Tuesday, June 12, 2007
Strength training, coupled with a diet rich in calcium and vitamin D, does your body good in many ways -- some likely to reduce your risk of bone fracture. But if you're looking for evidence that diet and exercise can match the effectiveness of drugs in staving off osteoporosis in middle age, you're going to be disappointed.
That's the conclusion of several experts in the field.
Until the age of 30 or so, diet and exercise can build bone mass. After that, what they do is less a matter of preventing inevitable age-related bone loss than keeping it from accelerating further.
Ethel Siris, a professor of clinical medicine at Columbia University and president of the National Osteoporosis Foundation, puts the message about weight training bluntly: "I don't know of any highly reliable studies that have ever shown that exercise clearly stops bone loss in a [middle-aged] woman who's . . . got adequate calcium and vitamin D. "
Says Siris: "If you do more exercise once you're in your 50s and 60s, it isn't going to make you lose less bone. . . . Exercise has value, but not for the reason people think." What it will do, she says, is build muscle strength, coordination and balance, making the falls that typically cause fractures less likely. Siris accepts consultancy and speaker fees from several drugmakers, including Merck, the maker of osteoporosis drug Fosamax, but says she tries "to handle [the conflict of interest] properly."
But don't put down those weights just yet. Joseph Lane, a professor of orthopedic surgery at the Hospital for Special Surgery in New York and chief of its Metabolic Bone Disease Service, says that the benefit of exercise in a middle-aged adult lies not in bone density but in bone quality -- its "micro-architecture" and strength -- which won't show up on a DXA scan. Still, he says, exercise should be an "additive, not an alternative" to drugs if bone loss is advanced. If you're middle-aged and you've had a fracture or have a family history of osteoporosis, you should take drugs, he says. (Lane accepts speaker fees from several drugmakers, including some with osteoporosis drugs.)
What are some good weight-bearing exercises? Curls, overhead presses, lateral raises, push-ups, squats, calf raises-- or just a circuit of your gym's weight machines, recommends Nicholas DiNubile, a spokesman for the American Academy of Orthopaedic Surgeons.
What's the latest advice on diet? Between 1,200 and 1,500 milligrams of calcium (calcium citrate is better than calcium carbonate, DiNubile says) per day, either in food or supplements. And 1,000 to 1,200 units of vitamin D3 -- cholecalciferol -- the same form that our bodies produce, Siris says.
-- Susan Morse
For more information about osteoporosis and bone density:
http:// · www.johnshopkinshealthalerts.com (click on "back pain and osteoporosis")