There are multiple reasons for GI distress in endurance athletes. Some of the most important reasons are: decreased blood flow to stomach; high osmolality in foods and drinks and improper dietary preparation.
Adequate blood flow to the stomach requires that the athlete have an adequate hemoglobin, meaning not have anemia. Runners and endurance multisport athletes loose blood in their gut from the pounding of the intestines during the run and the use of anti-inflammatory medicines. This group of athletes are most prone to anemia. It is important to check your hemoglobin or red blood cell count on at least a yearly basis and to use multivitamins with iron if indicated. An easily digested multi-vitamin with iron is recommended to avoid gut issues with the vitamin. Slow release or iron that is attached to a carbohydrate is more easily absorbed. If you have anemia and require iron, try different formulations to find one that is easily tolerated, like MultiV from First Endurance.
Adequate blood flow to the GI tract also requires that the athlete have adequate fluid on the run and prior to the race. Consume a sports drink that provides sufficient energy and electrolytes, is rapidly absorbed, has a good palatability, and quenches thirst. It has been suggested that a reduction in mesenteric blood flow by more than 50% causes a linear fall in the rate of glucose absorption. Liquids are the preferred source of energy during strenuous physical exercise. Note also that the body can sweat out two liters an hour but the stomach can only absorb 800 ml per hour, less than one half that amount. Thus it is important to hydrate before the race and if doing multisport racing, while on the bike. Due to oxidative stress and loss of blood in the gut, Ironman athletes and long distance runners, may have a higher susceptibility to ischemic colitis and various inflammatory diseases.
Ischemic colitis is a disorder in which part of our colon becomes inflamed and injured. This is usually caused by low blood flow to your colon, which can lead to inflammation and in some cases permanent colon damage. Urgent bowel movements and bloody diarrhea are common symptoms to look for. Ischemic colitis is complicated by running and long distance training under dehydrated and hyponatremic (low electrolyte levels) states. The avoidance of dehydration and animal based proteins which forms the basis of the western diet is an important factor in avoiding these complications and diseases.
Eating during and just prior to a race requires that the diet exclude foods that are going to increase intestinal motility. Thus fiber in the diet should be decreased during the days leading up to and during the race. Milk products and heavy proteins such as gluten, are not easily digested and will increase GI motility. Simple sugars and large meals will cause cramping and diarrhea. Carbohydrate loading “benefits” may be offset by diarrhea and abdominal discomfort. Athletes may take an alternate route by supplementing with a high carbohydrate beverage, and decreasing their intake of fiber and “heavy” foods the week of, the day before, and the morning of, a race. The goal is to minimize the residue in the upper digestive tract and not compromise the caloric needs.
Multiple small meals and/or grazing should be a part of the endurance athlete’s lifestyle. The use of foods that improve the ability to combat free radical injury should be a daily activity not something just prior to a race. Endurance racing results in the production of free radicals. The use of anti-inflammatory foods on a regular basis will help to reduce free radicals and the development of lactic acidosis. Anti-inflammatory foods help to keep the gut healthy as well as providing anti-oxidants for muscles that are stressed during exercise.
Inflammation, defined as a localized reaction of tissue to irritation, injury or infection, is in fact part of a healthy immune system. We all know how our body responds to a cut finger or sprained ankle; pain, redness and swelling – all signs of inflammation. There are many causes for inflammation but the most important one is diet. Scientists have found that over time low-level, chronic inflammation has been linked to serious illnesses, including heart disease, asthma, arthritis, diabetes, osteoporosis, Alzheimer’s disease, and even depression and mood disorders. Avoidance of animal based proteins which forms the basis of the western diet is critically important in avoiding western diseases.
There is an important distinction that needs to be made in order to classify the true inflammatory culprits in the human diet. Athletes in general are keenly in tune with their bodies and can identify foods that do not agree with their GI systems. This is very individual with what each body can digest. Such foods are not necessarily inflammatory, but rather difficult to digest or irritating for the GI system. On the other hand, inflammatory foods may play a big role in the process of cancers, arthritis and heart disease. Research (The China Study) shows the primary cause for true inflammation originates in animal proteins. Apparently animal proteins in our diet is more important than the toxins in our environment for the development of inflammatory disease, heart disease and cancer. This is very different from the problem of irritation of the intestinal tract which is due to inadequate blood flow and irritating foods. Avoidance of high osmolar foods and simple sugars is important. The use of medium chain triglycerides instead of heavy proteins should be considered and adequate hydration and training are critical.
Triathlon is a sport that age, wisdom and experience can be a tool and benefit. So we need to care for our bodies. The 42 year old Olympic silver medalist Dara Torres said, “We shouldn’t put age limits on our dreams.” Most of us do not have thousands of dollars to spend on our health and bodies. Diet is the simplest and most clear cut method to continue our passion and pursue our dreams late into life.
Examples of Irritating Foods:
- Processed sugars and refined carbohydrates white flour, simple sugars
- Gluten Wheat, rye, spelt, barley
- Dairy milk, cheese
- Hydrogenated Oils
- Inflammatory Foods:
- Beef, Pork especially high in non-grass fed animals
- Cheese, ice cream
Examples of Anti-Inflammatory Foods:
- Salmon Wild-caught, Omega 3 fatty acid foods
- Nuts walnuts, almonds, pecans,
- Dark Green leafy veggies kale, spinach, chard, Vit E and inflammatory-fighting carotenoids
- Fruits especially berries
- Sweet Potatoes
- Spices ginger, turmeric, garlic
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Murray, B, Stofan J, Sallis B. Return to competition following ischemic colitis caused by severe dehydration. Journal of Sports Rehabilitation. 2007 Aug;16(3):271-6.
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Your Healing Diet, 2005, Dierdre Earls
China Study, 2005, T. Colin Campbell