There are many misconceptions about vitamins and if they offer any health benefits. It is important to emphasize vitamins are not drugs or miracle cures. They are organic compounds that are involved in various metabolic functions.
According to research compiled by the Faculty of Health and Behavioral Sciences of Deakin University in Australia, vitamins and supplements can cause excessive damage, even death, if taken in too large amounts. Vitamins A, D, E and K are fat soluble, able to be stored in the liver and body fat for a long time. Taking high doses of these vitamins over a long period of time can result in harmful levels in the body. Even some of the water soluble vitamins can cause serious side effects in high doses. B6 has been linked with nerve damage when taken in high doses. Even Vitamin C, which may ease some of the symptoms of a cold, while not preventing you from catching a cold, can cause nausea, abdominal cramps, headaches, fatigue, kidney stones and diarrhea. It may also interfere with the absorption of other nutrients which could offer significant protection, such as raising the level of iron in the body to dangerous levels.
A study at The University of Washington conducted by Dr. Christopher G. Slatore and colleagues analyzed data from 77,126 people to determine if increased vitamins had an impact on the incidence of lung cancer. In this four year study, 521 subjects did develop lung cancer, which was in line for this low risk group. However, those who did develop lung cancer had a slight significant association between lung cancer and supplemental vitamin E.
Another detailed study reported in the American Journal of Epidemiology, 2009, examined associations of long term use of beta-carotene, retinol, vitamin A, lutein, and lycopene supplements with lung cancer risk. The findings suggest that long-term use of these supplements, at doses higher than in a typical multivitamin, may be harmful with regard to lung cancer risk. Use of tobacco clearly is a major contributor to lung cancer, yet long term use of these supplements should not be recommended for lung cancer prevention.
The findings warrant additional studies examining the effects of supplement use on risk of lung and other cancers.
Furthermore, a US National Institutes of Health report blasts a safety review from the Independent Vitamin Safety Review Panel, stating that their supplement study was biased. Dr. J. Michael McGinnis, M.D., chair of the panel said, “More than half of American adults are taking dietary supplements, the majority of which are multivitamins, and the bottom line is that we don’t know for sure that they’re benefitting from them…consuming single vitamins or minerals in large doses, may lead them to unwittingly exceed the Upper Levels of nutrients, which can be harmful. Given these safety concerns and the limitations of the available evidence, the panel advocated for changes in the regulation of dietary supplements-including multivitamin-minerals-by the Food and Drug Administration.”
The Deakin University study also references an aborted beta-carotene study, stopped because the mortality rate was higher in the people taking the supplements.
It is important to understand that it would take weeks or months before a vitamin deficiency would affect your health. An occasional lapse in good eating will not be harmful if your diet usually consists of a wide variety of fresh foods.