Cyclists are rightly concerned with eating foods that maximize energy and optimize recovery. But eating the right foods can also give your immune system a supportive boost. Unlike your heart and lungs, which are strengthened by training, your immune system may be a bit fragile. Combining training with work and a personal life can often overtax your resources, stress your body, and compromise your ability to fight off infection.
A healthy immune system consists of a defending army, always prepared to protect your body against attacks from viruses, bacteria and other foreign invaders. Your skin and the mucous lining in your lungs represent your body’s first line of defense, while various types of white blood cells are another crucial component of your immune system. A strong immune system should result in fewer colds and viruses, and if you do become ill, recovery should be quicker. Proper nutrition, with a focus on fresh whole foods, is essential to a strong immune system. For example, adequate vitamin A is required to maintain the protective barriers which line your mouth and lungs. If take-out and packaged foods are two of your regular dietary staples, and you get most of your carbohydrate needs from energy bars, recovery drinks and carbohydrate-electrolyte beverages, your diet may not be supporting your immune system. Let’s take a look at how specific foods can strengthen your immune system by adding certain nutrients to your diet. I call this the “build” period and usually schedule it to last six to eight weeks. The name “specific preparation” comes from training that is specific to the event for which you’re training. Intervals of all kinds, fast group rides, anaerobic hill repeats, and off-road time trials are typical in the specific preparation period. But they don’t have to be. The idea is to do workouts that simulate what you expect the race conditions to be like. Essential fatty acids One downside to the low-fat diet craze may be an inadequate intake of essential fatty acids. Because your body cannot manufacture them, you need to ingest small amounts of linoleic acid and alpha-linoleic fatty acids that support your immune system. Competition Period This is the period you’ve been aiming for – the week of an A-priority race. There should only be two or three competition periods in a season. Since you peak and taper for each of these, more than that will prevent you from maintaining your fitness. It may be necessary to return to an abbreviated base period following a competition period to regain some of that lost fitness. Linoleic acid is an omega-6 fat found in several vegetable oils, including safflower, sunflower and corn oils. Average Americans get plenty of omega-6 fat in their diets. Unfortunately, it is often consumed in the hydrogenated form – in margarine and commercial baked goods, for example. Stick with small amounts of liquid sources of these fats. What you should emphasize in your diet is alpha-linoleic acid, or omega-3 fatty acids. They are more limited in the American diet and are great for boosting your immune system. Good sources of omega-3 fatty acids include fish, flaxseed and flaxseed oil, walnuts and canola oil. Try to consume fish several times weekly, and use reasonable amounts of the omega-3-containing oils. Vitamin A and carotenoids Eating foods high in carotenoids, like beta-carotene, alpha-carotene, leutin and lycopene, is also a good investment in your immune system. Studies suggest that carotenoids may increase the activity of white blood cells called lymphocytes. Good sources of carotenoids include winter squashes, carrots, apricots, broccoli and green leafy vegetables such as collard greens. One recently published study suggests that lycopene, which gives tomatoes, guava, watermelon and pink grapefruit their red color, may have immune-enhancing properties. Researchers in Milan showed that a three-week diet rich in tomato purée helped protect white blood cells. Tomato sauce is one of the best sources of lycopene, and one of the most easily absorbed. Vitamin C Vitamin C has a wide-spread reputation as an immunity booster. While many individuals choose to take supplements of this popular vitamin, don’t short-change yourself on good food sources. Experts recommend a minimum of five servings of fruits and vegetables daily, but up to nine servings daily is ideal. Fruits and vegetables generally contain useful amounts of vitamin C, especially when super-fresh. More importantly, they also contain hundreds of phytochemicals which provide many preventative health benefits. Some good sources of vitamin C include citrus fruits and