Osteoporosis, or the weakening of bones, is a problem that affects approximately 10 million Americans. According to the Harvard School of Public Health, osteoporosis leads to more than 1.5 million fractures per year. Particularly for the elderly, fractures can lead to loss of independence, infections and even death. Adequate levels of calcium, which can be found in milk, help to prevent osteoporosis.
Milk and Calcium
Milk is believed to be important to bone health because it is rich in the mineral calcium which is needed to build and maintain bones and teeth. Around 99 percent of the calcium in your body is stored in bones and teeth. Calcium is obtained from food sources or from pulling calcium from bones, when the blood levels drop too low. Milk and other dairy products are an excellent source of calcium because they contain the highest concentration per serving of easily absorbable calcium.
Amount of Milk
Calcium is needed for bone development and to maintain bone health, but the amount of calcium needed from the diet is uncertain. The National Academy of Sciences recommends 1,000mg per day for people aged 19 to 50 and 1,200mg per day for people aged 50 or over. One glass of milk contains approximately 300mg of calcium, but milk goes into making other dairy products, such as cheese and yogurt. An 8-oz. serving of yogurt contains approximately 415mg of calcium.
Risks
While adequate calcium intake helps to prevent weak bones, increased milk intake or calcium supplementation does not seem to have a protective effect. A study conducted by the Harvard School of Public Health in 2007 showed no reduction in hip fracture risk with increased calcium intake. Additionally, some people do not tolerate milk well because of lactose intolerance and may develop bloating, gas or diarrhea. If you have this issue, using lactose-free dairy products may help. Finally, using low-fat or nonfat milk is important, as whole milk has a high saturated fat content which may increase your risk of heart disease.
Considerations
Other factors are important for bone health as well, including vitamin D intake, physical activity and vitamin K intake. Vitamin D is typically obtained through sunlight, though some foods are fortified with this vitamin or you can take it as a supplement. Vitamin K is found in broccoli, dark green lettuce and collard greens and helps with calcium regulation. Physical activity throughout life is important because it puts strain on your bones and forces them to retain density as you age. "Weight-bearing" activities are the most useful, such as walking, running, dancing, jogging and hiking.
References
- Harvard School of Public Health: Calcium and Milk: What's Best for Your Bones and Health?
- National Institutes of Health: Milk and Bone Health
- "American Journal of Clinical Nutrition"; Calcium Intake and Hip Fracture Risk in Men and Women: a Meta-Analysis of Prospective Cohort Studies and Randomized Controlled Trials; H.A. Bischoff-Ferrari, et al.; Dec. 2007
- Harvard School of Public Health: Calcium Sources in Food
