Besides being the easiest vitamin to absorb (milk, sunshine) Vitamin D may also be the one we know the least about. This glowing vitamin has been popping up all over the news lately: as a preventative measure for colon, prostate and breast cancer, leading the fight against osteoporosis, promoting good bone health, and being lit up in the headlines that we, as a world, are at risk for deficiency. However, deficiency may not be the only problem faced in the news surrounding this common supplement.
The U.S. Department of Health and Human Services National Institute of Health (NIH) recently announced that Vitamin D could have lasting effects on the body beyond good bone health, and some of these could be harmful, if not permanent. Researchers have been studying Vitamin D intake in the elderly for years, proving that additional Vitamin D can prevent people from falling as well as strengthen their bone density, but the findings are prevalent only in the senior age group and haven’t been approved for all ages. Gender and ethnicity also haven’t been studied well enough in support of vitamin D for the health effects to be proven.
The NIH cites lack of evidence for a sweeping generalization that excessive amounts of vitamin D are useful in everyday life. Mary Frances Picciano, Ph.D., a senior nutrition research scientist at NIH says, "Given recent findings, it’s easy to see why people are so enthusiastic about the potential power of vitamin D, but we must recognize the limitations of any study and exercise caution when making broad public health recommendations," in reference to recent claims that vitamin D deficiency is a worldwide cause for concern. The NIH cites the American Journal of Clinical Nutrition with their research, “Vitamin D and Health in the 21st Century: an Update,” which was published this month. In a study specific to the update, the author Anthony W. Norman reports, “Despite many publications and scientific meetings reporting advances in vitamin D science, a disturbing realization is growing that the newer scientific and clinical knowledge is not being translated into better human health.”
Both the American Journal of Clinical Nutrition and the NIH agree we don’t know enough about the negative or positive effects of vitamin D to recommend it to the general public. There are a lot of factors that are not constant in the research of vitamin D that make it harder to come up with solid conclusions. For example the laboratory blood tests used to determine the level of vitamin D in patients are widely varied.. None of the research up to now has been able to pinpoint the exact levels of vitamin D needed in the body throughout stages of life, including the reproductive state, and there is little to no evidence suggesting the varied levels of vitamin D within ethnicities.
Too little vitamin D could put you at risk for bone softening, numerous cancers and other conditions, but too much vitamin D could also put you at risk for other ailments such as nausea, vomiting, and kidney stones. So for now, until there is more evidence produced, give the old Goldilocks method a try and use “just enough,” or two healthy glasses of fortified milk a day (depending on age), the recommended daily dose of vitamin D.