Eat This, Not That to Fight Colds and Flu

Foods that 'train and maintain' your immune system
Five sardines lined up on a plate

The saying “You are what you eat” definitely applies to your body’s first line of defense — your immune system.

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Eating the right things will strengthen your immunity and you’ll more easily fend off microscopic invaders. Eat the wrong things, though, and you can weaken your immune system, leaving your body more vulnerable to attack.

So, what should you eat? And, how do your day-to-day food choices impact the system charged with protecting you from the inside out?

Clinical immunologist Leonard Calabrese, DO, has studied the diet’s effect on immunity for years and tells patients they can “train and maintain” their immune systems.

He shares his knowledge on the best fuel you can give yourself. “When it comes to your diet, it influences your immune health at the intestines,” he says. “There are more immune cells and antibodies in the gut than in all other tissues combined.”

He offers his insight about diet and your immune system, below.

Q: Do you recommend a specific ‘immune system diet’? 

A: The good news is that there’s no certain diet you must follow to maintain healthy immunity. Instead, you should try to eat a largely plant-based diet that’s also rich in whole grains and nuts, similar to the Mediterranean diet.

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Try to limit the meat (especially processed meat) that you eat, as well as processed and fried foods. Above all, be sure you eat plenty of fresh fruits and vegetables.

Q: How does a healthy diet boost your immunity? 

A: The existing evidence is clear that a healthy diet can help control the most significant symptom of immune responses — inflammation.

Reducing inflammation can also lead to a drop — or at least slowing — in changes associated with aging. For example, eating well can reduce arthritis and vascular symptoms, and it can lower the risk of degenerative disease.

Q: Can vitamins improve your immunity? 

A: Yes, they can, but you don’t need to take supplements. The amounts you get from the foods you eat should suffice, but make sure you’re actually getting enough of certain vitamins. They directly impact how well your immune system functions.

Make sure you’re eating the right foods so that you’re getting enough of these vitamins and minerals.

Eat these foods (and why) 

Fish (like salmon, herring, anchovies and sardines). They’re rich in omega-3 fatty acids that have potent anti-inflammatory properties to fight chronic disease.
Almonds, peanuts, hazelnuts and sunflower seeds. They contain antioxidants. Protect cells and boost production of infection-fighting antibodies to fight infection.
Chicken, turkey, seafood, beans, broccoli and kale. They contain iron needed to circulate oxygen to protective antibodies.
Garlic, broccoli, sardines, tuna, Brazil nuts and barley. They contain selenium. Slow down overactive immune responses.
Asparagus, garlic, Jerusalem artichokes, jicama, dandelion greens and onions. They contain “pre-biotics” in the form of fiber that are metabolized by bacteria into anti-inflammatory compounds.
Oysters, crab, lean meats, poultry, baked beans and yogurt. They contain zinc. Control inflammatory responses.
Citrus fruits, leafy green vegetables and strawberries. Contain vitamin C. Boost immune system.
Bananas, tuna, chickpeas. They contain Vitamin B6. Part of nearly 200 biochemical reactions in our bodies. Critical in how immune system functions.
Sweet potatoes, squash and carrots. Contain Vitamin A. Have an antioxidant effect to strengthen the immune system against infection.
Fortified milk, orange juice and fatty fish (salmon or sardines). They contain Vitamin D, which boosts your immune system.
Beans, peas and leafy greens. They contain folic acid, which also boosts your immune system.

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Q: Can any foods actively harm your immune system? 

A: Just as some foods can help you, other foods can have a negative impact on your immunity. If you avoid these foods, your immune system will be stronger. Remember to eat real foods, not processed ones.

Avoid these foods (and why)

Red meat (in excess). It increases risk of inflammation and shown to boost cancer risk.
Fried foods. They’re full of fat and trigger inflammation. Reverse the impact by removing fried foods from your diet.
Soda. Soda drinkers often get an inadequate supply of Vitamin A, calcium and magnesium.
Sugar (in excess). Sugar can suppress the immune system by actively targeting cells that fight bacteria. The effect can last for several hours after eating.
Salt (in excess). Has been shown to promote inflammation.

Fueling your body with what it needs most can go a long way toward girding your immune system for its daily battles.

Eating plenty of fresh fruits and vegetables, along with moderate amounts of whole grains, seafood, lean poultry, nuts and seeds, will help your body keep up the good fight against the foreign invaders that can make you sick.

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