The most recent 'People's Pharmacy' podcast is worth a listen. The first doctor they interview calls into question the usefulness of meta-analyses, and explains why he believes double-blind placebo controlled studies have been inappropriately applied to nutritional studies. After the break they have a second doctor on who also discusses the issues with the meta-analysis/JAMA report, and problems with meta-analyses. https://www.peoplespharmacy.com/2018/10/18/show-1139-will-supplements-keep-your-bones-strong/ "In December 2017, a meta-analysis published in JAMA demonstrated no benefit from vitamin D or calcium supplementation. People taking the supplements were just as likely to break a bone as people taking placebo pills. Those on vitamin D pills were at higher risk for kidney stones, though. To make sense of this research, we talked with two experts: one, a researcher who specialized in studying bone strength and osteoporosis, and the other a leading nutrition scientist. They explain how we can make sense of the confusion. Are placebo-controlled trials the best way to learn about nutritional supplements and their value? How can you tell if your vitamin D levels are low? Are there supplements you might consider to keep your bones strong?"