Vitamin D: Not as effective for bone health? Industry hits back amid controversy

29 Jul 2022 --- Supplemental vitamin D3 for bone health may not be as effective as it is believed to be, according to a US study of more than 1,500 adults. The findings have drawn the ire of industry, with the Council for Responsible calling the research a “disservice to public health.”

Although vitamin D supplements are widely prescribed and used to benefit bone health, definitive data on whether these supplements reduce fractures in the general population have been inconsistent, the study carried out by Brigham and Women’s Hospital explains. 

“Overall, the results from this large clinical trial do not support the use of vitamin D supplements to reduce fractures in generally healthy US men and women,” says lead author Meryl LeBoff, chief of the Calcium and Bone Section in the Endocrine Division at the Brigham.

Dr. Andrea Wong, CRN senior vice president of scientific and regulatory affairs questioned the choice of participants specifying :“The study focused only on generally healthy midlife or older adults instead of individuals with vitamin D deficiency, low bone mass, or osteoporosis who may be more vulnerable to fractures and derive a benefit from vitamin D supplementation.”

The findings add to the body of vitamin D research, CRN highlights, despite its disagreement with the way the study was carried out. Ineffective?
As part of the research, a total of 1,991 incident fractures in 1,551 participants were confirmed over a median follow-up of 5.3 years. Compared to placebo, supplemental vitamin D3 (2,000 IU/day) did not reduce total, non-vertebral or hip fractures.

The analyses also showed there were no effects of supplemental vitamin D3 on major osteoporotic fractures, wrist fractures, or pelvic fractures. Effects were not modified by baseline age, sex, race, body mass index, baseline vitamin D blood levels and personal use of supplemental calcium and/or vitamin D.

The study is an ancillary one to the VITamin D and OmegA-3 TriaL (VITAL), a clinical trial of more than 25,000 adults, also led by investigators from the Brigham.

Controversy abounds
According to the researchers, the findings do not apply to adults with vitamin D deficiency or low bone mass or osteoporosis. 

“Most participants in the trial were not deficient and may have already reached the vitamin D level needed for bone health. Our ongoing studies are focusing on whether free vitamin D levels or genetic variation in vitamin D absorption, metabolism or receptor function will provide information about individuals who may benefit from supplemental vitamin D on musculoskeletal health,” LeBoff underscores. 

The fact that participants were not vitamin D deficient was deemed to be problematic, Wong highlights. “The odds were stacked against this ancillary study before it even started.”

Calcium: an “obvious” omission?
Wong adds the results are unsurprising since VITAL was designed to assess vitamin D supplementation alone and did not include or control for calcium supplementation and intake.

“Vitamin D and calcium work in tandem to support bone health – calcium helps build and maintain bones, while vitamin D helps your body effectively absorb calcium. It seems obvious that investigating one without the other would produce disappointing results.”

Industry has long eyed the potential of vitamin D in combination with other ingredients, including calcium and vitamin K2. DSM also highlighted the potential of calcifediol to harness vitamin D potential amid immunity demands.Vitamin D is popular for immunity and bone health support.

An essential nutrient?
Wong adds the most recent Dietary Guidelines for Americans identifies vitamin D as a “nutrient of public health concern.” 

“The fact remains that vitamin D is an essential nutrient that supports numerous biological functions,” she remarks. “Dietary studies have repeatedly shown many people still fall short of obtaining adequate levels of vitamin D and may be missing out on health benefits.”

“Advising people to stop taking vitamin D supplements when natural food sources of this nutrient are scarce, and sun exposure may not be feasible for those who are most vulnerable, is a disservice to public health.”

Consumer demand for vitamin D spiked with the development of the COVID-19 pandemic, leading England to offer free supplements of the sunshine vitamin. Nonetheless, doctors have also been warning vitamin D overdose is on the rise.

“People should discuss with their health care practitioner whether testing their vitamin D levels or supplementing with vitamin D is appropriate,” concludes Wong.

By Andria Kades