18th century seafarers knew scurvy could be prevented with citrus fruit: The reason? Because citrus fruit is chock full of vitamin C. Unless your diet is as bad as a pirate's, you don't need to worry about scurvy, but you do need to keep your immune system strong, particularly during cold and flu season. Help support your immune system with 1,111% of your daily value of vitamin C. A water-soluble vitamin and powerful antioxidant, vitamin C helps the body form and maintain connective tissue, including bones, blood vessels, and skin. There are 100 1,000-milligram ascorbic acid caplets in a bottle.