HealthTip: Can Supplements Prevent Disease?

Over the past 20 years, there has been a lot of research into if large intakes of various vitamins could prevent chronic diseases. So far, we've found minimal benefits and possible harm from large doses of vitamins; however, research in the field is still continuing.
Folic acid was hypothesized to lead to a decrease in heart disease in those at risk. Several experiments have been conduced to test this idea, and none have detected a direct benefit. Vitamin E and Selenium were hypothesized to reduce the risk of prostate cancer. In the "SELECT" trial of 2001, data suggested no benefit in Vitamin E and Selenium supplements and possible evidence of harm in some participants. Vitamin E was considered to have the potential to decrease the risk of cancer and heart disease. Over 4-7 years it was found that in some patients with heart disease or diabetes, long-term Vitamin E supplementation may increase the risk of heart failure. However, patients with diabetes who had a specific form of a certain gene (homozygous for the Haptoglobin-2 polymorphism) showed a decreased risk of disease with Vitamin E. Research is still continuing. One study researched the ability of antioxidants to prevent several diseases and found that treatment with Vitamin A and Vitamin E may increase chances of death, while the roles of Vitamin C and Selenium need further study.
So, what does all of this information mean? It definitely doesn't mean that you should stop your 1-a-day multivitamin and stay away from supplements all together! Many of these studies used large doses of vitamins (higher than recommended daily doses), which could be a reason as to why negative effects were seen.
So who should be taking supplements?

• Newborns can get all their requirements from breast-milk, except for Vitamin D. Vitamin D drops should be provided for the infant to prevent deficiency. A Vitamin K injection is also given at birth.
• Women of child-bearing age are recommended to take a supplement including folic acid, in order to prevent neural-tube defects (in the fetus) if they become pregnant
• All women who are pregnant or breastfeeding need a multivitamin containing folic acid. Pregnant women need to ensure that their vitamin also contains iron because it may be difficult to get enough from food
• Vegetarians/ vegans may require iron, Vitamin B12, calcium, zinc, and/ or Vitamin D supplements depending on what they exclude from their diet
• Those over the age of 50 are recommended to take a Vitamin D supplement because their ability to make Vitamin D decreases, and often times this age-group gets less exposure to sun (FYI: we can get some of our Vitamin D from sun exposure)
• Those over the age of 50 may be recommended to take a Vitamin B12 supplement, as Vitamin B12 absorption can decrease with age

Those who are deficient (low) in certain vitamins and minerals may also need supplements. This can be determined through blood tests and other physical examinations. In all of these cases, a physician or dietitian should be consulted regarding the correct dosage of the supplement and to help determine if a supplement is required.

Information Sources:
Health Canada- Vitamin E
Canada's Food Guide
UBC FNH 471- Nutrition Across the Lifespan