One of the most contentious questions in nutrition science over the past decade has been whether older adults should be taking supplemental vitamin D and calcium. As the world’s population ages and broken bones and fractures become even more of a public health concern, with huge social and economic consequences, researchers have been trying to make sense of conflicting studies on the association between supplements and fracture risk.

A study published in the Journal of the American Medical Association on Tuesday took a fresh look by analyzing 33 randomized clinical trials involving more than 50,000 adults over age 50.

Each of these previous research papers involved comparing calcium, vitamin D or both with a placebo or no treatment. The analysis, conducted by Jia-Guo Zhao of Tianjin Hospital in China, was focused on older adults who live in the general community. The study sample did not include those in nursing homes, hospitals and other facilities.

The conclusion was clear: Vitamin D and calcium supplements do not seem to be warranted to prevent bone breaks or hip fractures in those adults. Such supplements had no clear benefit regardless of dose, the gender of the patient, history of fractures or the amount of calcium in the diet.

The U.S. Preventive Services Task Force, an influential federal advisory body, has raised questions about these supplements since 2013, when it issued recommendations saying evidence to support the benefit of the supplements in older adults without osteoporosis or vitamin D deficiency was “insufficient.”

Calcium and vitamin D have been known to be important to bone maintenance for a long time, and the best way to get the daily recommended doses are the natural way.

For calcium, that means eating dairy products such as milk, cheese, yogurt or calcium-rich leafy greens. For vitamin D, that means getting some sun exposure. Only a few foods contain vitamin D, and they include fatty fish like salmon.