DEAR DOCTOR K:
I am at increased risk for osteoporosis. Are there any foods or drinks I should avoid?
Osteoporosis is a bone-weakening condition that increases your risk of fractures. Though your bones may seem unchanging, they are continuously being broken down and rebuilt. (I’ve put an illustration of this process below.) Osteoporosis occurs when more bone is broken down than is rebuilt.
Osteoporosis is most common in postmenopausal women, but other people are also at risk. These include people with thyroid problems or eating disorders, and those who have used oral corticosteroid medications on a long-term basis.
Some foods you eat can make you more likely to get osteoporosis. On the other hand, some foods can reduce your risk.
There is evidence that several common food substances, taken in large amounts, may be harmful to bone health. I wouldn’t call the evidence airtight, but it is strong enough that I’d advise anyone at risk for osteoporosis to limit their intake of these substances:
- CAFFEINE. Drinking four or more cups of coffee a day can increase your risk of breaking a bone. The evidence is pretty strong. So, you may want to forgo that fourth cup.
- PROTEIN. High levels of protein, particularly protein from animal sources, may cause bones to lose calcium. This issue is still being investigated, and there is no consensus on how much, if any, protein may be harmful to bones. For now, I wouldn’t worry about protein harming your bones. Of course, as we’ve said here many times, the saturated fats that come with animal protein are not heart-healthy, so they should be eaten sparingly.
- ALCOHOL. People who consume more than two drinks per day may be at moderately higher risk of low bone density and fractures, compared with nondrinkers. On the other hand, some studies have found that moderate drinkers — men who have one or two drinks per day, and women who have one drink per day — have greater bone mass.
- VITAMIN A. Several studies have found a link between high vitamin A intake and fractures. Try not to exceed the current recommended daily amount of vitamin A, which is 700 micrograms (mcg) for women and 900 mcg for men.
As for the foods that help build bone, there are several:
- CALCIUM is the primary building block of bone. It is found in dairy products, spinach, dried beans, nuts, and fortified juices and cereals.
- VITAMIN D. Vitamin D helps raise calcium levels in the blood and helps calcium get into bone. Vitamin D is found in eggs, certain fish and liver. Many people also benefit from taking a vitamin D supplement.
- VITAMIN K helps blood clot, and (like vitamin D) also helps calcium get into bone. It is found in spinach, broccoli, Brussels sprouts, scallions, asparagus, cabbage and certain herbs.
Fortunately, a diet that protects bone health also tends to be healthy for the heart.
The cycle of bone construction and demolition
Bone is constantly being constructed and demolished. During resorption (A), cells known as osteoclasts break down bone, releasing calcium into the bloodstream. The trenches that are left behind (B) are then filled in by construction cells known as osteoblasts. The osteoblasts release collagen into these troughs and eventually evolve into structural bone cells, or osteocytes (C). Once these osteocytes mix together with calcium, phosphate, and other minerals to form a cement-like substance known as hydroxyapatite, the process of replacing the lost bone is complete (D).