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Be a Supplement Savvy Athlete

By Heidi Strickler | Sept. 03, 2019, 3:08 p.m. (ET)


“For that extra edge” … “Focus” … “My coach recommended it” …“To fill in nutritional gaps” … “I figure it wouldn’t hurt” … “My teammate uses it” … “I read it boosts endurance” … “To reduce muscle soreness” … “Isn’t this what the pro’s use?”

Fill in the blank with your own reason(s) behind using, or considering, a supplement, because the list is endless. Thus, every time a client of mine inquiries about a supplement, I respond with the following:  

Why do you want or feel like you need this supplement? What result are you looking for? And why do you feel like ‘Supplement X’ is the best option?

I am not only a Registered Sports Dietitian, but I am also a competitive endurance athlete. Professionally and personally, I respect the drive for next-level performance, and the demand athletes put on their bodies calls for supplementation at certain points in a training cycle. Just as an athlete will periodize their training, so too should they periodize their nutrition and supplement regime. Fluctuations like training load, nutrition, injury, time of year, blood and lab results, and performance goals, among other factors, should dictate supplement usage.

The American College of Sports Medicine (ACSM) and the International Olympic Committee (IOC) state that “dietary supplements are not needed in the presence of adequate energy intake from a balanced diet, but may benefit athletes who consume suboptimal diets with low micronutrient density or have increased energy or micronutrient demands that cannot be met through food alone.”  

In other words, food first, supplements second.

Here’s why …

Cost vs. Benefit: Is It Worth It? 

Evidence from research studies and surveys suggests that a majority of athletes today use supplements of some kind, with numbers ranging from 48-100%, and the average intake of three supplements on a daily basis. 

In the ever-growing world of nutritional supplements, there are only a few that are supported by solid scientific evidence. Furthermore, genetics, gender, age, training status, habitual diet, and other individual variations can influence the effectiveness of a supplement, regardless of evidence for its ergogenic effect. Finally, just because a supplement has proven benefits, doesn’t mean it is right for you. 

Nutritional Supplements for Triathlon

Carbohydrate: Daily Carbohydrate and Carbohydrate Loading

Despite the upsurge in low-carbohydrate, high-fat diets (LCHF), especially with endurance athletes, very few studies show improved performance in race-simulated settings. Chronically low dietary carbohydrate intake negatively impacts muscle glycogen stores and decreases an athlete’s ability to access and use carbohydrates when high-intensity efforts are needed, oftentimes at critical times in a race (surges, breakaways, hill climbs, and sprint finishes).

By no means am I suggesting a high carbohydrate intake every day, but it does mean fueling for the work required on a meal by meal basis. For carbohydrate loading (24 hours pre-race), which can be used with a LCHF or standard diet, ingestion of 7-12 grams of carbohydrate per kilogram of body weight can maximize muscle glycogen stores within 24 hours. By doing so, the size of your fuel tank is increased and topped off. Foods rich in carbohydrate and low in fiber and fat – such as bananas, mango, rice, pasta, potatoes, dates, maple syrup, crackers, wraps, and breads – can help you achieve high glycogen stores and avoid gastrointestinal (GI) distress.

Carbohydrate During Training and Racing  

Carbohydrate is ergogenic (performance-enhancing) during exercise for two reasons. The first is metabolic; carbohydrate ingestion helps maintain blood glucose and high carbohydrate oxidation, which delays fatigue by sparing glycogen stores. The second mechanism is neurological; glucose is a key fuel for the brain, and hypoglycemia contributes to central nervous system fatigue and poor performance. During exercise lasting longer than 2-3 hours, carbohydrate should be ingested to maintain effort. The hourly intake varies based on metabolic flexibility, the goal of the session, mode of training (swimming, cycling, or running), and digestion. Tried and true sports foods, bars, powders, and drinks can be used, in addition to, or instead of, real food options. 

Carbohydrate for Recovery

Finally, carbohydrate is needed for recovery. Ingesting 0.3-0.5 grams of protein per kilogram of body weight with 1.0-1.5 grams of carbohydrate per kilogram of body weight improves the absorption of protein and enables quicker recovery. Due to the high fructose content (fructose takes longer to digest than other forms of sugar), fruit should not be the first-choice carbohydrate for recovery, especially for women. Some great recovery ideas include non-fat Greek yoghurt with granola; cottage cheese on a bagel; instant oatmeal with protein powder, scrambled eggs and potatoes, or chicken and rice. 


