Calcium

What is calcium?

Calcium is the most abundant mineral in the body. According to the NIH Office of Dietary Supplements, it makes up much of the structure of bones and teeth and is also needed for muscle contraction, nerve signaling and blood vessel function. Vitamin D is required for calcium to be absorbed efficiently from the gut. Dairy foods, fortified plant milks, canned fish with bones, tofu made with calcium and some leafy greens are the main food sources.

In supplements, calcium appears as carbonate, citrate or phosphate salts. Tricalcium phosphate and dicalcium phosphate are also widely used as fillers and flow agents in tablets, which is often why they appear in “other ingredients.”

What the research says

Calcium is essential for building teeth during childhood and for keeping the skeleton, including the jawbone, healthy across life. However, the evidence that extra calcium from supplements improves gum or tooth health in well-nourished adults is limited. In a national survey of 6,150 Korean adults, low yogurt intake was linked with periodontitis, but calcium intake itself was not significantly associated with gum disease. Observational studies like this cannot prove cause and effect.

Tooth enamel is protected day to day mainly by saliva, which supplies calcium and phosphate to the tooth surface, and by fluoride, which helps enamel resist acid. Swallowing a few milligrams of calcium phosphate does not deliver minerals to enamel in a meaningful way.

Too much calcium has downsides. The ODS notes that higher intakes of supplemental calcium might increase the risk of kidney stones, and the tolerable upper intake level for adults is 2,000 to 2,500 mg per day depending on age. Calcium supplements can also reduce absorption of certain medicines, including levothyroxine, some antibiotics (quinolones), lithium and dolutegravir.

How it’s used in supplements

Bone-health supplements typically provide several hundred milligrams of calcium per dose, often split because absorption is better at smaller amounts. Oral health supplements usually contain far less, sometimes only as a tablet excipient. If you want to support your teeth and bones, aim to meet the RDA mainly through food and ask your doctor before adding a calcium supplement, especially if you have a history of kidney stones or take thyroid medication.

For enamel itself, the best-supported steps are brushing twice daily with fluoride toothpaste, limiting how often you snack on sugary or acidic foods and drinks, and keeping saliva flowing, since saliva naturally carries calcium and phosphate to the tooth surface.