Foods To Boost the Immune System

As coronavirus (COVID-19) has impacted communities around the world, many people have wondered whether there are steps they can take to stay healthy. Preventive measures—such as wearing a mask, getting vaccinated when you're eligible, handwashing, avoiding contact with sick individuals, and good hygiene—can help to reduce the risk for COVID-19 and other viruses, bacteria, and pathogens.

In addition, however, there is evidence that nutrition and other lifestyle measures influence immune strength and susceptibility to infectious diseases. Whether these measures do or do not influence susceptibility to COVID-19 or its clinical course is not yet known. However, there is every reason to put what we do know about foods and immune defenses to use. Here is what we know now:

Diet

Eating a low-fat, plant-based diet may help give the immune system a boost. The immune system relies on white blood cells that produce antibodies to combat bacteria, viruses, and other invaders. Vegetarians have been shown to have more effective white blood cells when compared to nonvegetarians, due to a high intake of vitamins and low intake of fat.¹

Eating a low-fat diet may also be protective. Studies have shown that limiting dietary fat helps strengthen immune defenses. Research also shows that oil may impair white blood cell function and that high-fat diets may alter the gut microbiota that aid in immunity.²

Maintaining a healthy weight can also benefit the immune system. Obesity has been linked to increased risk for influenza and other infections such as pneumonia.³ Plant-based diets are effective for weight loss, because they are rich in fiber, which helps fill you up, without adding extra calories. Fiber can also lower BMI, which is linked to improved immunity.⁴ A plant-based diet has also been shown to reduce inflammatory biomarkers.⁵

Vitamins, Minerals, and Antioxidants

Studies have shown that fruits and vegetables provide nutrients—like beta-carotene, vitamin C, and vitamin E—that can boost immune function. Because many vegetables, fruits, and other plant-based foods are also rich in antioxidants, they help reduce oxidative stress.⁶

Beta-Carotene: Beta-carotene is a powerful antioxidant that can reduce inflammation and boost immune function by increasing disease-fighting cells in the body. Excellent sources include sweet potatoes, carrots, and green leafy vegetables.

Vitamins C and E: Vitamins C and E are antioxidants that help to destroy free radicals and support the body’s natural immune response. Sources of vitamin C include red peppers, oranges, strawberries, broccoli, mangoes, lemons, and other fruits and vegetables. Vitamin E sources include nuts, seeds, spinach, and broccoli.

Vitamin D: Research shows vitamin D supplementation may reduce the risk for viral infections, including respiratory tract infections, by reducing production of proinflammatory compounds in the body. Increased vitamin D in the blood has been linked to prevention of other chronic diseases including tuberculosis, hepatitis, and cardiovascular disease. Food sources of vitamin D include fortified cereals and plant-based milks and supplements.⁷

Zinc: Zinc is a mineral that can help boost white blood cells, which defend against invaders. Sources include nuts, pumpkin seeds, sesame seeds, beans, and lentils.

Sleep

Our bodies need sleep to rest and recharge. Without a sufficient amount of sleep, we increase our risk for developing serious health problems—like heart disease, Alzheimer’s disease, and obesity. Inadequate sleep has also been linked to suppressed immune function. One study found that those who sleep fewer than five hours per night are more likely to have recently suffered a recent cold compared with those who sleep more.

Need help falling asleep? Try adding healthful fruits, vegetables, grains, and beans to your diet. One study found that diets rich in fiber and low in saturated fat can lead to deeper, more restorative sleep. Learn more about how a plant-based diet can lead to better sleep.

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