Young people don't give much thought to their bones unless they've broken one. Yet maintaining strong bones is arguably one of the most important things men and women can do to guarantee a robust old age.
Seventy-five percent of skeletal bone mass is formed during adolescence and peaks by the time you're about 20. If you did not get proper nutrition — particularly calcium — as a youngster, it's nearly impossible to reverse the damage.
"Osteoporosis is not only a geriatric problem," said Dr. Aurelia Nattiv, a family medicine physician and osteoporosis specialist and director of the UCLA Osteoporosis Center in the Department of Orthopaedic Surgery at UCLA.
Genetics is the main determinant of bone mass. If your parents have osteoporosis — weak, brittle bones that are susceptible to fracture — you have a higher risk of developing the disease. Others at risk include those who are or who have been extremely underweight, which includes women who have lost their periods due to eating disorders, excessive dieting or excessive exercise; post-menopausal women; and those men and women with a thin frame and fair skin. And while you can't control your genes and you can't completely stop the process of bone loss due to age, there's a lot that both men and women can do to make themselves less susceptible to osteoporosis.
Weight-bearing exercise — any activity that works bones and muscles against gravity (nearly everything except swimming and biking) is particularly important to bone health. A 2010 Medical College of Georgia study showed that those who exercised more than three hours a week retained greater bone density.
Balance and core strength fade with age, and exercises that improve muscle strength and flexibility, such as resistance training with weights, yoga and Pilates, also train the brain to respond quickly when needed (meaning you are less likely to fall and break a bone).
And what about supplements, particularly calcium and vitamin D?
Well, that question is more complicated. Both calcium and vitamin D are important to bone health, as vitamin D must be present for calcium to be absorbed from the digestive tract. But data suggest that most Americans do not get enough of either. Too many calcium supplements, however, can be a problem.
One recent study found a higher risk of heart disease among those who took more than 500 mg of elemental calcium daily in supplements. "Our society got so hyped up about calcium, people thought more was better," Nattiv said. "Now we're looking at the science, and more may not be better."
The Institute of Medicine recommends 1,000 to 1,300 mg of calcium a day from food and supplements from age 3 on, with the highest amounts required by women who are pregnant or breast feeding. "It's not a universal recipe," Nattiv said. "People should talk to their physician regarding personal history and specific needs for their bone health."
Vitamin D plays a unique role in bone health. It can actually decrease the number of bone-resorbing cells (cells that cause bone loss) and increase the number of bone-forming cells, said Dr. John S. Adams, an endocrinologist and director of UCLA's Orthopaedic Hospital Research Center and an expert on vitamin D. And its advantage over calcium is that it's fat soluble and can be stored in the body for later use.
"It's really hard to get too much vitamin D," he said. The challenge is in getting enough. The body was meant to get most of its vitamin D from skin exposed to the ultraviolet B radiation in sunlight. Sunscreen, while helping keep skin cancer and wrinkles at bay, has contributed to a national vitamin D deficiency.
Adams noted that Eskimos, though not exposed to the sun, rarely suffer from vitamin D deficiency because their diet includes a large amount of wild fatty fish, which is the richest natural food source of vitamin D. Wild fish, such as salmon, have four times more vitamin D than farm-raised fish because fish in the ocean eat phytoplankton, the "most efficient synthesizers of vitamin D on the planet," said Adams.
Adams universally recommends the 25-hydroxy vitamin D test, which your doctor can administer and is the most accurate way to measure how much vitamin D is in your body. If you are deficient, changing your diet and adding supplements can be an important step toward slowing the rate of bone loss.
A bone-density scan, administered by an orthopedic specialist, is also a good way to get a handle on bone health. This year, for the first time, the U.S. Preventive Services Task Force recommended screening for women younger than 60 if they have risk factors that increase the likelihood that they could experience a fracture within the next 10 years.
"If you are 80 years old and you have a hip fracture, you have up to a 50% chance of death within a year," due to the complications associated with the surgery and post-operative recovery in the hospital, Adams said. "It's important to ensure your bones are as strong as possible so you never have to get to that point."