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How Vitamin C Supports a Healthy Immune System

Contributors: Marisa Moore, MBA, RDN, LD

Reviewers: Academy Nutrition Information Services Team

Published: November 06, 2022

Reviewed: December 11, 2023

How Vitamin C Supports a Healthy Immune System
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Vitamin C, or ascorbic acid, is a water-soluble vitamin well known for its role in supporting a healthy immune system. Because your body cannot make vitamin C, it must come from the foods you eat every day.

Research shows vitamin C is essential for the growth and repair of tissue all over the body. Vitamin C helps heal wounds and repair and maintain healthy gums, skin and cartilage — a type of firm tissue that covers the bones. As an antioxidant, vitamin C fights free radicals in the body which may help prevent or delay certain cancers and heart disease and promote healthy aging.

Though it may not keep you from catching a cold, there is some evidence that supplemental vitamin C may help decrease the length and severity of cold symptoms. Check with your doctor or registered dietitian nutritionist before taking any new supplements.

There are a variety of food sources of vitamin C and they extend well beyond the ever-popular orange or orange juice. Many fruits and vegetables supply this vital vitamin. Sources of vitamin C include citrus fruits, tomatoes, potatoes, strawberries, green and red bell peppers, broccoli, Brussels sprouts and kiwifruit, among others. You can enjoy these foods raw or cooked, but it's important to note that fruits and vegetables lose vitamin C when heated or stored for long periods of time. To get the most nutrients, eat them as soon as possible after shopping and consider steaming or microwaving vegetables for short periods of time to limit nutrient loss.

Vegetarians may be especially interested to know that vitamin C helps the body to better absorb iron from plant foods such as beans, spinach and quinoa. To get this benefit, combine vitamin C-rich foods with iron-rich plant foods in the same meal. For example, combine black beans and salsa or create a flavorful spinach salad with strawberries and mandarin oranges.

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