Could Taking Dietary Supplements Benefit Your Running? Verifying the Claims and Understanding the Facts

The dietary supplement industry is a thriving multi-billion-dollar business that is growing each year. In 2011, consumer sales were $30 billion, up by 8 percent from the prior year.

More than half of U.S. adults take a dietary supplement, according to the Centers for Disease Control and Prevention (CDC), and approximately 85 percent of all elite track-and-field athletes use them.

Often claims are made about the supplements marketed towards athletes, such as, they can change the body’s composition, delay fatigue or simply improve performance.

Others claim to improve mental or physical functions, increase energy, or support overall health.

Some supplements may have beneficial effects, while others have no effect at all, and others have ingredients that may actually impair performance and health.

Also significant are the potential detrimental effects of taking supplements at an incorrect dosage.

While an entire category of books is dedicated to detailing the risks and benefits associated with each supplement type, my hope here is to review the small number of supplements that have been shown to provide some benefit to athletes with minimal negative health effects.

I will also briefly address those supplements that you should avoid, either because they lack efficacy or potentially would cause  harmful side effects.

Disclaimer

While many dietary supplements, such as vitamins and minerals, have a countenance similar to prescription or over-the-counter drugs, understand that these products are not regulated in the same way.

Since 1994, the Dietary Supplement Health and Education Act (DSHEA) has regulated dietary supplements with labeling guidelines, but the contents’ safety, effectiveness, or quality is not covered. Instead, it is left up to the consumer to arrive at these determinations.

Multivitamin/Multimineral Supplements

Claims:

  • Taking multivitamins is an easy, convenient, and generally inexpensive way to supplement nutrients that may be missing from your diet.
  • Some research suggests that using a multivitamin routinely can help prevent cancer and cardiovascular disease.

Facts:

  • Multivitamin use is likely unnecessary for an athlete regularly consuming a healthy diet, particularly when it includes high calories — more food means more vitamins and minerals, with added nutrients from fortified products.

Factors that increase deficiency risk for athletes include:

  • Consuming fewer than 1500 calories per day
  • Food allergies, restrictions or intolerances that limit food intake or gastrointestinal tract absorption
  • A vegan or vegetarian diet low in vitamin D, B2, B12, iron, and zinc, which can necessitate supplementation

For the prevention of cancer and CVD, health professionals have varying interpretations of multivitamin research, which is the reason daily nutrient recommendations vary.

If you choose to take a multivitamin, consider the following:

  • More is not better — look for a supplement that contains ~100 percent of the required vitamin and mineral daily value and avoid taking “megadoses” higher than the tolerable upper-intake level, which can be unsafe, particularly fat-soluble vitamins, which the body retains.
  • If you are deficient in one vitamin or mineral, consider supplementing with just that nutrient because many vitamins and minerals compete for absorption. The most common individual vitamins and minerals that are beneficial to take as supplements are iron, calcium, and vitamin D.
  • If you are taking any other medications or dietary supplements, discuss the addition of a multivitamin with your doctor or pharmacist.

Glucosamine/ Chondroitin Sulfate

Claims: These two supplements are often combined together in a product that manufacturers claim reduces pain and improves the functionality of joints. Consumers sometimes use it instead of ibuprofen or other NSAIDs for treating osteoarthritis.

Facts: The majority of studies examining this supplement have focused on osteoarthritis or cartilage damage. Recent study research has been positive, linking it to joint function improvement and symptom reduction. The glucosamine/chondroitin combination also appears to mitigate joint pain more effectively than ibuprofen and cause fewer side effects.

  • Recommended dose: 1500-2000 mg/day glucosamine, 1200 mg/day chondroitin
  • Take it daily for at least six weeks. If there is no improvement after eight weeks, this supplement is unlikely to help you.
  • You should not take chondroitin with blood-thinning medications as it may intensify the effects.

Fish Oil/ Omega-3 Supplements

Claims:

  • The supplements can also help curtail triglyceride levels thereby diminishing the risk of heart disease.

Facts:

  • Strong evidence exists for taking fish oil to reduce the severity of EIB.
  • Only limited and weak evidence supports its use for easing muscle soreness.
  • Strong support indicates that it decreases triglyceride levels and heart disease risk.
  • The levels of DHA and EPA in omega-3 fatty acid supplements vary. Read the label closely and select a product with a combined dosage of 500 mg of DHA and EPA.

Supplements to Avoid

“Immune-boosting” Supplements (antioxidants, glutamine, zinc, Echinacea)

  • There is no significant evidence supporting using these supplement types to prevent exercise impaired immune system function. In response to strenuous exercise, the body likely enhances its immune defenses naturally.
  • Antioxidants taken in high doses can actually be “pro-oxidative,” or stimulate oxidation, and negatively affect the body, e.g. impair muscle performance

Chromium (Chromium Picolinate)

  • Claims have said the mineral will increase muscle mass and decrease body fat
  • Current evidence does not support that chromium supplementation can change body composition
  • High chromium intake may reduce iron absorption and accumulation in the body can damage DNA

Anything that sounds too good to be true!

  • Ignore supplements supported by only testimonials and instead look for those backed by rigorously executed scientific studies, e.g. double-blind placebo-controlled, distinguished by effectiveness, safety and repeated positive findings.
  • Don’t buy anythin with a label that doesn’t provide a list of ingredients or includes the term “proprietary blend.” The product may not be standarized to a consistent dose and may contain illegal or unsafe substances.

References

1. Maughan RJ, Depiesse F, Geyer H. The use of dietary supplements by athletes. Journal of Sports Sciences. 2007:103S-113S

2. Mickleborough TD, Lindley MR, Ionescu AA, Fly AD. Protective effect of fish oil supplementation on exercise-induced bronchoconstriction in asthma. Chest 2006; 129:39-49.

3. Fletcher RH, Fairfield KM. Vitamins for chronic disease prevention in adults: clinical applications. Journal of the American Medical Association. 2002;287:3127-3129.

4. Gleeson M, NiemanDC, Pedersen BK. Exercise, nutrition and immune function. Journal of Sports Sciences. 2004;22:115-125.

5. Nieman, DC. Exercise immunology: nutritional countermeasures. Canadian Journal of Applied Physiology. 2001;26:S36-S44.

6. Sen CK. Antioxidants in exercise nutrition. Sports Medicine. 2001;31:891-908.

7. Pittler MH, Stevinson C, Ernst E. Chromium picolinate for reducing body weight: meta-analysis of randomized trials. International Journal of Obesity and Related Metabolic Disorders. 2003;27:522-529.

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