A flurry of recent reports trumpeting the health benefits of vitamin D have vaulted the supplement to a starring role on the merchandise shelves at Burns Drugs in La Jolla.
Pharmacist Wayne Woods, who owns the store, said he’s seeing a growing number of customers asking for bottles of high-dosage vitamin D.
“We barely carried it before, but physicians are recommending it as a normal supplement on a daily basis in addition to taking your multivitamin,” Woods said.
Vitamin D’s role in bone health has long been known – think rickets in malnourished children and osteoporosis in older people. But research tying vitamin D deficiency to cancers, heart disease, diabetes and other illnesses has transformed the nutrient into a potential miracle cure. A global network of influential scientists said daily intake should be up to 10 times higher than the U.S. government’s current recommendations.
Yesterday, more than 100 physicians, nutritionists, acupuncturists, massage therapists and others gathered at the University of California San Diego for a daylong conference extolling vitamin D.
But not everyone is as enthusiastic, especially after a succession of reports dimmed the spotlight on vitamin supplements. Last month, two major clinical trials debunked vitamin B as a treatment for Alzheimer’s disease and vitamins E and C as protectors against cancer.
The scientific uncertainty has generated debate over the virtues and dangers of vitamin D. One big reason for the researchers’ disagreements: The most promising studies suggest a relationship between low vitamin D intake and many diseases, but they have failed to show a direct cause and effect.
Skeptics of dramatically boosting vitamin D supplements point to the lack of large-scale, random and “double blind” clinical studies comparing the nutrient to placebos. Dermatologists also have bristled at suggestions that people spend more time in the sun to increase the natural production of vitamin D.
Those concerns didn’t deter several longtime advocates of vitamin D supplements at yesterday’s meeting, including Dr. Robert Heaney, a professor at Creighton University in Omaha, Neb.
Heaney said studies conducted in North America and Europe found low vitamin D levels in as many as 95 percent of participants. “I think we can take it as a given that the vast majority of patients in the U.S. are vitamin D deficient,” he said.
People get most of their vitamin D from exposure to sunlight, according to the National Institutes of Health. Spending 10 to 15 minutes outdoors two to three times each week is typically enough.
The best food sources of the nutrient are oil-rich fish such as salmon, tuna and mackerel. Milk and some cereals also are fortified with the vitamin.
Another speaker at the conference, Dr. Cedric Garland, said vitamin D might prevent certain cancers partly because it helps to form the glue that binds cells to each other. Without that glue, cells can become malignant and spread to other parts of the body.
Despite the academic nature of the presentations, the gathering at times felt more like a pep rally for campaign partisans.
Carole Baggerly of Encinitas opened the conference by leading the crowd in singing “You Are My Sunshine.”
She is a former computer sales and marketing executive who founded the conference’s sponsor organization, GrassrootsHealth, after surviving breast cancer.
Baggerly called on conference attendees to become part of her organization’s D*action campaign, a “grand mission” to promote testing for vitamin D deficiency.
“There is no need for a vitamin deficiency epidemic to go on and on and on,” she said.
GrassrootsHealth and some of the conference speakers want federal health officials to increase the daily recommended intake of vitamin D to as much as 2,000 international units.
Current U.S. nutritional guidelines call for 200 international units per day for children and adults up to age 50, 400 international units for people up to 70, and 600 international units for those 71 and older.
The American Medical Association and the American Academy of Pediatrics also have called on the government to raise its vitamin D benchmarks.
But the effort is opposed by the American Academy of Dermatology, which last month advised against too much sun exposure because of the heightened risk of developing skin cancer.
While there is a growing body of “exciting” discoveries pointing to the benefits of vitamin D, more research is needed before health officials adjust supplement standards, said Patsy Brannon, a professor of nutritional science at Cornell University in Ithaca, N.Y.
“The evidence on safety and efficacy is not as strong as what we would like it to be,” she said.
At least two studies meeting the rigorous criteria of large-scale clinical trials have offered reasons for caution.
The federal Women’s Health Initiative found that women taking 400 international units of vitamin D plus 1,000 milligrams of calcium daily had a 17 percent higher risk of developing kidney stones over seven years. Their risk of developing colorectal cancers was no different than that of women who took a placebo.
In Finland, male smokers who took high doses of vitamin D supplements had a significantly greater risk of developing pancreatic cancer.
Last week, an international group of cancer researchers warned that changes to vitamin D recommendations could end up harming people if higher doses are eventually found to elevate the risk for some diseases.
“There is insufficient evidence (to prove) a lack of harm due to long-term, higher levels of vitamin D,” the scientists wrote in a report prepared for the World Health Organization’s International Agency for Research on Cancer.
The bottom line is “controversy and conflicting evidence,” Brannon said, “so there is no consensus.”
For now, people concerned about their vitamin D levels should make sure they are following the government’s guidelines by tracking their daily intake through food and supplement labels, she said.
Elderly people at risk of developing brittle bones should consult their physicians before taking supplements.
Keith Darce: (619) 293-1020; keith.darce@uniontrib.com
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