A. Bess Dawson-Hughes, MD, lab director of the Bone Metabolism Laboratory at the Jean Mayer USDA Human Nutrition Research Center on Aging, answers: “While some people allergic to wool have reported an allergic reaction to vitamin D3 supplements (particularly at high doses), there is very little scientific data to support or refute this claim. According to ConsumerLab.com, vitamin D3 (cholecalciferol) supplements are derived from either fish oil or lanolin (a natural waxy substance that helps sheep shed water from their wooly coats). If your doctor has recommended vitamin D supplements and you are concerned about taking a lanolin-derived product, look for fish-oil derived D3. Another option is to take vitamin D2, which may not be quite as effective as D3 at raising blood levels but is a good choice none-the-less. Vitamin D is a fat-soluble vitamin, so be sure to take it with a meal or snack that includes some healthy fat.
“Our bodies produce Vitamin D when rays from the sun strike the skin. Sun screen and clothing interfere with this process but are important for preventing skin cancer. Americans get most of their dietary vitamin D from fortified foods, particularly milk, ready-to-eat breakfast cereals, orange juice, and yogurt, and from natural sources like fatty fish (tuna, mackerel, salmon). Beef liver, cheese, and egg yolk also naturally contain some vitamin D (mostly D3), and some mushrooms provide D2.”