It’s well established that Vitamin D is important in the regulation of the body’s calcium levels and bone development. If people don’t get enough, they are at risk of diseases like rickets and osteoporosis. But researchers have more recently discovered that vitamin D receptors are found on almost all tissues of the body. This has caused a “boom” in vitamin D research; scientists are investigating its role in everything from heart disease and diabetes to depression, cancer and the common cold.
You get Vitamin D in two ways: by consuming it in foods or supplements, and by making it in your skin when sunlight hits it. Vitamin D doesn’t occur naturally in a lot of foods – unless you’re a really big fan of cod liver oil or mackerel, you wouldn’t get nearly enough – so many foods are fortified with it. Almost all of the milk sold in the U.S. is fortified with Vitamin D, as are many cereals, juices and yogurts.
This time of year in Columbus ain’t exactly the most Vitamin D friendly environment – the sun seems to head south for the winter – so it’s not unusual for people around here to have a low Vitamin D level. But what does that really mean? How low is too low? And does having a low Vitamin D level increase your risk for depression, high blood pressure, the flu? We don’t know for sure. There’s even a lot of debate going on right now about whether or not the current cut off for a “normal” Vitamin D level is too high and that a lot of people are being told they have a deficiency when they really don’t.
That being said, people build up the majority of their bone density during their twenties so it wouldn’t hurt to take a daily adult multi-vitamin containing around 600 IU of Vitamin D to help prevent osteoporosis later in life. It’s also a good idea to get some regular sunlight exposure whenever you can; even if it’s cold, it’ll turn on your skin’s Vitamin D factory. But don’t overdo it – taking too much (over 4000 IU) can cause damage to the heart, blood vessels and kidneys. And excessive uv radiation exposure can damage your skin and put you at risk for really bad things.
The National Institutes of Health has a great site about Vitamin D supplements, and the Mayo Clinic also provides a lot of good information. And of course, you can always make an appointment to see us if you’re worried about your Vitamin D level.
John A. Vaughn, MD
Student Health Services
The Ohio State University