Calcium and Vitamin D are two essential nutrients long known for their role in bone health. Over the last 10 years there’s been a fair amount of controversy about how much people need to stay healthy. To help clarify this issue the Institute of Medicine (IOM) assessed the current data on health outcomes associated with calcium and vitamin D and used their research to update the Dietary Reference Intakes.
The IOM report published this month: 1) assessed whether Americans are generally getting enough vitamin D and calcium; 2) looked into what they’re for (biologically); and 3) proposed new reference values. They basically found that vitamin D and calcium are important for bone health but not for other health conditions and that the majority of Americans are getting enough vitamin D (mostly from sun exposure). The exceptions are people living in institutions (e.g. assisted living and nursing homes) and people who have dark skin pigmentation. The report found that girls aged 9–18 often don’t get enough calcium.
Vitamin D levels in the body come not only from the diet and intake, but also sunlight exposure. The body synthesizes vitamin D via UV rays. Very little sun exposure is actually needed to provide the body’s needs (for most people). The amount of sun exposure required varies greatly based on skin tone, sunscreen use, UVB rays, regional residence, time of day, and time of the year. In general most people benefit from sensible sun exposure which means 10-15 minutes/day to the arms and legs. This time could vary by up to 5 times that amount for darker complexions (as melanin slows down the reaction that creates vitamin D from sun exposure).