Calcium, milk, and osteoporosis

Originally Published: November 16, 1995 - Last Updated / Reviewed On: March 31, 2014
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Dear Alice,

In college, I was told that I needed four cups of milk a day to make my calcium requirement. So for the past year, I've run up a serious milk bill. But now I keep hearing that drinking milk, taking calcium supplements, etc. actually depletes the calcium from the body. I am worried about contracting osteoporosis in later life. (I'm now twenty-three.) What do you think?

Sincerely,
Milked

Dear Milked,

There may be some downsides to guzzling milk, like lactose intolerance or a hefty grocery bill, but calcium loss is not one of them! To build strong bones and ward off osteoporosis, milk (and calcium supplements to some extent) does a body good. However, if you dislike so-called "cow's juice," there are other tasty (and inexpensive) foods that are high in calcium. For more pros and cons about drinking milk, see Milk — Bad or good? in the Go Ask Alice! archive for Fitness and Nutrition.

According to the Food and Nutrition Board of the Institute of Medicine, the amount of calcium your body needs varies by age:

Recommended Daily Allowance (RDA) for calcium

Life Stage Group

Calcium (in milligrams)

Children 1 to 3 years

700 mg

Children 4 to 10 years

1,000 mg

Adolescents and adults

1,000 to 1,300 mg

Pregnant and breastfeeding women

1,000 to 1,300 mg

One of cup skim milk packs about 300 mg of calcium, so it's true that you would need to drink three to four cups a day to reach your RDA for calcium. However, some health experts warn it isn't necessary, or even healthy, to load up on dairy. Consider limiting your dairy intake to one or two low-fat servings a day, and getting more calcium from beans, tofu, and dark green veggies like broccoli, spinach, and Chinese cabbage. For a list of calcium levels in healthy foods, take a look at the chart in Calcium — how much is enough? in the Alice! Nutrition and Physical Activity archive.

Here are some tips to maximize calcium absorption and pave the way for healthy bones:

  • Seek out vitamin D. Spend 15 to 30 minutes in the sun each day (sunlight fuels vitamin D production), eat foods containing vitamin D (try fortified breakfast cereals, tuna fish, or salmon), or take a supplement.
  • Get enough vitamin K by munching green leafy veggies like broccoli, Brussels sprouts, and kale.
  • Pair calcium-rich foods with acidic ones. Try adding orange segments to your spinach salad or squirting lemon juice on steamed broccoli to facilitate calcium absorption.
  • Don't go overboard with dietary fiber, magnesium, tannins in tea, or high protein diets, all of which limit calcium availability.
  • Cut back on salt, caffeine, cola, nicotine, and antacids containing aluminum since these ingredients can rob the body of calcium.

Once calcium is absorbed into the body, more than 99 percent of it is used for building bones and teeth. Due to daily strain on the skeletal system, our bones are constantly broken down and reconstructed. After age 35 this rebuilding process naturally slows. In some cases, bone tissue deteriorates dramatically, leading to osteoporosis (literally meaning "little bone"), a disease characterized by bones that become more and more fragile. Even under slight pressure, bones can break and crush, causing broken wrists or hip fractures. Women are at a higher risk than men partly because the decrease in estrogen in their bodies after menopause increases bone loss. Those most at risk are non-black women. Men and black women tend to have a greater amount of initial bone mass, so are less likely to have problems with osteoporosis.

Many factors influence the rate at which bone density decreases, including heredity, hormones, diet, physical activity, smoking, and kidney performance. You can't change your genes, but you can strengthen your bones by getting plenty of calcium as part of balanced diet, exercising regularly, and quitting smoking. If you believe that you're prone to osteoporosis, you may want to see a health care provider to talk about ways to reduce your risk. Students at Columbia can contact Medical Services (Morningside) or the Student Health Service (CUMC) for an appointment. For more general information on osteoporosis, check out the International Osteoporosis Foundation.

If you dislike dairy, you don't need to sport a milk mustache to ward off osteoporosis. By getting lots of calcium and exercise, you can stay strong at 23 or 83!

Alice