Vitamin D: Distribution and requirement

Vitamin D occurs naturally in fatty fish, liver, and egg yolk. Milk, unless it is artificially fortified, is not a good source. The RDA for individuals ages 1–70 years is 15 μg/day and 20 μg/day if over age 70 years. Experts disagree, however, on the optimal level of vitamin D needed to maintain health. [Note: 1 μg vitamin D = 40 international units (IU).] Because breast milk is a poor source of vitamin D, supplementation is recommended for
breastfed babies.