Osteoporosis is a dread disease that accounts for ill-health and debilitation in millions of women and men throughout the world. The standard advice to treat and prevent osteoporosis, particularly in post-menopausal women, has been to prescribe calcium.
More recently vitamin D supplements have been added, together with various meditations such as bisphosphonates, calcitonin (the hormone that inhibits bone resorption), fluoride and oestrogen preparations.
Discrediting osteoporosis treatment
But these trusted aids to preventing or slowing bone loss are being discredited at an alarming rate. First there was the oestrogen scare which now prevents millions of women from using HRT (Hormone Replacement Therapy), which may or may not help to prevent osteoporosis. Then the use of calcitonin and fluoride were blacklisted and now even those stalwarts, calcium and vitamin D, are under attack.
Read: Osteoporosis - the basics
The anti-calcium supplement movement started when some studies reported that calcium supplementation increases the risk of cardiovascular incidents (heart attacks and strokes).
In 2008, Dr Mark Bolland together with Prof Andrew Grey and a team in New Zealand published a study entitled “Vascular events in healthy older women receiving calcium supplementation: randomised controlled trial”, in which they studied death, sudden death, myocardial infarction (heart attack), and stroke in a population of 1,471 postmenopausal women. Half the subjects received calcium supplementation, namely 1g of elemental calcium in the form of citrate, while the other half received a placebo (dummy) treatment.
The researchers found that more heart attacks (45 vs. 19 events), strokes and sudden deaths were reported in the treatment group than in the control group. The authors concluded: “Calcium supplementation in healthy postmenopausal women is associated with upward trends in cardiovascular event rates.” This is when the first ripple of alarm was felt in the field of osteoporosis treatment.
The calcium supplement industry reacted immediately, and products such as MenaCal.7 which contains calcium, vitamin D3 and vitamin K2 to “ensure that the calcium is deposited in the bones and not in the arteries”, were launched.
Read: Vitamin K is the new bone nutrient
Calcium intake from foods
However, other researchers also discovered negative links between supplemental calcium and heart and cardiovascular health. Xiao and co-workers published a study that investigated if dietary and supplement intake of calcium has an effect on deaths associated with total cardiovascular disease (CVD), heart disease and cerebrovascular disease (strokes).
More than 380,000 men and women between the ages of 50 and 71 years were followed up from 1995 to 1996 in the USA. The results indicated that in men the use of calcium supplements at levels of more than 1,000 mg per day increased the risk of death from CVD by 20%, but not in women, and that dietary intake of calcium from foods was not related to these deaths.
Read: Which foods have calcium?
But one or two studies do not provide indisputable proof, and in 2012, most experts, such as Dr Strawbridge, a former Editor of Harvard Health, cautioned the public not to discard their calcium supplements outright. Strawbridge pointed out that according to Dr Deepak Bhatt, a cardiologist at Brigham and Women’s Hospital, “no iron-clad evidence of a connection between calcium supplements and heart attack” had as yet been presented.
Dr Bhatt also suggested that the best source of calcium is the diet, but that most people did not eat sufficient calcium-rich foods to provide 1,000 – 1,200 mg of calcium a day. One could, therefore, deduce that the majority of people do require some supplementation of calcium but at a modest level of say 200-500 mg per day.
More negative evidence
Despite the cautionary approach of the above mentioned leading American experts, more evidence is building up that highlights a plethora of negative aspects of calcium supplementation. For example one study found that the benefits of calcium supplementation in healthy men do not appear to last and a meta-analytical study has once again confirmed that calcium supplementation is linked to an increase in heart disease. In addition, taking calcium supplements may increase the risk of developing kidney stones and gastrointestinal symptoms.
This growing evidence that all may not be well in relation to calcium supplementation has prompted Professors Andrew Grey and Mark Bolland (2015B) to publish a highly critical article in the prestigious British Medical Journal on “Web of industry, advocacy, and academia in the management of osteoporosis”. Grey and Bolland identify a host of reasons why the treatment of osteoporosis still relies so heavily on calcium and vitamin D supplementation despite evidence that this may not be safe or efficacious.
Is there a calcium supplement conspiracy?
Professors Grey and Bolland suggest that prescribing calcium and vitamin D supplementation and everything associated with the practice (e.g. tests to determine body calcium and vitamin D levels), is highly profitable to many players in the fields of medicine and health sciences.
Considering that 70% of older women in the USA take calcium supplements by prescription or over-the-counter, it is understandable that the US industry raked in $748 million in 2012 and $6 billion globally in 2013 from this source. Calcium- and vitamin D-enriched foods are also great money spinners overseas and testing for vitamin D cost the Australian economy $96 million Australian dollars in 2010.
Test yourself: Am I getting enough calcium from my diet?
Then there are the incentives that researchers are believed to receive from industry which may be fuelling the enthusiasm for prescribing calcium and vitamin D supplements for osteoporosis. Grey and Bolland maintain that authors of research papers should scrupulously disclose who they have received funding from, i.e. industry, pharmaceutical companies, manufacturers of fortified foods, etc.
According to Susan Perry, the professors believe that, “All those stakeholders benefit financially by promoting the use of supplements.”
So there may well be a calcium supplement conspiracy but what worries me, is what does all this controversy mean to you and me? We are still at risk of osteoporosis and although dieticians have been urging the public to make sure that they ingest sufficient calcium-rich foods from conception to old age, the number of people in most countries, South Africa included, who manage to achieve the recommended daily intake for calcium of 1,000 to 1,200 mg per day (depending on age and gender) from their diet, is frighteningly low.
Previously those members of the public who were able to afford this, topped up their dietary intake of calcium with supplements, something that they should perhaps no longer do.
It will always be best to go for dietary sources of calcium including tips for those people who do not use milk for reasons of religion or conviction or because of intolerances and allergies.
Calcium alone won’t prevent osteoporosis
Calcium quotas too high?
Vitamin supplements could be harmful
- Bolland M et al (2008). Vascular events in healthy older women receiving calcium supplementation: randomised controlled trial. British Medical Journal. 336:262.
- Grey A, Bolland M (2015).Web of industry, advocacy, and academia in the management of osteoporosis. BMJ;351:h3170.
- Mahan L K et al (2013). Kalluru R et al (2015). Bone density in healthy men after cessation of calcium supplements: 20-month follow-up of a randomized controlled trial. Osteoporosis Int, 26(1):173-8.
- Krause’s Food & the Nutrition Care Process. 13th Edition. Elsevier Publishers, USA; Perry, S (2015). A ‘complex web’ of vested interests promote calcium and vitamin D for osteoporosis, despite lack of evidence.
- Strawbridge H (2012). Link between calcium supplements and heart disease raises the question: Take them or toss them?
- Wallan SW (2015). Do dollars form the backbone of Osteoporosis Recs? cme/ceEndocrinology 07.23.1015 Comments.
- Xiao Q et al (2013). Dietary and Supplemental calcium intake and cardiovascular disease mortality: the National Institutes of Health-AARP diet and health study. (2013). JAMA Intern Med; 173(8):639-46.
Image: Osteoporosis risk from Shutterstock
Dr Ingrid van Heerden is a registered dietician and holds a doctoral degree in Nutrition and Biochemistry. She believes that "we are what we eat" and offers free nutrition and weight loss advice via her DietDoc service on Health24.com. Read more of her articles.