Login | July 23, 2018

Ask the experts: Kelli Jennings

Pete’s World

Published: October 2, 2017

I have to admit that my leaning in this column was to dispel the notion that athletes had to go above and beyond the RDA with respect to vitamin/antioxidant and mineral use. That’s until I contacted a professional sports nutritionist, Kelli Jennings, RD, owner of Apex Nutrition, LLC. Her answers gave me some new and important perspectives on this issue. So I decided to scrap my original idea and just present our short Q & A - where I let Kelli do all the talking.

Q: Most studies I’ve read report that athletes who consume high-calorie diets that contain the RDA of all nutrients have few vitamin or mineral deficiencies. Do you agree, and when would you recommend an athlete take additional vitamins such as multi-vitamins, vitamin C and vitamin E?

A: Unfortunately, the RDA’s for vitamins and minerals are more appropriate for a sedentary population than athletes (and of course, a sedentary population should not be consuming a high calorie diet). So, while most nutrients likely don’t require supplementation, some such as magnesium, can become deficient in athletes over time. On an individual and general basis, I recommend a good, whole-food diet, a food-based multivitamin, and a small amount of magnesium to most athletes daily. On an individual basis, I look at other potential deficiencies, such  as Vitamin D and iron as well.

Q: I’ve seen studies of athletes having taken 100-5,000 times the RDA of vitamins/minerals to improve exercise performance - with no significant results. Have you ever run across gross over supplementation situations, and what are a couple of the deleterious effects from this?

A: There is little need or benefit - and potential harm - in taking the extreme doses. I’ve run across high intakes with athletes often, but it’s usually because they are getting the same vitamin from many different sources and not realizing it, or just taking a whole medicine cabinet’s worth of different pills hoping one does the trick. A few detrimental effects include over-supplementation of vitamin D, causing the body to down-regulate its own production (negative-feedback), too much magnesium causing gastrointestinal issues, and too much or unnecessary iron supplementation causing iron poisoning.

Q: Athletes are bombarded with hype on the use of CoQ10 to improve O2 uptake. Does it work? 

A: Unfortunately, this benefit of CoQ10 has not been conclusively supported in research, and I don’t believe the extreme hype (there are no magic bullets). However, it is tough to depend only on studies for performance nutrition, as most of them have few participants and too short a duration to truly prove or disprove performance benefits over time (many look at acute blood-level changes). Sometimes, nutrients in an athlete’s body progressively deplete over a season, and an athlete feels a chronic fatigue or over-training symptoms after months of high-level training that would not show up in a study (this can be the case with a mineral like magnesium). Since CoQ10 is generally safe at daily doses of 90-200 mg, I’m not opposed to supplementing it, especially if there is reason to believe it’s low in an athlete such as with statin use. Much like using caffeine or beet juice, an athlete may feel better and see improved performance with it, without much risk. It is hard to say for absolute sure the cause and effect of a supplement. I do caution against larger dose medication combinations without MD approval, and taking multiple new supplements at once makes it really tough to identify a benefit.

Q: Is antioxidant supplementation beneficial for an athlete?

A: I believe there is some benefit for athletes. Although it’s easy to assume athletes eat super-high calories, many adult athletes have to watch  their intake to maintain a healthy lean weight, and the extra performance-nutrition doesn’t really offer many vitamins and minerals. Therefore, the small extra amounts of vitamin and minerals (antioxidants) in a good-quality multivitamin may have benefit, but the extreme doses can actually inhibit muscle recovery. I recommend small amounts along with a healthy, whole-food vegetable-and-fruit loaded diet. And, while we usually think of vitamins as antioxidants, we also get direct and indirect antioxidant-action from crucial minerals such as copper and magnesium, and other nutrients such as those found in ginger and turmeric. On an individual basis there can be value in supplementing these. Lastly, I do recommend nutrition habits that promote glutathione production within the athlete’s body, as this is a naturally powerful antioxidant within cells.