Calcium and Vitamin D Requirements

This article is all about the calcium requirements for adults, also view: Children Calcium Requirements

Sufficient amounts of calcium are required for bone strength. The body uses calcium for the heart, blood, muscles and nerves. Without the proper amount of calcium intake, the body will strip calcium from the bones where it is stored, causing the bones to get weaker. It is estimated that 55% of men and 78% of women over age 20 in the U.S. do not get enough calcium in their diet.1 It is important to note that since the human body cannot produce its own calcium, adequate calcium intake is vital.

Calcium Intake

The recommended amounts of calcium for adults are as follows:

  • For pre-menopausal women 25-50 years old and post-menopausal women on estrogen replacement therapy: 1,000-1,200 milligrams of calcium per day. 1,500 milligrams of calcium per day is recommended for pregnant or lactating women.
  • For postmenopausal women less than age 65 not on estrogen replacement therapy: 1,500 milligrams of calcium per day.
  • For men ages 25-65: 1,000 milligrams of calcium per day.
  • For all people (women and men) over age 65: 1,500 milligrams of calcium per day.2

Correcting a calcium deficiency has several components:

  • Eating a diet rich in calcium that provides the recommended daily amount of calcium. Calcium is especially prevalent in dairy products, dark green leafy vegetables (e.g., broccoli, kale, turnip greens, Chinese cabbage), beans and peas, calcium-set tofu, seeds, nuts and some fish. Many foods may also be fortified with calcium, such as orange juice, cereal and breakfast bars. Nonfat powdered dry milk can be added to many mixes and meals as another way to enhance their calcium content.
  • Adding calcium supplements if daily diet cannot be altered to provide adequate levels of calcium. Even though calcium supplements are available without a prescription, a health professional (e.g., doctor, dietician, pharmacist) should help patients determine what form, what compound, what amount of elemental calcium (varies across supplements), etc., is best for them. Usually, absorption of calcium supplements is most efficient at individual doses of 500 mg or less and when taken between meals.
  • Limiting foods known to cause the body to excrete more calcium than normal. Notable substances include sodium and chloride (found in table salt) and caffeine (primarily found in coffee, tea and soft drinks).
  • Addressing a vitamin D deficiency. Vitamin D helps with absorption of calcium from the gastrointestinal tract and with resorption of calcium in the kidneys that would otherwise have been excreted. Like calcium, it is estimated that most people do not get enough vitamin D. Data from the Institute of Medicine suggest that more than 50% of younger and older women are not consuming recommended amounts of vitamin D.3

Vitamin D Intake

The recommended amounts of vitamin D for adults are as follows:

  • For people over 65 or 70, at least 600 i.u. is usually recommended.
  • For people over 50 (and postmenopausal women): 400-800 i.u. of vitamin D per day.
  • For people 25-50 years old (and premenopausal women): 400 i.u. of vitamin D per day.

Correcting a vitamin D deficiency has several components:

  • Eating a diet rich in vitamin D. This is more challenging than calcium as vitamin D is found naturally in only a few foods, like fatty fish (e.g., salmon), liver and cod liver oil, and egg yolks. However, vitamin D fortified foods, such as many types of milk, cereal, bread, and orange juice, are widely available.
  • Exposing the body, primarily the face, hands and arms, to sunshine. With direct exposure to sunlight, vitamin D is manufactured in the skin. Ten to fifteen minutes of sunshine two to three times per week will satisfy the body’s need for vitamin D. However, as people age they are less able to make vitamin D through the skin. Additionally, sunscreen reduces the body’s ability to absorb sunlight needed to manufacture vitamin D.
  • As necessary, taking a vitamin D supplement. Calcium supplements and multivitamins also can contain vitamin D, so patients are advised to read all labels carefully, and if necessary, to discuss intake with their physician or pharmacist. Since excessive doses of vitamin D can be harmful, patients are advised to talk with their doctor about the right intake for their particular situation. The Institute of Medicine recommends no more than 2,000 i.u. per day.

Appropriate intake of calcium and vitamin D is crucial in the prevention and slowing of bone loss, but can be difficult to achieve on a daily basis. Careful planning and tracking are often necessary to ensure the individual is getting adequate amounts across all sources.


  • 1.National Institutes of Health, Office of Dietary Supplements. Dietary Supplement Fact Sheet: Calcium. Accessed 7/11/06.
  • 2.Optimal Calcium Intake. NIH Consens Statement Online 1994 June 6-8; 12(4):1-31. Accessed 6/14/06.
  • 3.Institute of Medicine, Food and Nutrition Board. Dietary Reference Intakes: Calcium, Phosphorus, Magnesium, Vitamin D and Fluoride. National Academy Press, Washington, DC, 1999. Referenced in National Institutes of Health, Office of Dietary Supplements. Dietary Supplement Fact Sheet: Vitamin D. Accessed 7/11/06.