University of Illinois Extension


Dietary supplements can contain vitamins, minerals, fiber, amino acids, herbs, or hormones in them. Supplements are available as pills, capsules, powders, gel tabs, extracts, or liquids. Sometimes they are added to drinks or energy bars. Most supplements are available without a prescription.

Supplements are available in a wide variety of combinations. Calcium supplements often come in combination with vitamin D which is needed to aid the absorption of calcium. Calcium and vitamin D do not need to be taken together or in the same preparation in order to be absorbed by the body. Minerals including magnesium and phosphorus are also important but are usually obtained through food or multivitamins. The best source of nutrients should be the food you eat. Multivitamins can be used to supplement dietary deficiencies. To check the amounts of each type of food you should be consuming every day, check the website

One key to taking supplements is to take no more of a particular nutrient than the amount recommended by the National Academy of Sciences for safe and adequate intake of that nutrient.

The recommended daily intake of calcium is 1000 mg/day for adults age 19 to 50 and 1200 mg/day for those over age 50. While it is best to get the calcium your body needs from the foods you eat, sometimes individuals either can't or don't consume foods rich in calcium (dairy foods). They may then choose to take a calcium supplement to make sure their bodies are getting enough calcium.

Calcium supplements are available in a wide range of preparations and doses. The following are some calcium supplements (see chart):

Calcium supplementation absorption is optimal when taken as individual doses of 500 mg or less and when taken between meals. The exception to this general guideline is calcium carbonate supplements which are absorbed better when taken with meals. Calcium citrate is often recommended for older individuals whose gastric acidity might be reduced since this form of supplement does not require an acidic environment for optimal absorption. If calcium supplements are required, it is recommended to choose a supplement with the USP (United States Pharmacopeia) designation.

To see how much calcium and vitamin D are in various supplements, check out our Supplement Information table.