juices, strawberries, bell peppers, broccoli and cauliflower, kiwi fruit, kale and dark leafy greens. Try to maintain a variety of them in your diet. Trace minerals Minerals, such as iron, zinc and copper are an important part of keeping your immune system healthy. Moderate amounts of these nutrients in your diet are entirely sufficient. In fact, an excess of these helpful minerals may even depress your immune system and exacerbate the infection process. But you can boost your immune system by ensuring that your diet provides good food sources of these nutrients, and you are unlikely to overdo your intake if you stick with food and avoid mega-supplements. Good sources of iron include animal foods such as lean meats. You can also obtain iron from plant foods, though it is less well absorbed. Plants sources include lentils and dried beans, wheat germ, apricots and fortified cereals. Combining these plant sources with food sources of vitamin C will increase your absorption of plant iron. Zinc has recently gained a reputation as an immune booster that can decrease the severity of colds. It may also be lacking in your diet. Zinc is abundant in oysters and in other seafood sources like tuna and shrimp. Lean meats also provide zinc, as do some plant foods such as dried peas and beans, and wheat germ and whole grains. It may also be worth looking at good food sources of copper. Foods such as seafood, lean meats, nuts, beans and grain products supply this mineral, which works closely with iron. Odds and ends Garlic has intrigued researchers in regards to its ability to strengthen the immune system. This immune boost probably comes from the most active ingredient in garlic called allicin. (Of course, if you eat enough raw garlic, no one will come near you, which will also keep germs at bay.) Research shows that you need the equivalent of one clove of garlic daily. Pure garlic powder also contains allicin, but it is such a culinary abomination that you’re better off sticking with the fresh stuff. Shiitake mushrooms have been prized by people in China, Japan and other countries in Asia for thousands of years for a variety of health benefits, including boosting the immune system. Lentinan is a substance extracted from shiitake and is thought by scientists to be the active ingredient. Shiitake mushrooms are sold in most grocery stores, in both fresh and dried varieties. Look for meaty, plump caps and try them sautéed, stir-fried, marinated or grilled. Immune system blueprint Good wholesome food sources can go a long way in keeping your immune system healthy. Try to eat a wide variety of foods including whole grains, five to nine servings of fruits and vegetables daily, moderate amounts of nuts and seeds, dried peas and beans, and good sources of trace minerals. Keep your fat intake to less than 30-percent of total calories, using only small amounts of liquid polyunsaturated oils. Increase your intake of flaxseed oil, and sources of omega-3 fatty acids. Taking a multivitamin and mineral supplement providing 100 percent of the daily values may also be of benefit to your immune system, as may other supplement strategies.
Monique Ryan, MS, RD, LDN is a nationally recognized nutritionist with over twenty-two years of experience and is owner of Personal Nutrition Designs, a Chicago based nutrition consulting company that provides nutrition programs for endurance athletes across North America. Monique consults with the Chicago Fire Soccer Team, and was the nutritionist for Saturn Cycling from 1994 to 2000. She has also consulted with the Volvo-Cannondale Mountain Bike Team, the Gary Fisher Mountain Bike Team, and the Rollerblade Racing Team. Monique has consulted with USA Cycling, and was a member of the Performance Enhancement Team for the Women’s Road Team leading to the 2004 Athens Olympics. She has also provided nutrition consultation services to USA Triathlon for coaching clinics, athlete clinics, and for the resident athlete team and was a member of the USAT Performance Enhancement Team for the 2004 Athens Olympics. Monique is the author of “SportsNutrition for Endurance Athletes,” 2nd edition (March 2007), from VeloPress,which provides sports specific nutrition for road cycling, mountain biking, running, triathlon, swimming, rowing, and adventure racing. She is also author of “PerformanceNutrition for Winter Sports” (PeakSports Press), “Performance Nutritionfor Team Sports” (PeakSports Press), and “Complete Guide to Sports Nutrition. Monique is a regular contributor to VeloNews, Inside Triathlon, Outside, and ACE Fitness Matters. Please send your questions to firstname.lastname@example.org.