Popping pills for ‘better bone health’? Think again. There is blind enthusiasm to take calcium and vitamin D for the treatment and prevention of osteoporosis, despite mounting evidence that contradicts their effectiveness.
You are not alone if your last family photograph left you wondering if you are shrinking, particularly if you are over 60. In New Zealand, 50% of women and 30% of men over 60 are affected by osteoporosis. Many older adults are advised to take calcium and vitamin D supplements to prevent bone fracture, especially as dietary calcium is inadequate in most countries.
We rely on absorbing calcium from our diets because our bodies do not produce calcium. However, absorption is affected by a number of factors including the presence of other vitamins (especially vitamin D), medications and smoking.
Supplements have been promoted for many years under the guise that they prevent bone fracture – an increasing problem that occurs due to a loss of bone density as we age, particularly in postmenopausal women. The loss in bone density is described as osteoporosis and results in bone deformity, postural deviations and fractures.
The total cost of osteoporosis in New Zealand is estimated to be over $1.15 billion per year and the number of osteoporotic fractures and the cost of healthcare associated with osteoporosis in New Zealand is expected to increase by over 30% between 2007-2020. This is an enormous problem.
The reality unveiled
A New Zealand led study, published in The British Medical Journal (the BMJ) in September, challenges the effectiveness of calcium to prevent osteoporosis. The team of researchers delved into the literature and concluded from two studies that increasing calcium intake from both supplements and dietary sources did not reduce the risk of fracture in people aged over 50.
The new study follows an analysis of calcium and vitamin D supplements, published in July in the BMJ by two of the same authors, Andrew Grey and Mark Bolland – both doctors and researchers at the University of Auckland.
They put forward an assertive exposé on how supplementation goes against recent evidence that such supplements “do not reduce the risk of fracture and may result in harm”.
“Collectively, these results suggest that clinicians, advocacy organisations and health policymakers should not recommend increasing calcium intake for fracture prevention, either by use of calcium supplements or dietary sources,” says Dr Bolland.
The back story
Calcium supplements were initially promoted in the 1960s when there were few alternatives for the prevention of osteoporosis. Other therapies, such as oestrogen and fluoride, were later abandoned after they were found to be ineffective or harmful.
We are bombarded with messages promoting calcium as essential for bone health from television advertisements, newspaper inserts, health stores and GPs. Surprisingly, the highly influential Family Health Diary NZ, an industry-funded health campaign, is permitted to boast the merits of various health interventions, including calcium, on prime time television.
It emphasises that “it is important to get enough calcium into the body to preserve bone mass … Calcium and vitamin D supplements can help prevent osteoporosis getting worse”.
However, Dr Bolland asserts, “For most patients who are concerned about their bone health, they do not need to worry about their calcium intake”.
Bone remodelling in adults is a dynamic process involving specialised bone cells – osteoblasts and osteoclasts. Professor Ian Reid from the University of Auckland explains that although calcium is important to strengthen bone, an oversupply is not likely to be beneficial. It is the balance of osteoblasts and osteoclasts that is essential for the change in bone density over time, not calcium.
Accumulating evidence gives a clear indication that supplementation should be reconsidered.
Fourteen large randomised trials, involving more than a thousand participants, studying calcium supplements with or without vitamin D were published by 2010 – nine of which reported no effect and two described an increased fracture risk.
There is even evidence suggesting calcium supplementation precipitated hospital admission for gastrointestinal symptoms, kidney stones, heart attacks and strokes.
So why is it taking so long for evidence that challenges the efficacy of calcium and vitamin D to be accepted and considered in practice?
Doctors Grey and Bolland tracked down several entwined groups and provided evidence of the complex commercial incentives likely to be the driving force behind the unnecessary and potentially harmful treatment of osteoporosis with calcium and vitamin D. They want advocacy organisations, specialist societies and academics to break ties with industry.
“Advice about medical practices and/or health behaviours should be as free of bias as possible. Conflicts of interest, particularly financial ones, introduce bias. Thus, organisations and individuals who provide advice should be free of conflicts of interest,” says Dr Grey.
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 markets calcium-enriched milk products for optimal bone health in Asia, part of a $4 billion industry.
Taking a walk down the supplement aisle of your local Health 2000 store reveals a plethora of fourteen different brands and more than twenty different formulations of calcium and vitamin D supplements. They range in price hugely – from $10 to $150 dollars for a months supply, following dosage directions. The brutal reality behind supplementation exposes the exploitation of a vulnerable public, the ageing population.
“I think a lot of people don’t appreciate the size of the supplement industry. The calcium supplement sales around the world are six billion dollars … and that’s just one of the supplements. The supplement industry is enormous,” says Dr Bolland.
A range of commercial sponsors that support the use of these supplements heavily influence the judgement of advocacy organisations, such as the US National Osteoporosis Foundation and the International Osteoporosis Foundation. Sponsors include companies that market supplements, dairy products and nutrition-related laboratory tests. In an attempt to gain corporate sponsorship, the osteoporosis foundations “offer the opportunity for corporate members to influence the strategic direction of the organisation at both formal and informal levels,” Grey and Bolland write.
A disregard for evidence
Dr Bolland said in an interview that “when recommendations of calcium intake for older people were first made in the late 1960s and early 70s, they were based on the best evidence available at the time … but the evidence moved on over the next 30 years, particularly in the last 15 years. The guidelines and recommendations for calcium intake have not kept up with new evidence.”
