Immune-Boosting Foods

Your immune system is your body's best defense against disease. That's why a weakened immune system can put you at risk for things like colds and the flu, digestive issues, fatigue and frequent infections.

The good news is, you can strengthen your immune system with proper nutrition. While there isn't a single food that provides all the nutrients your body needs, eating a variety of foods from all the food groups can help ensure you're getting everything you need to stay healthy.

Victoria Othersen, DO, a board-certified family physician with Franciscan Physician Network in Beech Grove, Indiana, shared foods that strengthen the immune system and tips to incorporate them into your diet.

Foods That Help The Immune System

Good nutrition - along with exercise and getting enough sleep - is key to keeping your body in peak condition so it can fight off germs.

Essential nutrients

Certain vitamins and minerals are essential to support a healthy immune system. Without them, your body is more prone to illness and infection. Essential nutrients include:

• Selenium
• Vitamin A
• Vitamin B
• Vitamin C
• Vitamin D
• Vitamin E
• Zinc

5 foods that are nutrient powerhouses

Get minerals through your diet rather than using supplements. Stock your kitchen with these five nutrient powerhouses:

Lemons

Lemons are loaded with vitamin C and bioflavonoids (an antioxidant that protects cell health). Vitamin C does a lot to keep our bodies healthy, including supporting the immune system. Because our bodies don't make vitamin C, we have to rely on our diet to get the recommended amount of this vital nutrient.

An easy way to do that? Sip lemon water throughout the day. A quarter cup of lemon juice provides 31 percent of your daily needs. Or squirt it on vegetables or into salad dressings. You can also cook with it in recipes like this one for lemon dill salmon.

Garlic

Garlic contains a number of vitamins and minerals crucial to the immune system. But it also has a compound called allicin, which may be a powerful weapon against bacteria and viruses.

It's not hard to find recipes that use garlic, but you can also eat it raw, which preserves more of its health-promoting qualities. Add fresh garlic to salad dressings, dips and marinades.

Almonds

These popular nuts are high in vitamin E, which fortifies the immune system. Keep a bag of almonds in the pantry and grab a handful to eat as a snack. They're packed with protein, fiber and healthy fats to help you feel full until your next meal. You can also toss them into salads, homemade granola or trail mix.

Mushrooms

Mushrooms are filled with selenium, a mineral that protects the body from infection, as well as zinc and vitamins B and D. (The body makes vitamin D when skin is exposed to the sun, but most people need to get some of this nutrient through their diet, as well.)

Grilling portobello mushroom caps like steaks is a favorite recipe for vegetarians and for meatless Mondays. You can also include mushrooms in casseroles or roast them as a simple side dish. (Learn how to roast vegetables in the oven.)

Sweet potatoes

This sweet spud is a delicious immune booster, brimming with vitamin A, which your body needs to protect your cells and fight germs. One sweet potato is enough to meet your daily recommendation of vitamin A.

Just like regular potatoes, you can mash and roast sweet potatoes. You can also use them to make oven-baked fries, hash browns or creamy soup.

Phytochemicals

Phytochemicals, the substances that give fruits and vegetables their bright and varied colors, make our bodies strong and keep them disease-free.

Here are some of the benefits of all four color groups:

Red

Plants like strawberries, raspberries, tomatoes and red bell peppers possess some of the strongest antioxidants known to science. Antioxidants trap and absorb free radicals, those unstable oxygen molecules in the body that can damage cells and lead to cancer. Free radicals are also linked to heart disease.

Orange/yellow

Mangos, carrots and sweet potatoes are loaded with the antioxidant beta-carotene. They're also packed with vitamin A, which boosts your immune system and is crucial to healthy eyes and strong bones. Besides being a powerhouse of vitamin C, oranges contain disease-fighting chemicals known as limonoids and flavonoids. (One flavonoid found in oranges, hesperetin, is thought to protect against cancer, heart disease and infections.) Bananas are full of potassium, which can prevent or reduce high blood pressure (and may help keep plaque from forming in the arteries).

Green

Chlorophyll, the phytochemical that makes plants green, is not a huge disease-fighter. Still, green vegetables are stuffed with other nutrients and substances essential to good health. Broccoli, for example, is the king of cancer-fighters, with its rich supply of vitamins C and K (used in photosynthesis), as well as specific cancer-preventing compounds like indoles (thought to be especially effective in fighting breast cancer). In addition, spinach is a rich source of vitamin K, folic acid and lutein, which help prevent age-related macular degeneration (and may reduce cataracts, as well).

Blue/purple

Blueberries are extremely rich in antioxidants and contain nearly 100 phytochemicals, which help protect against cancer, bacteria and ulcers, among other things. They may also help protect the brain against aging.

In addition to adding fruits and vegetables, such as citrus fruits, broccoli, peppers and garlic, to your diet, you can also add proteins, Dr. Othersen said. Choose beans, nuts, seeds, tofu, lean meats, fish, and dairy products that contain probiotics, like yogurt.

What's Borderline For Immunity

When it comes to your immune system, balance matters. Too little of a nutrient can leave your defenses weak. Too much — especially from supplements — can tip the balance the other way and even cause harm.

Vitamins and supplements

While some vitamins and supplements on the market claim to promote immunity, Dr. Othersen cautioned against relying on this approach. It's much better — and much safer — to get nutrients from the foods you eat.

"In general, I don't recommend vitamins to my patients unless you have a specific deficiency or certain eye diseases," she said. "If you take too much zinc, it can actually inhibit your immune function. Too much vitamin C can give you nausea, vomiting, diarrhea, heartburn, insomnia and headache. Certainly, a little is OK. But talk to your physician and make sure a supplement is appropriate for you."

Foods That Hurt Immune Processes

Some foods can make it harder for your immune system to do its job. Processed foods made with refined white flour and added sugars are common culprits. These foods often cause inflammation and don't provide much nutrition.

Fried foods and fats, such as margarine, shortening and lard, also promote inflammation. So do processed meats, like bacon, sausages, hot dogs, salami and other deli meats. You should even limit lean red meat to once or twice a week. Salty, fried and processed foods suppress anti-inflammatory processes in the body, especially in the gut. Replace these foods with those known to be anti-inflammatory, those high in natural antioxidants and other protective compounds.

"The stomach is a huge part of our immunity," Dr. Othersen said. "Our good gut bacteria help protect us. But when you eat all those processed foods, it kills good bacteria, and bad bacteria start to grow. So, things like processed meats, charred meats, fast food, sweets — they may taste good, but they're not good for your immune system."

Small Steps, Big Immune System Rewards

Changes to your immune system won't happen overnight, so it's important to be consistent. Make sure you incorporate immune-boosting foods every day, and drink plenty of water. Even small changes will eventually make a significant difference in your immunity.

"What I tell my patients is it's not all or nothing," Dr. Othersen added. "You don't have to be perfect. I always say, 'Small steps, big rewards.'"

To strengthen your body's natural defenses with simple ways to boost the immune system learn about the nutrition counseling services available at Franciscan Health.