Released June 24, 2008
AUBURN UNIVERSITY, Ala.-- Some of the nation’s leading health experts fear another epidemic is sweeping America, and it involves an essential vitamin that many people appear to be wantonly taking for granted.
The essential vitamin is D, the sunshine vitamin. And as researchers are learning, much to their dismay, millions of Americans are mildly to significantly deficient in this vitamin.
Infants are an especially troubling case in point. One study found that 12 percent of infants — roughly one out of every 8 — were outright deficient in vitamin D, while an additional 40 percent was marginally deficient.
U.S. adults apparently fare no better.
“Studies have shown there are a lot of adults who don’t have nearly the blood levels [of vitamin D] considered adequate,” says Dr. Robert Keith, an Alabama Cooperative Extension System nutrition and health specialist and Auburn University professor of nutrition and food science, who has been following the vitamin D issue for years.
Based on these stark findings, many of the nation’s nutrition and health experts have concluded that current recommendations for getting adequate amounts of vitamin D simply are insufficient in many cases.
Based on recent blood level measurements, just trying to consume adequate amounts of vitamin D from food requires a conscious, motivated effort. Now more than ever before, scientists are convinced that vitamin D is critical to living a long and healthy life.
Vitamin D deficiencies are now known to contribute to all sorts of chronic diseases. Researchers have known for a long time that this deficiency contributes to rickets in children and osteoporosis in adults. More recently, though, they’ve discovered that it may also be a key factor contributing to diabetes, certain types of cancer, heart diseses and even multiple sclerosis and other autoimmune diseases.
“Suddenly, researchers are realizing that we’re not only significantly deficient in this vitamin, but also that vitamin D relates to all sorts of health issues beside just healthy bones,” Keith says.
According to the current recommended daily allowances for vitamin D, Americans should derive between 200 and 600 IUs from their diet, depending on their ages. But the most recent findings have prompted some experts to consider raising this recommendation to between 800 and 1,000 IUs, an amount that may be hard to obtain through diet alone.
One reason vitamin D has tended to be taken for granted is because many nutritionists assumed — mistakenly, it seems — that adequate sun exposure could more than make up for any dietary deficiencies, Keith says. But as they are learning, this doesn’t always work.
Except for the sunny South and West — and by that, Keith means the Deep South and the southernmost latitudes of the Southwest — getting adequate amounts of vitamin D from sun exposure is a lot harder than first believed, at least for Americans who live in the higher latitudes of the country. Between 15 and 30 minutes of exposure on the face and arms is considered adequate.
Adding to this problem is the fact that the sun’s rays are generally insufficient during the winter months. Darker complexioned people have even more difficulty making sufficient vitamin D.
So, if vitamin D isn’t always readily available from the sun in most parts of the country, where should people turn?
Among all the food sources available, fatty fish offers the best source of vitamin D — for many Americans, however, this is not a viable option.
“It’s okay if you eat fatty fish on a regular basis, but what if you don’t, which includes the vast majority of Americans?” Keith asks.
Since World War II, milk has been fortified with vitamin D at the current levels of 400 IUs a quart. But if researchers are correct, and Americans need considerably larger daily dietary intakes of the vitamin, where will those sources come from?
“Even a quart of milk a day would only meet half of the newer recommendations that are currently being tested,” Keith says.
He believes the market ultimately will address part of the problem, turning out new lines of functional foods, such as breakfast cereals, fortified with higher levels of vitamin D.
Another option would be for the federal government to mandate the fortification of one or more food products with vitamin D, much as bread products currently are fortified with folic acid to reduce birth defects. Increasing the levels of vitamin D in milk may be a good first step, Keith says.
But for some Americans, the only option likely may involve taking vitamin D supplements, especially people who live in the higher latitudes and other groups who, for whatever reason, have a harder time converting vitamin D from sun exposure.
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http://www.aces.edu/department/extcomm/npa/daily/archives/003663.php
Contact: Jim Langcuster
