10 Foods That Boost Your Immune System

Even though we’re well into spring, here at Westchester Health, we’re still seeing a lot of colds and viruses. To try and help keep everyone healthy and germ-free, we continually emphasize to our patients that their diet plays an important role in the strength of their immune system. Certain foods may actually decrease their chances of getting sick, while others can help them recover more quickly if they do get ill.

Regularly consuming the foods listed below can make a real difference in strengthening your immune system, helping you resist illnesses and shortening the time you are sick.

If you are unable to eat some of them, you may want to consider taking supplements which have immunity-boosting properties. No matter the season, keeping your immune system healthy is very important to your overall health and well-being.

10 foods to eat if you want to boost your immune system

  1. Iron-rich foods


    Margaret Andersen, MD

    Iron plays an important role in immune function. A diet containing too little iron can cause anemia and weaken the immune system. Foods rich in iron include meat, poultry, fish, shellfish, legumes, nuts, seeds, cruciferous vegetables and dried fruit. You can also improve your absorption of iron from foods by using cast-iron pots and pans to cook with, and avoiding tea or coffee with meals. Combining iron-rich foods with vitamin C can help boost your absorption even further. Keep in mind, however, that overly high iron levels in your blood can be harmful and may actually suppress the immune system. Therefore, it’s best to take iron supplements only if you have an iron deficiency or on the advice of a doctor.

  1. Probiotic-rich foods

Probiotics are beneficial bacteria that live in your gut and help stimulate your immune system. They also help maintain the health of your gut’s lining, which may help prevent unwanted substances from “leaking” into the body and provoking an immune response. In fact, recent studies show that probiotics may reduce the risk of developing upper respiratory tract infections by up to 42%. Studies also show that when people do get sick, those who regularly consume probiotics are 33% less likely to need antibiotics. In certain cases, regularly consuming probiotics may also lead to a faster recovery from illness. Effective sources of probiotics include sauerkraut, naturally fermented pickles, yogurt, kefir, buttermilk, kimchi, tempeh, miso, natto and kombucha.

  1. Citrus

Vitamin C is known for its antibacterial and anti-inflammatory properties. It also helps maintain the integrity of your skin, which acts as a protective barrier against infection. In addition, vitamin C can act as an antioxidant, helping protect your immune cells against harmful compounds formed in response to viral or bacterial infections. Therefore, getting enough vitamin C is a great way to strengthen your immune system and may reduce your likelihood of infection. Some studies also report that increasing your vitamin C intake during a cold may help you get better more quickly. Fruits like oranges, grapefruits and tangerines are high in vitamin C. Other foods high in vitamin C include bell peppers, guavas, dark leafy greens, broccoli, berries, tomatoes, papaya and snap peas.

  1. Ginger

Ginger is rich in gingerol, a bioactive substance thought to help lower the risk of infections. In fact, ginger has antimicrobial properties that may inhibit the growth of several types of bacteria, including E. coli, Candida and Salmonella. Fresh ginger may also help fight the human respiratory syncytial virus (HRSV), a virus responsible for many respiratory infections. However, more studies on this are needed. As many people know, ginger is also effective at combatting nausea, and may help decrease your nausea symptoms when you have the flu.

  1. Garlic

Like ginger, garlic also contains active compounds that may help reduce your risk of infection and improve your immune cells’ ability to fight off colds and the flu. Garlic also seems to have antimicrobial and antiviral properties that may help it fight bacterial and viral infections. To maximize garlic’s immune-boosting effects, eat one clove two to three times per day. Crushing the garlic and allowing it to stand for 10 minutes prior to cooking can also help increase its immune-supportive effects.

  1. Berries

For centuries, berries have been used by Native Americans to treat infections like the common cold. This could be because berries are a rich source of polyphenols, a group of beneficial plant compounds with antimicrobial properties. Studies show that berries and their polyphenols have the ability to protect against the influenza virus responsible for the flu. They may even offer a defense against bacterial infections such as Staphylococcus, E. coli and Salmonella infections. Berries also contain good amounts of vitamin C, which adds to their immune-boosting properties.