Following the release of the most recent NZ led studies, the Council for Responsible Nutrition (CRN), a member of the National Osteoporosis Foundation, issued a statement criticising the data used in the analysis. The CRN believe that the results, “albeit weak positive”, actually suggest calcium supplements reduce fracture risk.
“Calcium is needed at every life stage for a variety of health reasons, including maintaining strong bone health … Supplementing with calcium is a safe and beneficial avenue to address [the] issue of nutrient shortfalls in the American population,” writes Duffy MacKay, Senior Vice President, CRN.
The nutrition industry continues to partner with osteoporosis advocacy organisations, promoting the extensive use of supplements, even after unfavourable evidence has come to light. Companies implicated include vitamin D manufacturer DSM, Danone, Bayer HealthCare and Fonterra. Fonterra has supported osteoporosis advocacy groups, both financially and ideologically, throughout Asia since 2010, write Grey and Bolland.
When evidence of cardiovascular harm from calcium emerged in 2010, the CRN responded with a press release to reassure consumers, stating that the findings “should not cause consumers to doubt the value of calcium supplements for maintaining bone health.”
Further unfavourable evidence of cardiovascular harm from calcium came to light in 2011, which strengthened previous claims and propelled the CRN to develop an action plan. One concern expressed was that the evidence had “the potential to negatively influence consumers’ views of the importance of calcium.”
The CRN urged companies who benefit from calcium supplementation to support an initiative in order to actively counter media coverage of the negative findings, which they perceived as being ‘unwarranted’.
The overwhelming refusal from industry-sponsored advocacy organisations to acknowledge conflicting evidence is reinforced by cherry-picked, spurious findings from less rigorous research that support the use of these supplements, thereby perpetuating the mantra that calcium supplements are beneficial for our bones.
The nutrition industry funds academic research into 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 by prominent academics that continues to promote the use of supplements. These academics routinely sit on the scientific advisory committees of advocacy organisations, backed by industry.
A good example occurred in 2013 when hip fracture data from the US Women’s Health Initiative trial of calcium and vitamin D was reanalysed. Even though no effect was present overall, the National Osteoporosis Foundation identified the positive result among a subgroup as “underscoring the well-documented benefits of calcium.”
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 Grey and Bolland point out.
Most groups that are involved 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. Worse, confidence in the medical system is jeopardised. Opportunities for the implementation of treatments with proven efficacy are lost.
Grey and Bolland believe that the translation of evidence into practice could be improved by separating industry and academia. The complex, entangled relationships of the groups involved makes each reliant on the other for survival – a dependency that leaves them chronically deluded.
What are the alternatives?
When asked what is beneficial for osteoporosis, Dr Grey focused mainly on lifestyle changes. Two main risk factors he addressed were being underweight (body mass index <20kg/m2) and smoking.
Dr Bolland says that “generally the recommendation now is if you’re at high risk of fracture, take a medicine that is proven to prevent fractures; if you’re at low risk of fracture, make sure that you’re doing everything lifestyle-wise”. These lifestyle recommendations include stopping smoking, maintaining a healthy body weight and exercising regularly.
The Auckland Bone Density clinic, where both Dr Reid and Dr Grey work as physicians, recommends a daily “healthy food intake of calcium (800-1000mg)”. A monthly vitamin D supplement is mentioned, although sunlight exposure is considered to be sufficient for most people to gain adequate vitamin D.
The clinic describes ‘osteoporosis medications’ as effective, especially with adequate calcium and vitamin D. When Dr Bolland was questioned about this reference, he explained that the long-held view around the world is that you need to have good calcium intake and vitamin D levels when taking osteoporosis medications.
“There is quite a lot of indirect evidence that actually the medicines work perfectly well without calcium and vitamin D supplements. I don’t think there is any difference between the risks [of harm] from taking calcium and vitamin D whether you’re at low risk or high risk of fracture, taken with other drugs or not,” says Dr Bolland.
These latest publications add to the growing body of evidence that is inconvenient for the entwined network of groups that are benefitting from the mass medication of older people. This inconvenient evidence flies in the face of the firmly embedded beliefs of the healthcare profession worldwide. Dr Bolland made it clear that challenging dogma and long-standing beliefs was a difficult task.
“Prominent academics willing to criticise our research have been very easy to find while supporters have largely remained silent. The critics have repeatedly disputed every aspect of our research, often with fairly tenuous objections. These academics often have links with the major osteoporosis advocacy groups and medical specialist societies, and are likely an important reason why these organisations are yet to make meaningful changes to their recommendations about calcium intake.”
Calcium and vitamin D represent just one of several examples, such as fish oils, where supplementation advice does not follow evidence-based research. Let’s hope that these recent publications open a can of worms for the nutrition industry. While they decide where their priorities lie, it might be best to err on the side of caution.
Dr Bolland is the recipient of a Hercus Fellowship from the Health Research Council of New Zealand (HRC), and receives research funding from the same organisation. The HRC is the independent agency that manages the NZ Government’s health research funding through an independent, competitive process of research grants. Dr Grey receives research funding from the HRC and Pharmac, the New Zealand Government’s Pharmaceutical Management Agency. These funders had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; and preparation, review, or approval of the manuscript.
Conflict of interest statement: Dr Grey is a shareholder in Auckland Bone Density, a company that provides bone mineral density measurements. Dr Grey and Dr Bolland have co-authored publications on the efficacy and safety of calcium supplements and vitamin D. Otherwise, they have no other conflicts to declare.
Featured image credit: hitthatswitch – flickr.
Homepage image credit: University of Liverpool Faculty of Health & Life Sciences, skeleton from French anatomical engraving – flickr.