How Does Ascorbic Acid Help The Immune System?

Ascorbic acid -- vitamin C -- is water-soluble. Any amount in excess of what your body needs at the moment dissolves and gets flushed out in your urine. It is vital that you maintain an adequate daily intake of this nutrient. Vitamin C is essential for the healthy functioning of different areas of your body, including your immune system. If you are concerned about your ability to fight disease, talk to your doctor before using ascorbic acid.

Ascorbic Acid and Immunity

Vitamin C boost the immune system by increasing levels of certain antibodies and other substances. The authors of "Nutrition and Immunology: Principles and Practice" cite research showing that ascorbic acid raises the levels of immunoglobulin G and M -- IgG and IgM -- as well as the concentration of a substance known as C3 in your bloodstream. Immunoglobulins are antibodies that kill harmful viruses and bacteria. IgG is the most plentiful class of antibodies in the bloodstream and protect you from viral infections. IgM antibodies are first responders that begin the fight against disease agents as soon as they invade your body. IgM also triggers the other components of the immune system to enter the battle for your health. The "C" in C3 stands for "complement system." Its role is to support the immunoglobulin fight against disease. The study participants were elderly women who took 400 milligrams of ascorbic acid for an unspecified length of time. Researchers "found significantly increased IgG, IgM and complement C3 levels" in the women who supplemented their diet with vitamin C.

Recommended Intake

The Food and Nutrition Board of the U.S. Institute of Medicine recommends that babies to 6 months of age get 40 milligrams ascorbic acid daily. The intake should go up to 50 milligrams daily at 7 months and drop to 15 milligrams when they turn 1 year old. At 4 years of age, children need 25 milligrams ascorbic acid daily. When kids turn 9, offer them a daily diet that provides 45 milligrams vitamin C. Fourteen-year-old boys thrive on 75 milligrams ascorbic acid and 14-year-old girls need 65 milligrams of the nutrient daily. From age 19 through adulthood, men require 125 milligrams vitamin C and women 110 milligrams. These recommendations fall short of the 400 milligrams of ascorbic acid the elderly women in the study took. The authors who cite the research in their book do not address how the difference affects the researcher's conclusion.

Food Sources

Eating foods rich in ascorbic acid regularly can help to keep your immune system strong. The vitamin is in all citrus fruits. Raw and lightly cooked greens are also good sources of the nutrient. Besides, tomatoes, green peppers, kiwi, papaya and strawberries provide ascorbic acid. Manufacturers also enrich certain processed foods such as bottled juice. If a product is fortified with vitamin C, the the nutrition facts label will list the nutrient.

Other Ascorbic Acid Benefits

Besides strengthening your immune system, ascorbic acid antioxidant properties disable free radicals. Free radicals are damaging molecules that appear as a result of digestion. Exposure to tobacco smoke and radiation also generates free radicals. They can cause illnesses if they stay active in your body. In addition, the University of Maryland Medical Center says that vitamin C plays a role in preventing high blood pressure, heart disease and asthma.