Bone growth and loss is a natural, regenerative process called bone turnover. During childhood, bone formation exceeds bone deterioration resulting in bone growth. However, around age 30, breakdown exceeds formation and normal bone loss occurs.
By midlife, because of hormone changes, diet, and lifestyle, about half of all women and a quarter of all men over 50 will break a bone because of excessive bone loss; a broken bone is often the first symptom of osteoporosis. Broken bones are not only painful, they can force unwanted lifestyle changes.
Causes of bone loss
In addition to aging, excessive bone loss is caused by certain chronic conditions or disorders (and side effects of treatment) such as: 
- Autoimmune disorders such as rheumatoid arthritis and lupus
- Gastrointestinal diseases like celiac, Crohn’s and inflammatory bowel disease
- Diabetes, hormone deficiencies and thyroid conditions
- Blood disorders and cancers
- Depression, eating disorders (and other diseases)
Treating your bones right
To keep your bones strong, the American Academy of Orthopedic Surgeons recommends the following:
- Get regular weight-bearing exercise. Weight bearing activities include “impact” exercise where your bones carry the weight of your body–such as running, dancing and weight lifting. Leisurely walking or bicycling typically does not put enough force on the bones to stimulate growth.
- Consume plenty of calcium. Natural food sources of these important vitamins are milk, cheese, yogurt and leafy green vegetables like spinach, kale and broccoli. Because many Americans do not gain enough calcium from their diet, you may want to consider taking supplements to meet the 1000 mg daily requirement.
- Supplement your diet with vitamin D. Vitamin D helps your body absorb calcium. A natural source of vitamin D is sunlight, however, many Americans are deficient in vitamin D. Consider a lab test for vitamin D and adding a supplement if you are vitamin D deficient.