Haven’t we been taking calcium supplements and drinking milk for years in the belief that we will prevent our bones from fracturing? North Americans are the highest consumers of dairy products and calcium supplements in the world. So why do we still have the highest osteoporosis rates?

Doesn’t calcium strengthen bones? In February 2006 the New England Journal of Medicine published a seven-year-long study of more than 36,000 women that questioned the effectiveness of calcium and vitamin D in preventing hip fractures related to osteoporosis.

Dosage Dos and Don’ts

Recommended daily allowances vary from 500 mg to 1,500 mg per day worldwide. So how much is enough? The answer depends on your age, how calcium deficient you are, and the balance between the presence of magnesium and vitamin D, cofactors that are crucial for maintenance of bone health.

The maximum benefit appears to be within the range of 800 and 1,000 mg daily, when both diet and supplementary sources are combined. In studies where calcium supplementation made no difference to bone mass, the diets of both the nonsupplemented and supplemented groups already contained 800 to 1,000 mg of calcium. Those who get enough calcium in their diets, in other words, are least likely to benefit from a supplement. Adding more calcium seems to have little beneficial effect, and excessive calcium has been linked with increased kidney stones, increased heart disease, and inhibited the absorption of magnesium, another key nutrient for bone strength.

In a study published in the Journal of International Medical Research (1999), combining low-dose calcium supplements and calcium sources in the diet seems to work best. Those taking 550 mg per day in a calcium supplement, in addition to 930 mg of calcium in their diets, increased their bone mass by 0.83 percent. In a group supplementing with 1,500 mg of calcium, in addition to only 651 mg per day in their diets, bone mass increased by only 0.02 percent.

The message? Get more calcium from your diet.

Sourcing Calcium

Get your calcium from a variety of food sources, especially fruits and vegetables (see sidebar). Studies of children, pregnant women, and the elderly have all found that those with the highest fruit and vegetable consumption have the best bones. Relying solely on dairy products for calcium is a mistake, particularly because they are low in magnesium, an element that is needed to properly distribute calcium in the body.

Get the Ratio Right

The average calcium consumption in North America is approximately 800 mg per day, yet our magnesium intake is as low as 165 mg per day. The ideal calcium-to-magnesium ratio is 2:1 (based on current RDAs). The ratio is already 4:1 in our diets, so if we supplement with high doses of calcium, we make the ratio worse. Taking a 1:1 calcium-to-magnesium supplement can help to restore the balance between these two nutrients.

An Early Start

The most crucial time to get adequate calcium is in childhood when the bones are still growing. Ninety percent of bone mass is laid down in the body by age 17. Children need two to four times the amount of calcium as adults for their body weight.

It is estimated that only 19 percent of girls and 52 percent of boys have adequate intake of calcium. Fracture rates and rickets are on the rise in children as are concerns for explosion of osteoporosis rates later in life.

Mothers can improve the health of their unborn children’s bones with adequate intake of calcium, magnesium, and vitamin D. Adequate calcium intake during pregnancy has been shown to provide protection for the mother against osteoporosis. Adequate intake is also necessary for preventing two serious complications in pregnancy: high blood pressure and pre-eclampsia.

Calcium is a crucial nutrient for bone health and beyond.

Food Sources of Calcium

  • dark leafy greens
  • tofu
  • yogourt
  • nuts and seeds
  • chickpeas
  • broccoli
  • fish with bones (e.g., canned salmon)

Favourite Use: PMS

One of my favorite uses of calcium is treating premenstrual syndrome. In one study, women with PMS showed improved mood and decreased fluid retention, less pain with periods, and diminished food cravings when using calcium supplementation over three menstrual cycles.

I like to combine calcium with magnesium as it reduces premenstrual depression, headaches, and chocolate cravings.

About the Author

Cathy Carlson-Rink, RM, ND, is a mother of two, licensed naturopathic physician, and registered midwife with a focus on pregnancy and women's and children's health.