Is Dietary Calcium Linked to Reduced Fracture Risk?
You may have heard in the media, “Calcium from supplements or dairy doesn’t strengthen bones,” or seen recent research seeming to minimize the relationship between calcium from dairy foods or supplements and reduced risk of bone fracture. As health and wellness professionals, you may be wondering how best to reconcile this new information with current recommendations so you can better answer questions from your clients, friends and family.
In late September, two systematic reviews were published in the British Medical Journal on calcium and bone health (Tai, 2015; Bolland, 2015). The authors themselves paint their findings as disappointing, saying, “Dietary calcium intake (from foods) is not associated with risk of fracture, and there is no clinical trial evidence that increasing calcium intake from dietary sources prevents fractures. Evidence that calcium supplements prevent fractures is weak and inconsistent”.
However, the researchers found some modest, but significant benefits (as often seen in nutrition research) that shouldn’t be ignored:
- The first review found that increases in calcium consumption (from food or supplements) produced modest but significant increases in BMD estimated to produce a 5-10 percent reduction in risk of fracture.
- In the second review when fracture was the outcome, results were mixed. Calcium supplements were associated with a significantly reduced risk of total and spinal fracture in the 26 randomized controlled trials examined. Although no clinical evidence showed a benefit of calcium from foods, this is a research gap, since only two studies were examined. Most of the observational studies of calcium supplements, or milk/total dairy showed no association, with only a few showing benefit.
On the other hand, some studies have shown a benefit of consuming dairy foods (milk and yogurt) or dairy nutrients (calcium/protein) for reducing risk of hip fracture (Sahni, 2014; Sahni, 2010). Most recently, a prospective study in Australia found that higher calcium consumption from food (up to 1,348 mg/d) was associated with a reduced risk of fracture, non-fatal CVD, stroke, and all-cause mortality.
Why do we find such mixed results for calcium/dairy and bone fracture? It may have to do with the multifactorial nature of fracture risk. To reduce the risk of bone fracture, consider all the nutrition and lifestyle factors that work together to maintain healthy bones and optimize peak bone mass – then add factors that help reduce the risk of falls, such as skeletal muscle mass, balance, and vitamin D status. Also note that studies in adults may not control for differences in peak bone mass, which significantly influences fracture risk.
That’s why we shouldn’t expect one nutritional factor, such as calcium, to be the sole determinant of fracture risk. But that doesn’t mean that eating the recommended amounts of calcium and dairy foods is not important.
A recent narrative review discusses the role nutrition plays in developing and maintaining healthy bones throughout life – contending that calcium, vitamin D and protein are the nutrients most critical for achieving peak bone mass in children/adolescents, maintaining healthy bones and avoiding premature bone loss in adults and seniors.
As health and wellness professionals, we need to do everything we can nutritionally to help people maintain good bone health throughout life. That includes getting the recommended three servings of low-fat or fat-free milk, yogurt or cheese daily.
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