Deficiencies in some vitamins are a risk factor for several chronic diseases, according to a clinical review published in the June 12, 2002, issue of the Journal of the American Medical Association. The study states that vitamin deficiencies are common among the American adult population, particularly the elderly. Researchers say that because most individuals do not consume adequate levels of certain vitamins through diet alone, adults may be able to reduce the risk of cancer, osteoporosis and cardiovascular disease by taking vitamin supplements.
Vitamin D
Low levels of vitamin D can contribute to osteoporosis, a condition that increases a person's risk for bone fractures. Vitamin D is needed for calcium absorption and bone growth. The vitamin also plays a role in neuromuscular and immune function. Because vitamin D is not found in many food sources, it is added to milk. Other foods fortified with vitamin D include some brands of cereals, yogurt, orange juice and margarine. The best natural sources of vitamin D are salmon, tuna and mackerel. The Food and Nutrition Board has established 200 IU as an adequate intake of vitamin D for healthy men and women ages 18 to 50. Older individuals require a higher intake.
Vitamins E and C
Consuming inadequate levels of vitamins E and C can have negative effects on your health. Because fruits and vegetables are main dietary sources of these vitamins, the Dietary Guidelines for Americans recommend eating at least four servings of fruits and five servings of vegetables each day. Yet the American Medical Association points out that only about 20 to 30 percent of the population currently meets this nutrition goal. Findings of a study published in the June 2003 issue of the American Journal of Clinical Nutrition show that deficiencies of vitamins E and C in guinea pigs damage the central nervous system and cause limb paralysis. Guinea pigs need the anti-oxidant vitamins E and C just as humans do.
Vitamin B9
It is especially important for women of childbearing age to get enough vitamin B9, or folate, in their daily diets. Food sources of folate include dark green leafy vegetables, peas, and fruits such as oranges, cantaloupe and bananas. Folic acid is also added to enriched breads, pastas, rice and cereals. Folate is needed for DNA and RNA synthesis, and therefore, is a particularly essential nutrient during pregnancy and infancy. Excessive use of alcohol, anti-convulsant medications and malabsorption problems can lead to folate deficiency and increased levels of homocysteine in the blood. The National Heart, Lung, and Blood Institute has identified elevated homocysteine as a risk factor for cardiovascular disease and stroke.
Vitamins B6 and B12
Deficiencies in vitamins B6 and B12 are a risk factor for colon and breast cancer, cardiovascular disease and neural tube disorders. A fact sheet published by the Office of Dietary Supplements explains that like folate, vitamins B6 and B12 play a role in homocysteine metabolism. When there isn't enough vitamin B12 in the body, homocysteine levels can rise. Elevated levels of this amino acid have been identified as a possible risk factor for heart disease. The Linus Pauling Institute at Oregon State University points to the significance of vitamin B12 in DNA methylation, a chemical reaction that may play a role in cancer prevention. Vitamin B12 deficiency can also cause neurological symptoms such as tingling and numbness in the extremities, disorientation and problems with walking. In some cases, memory loss and dementia may occur. Symptoms often progress gradually.
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