Citrus Fruits

Vitamin C, most commonly found in citrus fruits, is an antioxidant that can reduce cold symptoms by 23 percent, studies have found. A review of 21 studies found that just 1 to 8 grams (1,000 to 8,000 milligrams) of the vitamin will do the trick, which you can get from supplements or from citrus fruits, red bell peppers, broccoli, brussels sprouts, butternut squash, papaya, sweet potatoes, and tomatoes. For some people, high amounts of vitamin C can cause digestive problems, so cut back on your dose if symptoms arise.

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