A new review in Mayo Clinic Proceedings looks at a sea of vitamin D research conducted up to April 2013 and shows that vitamin D may also directly or indirectly regulate our genes. In fact, vitamin D levels could impact future generations' health too, since scientists are finding that a mother's vitamin D status during pregnancy could affect the way her child's genes work throughout life.
The problem? We're in the midst of a worldwide vitamin D deficiency pandemic. And low levels cause not just musculoskeletal health problems, as seen in extreme deficiency cases like rickets, but also more subtle health problems that promote serious disease, including some cancers, autoimmune diseases, infectious diseases, type 2 diabetes, and neurocognitive disorders.
The study authors suggest people should increase vitamin D levels to above 30 ng/mL. A simple blood test at the doctor's office could help ID your baseline levels, and you can schedule routine retests to see if using vitamin D supplements are boosting your vitamin D levels.
You can get a little vitamin D from foods like egg yolks and fatty fish, but to achieve optimal levels, supplements or sensible sun exposure are usually needed.
So even though another recent study suggested that many Americans are wasting their money on supplements, that does NOT appear to be the case when it comes to vitamin D—just keep track of your levels to make sure you're not oversupplementing.