Calcium and vitamin D: how much do you need?

One component of bone strength is measured as bone mineral density, or BMD: the amount of mineral content in an area of bone. The key mineral being measured is calcium, your skeleton’s major building block. That’s why getting enough calcium is so important to bone health.

The other nutrient that’s crucial for bone health is Vitamin D, which helps your body absorb calcium from your gut. In order to produce vitamin D, our bodies need exposure to sunlight, which is not as strong in northern climates like Canada’s. In addition, vitamin D occurs naturally in very few foods, so it’s extremely difficult to get adequate amounts of vitamin D from diet.

Bone repair and maintenance

Bones might seem static or unchanging, but they are living tissue that is constantly rebuilding itself through an ongoing process of repair and maintenance. That’s why bones need calcium and vitamin D at every age.

“In general, adequate calcium intake for good bone health is in the range of 1,000 to 1,200 milligrams per day,” says Dr. Sandra Kim, medical director of the Centre for Osteoporosis and Bone Health at Women’s College Hospital. “We generally recommend that calcium intake is mainly from dietary sources. However, there are some people who are not able to obtain that adequate amount of calcium intake through their diet and therefore may need to use calcium supplements.”

Dietary sources of calcium include dairy products such as milk, yogurt and cheese, as well as almonds, canned salmon or sardines with bones, beans, tofu and figs. Most people obtain approximately 300 mg of calcium from their diet without counting dairy products or other calcium rich foods.  Therefore, with about two to three servings of dairy or other high calcium rich foods added to a regular diet, will provide the recommended daily intake of 1,000 to 1,200 milligrams.

“For most people who live in Canada, with our limited sun exposure and our long winters, vitamin D supplementation is required.  Most people who are under the age of 50 are recommended to take 400 to 1,000 units of vitamin D supplementation per day,” says Dr. Kim. “If you’re someone who is older than 50, and in particular if you’re someone who has osteoporosis, then you may need higher levels of vitamin D supplements, between 800 and 2,000 units per day.”

Some people, such as those at risk for vitamin D deficiency, may need even more vitamin D.

“There are certain medical conditions that are associated with vitamin D deficiencies, as well as certain medications that affect vitamin D metabolism,” Dr. Kim says. “If you’re someone at risk, this is something to talk to your doctor about.”

Potential calcium risks

There has been some controversy about calcium supplements and possible health risks.

“This is based upon some publications that have shown an association between people who take calcium supplements and the risk of cardiovascular disease – in particular heart attacks. However these studies have some issues in terms of methodology, and there have been other studies that have refuted that finding,” Dr. Kim says.

Although no cause-and-effect relationship has been established between calcium supplements and heart disease, it’s one more reason to get calcium from your diet.

“Because of that possible concern, the recommendation is that you strive to get your calcium intake through dietary sources rather than calcium supplements,” Dr. Kim says, adding that people who are getting sufficient calcium from their diets don’t need to take extra calcium in supplements.

“The other risk for taking too much calcium is that you could be at risk for kidney stones,” she says. “This is more of a concern than the controversy over heart disease.”