes. Compared with athletes who eat a lot of ultra-processed foods, they tend to have a more active microbiome. Maybe diet is the driving force in reducing inflammation-more important than genes? We have a lot to learn...

The metabolic response of athletes to strenuous exercise and the way food affects this response vary greatly. Although we don’t yet know what causes the mutation (genetics? Diet? Microbiome?), we know that diet can reduce inflammation, soreness, and muscle damage. By regularly eating colorful fruits (berries, cherries, apples, etc.) and colorful vegetables (spinach, carrots, tomatoes, etc.), and spending this money on nutritional advice that may be problematic. Be patient; the future of sports nutrition is here.

Sports nutritionist Nancy Clark, MS, RD advises recreational and competitive athletes in Newton MA (617-795-1875). Her best-selling sports nutrition guide is a popular resource, as is her online seminar. For more information, please visit www.NancyClarkRD.com.

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