Certain foods containing various vitamins and minerals, amino acids, fatty acids and plant compounds strengthen the immune system and help the body prevent and fight colds, flu and other diseases.
Nutrients in citrus fruits, leafy greens, oily fish, vegetables and more promote a healthy gut microbiome, boost immune cell response and fight harmful inflammation and oxidative stress.
This article looks at the best foods that boost immunity and foods that can weaken the immune system.
Citrus fruits
Citrus fruits such as grapefruits, oranges, tangerines, lemons and limes are high in vitamin C, which helps boost white blood cells that fight infections. Vitamin C is also an antioxidant that fights free radicals that can prevent the immune system from working properly.
Citrus fruits also contain flavonoids (anti-inflammatory plant compounds) that help strengthen the immune system and disease recovery. Flavonoids in citrus fruits can help relieve coughs and aid digestion.
It is important to regularly consume foods high in vitamin C, especially when you are sick. The body cannot make it itself.
Broccoli is considered one of the best foods to strengthen the immune system. This cruciferous vegetable is high in immunity-boosting vitamins C, E and A and contains numerous plant compounds known for their antioxidant properties, including sulforaphane, a powerful anti-inflammatory. Consume broccoli raw, steamed or lightly cooked to retain its nutrients.
Dark chocolate
Dark chocolate is made from cocoa, which is rich in polyphenols, plant compounds with antiviral and anti-inflammatory properties. A diet high in cocoa benefits the body's immune system and gut microbiome and reduces inflammation.
Strawberries, blueberries and raspberries are high in vitamin C and other disease-fighting nutrients. Polyphenols, such as resveratrol, are found in berries and have antiviral and anti-inflammatory effects that also help improve immune system function.
Fatty fish is rich in omega-3 fatty acids, tryptophan (an amino acid), taurine and polyamines. These compounds help strengthen and regulate the immune system and increase the number of beneficial bacteria in the gut microbiome.
Bell pepper
Peppers are high in powerful immunity-boosting vitamins C and A and beta-carotene
is converted in the body into vitamin A. Red bell pepper contains more vitamin C than most citrus fruits. Peppers are also high in lycopene, a plant pigment with antioxidant and anti-inflammatory properties.
What about Echinacea?
Green and black tea are rich in flavonoids and antioxidants that help strengthen the immune system. Green tea also contains epigallocatechin gallatean antioxidant that improves immune system function, lowers the risk of certain diseases and reduces inflammation.
Herbal tea is made from mixtures of different dried plant parts, such as chamomile, ginger, cinnamon,
ginseng and cloves. These ingredients have anti-inflammatory, antiviral, antibacterial and antioxidant properties that can strengthen the immune system.
Freshly pressed garlic contains many sulfur-containing compounds with antiviral properties, which stimulate T cells and lymphocytes that fight viruses and diseases. Components of garlic are also known to block inflammatory pathways in the body. Consuming garlic can help the body produce and release nitric oxide, which aids in processes that protect against viral diseases.
Yogurt is made by fermenting milk with lactic acid bacteria. This makes yogurt a good source
of probiotics, which help the immune system function by increasing the growth of beneficial bacteria and hindering harmful bacteria in the digestive system to protect against disease.
Eating plain, unsweetened yogurt is best because flavored yogurt and yogurt drinks often contain a lot of sugar.
Nuts and seeds
Nuts and seeds contain a lot of vitamin E, which supports the production of antibodies and protects against oxidation. Almonds are known to be effective immune boosters as they contain a blend of fats and plant sterols that help the immune system function properly and fight inflammation. Sunflower seeds are also notable because they contain zinc and selenium, minerals with numerous disease-fighting properties.
What about elderberries?
Spinach and other leafy vegetables
Leafy greens such as spinach, kale and collard greens are high in vitamin C, one of the most important vitamins for immune system function. Leafy greens are also high in beta-carotene, which converts to vitamin A, an anti-inflammatory vitamin that helps antibodies fight viruses.
The active ingredient in turmeric is curcumin, a powerful anti-inflammatory, immunity-boosting and antiviral agent. Curcumin helps strengthen the function of immunity cells, while other turmeric compounds have anti-inflammatory properties.
Foods to avoid for a healthy immune system
Certain foods are known to damage the immune system and prevent it from working properly, especially if consumed in large quantities. Foods to avoid (or limit) for a healthy immune system include:
- Sugary food: High amounts of sugar can cause inflammation and keep the immune system cells from working properly.
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Alcohol: Alcoholic drinks can damage immune cells in the blood and digestive system
disrupt communication between the cells of the immune system. - Fast food: These foods are highly processed and high in salt and saturated fats. Eating a large amount of unhealthy fast food can damage the immune system and gut microbiome.
Certain foods have been found to be helpful in supporting the immune system. Adding citrus fruits, leafy greens, dark chocolate and other foods to your diet can be an important strategy for fighting colds, flu and other illnesses. These foods help support the immune system by boosting immune cell activity, supporting the gut microbiome and reducing inflammation. Sugary foods, fast foods and alcohol are known to be harmful to the immune system and should be avoided or consumed only in small quantities.