Vitamin D is a key player in bone health, but do we need to take supplements to get enough of it?
The United Kingdom’s independent Scientific Advisory Committee on Nutrition, a community of experts that advises government agencies, thinks so. It announced draft recommendations last week for a 10 microgram dietary supplement of vitamin D for U.K. citizens aged 1 year or older.
Last year, the vitamin supplement industry was worth about $36.7 billion, a record high, according to the Nutrition Business Journal, and industry experts expect it will continue to grow. While sales of most letter vitamin supplements decreased in that time, sales of vitamin D — which helps the body absorb calcium from foods and supplements — increased 8.1%.
The Institute of Medicine, a nonprofit public policy consulting organization, recommends a daily dose of 600 international units, or 15 micrograms, for the average American or Canadian.
Dr. John Cannell, founder of the vitamin D Council, said natural levels, or those of people exposed to the sun for the majority of their day, are around 5,000 to 10,000 IUs. He added that changing attitudes toward sun damage have limited people’s opportunities to produce vitamin D in the skin.
“There are two choices, to get it from sunlight or take it as a supplement. There is no third choice,” Cannell said. “People have to make a choice.”
Cannell said there is no definitive answer to how much sun exposure will allow your skin to produce an adequate amount of vitamin D.
He added that vitamin D is incredibly important for growth and development, especially in pregnant women and young children.
Cannell said he recommends people take 5,000 IU a day if they are not out in the sun, though in an ideal world the most effective method of administration would be to eat foods fortified with vitamin D. Most foods don’t currently contain a lot of vitamin D, but he said manufacturers could add it to more foods.
Deficiency in the nutrient has been linked to poor health conditions, including heart disease, cancer and osteoporosis. However, as two studies — published in the January 2014 issue of The Lancet — from researchers in France and New Zealand suggest, low vitamin D levels may be a result of poor health rather than a cause.
“What [the researchers] concluded was that there are associations with many different health problems that lead to low vitamin D levels,” said Steven Salzberg, a biomedical engineering, computer science and biostatistics professor at Johns Hopkins University.
Unless your doctor finds that you have a vitamin D deficiency, “routine supplementation of vitamin D does not provide any benefits,” Salzberg said.
Exposing your skin to sunlight for half the time it takes for it to turn pink can give you the adequate amount of vitamin D, according to the vitamin D Council, a nonprofit organization.
Dr. A. Marc Gillinov, a heart surgeon at the Cleveland Clinic, wrote in a blog for the Huffington Post that just 10 minutes of direct sun exposure to your arms and legs while not wearing sunscreen can give you about 3,000 IUs of vitamin D — five times the recommended daily dosage.
“Most healthy adults do not need to take vitamin D supplements,” Gillinov wrote. “Extra vitamin D does not improve health in those without bone disease. Get your vitamin D the old fashioned way.”
Too much vitamin D, which the National Institute of Health states as more than 10,000 IUs for children 9 years and older and adults, can cause nausea, vomiting, disorientation, problems with heart rhythm and kidney damage.
“You think that since a little bit is good for you, more is probably better,” Salzberg said. “But it’s not.”