The idea behind taking antioxidant vitamins, which include vitamin A (usually taken as beta-carotene, which is a safer form of the vitamin), and vitamins C and E, is that these vitamins reduce damage caused by free radicals. A free radical (also called an oxidant) is a molecule in the body that has an unpaired electron. These molecules are very unstable because they are constantly trying to pair their unpaired electron. This causes them to react with other substances in the body, resulting in oxidative damage. The RDA of antioxidant vitamins can be obtained by eating 3 to 4 servings of vegetables and 2 to 4 servings of fruits every day. The safety of taking antioxidant vitamin supplements in amounts exceeding the RDA has not been established in people with MS and there is a theoretical risk that these vitamins may stimulate the immune system, which is already overactive in MS.
Vitamins C and E, in combination with selenium, have been tested in a small study conducted in people with MS. Although the combination was well tolerated, the study was too small to make any determination about effectiveness.
It is also thought that vitamin C may be useful in helping prevent urinary tract infections, which can occur commonly in people with MS. The idea behind this is that vitamin C may help to make urine more acidic, which in turn makes it more difficult for bacteria to colonize the urinary tract. However, evidence indicates that vitamin C does not acidify urine. Therefore, there is some controversy about whether intake of high amounts of vitamin C is beneficial for a person with MS. Evidence does support the use of cranberry (in pill or juice form) to acidify urine and protect against urinary tract infections.
Vitamin E, which is available in vegetables, nuts, meats, vegetable oils, and fruits, prevents oxidative damage in the body. If you are taking polyunsaturated fatty acid (PUFA) supplements or consume a diet high in PUFA, which is thought to be beneficial in MS, your requirements for vitamin E will go up. Before you start increasing PUFA intake, talk to your doctor about how this will increase your need for vitamin E.
Vitamin A is an important vitamin for eye health as well as normal cell growth throughout the body. Sources of vitamin A include liver, eggs, and cod liver oil. Vitamin A is a fat soluble vitamin which is stored in the body and may accumulate over time. Therefore, you should avoid taking too much of this vitamin. The RDA for men and women ranges from 2,300 to 3,000 international units (IU) and daily intake should not exceed 10,000 IU. If you are pregnant, you should not consume high amounts of vitamin A because intake of excessive amounts of this
vitamin may result in birth defects. Pregnant women should limit vitamin A intake to the safer form of the vitamin found in fruits and vegetables called beta-carotene.
B complex vitamins, which contain vitamin B6 (pyridoxine), are taken to increase energy. Natural sources of vitamin B6 include many different foods, such as fish (salmon and tuna), vegetables, chicken and pork, beans, and bananas. The RDA for vitamin B6 is 1.3 milligrams for adults ages 19-50 years and high amounts of the vitamin (such as 1,000 milligrams) can cause numbness, tingling, or pain. These symptoms are reversible once supplementation is decreased.
Claims have been made that vitamin B12 (cobalamin) is an effective treatment for MS. However, there is little evidence to support these claims. Deficiencies in vitamin B12, which can lead to MS-like neurological symptoms, are typically found in only a small number of people with MS. In patients who have low levels of vitamin B12, a supplement should be used. Natural sources for vitamin B12 include meat, poultry, shellfish, eggs, and dairy products.