Vitamin D Is Key to a Healthy Immune System, and These 7 Foods Have It in Spades

Adults require about 600 to 800 IU of vitamin D each day, according to the Institute of Medicine. One serving of farmed salmon contains nearly a third of your daily vitamin D needs. Not only does salmon supply your body with vitamin D, but it's also loaded with immune-supporting omega-3 fatty acids. Specifically, choosing Chilean farmed salmon gives you more omega-3s compared to other types of fish, with no mercury or antibiotics.