Naturally occurring chemicals that are necessary for the processes and functions of the human body. Food supplies nearly all of vitamins that people ingest, although the skin produces vitamin D in response to sunlight. Different vitamins are essential for specific functions in the body. When the diet cannot meet the body’s nutritional needs (for vitamins as well as minerals and other nutrients), doctors and nutritionists recommend vitamin supplements. The B vitamins (thiamin, riboflavin, pyridoxine, cyanocobalamin, niacin, pantothenic acid, biotin, and folic acid) and vitamin C are water-soluble; they dissolve in water and in the bloodstream. These are vitamins the body cannot store, so it needs a steady and regular intake to meet its needs. Vitamins A, D, E, and K are fat-soluble; they dissolve only in fatty acids (lipids). The body can and does store these vitamins, so it needs smaller amounts of them in the diet.
The B vitamins are particularly important because they supply the coEnzymEs necessary for MITOCHONDRIAL ELECTRON TRANSPORT CHAIN activity, the process through which cells generate energy. This property makes them essential for nearly every bodily function; chronic insufficiency results in numerous and widespread health problems. People who are chronically malnourished, such as those who cannot eat an adequate diet, sometimes require cyanocobalamin (vitamin B12) injections to meet the body’s need for this important B vitamin. Laboratory tests to measure blood levels can determine whether there is a deficiency of vitamin B12.
Many people take vitamin supplements as a means of bolstering the body’s natural immune and repair systems. As long as dosages are within the recommended dietary allowance (RDAs), there is no harm in this practice. Whether there is benefit remains a matter of debate. For people with poor nutrition that cannot be remedied through changes in the diet, as when the abilities to chew and swallow become compromised as in the later stages of Parkinson’s, vitamin supplements often are necessary to meet the body’s needs. Health care providers typically recommend a general multivitamin that also contains minerals, as minerals and vitamins work together in the body.
Excessive dosages of vitamins seldom have any therapeutic value and can be harmful. The body excretes excess amounts of water-soluble vitamins, but toxicity is still possible particularly in people with compromised kidney function. Excessive dosages of fat-soluble vitamins can be toxic, causing serious health problems and, rarely, death. Although it is generally difficult to overdose on any particular vitamin via food, routine supplementation of any particular vitamin or mineral that greatly exceeds the recommended allowance should be avoided unless thorough research supports no expected ill effects. There is no research-supported evidence that higher than recommended dosages of any vitamins relieve Parkinson’s symptoms or slow the course of the disease. For a time there was hope that the antioxidant functions of vitamin E (alpha-tocopherol) could slow Parkinson’s, but controlled clinical research studies have not borne this out.