Vitamin D is essential for strong bones. When young children don’t get enough vitamin D, they can develop a bone deformity called rickets. This nutrient acts as a hormone in the body. It is vital for hundreds of activities, including calcium regulation. But do vitamin D supplements make for stronger bones?
Studies Don’t Support Stronger Bones from Vitamin D Supplements:
Millions of people take both vitamin D and calcium supplements in an effort to maintain strong bones as they age. But a new meta-analysis of 81 randomized controlled trials involving over 50,000 participants concludes “that vitamin D supplementation does not prevent fractures or falls, or have clinically meaningful effects on bone mineral density” (The Lancet Diabetes & Endocrinology, online Oct. 4, 2018). This was true even in studies that used doses of 800 IU vitamin D daily.
Can supplements adequately replace the vitamin D that human skin makes when it is exposed to sunshine? We don’t have the studies to answer that question.
Task Force Didn’t Recommend Vitamin D for Stronger Bones:
More than six years ago, the US Preventive Services Task Force issued confusing guidelines on the topic of vitamin D supplements for stronger bones. For years, women have been told to take high doses of calcium along with some vitamin D to strengthen bones. But in 2012, the USPSTF advised postmenopausal women that taking calcium and vitamin D won’t prevent broken bones after all.
Studies showed that 400 IU of vitamin D and 1000 mg of calcium daily do not prevent osteoporotic fractures. Such supplements might increase the risk of kidney stones, however. Some research suggests that 400 IU of vitamin D as a daily supplement is not enough to achieve optimal blood levels of circulating 25-hydroxyvitamin D (Nutrients, Dec. 2015). Individuals vary greatly in their response to vitamin D supplements. Consequently, the dose should be personalized to achieve 25-hydroxyvitamin D levels over 30 ng/ml.
“400 IU of D3, while it may be the RDA, won’t move the needle. The relevant measure that needs to be reported in this study is, what was the blood level of D3 of the participants who suffered broken bones? My doctor believes it takes +-1000 IU of D3 to move blood level by 10 ng, more if you’re fat.”
Preventing Bone Loss:
What can you do to keep your bones strong? If you get calcium from your diet and vitamin D from moderate sun exposure, you should have the nutritional foundation for bone health. Bones also respond to regular exercise such as running, walking, dancing or playing tennis.
You can learn more about preventing bone loss in our Guide to Osteoporosis, while our Guide to Vitamin D Deficiency tells more about sources and doses of this very important vitamin.
The USPSTF did not compare supplements and osteoporosis drugs. When possible, preventing bone loss with weight-bearing exercise, a diet rich in calcium from a variety of sources including green leafy vegetables (which also supply vitamin K, magnesium and other nutrients vital for stronger bones) and vitamin D from the sun or from fatty fish may be the best approach. Our interview (Show 752) with Michael Castleman, co-author of Building Bone Vitality: A Revolutionary Diet Plan to Prevent Bone Loss and Reverse Osteoporosis, and Walter Willett, MD, DrPH, Chairman of Nutrition at Harvard School of Public Health, may also be of interest.