Vitamins on the Carcinogen List

If you believe taking a vitamin supplement will protect you from cancer, you might be surprised to know that some types of vitamins actually increase the risk of cancer in some individuals. Science now knows that vitamins found in food are safe and health promoting, while high doses of synthetic supplements may have a more detrimental effect on your health and act as carcinogens in the human body.

Betacarotene (Pro-vitamin A)

• Carrots are a excellent source of natural betacarotene.

  Betacarotene is a chemical precursor to vitamin A that is found naturally in a variety of vegetables such as kale, spinach, collard, winter squash, carrots and sweet potatoes. While marketed as an antioxidant and anti-cancer vitamin, research suggests otherwise. A study in the "Journal of the National Cancer Institute" in 1998 showed male smokers who took betacarotene supplements were 23 percent more likely to develop prostate cancer.

Alpha/Beta Tocopherol (Vitamin E)

• Nuts and seeds provide good amounts of natural vitamin E.

  Vitamin E is a fat-soluble vitamin sourced from wheatgerm, vegetable oils, nuts, seeds, red meat, fish, dairy, eggs and leafy vegetables. According to Henry Osiecki, author of "The Physician's Handbook of Clinical Nutrition," vitamin E plays an important role in preventing cancer, especially in smokers. However, research reported by the BBC in 2008 found people supplementing with 400mg of vitamin E were 28 percent more likely to develop lung cancer, with smokers at most risk. Vitamin E in high levels acts as a pro-oxidant, reversing the desired medicinal effect of supplementation.

Ascorbic Acid (Vitamin C )

• Oranges, apples, kiwis and berries are all rich sources of vitamin C.

  Ascorbic acid, or vitamin C, is a powerful antioxidant within the body and can be found throughout a wide variety of fresh fruit, leafy greens and vegetables. According to Henry Osiecki, there is a wealth of information and research to support the use of vitamin C in preventing cancer. However, when other chemicals are bound to vitamin C, the opposite effect is true. In a study published in the journal "Cancer Research," vitamin C in the form of sodium l-ascorbate was studied and found to increase the risk of bladder cancer. Vitamin C is also known to potentiate the effects of the cancer-causing chemical Chromium 6 in the body.

Folic Acid (Vitamin B9)

• Spinach leaves contain high amounts of folic acid.

  Folic acid is a vitamin found in high quantities in liver, spinach, beans, lentils, asparagus, fortified grains and collard greens. While folic acid prevents several types of cancer such as ovarian, cervical and bronchial cancer, one study published in the "Journal of the National Cancer Institute" in 2009 found folic acid increased the risk of colorectal cancer by 67 percent. High levels of folic acid supplementation causes increased DNA replication, and may mask symptoms of deficiencies of other vitamins necessary for preventing cancer.