Vitamin D, Calcium Work Together to Strengthen Teeth and Bones
Like calcium, vitamin D plays a crucial role in keeping your teeth and bones healthy. In fact, taking calcium to shore up teeth and bones does little good if your vitamin D levels are insufficient. Although called a vitamin, this micronutrient is actually a hormone—that is, a substance made by one organ that sends a chemical message to another organ to elicit a specific response. In this case, vitamin D signals your intestines to absorb calcium into the bloodstream.
Regardless of whether vitamin D comes from fortified foods, a supplement bottle, or a natural chemical reaction between skin and sunlight, it starts out in a relatively inactive form called a precursor. The liver and kidneys help activate the precursor whenever blood levels of calcium fall too low to meet important needs, such as muscle and nerve function and blood clotting. Trouble brews if you don't have enough precursor to convert to the active form of vitamin D. If there's not enough active vitamin D to signal your intestines to absorb calcium, your body will break down bone to get the calcium it needs—no matter how much calcium you consume through food and supplements.
Research shows that vitamin D supplementation lowers the rate of bone resorption and boosts bone mineral density. When combined with calcium, it appears to have other benefits as well. In a randomized controlled trial reported in the New England Journal of Medicine in 1997, several hundred people ages 65 and over received either supplements—daily doses of 500 mg of calcium and 700 international units (17.5 micrograms) of vitamin D—or a placebo. In three years of treatment, the people taking the supplements had moderately lower bone loss and fewer non-spinal fractures. There is also evidence that high doses of vitamin D may lower the risk of fractures without the help of calcium supplements.
Source: Vitamins and Minerals: What You Need to Know. Copyright © by Harvard University. All rights reserved.