Test Your Knowledge

The vitamins are involved in major processes throughout the body, making life possible. Without them, food could not be converted to energy, there would be no vision, and wounds would not heal. In addition to these functions, physicians have found that supplements of certain vitamins may help prevent or treat a variety of conditions. Some examples of these uses include:

• Birth defects. Folic acid (B9) is recommended for women of child-bearing age to reduce the risk of neural tube defects, such as spina bifida. During pregnancy, women should not take any vitamin supplements without the advice of a physician due to the possibility of resulting birth defects.
  
  
• Cholesterol. B3 supplements (niacin) are frequently prescribed to reduce levels of low-density lipoproteins (“bad cholesterol”). They also raise the amount of high-density lipoproteins (“good cholesterol”) in the blood, but with a less significant effect.
  
  
• Anemia. Several of the B vitamins are involved in making red blood cells and hemoglobin. Deficiencies of these vitamins may cause several types of anemia, which can be treated with supplements. Supplements may also be used to treat other types of the condition, such as B6 for hereditary sideroblastic anemia.

In addition to these conditions, some vitamins may be recommended to reduce the impact of free radicals. Free radicals will take electrons from other molecules, creating more free radicals. If this process continues, cell and tissues can be damaged, which contributes to some types of cancer and cardiovascular disease. Antioxidants, such as vitamins A, C and E, contribute electrons to free radicals, but remain stable. They can also accept electrons from other sources, allowing them to function repeatedly as antioxidants. This stops the destructive cycle and prevents cell damage and resulting diseases.

Links have been found between lower incidences of some diseases and increased vitamin intake through supplements or diet. Research continues on the mechanisms responsible. Topics of study include:

• Cardiovascular disease and dementia. Vitamins B6, folic acid and B12 are being investigated for their ability to lower homocysteine levels. This amino acid is found in high levels in people suffering from heart disease, blood clots, strokes, and Alzheimer's disease. To date, reducing the amount of homocysteine has not been proven to reduce health risks. Research continues into the use of vitamin C, which so far has yielded mixed results. Mortality rates due to cardiovascular disease actually increase among smokers who use vitamin A, especially in the form of beta carotene supplements.
  
  
• Hypertension (high blood pressure). Supplements of vitamins B9 and D are being studied for possible links to reduced hypertension. Results have been mixed, with some populations showing benefits while others have not.
  
  
• Cancer. Folic acid supplements have been associated in some cases with reduced incidence of colon and breast cancers, especially for moderate users of alcohol. High levels of vitamin D are also associated with reduced risk of developing cancer, but scientists are unsure what amount of supplementation produces this effect.
  
  
• Osteoporosis and bone fractures. Supplements of vitamins folic acid (B9), B12 and D may help reduce bone decay and the incidence of fractures. However, dietary sources of calcium along with weight bearing exercise have consistently been shown to reduce the risk of osteoporosis.