Gut Feelings — GI Distress in Athletes
Today’s Dietitian
By Victoria Shanta-Retelny, RD, LD
Vol. 7, No. 3, p. 38

Grueling schedules and striving for top-level performance often put athletes at risk for GI distress. How can you help them?

The last thing an athlete needs when in the “zone” during a competition is for his or her gastrointestinal (GI) tract to act up. GI conditions such as heartburn, gas pains, bloating, diarrhea, constipation, nausea, or vomiting often affect competition. A number of factors, such as type of sport, timing of meals, irregular schedule, preexisting health conditions, frequent travel, environmental temperature, age, and gender, result in an athlete’s gut being overactive or underactive.

“It can be an athlete’s biggest worry,” says Nancy Clark, MS, RD, a Boston-based sports nutritionist and author of Nancy Clark’s Sports Nutrition Guidebook, third edition. Clark works with the whole spectrum of athletes in various age groups and at various athletic levels. “To get people to talk about GI problems can be difficult, but it is a big concern,” she explains. By normalizing the GI symptoms—whether upper (heartburn, nausea and vomiting, belching) or lower (bloating, gas, diarrhea, or constipation)—patients will more easily disclose their symptoms. “Make it a normal part of the nutrition assessment to ask if a patient/client is experiencing constipation or diarrhea,” Clark says. “A big part of training is to train the intestinal tract.”

Age and athletic level play a big role when making nutritional recommendations. “Although little children don’t like to talk about vomiting and diarrhea, more competitive college-age and professional athletes know that performance will suffer if they don’t talk about it,” explains Roberta Anding, MS, RD, LD, CDE, a national spokesperson for the American Dietetic Association (ADA), clinical dietitian in adolescent/sports medicine at Baylor College of Medicine, and nutrition consultant for the Houston Texans National Football League team. “In my experience, 10% to 15% of professional athletes talk about their GI distress,” cites Anding.

Sweating It Out
One of the more difficult causes of GI distress is extreme sweating and fluid losses in athletes. When cyclists exercise at competitive intensities for two hours in the heat at the sweat rate of 1,400 milliliters per hour, the closer that fluid consumption matches sweating rate (at least up to 80% of sweating rate), the better for both performance and maintaining normal GI function.1 In hot and humid climates like Houston, the Texan players’ high sweat rates make it difficult to keep up with volume of fluid losses, explains Anding. “We have a problem of players losing sweat everywhere—especially in their trunks—and it is difficult to get the stomach to empty fast enough to accommodate the fluid needs. As a result, players are ‘sloshing’ on the field with a stomach full of liquid,” explains the Texans’ dietitian.

To enhance, not hinder, performance, the type and quantity of fluids matter. According to an ADA position paper, beverages should taste good to promote consumption but not cause gastric distress.2 Beverages that use fructose as the principle carbohydrate source may cause gastric distress in some athletes and require more time before they can be used by the muscles as fuel because of the time needed to convert fructose to glucose.3

“In terms of beverage recommendations, noncarbonated is better because it delays gastric emptying,” says Leslie Bonci, MPH, RD, director of sports medicine nutrition at the University of Pittsburgh Medical Center and author of the ADA’s Guide to Better Digestion. In her presentation “Gut Reaction: How To Manage Gastrointestinal Distress in Athletes” at the ADA Food & Nutrition Conference & Expo in October 2004, Bonci recommended that athletes hydrate with a maximum of 6% carbohydrate solution. “Anything greater than 10% carbohydrate solution leads to delayed gastric emptying and is not comfortable for our athletes,” Bonci explains. She recommends no more than 2 liters or 20 to 40 ounces per hour due to potential hyponatremia and/or water toxicity. “We want our athletes to drink enough, not overdrink,” she says. According to Bonci, a good rule of thumb is to have athletes practice gulping, not sipping, fluids prior to the day of the event. She recommends bringing a sports bottle with a pop top to competition or a cup with a wider mouth to force larger volumes. “By gulping repeated volumes of fluid, it allows for maintenance of higher stomach volumes, and it’s more comfortable in preventing dehydration and stomach upset.”

Performance Jitters
Imagine the bundle of energy, nerves, and excitement that an athlete is on game day or right before he or she is to perform in a competition. Whether a figure skater, wrestler, football player, ballet dancer, swimmer, or marathon runner, the potential for GI distress is there. The emotional intensity of competition can pose GI problems.

One of those problems is vomiting. “I have a player who throws up before each game because he is so intense and keyed up,” describes Anding. “We have tried everything from setting his alarm early so that he has ample time to eat before the game, eating less food closer to game time, and bringing his own food on the road so he does not have to rely on room service.”

