I fear getting sick when I travel to competitions. Anything I can eat to prevent illness?
What are the best foods to boost my immune system?
I have nasty scrapes on my knees from when I fell. Will extra protein help speed recovery and fight infection?”
Staying healthy is a top priority for athletes who want to be able to train well, improve their athletic performance, and compete at a high level. But athletes get sick and injured. Even if you eat the healthiest diet around, ACL tears, broken bones, cuts, scrapes, and bruises happen—to say nothing of colds, Covid, and the flu. Nutrition is key to reducing the risk of illness and injury, as well as speeding up recovery. Older athletes, in particular, want to enjoy an immuno-protective diet due to reduced immune function with aging.
The immune system is a highly active organ system, distributed through the whole body. How well it functions depends on how well you nourish it. Athletes who skimp on food and have lackluster nutrition are more likely to get sick and injured compared to well-nourished athletes. Fighting inflammation demands a good diet.
Moderate exercise itself improves immune function and is health protective. In comparison, intense and prolonged endurance exercise is associated with depressed immune function. That’s why athletes (and everyone, for that matter) want to eat well on a daily basis, to reduce their risk of illness and injury. Inadequate sleep, anxiety, mental and physical stress can also erode immune function, as can dehydration. (The first line of immune defense is a mouth moist with saliva.) Good nutrition helps nip in the bud little niggling injuries that can explode into bigger ones, and sniffles that can turn into pneumonia This article offers nutrition tips for athletes who want to optimize their immune function to fend off illness and injury as well as enhance recovery from daily training sessions.
- Eat enough calories. The less you eat, the less energy your body has to repair and heal itself—and the fewer nutrients you consume. Chronically skimping on food (i.e., stopping eating because you think you should or the food is gone, and not because you feel satisfied) can easily predispose an athlete to muscle, tendon, and ligament injuries and is associated with deficiencies in calcium, iron, vitamin D, carb and protein.
- Eat enough protein. Protein provides amino acids that are the building blocks needed to make antibodies and other antimicrobial factors involved in the healing process. Athletes should target about 20 to 30 grams of protein per meal. That’s the equivalent of three eggs or a can of tuna or 1 cup of cottage cheese or 5 tablespoons of peanut butter or the whole 15-oz. can of kidney beans. Note: you need to eat more calories of plant (as compared to animal) protein to consume enough of the amino acids that are essential for fighting infection. Injured athletes who are unable to train can easily consume too little protein if they fear weight gain and cut too many calories. After surgery such as ACL repair or joint replacement, athletes may also fail to eat enough protein due to lack of appetite.
- Eat enough carbohydrates: Without carbs for fuel, the body burns protein. Hence, a steady carbohydrate intake (preferably from nutrient-dense, fiber-rich whole grains, vegetables, and fruits) can spare protein from being used for fuel. The recommended intake (1.5 to 2.25 g carb/lb body weight (3-5 g/kg) per day translates into consuming about 200 to 350 calories from starches, fruits, and veggies per meal. Don’t be one of the too many athletes who overeat protein and skimp on grains. If that sounds familiar because you fear carbs are fattening, think again. Excess calories of any kind of food are fattening.
- Carbs are particularly important during prolonged exercise. Endurance athletes should consume at least 30-60 grams of carb per hour during exercise—and >60 g/h during sessions lasting for more than two hours—to reduce hypoglycemia with its stress-hormone response that negatively impacts the immune system. After a hard workout, refueling with carbs+ protein (for example, chocolate milk) within 2 hours helps restore immune function and optimizes recovery.
- Enjoy healthy fat at each meal. Healthy fats that knock down inflammation include avocado, peanut butter, olive oil, and oily fish (salmon, sardines). Including some healthy fat in each meal not only helps tame inflammation but also enhances absorption of health-protective vitamins A, D, E, and K. Fat also makes the food taste good; it carries flavor. You’ll want to adjust your fat intake according to how many calories you need after having met your protein and carb requirements.
- Choose primarily nutrient-dense foods for vitamins and minerals. Deeply colored fruit (oranges, blueberries, strawberries) and veggies (broccoli, carrots, red peppers) are rich in not only vitamins and minerals but also many immune-boosting phytochemicals. They are better than anything you’ll find in a pill. Some nutrients can be hard to consume without supplements:
—Vitamin D (2,000-4,000 IU/day during winter months to maintain a normal blood level),
—Iron (pills should be taken under medical supervision), and
—Omega-3 fats DHA and EPA if you don’t eat fish (250 mg/day may benefit immune tolerance and reduce inflammation).
Supplements such as HMB, creatine, collagen, and probiotics may or may not be helpful; responses vary from athlete to athlete. - Keep your gut happy. An estimated 80% to 90% of immune function stems from gut microbes. They thrive on fiber-rich fruit, vegetables, and whole grains, as well as fermented foods such as yogurt, kefir, and kombucha.
The bottom line: To create a strong defense system that helps fend off illness and the risk of getting injured, you want to keep your immune system well-fortified with adequate protein, calories, and fiber-rich carbs. By eating for health (more so than dieting to lose weight), you’ll boost your chances of getting to the podium.
Reference:
Kozjek NR et al. Nutrition for Optimising Immune Function and Recovery from Injury in Sports, Clinical Nutrition ESPEN, Jan 2025
Nancy Clark MS RD CSSD counsels both fitness exercisers and competitive athletes in the Boston-area (617-962-4382). Her best-selling Sports Nutrition Guidebook is a popular, easy-to-read resource. Visit NancyClarkRD.com for more information.