Caffeine is a naturally-occurring plant phytochemical and is one of the most consumed substances in the world. Caffeine can reduce pain perception by activating endorphin release in the brain, stimulate muscle contraction by activation of calcium, and lessen muscle fatigue by activating adrenaline secretion and increased potassium uptake. Caffeine further benefits endurance athletes because it increases fat utilization and decreases glycogen breakdown at the start of exercise, which spares carbohydrate stores. 

Current dose recommendations for caffeine are 3-6 milligrams per kilogram of body weight. Higher doses (>9 milligrams per kilogram of body weight) have no additional benefit but come with increased risk of GI distress, tremors, tachycardia, arrhythmia, nervousness, insomnia, headache, and irritability. Generally, caffeine levels peak in the blood approximately 1 hour after ingestion; however, when taken with carbohydrate, the rate of appearance can be faster.  As with any supplement or food, try caffeine in training before using it in competition and start with the lowest recommended dose. 

Dietary Nitrates and Beet Root Juice?

Dietary inorganic nitrate supplementation in the form of beetroot juice has become a popular ergogenic aid among athletes. It is known in endurance sport for reducing the amount of oxygen needed for a set effort, in addition to enhancing blood flow. In other words, saving energy, making exercise seem easier, reducing fatigue, and delivering more oxygen and nutrients to working tissue. However, a 2019 study found that the benefits of beet root and nitrates/nitrites might be gender-specific, and benefits in the female athlete population to be undetermined.

For male endurance athletes, evidence is strong for enhanced endurance with both acute (2-3 hours pre-exercise) and chronic (>6 days) intake of 310-560 milligrams of dietary nitrate. Achieving this level through food alone would be challenging, and concentrated beet juice is oftentimes preferred. Because bacteria in the mouth are needed for nitrate breakdown, beetroot should not be consumed after the use of chewing gum, mouthwash or toothpaste. Recreational/untrained athletes see more benefit from supplementation, and trained athletes need higher doses or longer duration regimens (7-15 days). Doses greater than 560 milligrams have been associated with GI distress and long-term dosing may not be realistic as the antioxidant properties of beetroot may interfere with exercise adaptation.

Boosting Daily Nutrition – Food First, Supplements Second 

With few exceptions, food-source vitamins, minerals, and nutrients are absorbed better than a pill or powder form. Moreover, real foods come with additional benefits such as fiber and antioxidants, and oftentimes include a combination of nutrients that enhance each other’s absorption, such as the vitamin D and fat in egg yolks, or the spectrum of amino acids in quinoa.

Choosing to supplement your daily food intake with a vitamin or mineral should be focused on your present need or individual characteristics. These include, but are not limited to, injury, menstrual cycle phase, age group, dietary practices, time of year and where you live, and most definitely, personal lab results.

Final Tips When Purchasing Supplements

Athletes are especially susceptible to supplement-overdose. Unfortunately, the supplement industry is poorly regulated. A 2017 investigation of 274 supplements found that all contained unclaimed ingredients, from stimulants and hormones, to plastics and tars. Furthermore, allergic reactions and adverse side effects can occur in even clean supplements.

Some tips when buying a supplement: 

  • Choose products that have “Nutrition Facts” labels (these are regulated), rather than “Supplements Facts”
  • Look for third-party quality assurance, such as NSF Certification, USP verification, and the Informed Choice checkmark. A web search of these labels will also generate a list of approved companies and products. NOTE: just because one supplement from a company is assured, that does not mean ALL of their products are. 
  • Read the ingredient list, but know that this list may not be all-inclusive, and there is always a risk for contamination and undeclared substances.
  • Stay away from “proprietary” or “herbal” blends
  • Consider financial cost, medication interference, and practicality
  • Talk to a Registered Sports Dietitian with the credentials RD, CSSD, with a minimum of a master’s degree in a performance nutrition-related field.

Heidi Strickler, RD, CSSD, METS I, ISAK I is a Registered Sports Dietitian with eNRG Performance in Colorado. An avid endurance athlete, triathlete, and ultra-runner herself, she has a passion for providing nutrition coaching to endurance athletes. She also specializes in plant-based nutrition, female physiology, and collegiate athlete nutrition. In July, she will graduate with a Master’s degree in Sports Nutrition from Liverpool John Moores University in England, United Kingdom. Find out more about Heidi at

The views expressed in this article are the opinion of the author and not necessarily the practices of USA Triathlon. Before starting any new diet or exercise program, you should check with your physician and/or coach.


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