Since each player has different needs, it is all about trial and error. Anding refers to the “learned food aversion” theory in which players do not want to chance eating a particular food or beverage if it made them feel GI discomfort in the past.

GI Nutrition Assessment
“There are obvious signs to look for during the nutrition assessment, such as fiber intake, constipation, and hydration status,” says Clark. “Adjust the fiber if its too much, add more water for constipation, and if he or she is urinating every two to four hours, then hydration status is good.” Gathering information about GI symptoms is all in the way that the sports nutritionist communicates with the patient/client. Athletes are eager learners and recognize that proper fueling is an important and integral part of a training program, and they commonly have a keen interest in nutrition.4 To be an effective sports nutrition communicator and determine the correct nutrition
recommendations, the following characteristics should be assessed:

• normal nutrition needs to support growth and health;

• nutrition needs during daily training;

• sport-specific needs preceding, during, and following competition; and

• special nutrition needs due to health concerns (eg, gastroesophageal reflux disease [GERD], irritable bowel syndrome, Crohn’s disease, lactose intolerance).5

Influencing Factors
In the book Sports Nutrition: An Introduction to Energy Production and Performance, the authors, Asker Jeukendrup, MSc, PhD, and Michael Gleeson, BSc, PhD, have identified the major factors that affect gastric emptying in athletes: the smell and sight of food, thought of food, volume of a drink, energy density of a drink, temperature of a drink, osmolarity of a drink, body temperature and dehydration, type of exercise, exercise intensity, gender, and psychological stress and anxiety.6 In an athlete’s competitive life, all these play a factor in gastric well-being. Jeukendrup and Gleeson point out that GI problems are a common phenomenon, mainly among endurance athletes, and the incidence is increased by ingestion of concentrated carbohydrate drinks during the race, a high-fiber or high-fat intake before the race, and dehydration.6

Type of Sport
As for type of sport with the most GI complaints, “jostling activities, such as running, basketball, and soccer, are more of a problem,” according to Bonci. The more GI-stable sports, such as cross-country skiing, swimming, and cycling, are less problematic for the gut. Sports medicine experts speculate that the vertical up-and-down gut movements during running activities is the primary culprit. Therefore, it makes sense that the majority of studies, which have investigated the incidence of gastrointestinal symptoms during competition, typically involve running or triathlons.

In a study of 1,700 participants after a marathon race, lower-GI symptoms, such as diarrhea, abdominal cramps, urge to defecate, flatulence, and gastrointestinal bleeding, were found to be more common than upper-GI symptoms, such as nausea, vomiting, heartburn, bloating, and side ache (stitch).7 The urge to defecate during and after running was the most common symptom, with 36% to 39% of the participants reporting this symptom. The others were bowel movements at 35% and diarrhea at 19% quite frequently right after running. During the race, 16% to 18% of the participants had to stop to defecate and 8% to 10% had to stop because of diarrhea. Bloody bowel movements were reported by 1% to 2% of the participants.7

Gender and Age
Gender makes a difference. Research has shown that lower-GI complaints are more often observed in women than in men. The literature contends that women have a slower gastric-emptying rate than men, yet it does tend to speed up somewhat during ovulation.6 Lower-GI symptoms may worsen around the time of a woman’s menstrual cycle due to an increase of estrogen and progesterone, as well as the production of prostaglandins. Estrogen has been found to slow gastric emptying, resulting in a decrease in GI motility and transit time. The all-too-common menstrual cramping and diarrhea that often accompany menses are believed to be caused by the release of prostaglandins, which affect muscle contraction in the colon.8 This is most likely why women are more prone to GI complaints after prolonged endurance exercise.

Age plays a role when it comes to the GI tract as more symptoms are reported in younger compared with older participants. Younger, novice athletes have more of a problem with GI distress because unlike older, more seasoned athletes, they have not learned how to condition both the muscles and the gut. Keep in mind that young athletes are still children and will be tempted to eat foods that aren’t the best choices for them. The perfect diet for a growing athlete is about balance; he or she needs to understand how food affects performance.9

Keeping in mind that “a happy gut is a happy player,” Bonci contends that there are ways to help with GI symptoms as they arise. She has her clients keep a “symptoms log” to report any changes in bowel movements to more effectively treat the specific problem(s). Avoid competition-day bathroom troubles by having athletes experiment during training with liquids over solids. It’s more about “training the gut, not just the muscles,” according to Bonci.

Travel
What should athletes pack when traveling? Travel can wreak havoc on even the most health-conscious athlete. Since traveling can significantly limit food choices, create difficulty with scheduling meals, and cause athletes to eat in a hurried, rushed fashion, Bonci recommends some eating essentials for the road to keep the GI tract functioning well.

