Calcium and vitamin D continue to be hailed as effective supplements to treat and prevent osteoporosis, despite mounting evidence to the contrary, warn two New Zealand doctors.
They contend that blind enthusiasm for supplementation is being perpetuated by the vested interests of an insidious network of groups including industry, advocacy organisations and academia.
Many older adults are advised to take calcium and vitamin D supplements to prevent bone fracture, especially as dietary calcium is deficient in most countries. Supplementation has been promoted for many years – now more than half of older Americans take calcium and vitamin D supplements for their bone health.
As the authors, Andrew Grey and Mark Bolland from the University of Auckland explain in the editorial featured in The BMJ, this behaviour goes against evidence, surfacing since 2002 that such supplements “do not reduce the risk of fracture and may result in harm.”
Previous therapies for osteoporosis, such as oestrogen and fluoride, have been abandoned after they were found to be ineffective or harmful.
Why is it taking so long for evidence that challenges the efficacy of calcium and vitamin D to be accepted and considered in practice?
The authors illustrate how complex commercial incentives of several intertwined groups may be the driving force behind the unnecessary and potentially harmful treatment of osteoporosis with calcium and vitamin D. They appeal to advocacy organisations, specialist societies and academics to break ties with industry in order to bring about change.
Motivations behind the fallacy
These supplements are highly profitable to both industry and associated companies that have joined the bandwagon and market foods rich in calcium or vitamin D, promoting the misconception of their efficacy. For example, Fonterra market calcium-enriched milk products for optimal bone health in Asia, part of a $4bn industry.
The objectivity of advocacy organisations, the US National Osteoporosis Foundation (NOF) and the International Osteoporosis Foundation (IOF), who support the use of these supplements may be undermined by the influence of a range of commercial sponsors, including companies that market supplements, dairy products, and nutrition related laboratory tests. In their attempt to gain corporate sponsorship the NOF and IOF “offer the opportunity for corporate members to influence the strategic direction of the organisation at both formal and informal levels,” the authors write.
A disregard for evidence
The nutrition industry continues to partner with osteoporosis advocacy organisations, promoting the extensive use of the supplements, even after unfavourable evidence has come to light. This includes vitamin D manufacturer DSM, Danone, Bayer HealthCare and Fonterra. Fonterra has supported osteoporosis advocacy groups, both financially and in ideology, throughout Asia since 2010 when it became the IOF Asia Pacific Regional Nutrition Partner.
The US Preventive Services Task Force panel concluded in 2013 that older adults do not benefit from either calcium or vitamin D supplementation. However, both the NOF and IOF cling to the notion that this intervention is essential to prevent fracture.
The Council for Responsible Nutrition, a member of the NOF, urged companies who benefit from calcium supplementation to support an initiative to actively counter negative media coverage of the evidence of cardiovascular harm from calcium in 2011.
The Vitamin D Council, another industry sponsored advocacy organisation, refuse to acknowledge conflicting evidence, and cherry-pick spurious research findings that support its use.
Implication of academia
The nutrition industry funds research with the intention of gaining results that favour the use of calcium and vitamin D. The extent of the affiliations between the nutrition industry and academics is not always fully acknowledged. The most insidious example being the support of research that continues to promote the use of supplements by prominent academics on the scientific advisory committees of advocacy organisations, backed by industry.
Although the nutrition industry plays a huge part in the sponsorship of specialist societies and their scientific meetings, conflict of interest statements from academics do not appear on the societies’ websites. In addition to finances, academics involved may also have academic conflicts of interest, as the authors point out.
Most parties benefit – Industry’s masquerade of scientific credibility boosts the sales of its products by indirect marketing from advocacy groups. Advocacy organisations and societies gain funds, enabling their existence. Academics gain research funds for career-enhancing publications thereby improving their status.
The public is disadvantaged, and may be put at risk. Confidence in the medical system is jeopardised. Opportunities for the implementation of treatments with proven efficacy are lost. The authors believe that the translation of evidence into practice could be improved by disentangling industry from academia.