  1. Coconut oil

Coconut oil contains medium-chain triglycerides (MCTs), a category of fats with antimicrobial properties. The most common type of MCT found in coconut oil is lauric acid, which is converted into a substance known as monolaurin during digestion. Both lauric acid and monolaurin have the ability to kill harmful viruses, bacteria and fungi. In fact, researchers report that coconut fats may help fight off the types of bacteria that cause stomach ulcers, sinusitis, dental cavities, food poisoning and urinary tract infections. Researchers also believe that coconut oil may be effective against the viruses responsible for influenza and hepatitis C. It may also help fight Candida albicans, a common cause of yeast infections in humans. You can easily add coconut oil to your diet by using it instead of butter or vegetable oils in cooking or baking. Consuming up to two tablespoons (30 ml) per day is recommended, allowing you to include other healthy fats in your diet, such as avocados, nuts, olives and linseed oil.

  1. Licorice

A spice made from the dried root of the Glycyrrhiza glabra plant, licorice has been used in traditional Asian and European herbal medicine for thousands of years. Studies show that licorice has the ability to fight some fungi and bacteria, including E. coli, Candida albicans and Staphylococcus aureus. It may also be able to fight the viruses responsible for the flu, gastroenteritis and polio. However, many products containing licorice are also very high in sugar. If you are trying to reduce your sugar intake, look for lower-sugar options, such as licorice tea. In addition, consuming too much licorice may have a number of adverse effects, including high blood pressure, abnormal heart rhythm and an increased risk of premature birth. If you’re at risk for any of these, you should limit your consumption.

  1. Nuts and seeds

Nuts and seeds are incredibly rich in nutrients, including selenium, copper, vitamin E and zinc, all of which play a role in maintaining a healthy immune system. Sesame seeds and almonds are particularly good sources of copper and vitamin E, while pumpkin seeds and cashews are rich in zinc. To get your daily requirement of selenium, eating just a single Brazil nut per day will do it. Nuts and seeds are also great sources of fiber, antioxidants and healthy fats, all of which are beneficial for health.

  1. Sweet potatoes

Sweet potatoes not only taste great but they’re also rich in vitamin A. Not consuming enough vitamin A can lead to a deficiency, which studies link to a weaker immune system and a higher sensitivity to infections. However, excessive vitamin A intake can lead to adverse effects such as nausea, headaches, weaker bones, coma and even premature death, especially if you take vitamin A in supplement form. High intakes of vitamin A supplements during pregnancy may also increase the risk of birth defects. Therefore, it might be safest to meet your vitamin A requirements through diet instead of supplements. As well as sweet potatoes, other foods that are high in vitamin A include carrots, dark-green leafy vegetables, squash, romaine lettuce, dried apricots, red peppers, fish and organ meats.

Immunity-boosting supplements

A well-functioning immune system requires an adequate and consistent intake of several nutrients. Individuals eating a well-balanced diet rich in the foods described above should have no difficulty reaching their daily requirements. However, some may be unable to meet their recommended daily nutrient intakes through diet alone.

If this is the case for you, consider adding the following supplements to your diet:

  1. Probiotics

Ideally, Lactobacillus or Bifidobacterium strains in amounts between 2–3 billion colony-forming units (CFUs) per day.

  1. Vitamin C

Take approximately 75–90 mg per day, and increasing your daily dose to 1 gram per day may provide extra benefits during illness.

  1. A multivitamin

Look for one containing iron, zinc, copper, vitamin E and selenium in amounts sufficient to help you meet 100% of the RDIs.

  1. Zinc lozenges

Doses of at least 75 mg per day at the first onset of cold symptoms may help reduce the duration of the infection.

  1. Vitamin D

Low blood levels of vitamin D may increase the risk of respiratory infections, including the flu, sinus infections and bronchitis. Therefore, those living in northern climates where sunlight is limited might also want to consume at least 600 IU (15 mcg) from vitamin D supplements per day.

Want to know more about boosting your immune system? Come see us.

If you’d like more information on ways to improve your body’s immune system, please call (914) 232-1919 to make an appointment with one of our Westchester Health Internal Medicine specialists. We can discuss the details of an immune-boosting diet with you and determine if you would benefit from certain supplements. We can also perform tests to determine if you have a weakened immune system and should make adjustments to your diet and lifestyle. Whenever, wherever you need us, we’re here for you.

By Margaret Andersen, MD, an internist with Women Caring For Women, an internal medicine practice focused solely on women, part of Westchester Health, member of Westchester Health Physician Partners

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