ABCs of Bone Health

Posted on Wed., Aug 5, 2009
By Sonika Shah, M.D.

A 72-YEAR-OLD grandmother was pushing in her chair after dinner when she lost her balance and fell, fracturing her hip.

Annually, more than 1.3 million Americans suffer fractures due to osteoporosis, a condition causing bones to become brittle, weak and easily broken.

Women are four times more likely than men to have osteoporosis, mainly due to lower levels of estrogen (a female hormone that helps maintain bone mass) after menopause.

Fortunately, you can take steps to reduce your risk of bone loss and fractures.

Avoid smoking and excessive alcohol

Avoid smoking and excessive alcohol. Besides being a major risk factor for heart disease and cancer, smoking cigarettes is known to accelerate bone loss.

Heavy drinking increases the risk of fracture from poor nutrition and raises the risk of falling. Women should limit consumption to one alcoholic beverage per day.

Bone density testing

Experts recommend bone mineral density (BMD) testing for all women 65 and older as well as high-risk men and women under 65. Major risk factors include:

Previous fracture due to fragile bones
Parental or sibling history of hip fracture
Low body weight (less than 127 pounds)
Long-term steroid therapy (e.g. prednisone)
Cigarette smoking
Excessive alcohol consumption

DEXA scan, the most common method for measuring BMD, accurately measures at important bone sites (spine, hip, forearm) with minimal radiation.

Calcium

Total daily calcium intake (diet plus supplements) should be at least 1,000 mg for men and premenopausal women, and 1,500 mg for postmenopausal women. Good sources are low-fat dairy products (milk, cheese and yogurt) and dark green vegetables (spinach and broccoli).

Men and premenopausal women need 3-4 dairy servings per day, while postmenopausal women require 5 servings per day. One serving is 8 ounces of milk or yogurt or 1 ounce of hard cheese.

Most women 50 and older and those who lack adequate calcium in their diets require calcium supplementation. The most common calcium supplements are calcium carbonate and calcium citrate.

While calcium carbonate contains the most elemental (usable) calcium per dose, is cheaper and best absorbed with meals, calcium citrate can be taken with or without meals and is preferred in those taking acid-blockers or iron supplements.

Avoid calcium preparations from unrefined oyster shell, coral, bone meal or dolomite, as these forms may contain toxic metals. To maximize calcium absorption, divide doses greater than 500 mg. Total daily calcium intake should not regularly exceed 2,000 mg due to potential harmful side effects.

Vitamin D

Vitamin D, formed naturally in the skin after exposure to sunlight, enables your body to absorb calcium and build strong bones. Sunscreen can prevent this, but you only need about 10-15 minutes of sun exposure per day.

The recommended daily intake of vitamin D is 800 international units for adults. This dose, with adequate calcium intake, reduces bone loss and fractures in older adults.

Milk, the best dietary source of vitamin D, contains approximately 100 IU per cup.

Exercise

Those with or seeking to prevent osteoporosis should exercise at least 30 minutes three times per week.

Weight-bearing exercise regimens, such as walking/jogging, dancing, team sports, yoga/tai-chi or weightlifting, have been associated with improvements in or maintenance of bone density.

Talk with your doctor about risks and take steps now to keep your bones healthy.

Shah is a board-certified internist with Contra Costa Regional Medical Center in Martinez.