I’ve heard that taking vitamin D doesn’t actually benefit bones or prevent fractures. Should I stop taking it?
New evidence has shown that taking vitamin D supplements doesn’t protect against bone loss, fractures or falls, no matter how high or low the dose. These findings come from an analysis of 81 randomized controlled trials that included data on 53,537 participants who were taking vitamin D. The researchers, from New Zealand’s University of Auckland and the University of Aberdeen in Scotland, also saw no significant effect on bone density in the lumbar spine or femoral neck (the part of the thigh bone that connects to the hip joint).
The new investigation wasn’t the first to cast doubt on the benefits of taking vitamin D (and calcium) to reduce the risk of fractures. Earlier this year, I reported on research from China that came to the same conclusion after analyzing information from 33 randomized, placebo-controlled trials with data on 51,145 participants. Some of the trials focused on both supplements, while others looked at one or the other. The latest analysis looked only at vitamin D.
Based on the results of the investigation, the researchers saw “little justification to use vitamin D supplements to maintain or improve musculoskeletal health.” However, keep in mind that analyses are not studies – they can’t answer questions in the same way that studies can, and much other research supports the use of supplemental vitamin D, so it is unlikely that recommendations to take calcium and vitamin D will change.
As you may know, I recommend that everyone take 2000 IU of vitamin D daily for its many positive health effects. Even if further research suggests that it doesn’t benefit bones, there are other important reasons to continue taking vitamin D. It helps strengthen the immune system, protects against a number of serious diseases including rickets and osteomalacia, and may protect against hypertension, psoriasis, multiple sclerosis and rheumatoid arthritis.
Vitamin D also appears to play a role in defending against cancer. Studies have linked vitamin D deficiency to as many as 18 types of cancer.
The body makes vitamin D with exposure to sunlight, but many people don’t get optimal amounts, especially those living in industrialized countries in northern latitudes. In addition, sunscreen blocks vitamin D synthesis in the skin, and dermatologists have made us so fearful about UV damage that many people don’t get enough exposure to sunlight regardless of where they live. Food sources of vitamin D include fortified milk and cereals as well as eggs, salmon, tuna, mackerel and sardines but it’s hard to get what you need, or optimal amounts, from diet alone.
Andrew Weil, M.D.
Allison Avenell et al, “Effects of vitamin D supplementation on musculoskeletal health: a system review, meta-analysis, and trial sequential analysis.” The Lancet Diabetes and Endocrinology, October 4, 2018, DOI: doi.org/10.1016/52213-8587