The U.S. Preventive Services Task Force (USPSTF) is recommending that healthy postmenopausal women avoid low-dose supplements of vitamin D (up to 400 IU) or calcium (up to 1,000 milligrams) because evidence is lacking for a protective effect and there may be a small increase in risk of kidney stones.
It’s not really clear whether these supplemental doses are too low to have an effect (the evidence was lacking for a recommendation regarding higher doses) or whether it’s just that supplements are unnecessary if your diet already provides enough of these nutrients. The preliminary draft report makes no mention of diet (other than the incorrect statement that vitamin D2 (ergocalciferol) is the main dietary source of vitamin D and is provided by plants and fish—which leaves me a little worried about general nutrition knowledge among the members of this task force).
It’s important to note, though, that no one is saying you don’t need to meet needs for these nutrients. While it may not be beneficial to take vitamin and mineral supplements in addition to a diet that already meets requirements, it doesn’t mean that it’s okay to not meet needs. For almost all people who don’t get adequate sun exposure, the only sources of vitamin D are supplements and fortified foods. Technically, omnivores can get it from fish, but they would have to eat fish daily which is certainly not practical for most or a responsible and sustainable choice. And most fortified foods don’t have enough to meet needs; you’d need to drink 6 cups daily of cow’s milk or plant milk to meet the RDA for vitamin D.
Here in the Pacific Northwest where I live, I could probably make enough vitamin D during three months of the year if I went out in the sun without sunscreen (which I generally don’t do). I don’t consume any vitamin D-fortified foods on a regular basis so, for me, vitamin D supplements continue to be essential.