DEAR MAYO CLINIC: Should all postmenopausal women take calcium supplements to prevent osteoporosis, or are there other things I can do to prevent it? Also, I know caffeine is bad for bone health, but can eating a high-protein diet also hurt my bones?
ANSWER: Calcium is crucial for long-term bone health. A calcium supplement is not always necessary, though. You may be able to get the calcium you need from your diet. Along with calcium, getting enough vitamin D and regularly engaging in weight-bearing aerobic and strengthening exercises also can protect your bones.
Your body regularly makes new bone and breaks down old bone. When you’re young, your body makes new bone faster than it breaks down old bone, and your bone mass increases. Most people reach their peak bone mass in their mid-20s to mid-30s. The higher your peak bone mass, the more bone you have to sustain bone health throughout the rest of your life.
Osteoporosis risk rises with age because as you get older, you lose bone faster than your body can make it. Osteoporosis can occur when the body’s creation of new bone can no longer keep up with the breakdown of old bone. Bones may become weak and brittle and are easily broken.
Women near the age of menopause are particularly vulnerable to bone loss. On average, in the three years around menopause — one year before the last menses and two years after it — women go through a rapid phase of bone loss, losing about 2 percent of overall bone mass each year during that time.
Getting enough calcium in your diet throughout your life can help keep your bones healthy. Women between the ages of 18 and 50 need about 1,000 milligrams of calcium a day. That increases to 1,200 milligrams when women turn 50. Good sources of calcium include low-fat dairy products, dark green leafy vegetables, canned sardines with bones, canned salmon and soy products. Many cereals and juices are also calcium-fortified.
If you can’t get enough calcium in your diet, your doctor may recommend a supplement. Don’t take a calcium supplement before checking with your doctor first. Too much calcium can lead to other health concerns, especially kidney stones.
Protein is an important part of your diet and is vital for good health. But taking in high amounts of protein every day can cause your body to lose calcium. Caffeine in large amounts may also make it hard for your body to retain calcium. If you’re concerned about the amount of protein or caffeine in your diet, talk with your doctor.
Vitamin D is necessary for your body to absorb calcium. Many people can get enough vitamin D from sunlight, but it depends on many factors and varies with the seasons. Your doctor can check a blood test to determine your vitamin D level. If it’s too low, you may need a supplement. The recommended dietary allowance of vitamin D is 600 international units daily, until age 70, when 800 international units is recommended. The upper limit of vitamin D intake is 4,000 international units a day.
Regular exercise may help slow bone loss. A combination of strength-training exercises with weight-bearing exercises is usually best. Strength training helps strengthen muscles and bones in your arms and upper spine. Weight-bearing exercises — such as walking, jogging, running, stair climbing, skipping rope or skiing — have a positive effect on the entire skeleton, and particularly benefit the bones in your legs, hips and lower spine. Balance exercises such as tai chi can help reduce the risk of falls, which cause most bone fractures.
Along with the other suggestions already mentioned, to ensure the best bone health, postmenopausal women should limit alcohol to no more than one drink a day. And finally, for many health reasons, including protecting against bone loss, don’t smoke. — Dr. Robert Wermers, Endocrinology, Mayo Clinic, Rochester, Minnesota