Who is most affected?

Osteoporosis affects about 25% of women over the age of 50, compared to about half as many men. That's probably because estrogen plays an important role in bone health. When estrogen levels fall dramatically, after menopause for instance, bone loss is accelerated. Most women lose about 2-3% of bone mass every year during the five to ten years after menopause. Left unchecked, that could amount to about one-third of your bone mass over one decade. Experts suggest that in addition to adequate calcium intake and exercise, estrogen replacement therapy may be needed to address bone loss.

When should prevention start?

Prevention begins very early in life, because the bone we build in youth is being "banked for the future", until we reach our peak bone mass in our mid-thirties. That's why failing to develop your bones' maximum strength and density is a key risk factor for developing osteoporosis later in life.

Ideally, you would receive most of the calcium you need from your diet. Dairy products such as milk, cheese and yogurt provide high amounts of calcium - about 315 mg per 250 mL (1 cup) serving. And low-fat dairy products contain just as much calcium as those higher in fat. Canned salmon and sardines (with the bones) are good sources of calcium, as are leafy green vegetables like broccoli and kale, to a lesser extent (e.g. about 76 mg calcium per 250 mL broccoli).

Assess your diet to determine if you are getting your recommended intake - studies show that most adolescent girls and adult women do not get sufficient calcium from dietary sources. If you don't eat dairy products, you should monitor your calcium intake carefully and avoid consuming excessive amounts of salt, protein, or caffeine, which increase urinary excretion of calcium.

What other nutrients help build bones?

Calcium absorption is aided by vitamin D. Adults require about 400 international units (IUs) of vitamin D daily. Exposing your face, hands and arms (without sunscreen) to sunlight for 15-30 minutes a day triggers your body to produce vitamin D, but unfortunately this tends to decline during the cold months in Canada. Vitamin D is added to our milk, and exists in small amounts in a few foods such as margarine, eggs, and some fatty fish, like sardines.

Minerals such as manganese, copper, magnesium, and zinc are also important to bone health. Low levels of these minerals can negatively affect bone development, although adequate amounts are provided by most varied diets.

Physical activity is key

Like vitamin D, physical activity is indispensable in building and maintaining strong bones. A regimen that includes adequate calcium intake along with regular exercise will have a favourable combined effect on bone health. Getting active does more than build bones - it will improve your balance, reducing your risk of falls, and add to your muscle mass, so you have extra protection if you do fall.

The pull of muscle on bone helps to stimulate bone growth and weight-bearing activities are preferred. Try walking, jogging, or any sport like tennis that is played on your feet. Another option is resistance training (weight lifting), with dumbbells, wrist and ankle weights, or even household objects like water jugs or soup and juice cans. Choose activities that are fun and safe - consider consulting a fitness specialist or physiotherapist. Always consult with your doctor before starting any exercise program.