Research, evidence, and sources
What this page is for
Food is the starting point on the fact sheet. Supplements are described for people who cannot otherwise meet the recommended amount.
What the reviewed sources say
“Taking vitamin D and calcium supplements slightly increases bone strength in older adults, but it’s not clear whether they reduce the risk of falling or breaking a bone.”
Vitamin D helps the body absorb calcium, one of the main building blocks of bone. Together with calcium, it helps protect against osteoporosis, the condition in which bones become thin and more likely to break. Getting recommended amounts of both from food, and from supplements if needed, helps maintain healthy bones and prevent osteoporosis.
Taking vitamin D and calcium supplements slightly increases bone strength in older adults. The fact sheet says it is not clear whether they reduce the risk of falling or breaking a bone. A slightly stronger bone measurement in a study is not a promise about one bottle, and it is not evidence that a product keeps someone active.
Older adults make less vitamin D from sunlight. The fact sheet lists 15 micrograms (600 IU) a day for adults through age 70, and 20 micrograms (800 IU) for adults 71 and older. Those figures are reference amounts, not a dose prescribed here. Blood levels below 30 nmol/L (12 ng/mL) are described as too low and might weaken bones. Levels of 50 nmol/L (20 ng/mL) or above are described as adequate for most people for bone and overall health. Very high vitamin D intakes from supplements can be harmful. Sunshine does not cause vitamin D toxicity.
Vitamin D — Consumer Fact Sheet NIH Office of Dietary Supplements. Updated 2022-11-08. Retrieved 2026-10-07.
How to compare a label
“The nutrition label for a dietary supplement is called a “Supplement Facts” panel.”
Start with the Supplement Facts panel. The FDA’s labeling guide uses that name for a dietary supplement’s nutrition label.
Read the ingredient name, the amount per serving, and the serving size. A blend that lists several ingredients is a different product from a bottle that is only one of them. The price on a retailer card is the package price, not a price per serving, and a sale ribbon is not a checked comparison price.
- Dosage unit converterConvert grams, milligrams, and micrograms. IU converts only when the vitamin form is known.
- Price per servingSee what one serving costs from the container price and the servings on the label.
- Cost per labeled amountSee what a labeled amount of an ingredient costs. A second product is optional.
- Daily nutrient targetsPublished folate, magnesium, and vitamin A figures for a life stage.
Dietary Supplement Labeling Guide: Chapter IV. Nutrition Labeling U.S. Food and Drug Administration. Retrieved 2026-10-05.
Sources
- Vitamin D — Consumer Fact Sheet NIH Office of Dietary Supplements. Updated 2022-11-08. Retrieved 2026-10-07.
- Dietary Supplement Labeling Guide: Chapter IV. Nutrition Labeling U.S. Food and Drug Administration. Retrieved 2026-10-05.
