I've been reading quite a bit lately about vitamin D's role in overall health -- and why many Americans are at risk for vitamin D deficiency. According to the Vitamin D Council, current research indicates vitamin D deficiency plays a role in causing seventeen varieties of cancer as well as heart disease, stroke, hypertension, autoimmune diseases, diabetes, depression, chronic pain, osteoarthritis, osteoporosis, muscle weakness, muscle wasting, birth defects, and periodontal disease.
Vitamin D is produced in the skin from exposure to direct sunlight and can also be found in foods such as fish oil, fatty fishes, fortified milk and other dairy products, and liver and beef. According to federal government recommendations, Americans should take in 200 IU of vitamin D daily to ward off vitamin D deficiency. BUT, researchers from the University of Maine now say this might not be enough for those people who live in less sunny environments.
Here's what I didn't know -- the government's recommendation for a daily dose of 200 IU of vitamin D (equiv. of 2 glass of fortified milk) comes from research done on people who have pretty consistent levels of vitamin D in their bodies year round (meaning they might have tracked people in Florida, Southern California, or other southern states to come up with these recommendations).
Mainers (and anyone else living above the 40th degree of latitude) do not have these same consistent yearly levels, according to Susan Sullivan, a researcher at UMaine's food science and nutrition department. Sunlight assists in the creation of vitamin D in the body, which means that Maine's short winter days that lack direct sunlight leave Mainers with less consistent vitamin D levels than most Americans. If diet does not make up for this shortfall, it becomes much more likely that a deficiency will develop.
How much vitamin D do residents of the Pine Tree State need to keep levels normal and avoid deficiency? According to this research study from UMaine, older men and women need more than 800 IU of vitamin D (it's unknown how much infants or young children need). Sullivan recommends the increased amount of vitamin D comes from food-based sources like fatty fishes, dairy products, liver and beef. Vitamin D found in vitamins and other supplements are not as readily absorbed into the body as food-based sources.
It's been a l-o-n-g winter here in New England and based on my diet and the infrequency with which I've been able to get outside, I don't doubt that I have some kind of temporary deficiency right now. Symptoms of too little vitamin D in the body include: muscle pain, weak bones/fractures, low energy and fatigue, lowered immunity, depression and mood swings, and sleep irregularities.
I've started fish oil supplements over the past few weeks and feel a bit better. As the weather improves, I'm starting to spend more time outdoors --though officially where I live, my skin won't receive enough direct sunlight until at least May. During the summer months, when sunlight is direct, 10 to 15 minutes of direct sunlight twice a week is sufficient to create enough vitamin D in the skin to avoid deficiency, according to the National Institute of Health.
For more on vitamin D, here's is more information on preventing vitamin D deficiency.