How to Eat for Immunity

Protect your health with these immune-boosting nutrition tips.

You are what you eat — and what you eat can make or break your immunity. A poor diet that delivers empty calories and artificial ingredients into your body combined with an intense exercise regimen, lack of sleep and stress can compromise your immune system, making you more prone to injury and putting a halt to your results. Bulletproof your health with these research-backed nutritional strategies and avoid being bedridden by bad bugs.

Keep Quality Carbohydrates

Carbs are getting a bad rap these days, especially with the popularity of the ketogenic diet, but they happen to be the main fuel source for athletes and the preferred source of fuel for your brain. However, the kind of carbohydrates you ingest affects not only your brain power and physical strength but also your immunity. Simple sugars (glucose, fructose, sucrose, honey) such as are found in candy and soda can negatively impact immunity by hampering the ability of white blood cells to engulf and kill invading bacteria by as much as 50 percent, according to a study published in The American Journal of Clinical Nutrition. Complex carbs did not cause the same problem, according to the same study: They are slower to digest, thereby stabilizing blood sugar levels, reducing your stress response, decreasing cortisol and moderating the undesired activation of immune cells. The soluble fiber found in complex carbs such as oatmeal, broccoli and carrots also helps remove toxins from the gut and acts as a prebiotic to nourish the good bacteria that reside in there, and which comprise a good portion of your immune system.

Whenever possible, skip sugary and processed foods and stick to complex and fibrous carbohydrates. If you’re training intensely, carbs should make up 40 to 50 percent of your daily diet. If you’re training more moderately, you can cut that back to about 30 percent. But no matter what your intensity level, eat your carbs close to workout time: Recent research published in the Journal of Applied Physiology found that eating carbs during or after a tough workout helps boost your immune system.

Power Up Your Postworkout Protein

Having protein after training can help accelerate muscle gains and speed recovery, but it also can improve immunity: The antibodies that fight disease are made of protein, so ingesting quality protein after training supplies your body with all it needs to repair and rebuild muscle tissue as well as fight infection. Certain amino acids also help fight inflammation, and proteins that contain zinc such as lean beef, beans and seafood help with the production of infection-fighting white blood cells.

As an athlete, you should err on the higher side of the intake spectrum, getting about 1 gram of protein per pound of bodyweight per day. Choose a variety of clean sources like lean meats, turkey breast, eggs, fish, whey and plant-based protein powders.

Don’t Forget D3

Vitamin D is essential for athletes and has been shown in research to boost athletic performance and to reduce abdominal fat. In terms of immunity, vitamin D can reduce your risk of infectious disease by triggering a strong anti-microbial response to fight off unwanted invaders, stopping infection and disease before they even start.

However, even if you live somewhere sunny, you could still be deficient in vitamin D, especially if you are conscientious and use your daily sunscreen. Supplement in the morning with 1,000 IUs of vitamin D3 (cholecalciferol), the natural form your body makes as a reaction to sunlight, either with or without food.

Be Pro-Active

It’s estimated that 70 to 80 percent of the immune system originates in the gut, and the 10 trillion microorganisms that reside there are mostly responsible for your overall health. Probiotics can help improve digestion and optimize overall health by balancing the “good” and the “bad” bacteria, which is especially important for athletes who are training hard and constantly asking their bodies to perform: Research in the Journal of Science and Medicine in Sport found that athletes had 40 percent fewer colds and gastrointestinal issues when they took a probiotic as compared to those who took a placebo.

Include probiotic foods such as yogurt, kimchi, kefir, sauerkraut and sourdough bread in your weekly diet, and/or choose a probiotic supplement that contains live bacteria to keep your GI tract in the pink.

Cutting Calories = Colds and Flu

It’s common practice to reduce calorie intake when trying to lose fat quickly, but under-eating can do more harm than good. Research from Michigan State University found that cutting back on calories can make you more susceptible to the flu. The reason? With fewer fat stores, your body breaks down your lean tissue to help fight infection, decreasing your metabolic rate. In addition, levels of leptin — the hormone that controls appetite and makes you feel full — decrease when you’re hungry. And because leptin helps regulate basal metabolic rate, a reduction means your metabolism comes to a screeching halt. Low leptin levels also initiate an inflammatory response, further compromising immunity.

Instead of slashing calories, adjust your macronutrient balance to optimize your fat-loss potential, and be satisfied to lose at a slower rate.

Water Works

Staying hydrated is often the most difficult task to master on a daily basis, but maintaining good hydration ensures your blood carries enough oxygen and nutrients to cells, flushes toxins, prevents insomnia and can even reduce your risk of depression. Water also helps produce lymph, which circulates white blood cells, and keeps your eyes, nose and mouth clean to repel dirt, dust and parasites. Furthermore, without adequate water, your GI tract is susceptible to bacterial overgrowth, compromising immunity.

Make it your goal to drink one large glass of water per hour. Add a little lemon to your H2O and get a boost of vitamin C to help fight colds and protect cells, help digestion and aid in detoxification.