The Calcium/Dairy Myth

Although calcium intake is essential, bones are complex and dynamic and have a wide range of nutritional needs. Taking a calcium pill does not guarantee that it will end up in your bones and it does not appear to prevent fractures. Too much supplemental calcium can even be harmful.

So what about the instructions to drink lots of milk, particularly while young? The milk/bone link has long been disputed but the evidence is finally becoming irrefutable that we have, yet again, been misinformed en masse. So much for the massive advertising campaigns exhorting us to drink more milk for healthy bones! Awareness is finally dawning that the countries with the highest rates of osteoporosis are the biggest consumers of dairy products (i.e.USA, Australia, New Zealand, Switzerland, the UK and Northern Europe) and that Asian countries like China where dairy consumption is rare, have the lowest rates of hip fracture in the world. Most Chinese people eat no dairy products and get all their calcium from vegetables. Yet while they consume only half the calcium of most Westerners they have one of the lowest rates of hip fracture in the world.

A recent review of 57 studies looking at dairy food and bone health concluded that "…the body of scientific evidence appears inadequate to support a recommendation for daily intake of dairy foods to promote bone health in the general US population." The famous Nurses Health Study in the U.S. followed the dietary calcium intake of 77,000 women over a 12 year period and found that those with the highest consumption of dairy products had the highest rate of fracture.

Now there is another study. Kanis and colleagues from the University of Sheffield in the UK reported the results of a meta-analysis of milk intake in 39,563 women and men from 6 studies to the October 2004 annual meeting of the American Society for Bone and Mineral Research. The results showed there was no fracture benefit for those who consumed milk. At the same meeting the results of an Australian 5-year, prospective, randomized placebo-controlled trial involving 1406 women older than 75 years found questionable benefit from calcium supplementation. Dr Ego Seeman largely dismisses any benefit in his review of the study.

Getting the recommended daily allowance of calcium at all ages is important, preferably from dietary sources. But bone nutrional requirements are wide and complex. A diet that covers the diverse nutritional needs of bone including calcium, magnesium, vitamin K, boron, manganese, zinc, copper, silicon and others nutrients is ideal. Fresh vegetables, fruits, nuts and seeds are good sources of these foods. Limit heavy protein and salt intake, reduce alcohol, don't smoke, and for essential vitamin D, get sunlight on your skin at safe times of the day.

An 18 year analysis of 72 337 postmenopausal women published in the February 2003 American Journal of Clinical Nutrition, found that an adequate vitamin D intake is associated with a lower risk of osteoporotic hip fractures in postmenopausal women. Neither milk nor a high-calcium diet appears to reduce risk. The authors suggest that because women commonly consume less than the recommended intake of vitamin D, a supplement of the vitamin or dark fish consumption may be prudent.

References:

Weinsier, R L. "Dairy foods and bone health: examination of the evidence." American Journal of Clinical Nutrition 2000;72:681-9

Feskanich,D et al. "Milk, dietary calcium and bone fractures in women: a 12-year prospective study." American Journal of Public Health 1997;87:992-997

Seeman, Ego. Highlights of the ASBMR 26th Annual Meeting 2004 http://www.medscape.com/viewarticle/491496_4

Feskanich, D. Willett, W. C. ,Colditz G.A. "Calcium, vitamin D, milk consumption, and hip fractures: a prospective study among postmenopausal women." American Journal of Clinical Nutrition, Vol. 77, No. 2, 504-511, February 2003