Bonci mentions the following key items: sports drink powder because it’s simple to use and helps with nausea and vomiting; chamomile tea as it is known for its antispasmodic properties; flaxseed to help with constipation; candied ginger root to settle the stomach and rid the body of nausea; and real raspberry (not flavored) tea because the natural tannins can help with diarrhea.

Supplements
Many stomach upsets are due to the ingestion of dietary supplements. According to Anding, “Most collegiate and professional athletes use supplements.” The key is making sure their supplementation use is approved by both a doctor and/or dietitian. For example, lactose-intolerant individuals taking supplements that they are unaware contain lactose are going to experience GI distress and not know why. Another example is iron supplementation; taking iron on an empty stomach can induce nausea and/or constipation. Magnesium supplements can create GI problems, such as cramps and/or nausea.

A survey by the National Strength and Conditioning Association showed that 71% of coaches encouraged supplement use among athletes.10 A large number of coaches (92%) believed the performance of professional athletes was enhanced. A similar number of coaches (91%) believed the performance of collegiate athletes was enhanced, and 65% believed the performance of high school athletes was enhanced.10 The purpose of nutrition ergogenic aids is to enhance performance above levels anticipated under normal conditions.11 However, this is not always the case as some detract from performance by causing GI distress. Bonci named a number of ergogenic aids that can have adverse GI effects, including flaxseed oil, which can cause a laxative effect; echinacea, which can cause nausea; bee pollen, which can upset the stomach; gamma linoleic acid, which can also upset the stomach; ginseng, which can cause extreme nausea; and fish oil, which can cause heartburn.

Disease-Specific GI Distress
Helping athletes manage a specific intestinal disorder can be a daunting task without the right tools. In Bonci’s book, she mentions “gut survival skills,” which concentrate on four areas: appropriate food choices, eating behaviors, lifestyle activities, and stress management.8

When managing the nutritional concerns of an athlete with a GI disorder, whether it’s ulcerative colitis, Crohn’s disease, GERD, or constipation, allow the athlete to listen to his or her body. When making food choices, what is appropriate for one person may not work well for another. Emphasize that a balanced, varied diet is essential for good health and optimal performance. The key is customizing the meal plan to include foods and portions that can be easily tolerated. For example, if an athlete has GERD, eating small, low-fat meals at regular intervals of the day would make for a happier, healthier GI tract.

Since athletes are usually on the go, it is important that they stop long enough to eat. Many athletes’ eating behaviors are less than gut-friendly, and as a result they often end up with an upset stomach. Remind athletes that eating habits are just as important as food choices. Tell them that eating should be a priority—not an afterthought—and mealtime should be a relaxing experience.

— Victoria Shanta-Retelny, RD, LD, is a practicing dietitian at Northwestern
Memorial Wellness Institute in Chicago, a freelance food and nutrition writer, and a culinary spokesperson.

References
1. Coyle EF, Montain SJ. Benefits of fluid replacement with carbohydrate during exercise. Med Sci Sports Exerc. 1992;24(9 suppl):S324-S330.

2. Position of the American Dietetic Association and the Canadian Dietetic Association: Nutrition for physical fitness and athletic performance for adults. J Am Diet Assoc. 1993;6(93):1-13.

3. Fruth JM, Gisolfi CV. Effects of carbohydrate consumption on endurance performance: Fructose versus glucose. In: Fox EL, ed. Nutrient Utilization During Exercise. Columbus, Ohio: Ross Laboratories; 1983.

4. Clark N. Communicating with athletes about nutrition. Sports nutrition: A guide for the professional with active people. ADA. 2000:247.

5. Storlie J. Nutrition assessment of athletes: A model for integrating nutrition and physical performance indicators. Int J Sport Nutr. 1991;1:192-204.

6. Jeukendrup A, Gleeson M. Gastric emptying, digestion, and absorption. In: Sports Nutrition: An Introduction to Energy Production and Performance. Champaign, Ill.: Human Kinetics; 2004:81-99.

7. Keeffe EB, Lowe DK, Gross JR, Wayne R. Gastrointestinal symptoms of marathon runners. West J Med. 1984;141:481-484.

8. Bonci L. American Dietetic Association Guide to Better Digestion. Wiley; 2003:102-103.

9. Litt A. Fuel for Young Athletes: Essential Foods and Fluids for Future Athletes. Champaign, Ill.: Human Kinetics;2004.

10. National Strength and Conditioning Association. Use of dietary supplements in sports training. Bulletin. 1998;19:1.

11. Skinner R, Coleman E, Rosenbloom CA. Ergogenic aids. In: Rosenbloom CA, ed. Sports Nutrition: A Guide for the Professional Working with Active People. Chicago: The American Dietetic Association; 2000:107.

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