Some vitamins boost immunity and are particularly useful for individuals with nutritional deficiencies. Good overall immunity comes from regular exercise and a healthy diet of foods that contain essential nutrients to fight infection. Disease states, some medications, chronic stress and age increase vulnerability to infection. Vitamin deficiencies can also occur from poor dietary habits, leading to frequent infection and vulnerability to other illnesses such as cancer and autoimmune disorders.
Vitamin E
Findings published in "The Journal of the American Medical Association" show that vitamin E can help prevent respiratory infections in elderly individuals. Although the study failed to show benefit for reducing the length of time of colds if they did develop, the vitamin did show benefit in preventing respiratory infections in the first place. Wheat germ, almonds, kiwi, tomatoes and spinach are examples of foods rich in vitamin E.
Vitamin B6
Vitamin B6 is a water-soluble vitamin important for immunity. Low levels, especially in the elderly, have been linked to immune system dysfunction. According to Oregon State University, vitamin B6 deficiency causes decreased production of lymphocytes, a type of white blood cell needed to fight infection, in addition to lower production of Interleukin-2, an infection-fighting protein. Some examples of commonly consumed foods containing the vitamin include peanut butter, bananas, oatmeal, spinach and chicken breast.
Vitamin D
Vitamin D is important for improving immune function because it activates T-cells that help fight infection and chronic diseases. A study published in the journal "Nature Immunology" found vitamin D to be important for cell signaling. Without enough of the vitamin, infection-fighting cells remain dormant, increasing susceptibility to disease. Vitamin D comes from fortified foods, dairy products and fatty fish.
Vitamin A
Vitamin A deficiency has been linked to lower immune function. According to the "Journal of Infectious Diseases" metabolites of the vitamin, retinoic acid and retinoid X receptors are necessary for enhanced immunity. The metabolites promote a strong antibody response to foreign substances, or antigens that cause infection, cancer and other diseases. Consuming green, orange, yellow and red vegetables provides vitamin A that can improve immune function.
