DEAR MAYO CLINIC: My doctor says that exercise is even better than calcium supplements for helping maintain bone density and prevent fractures. Can you explain why?
ANSWER: Both calcium and physical activity are important for bone health. But when you consider the net benefits of calcium, especially in supplement form, it’s unlikely to serve as a good substitute for regular exercise.
Calcium is an important mineral that your body uses to build and maintain strong bones. Foods that are high in calcium include dairy products, dark green leafy vegetables and certain fish, such as sardines. Various foods and beverages, such as cereals and fruit juices, may be fortified with calcium and vitamin D, as vitamin D enhances absorption of calcium.
Calcium in supplement form may help people who can’t get enough calcium from their diet or who poorly absorb calcium because of conditions such as untreated celiac disease or bariatric surgery.
However, recent evidence suggests that increasing calcium intake through supplements has a modest and limited effect on bone density. Calcium supplements also can have certain side effects. They can cause constipation, interfere with other drugs and, at higher doses, may be linked to the development of kidney stones. Studies suggest a potential link between excessive amounts of calcium and conditions such as heart disease and prostate cancer.
On the other hand, regular exercise that uses a variety of muscle groups and includes some strength training helps you build a protective framework around your skeleton. It also helps you move more easily and improves your balance. Exercise helps decrease your risk of falling and breaking a bone, which is the ultimate concern.
Ingesting the recommended daily amounts of calcium primarily through dietary sources and staying physically active appear to be the best approaches to limit your fracture risk. — Dr. Matthew T. Drake, Endocrinology, Mayo Clinic, Rochester, Minnesota