Vitamin Information Center

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

By Jean Carper
Anti-Aging Expert, Best-Selling Author and USA Weekend Columnist
Vitamin D is the hottest nutrient in medical circles now. It has been credited with fighting everything from cancer to chronic pain. The latest news:

Cuts heart attacks. Men with low levels of vitamin D are about two times more apt to suffer a heart attack than men with sufficient D, Harvard researchers say. Their theory: Vitamin D lessens inflammation, high blood pressure and vascular calcification, all factors in cardiovascular disease.

Curbs cancer. A research team at the University of California-San Diego says that 2,000 IU of vitamin D daily could reduce breast cancer rates by half and slash the risk of colon cancer by two-thirds.

Prevents diabetes. Men with blood richest in vitamin D were 72% less apt to develop type 2 diabetes after age 40 than men with the least vitamin D, says a new Finnish study.

Boosts brain. Older people with depression or dementia may benefit from extra vitamin D, Dutch researchers say. Men and women over 65 with major or minor depression had 14% lower vitamin D levels than their non-depressed peers. And among Alzheimer’s patients, those with higher vitamin D levels scored better on tests of cognitive function.

RELATED PRODUCTS: Our Multi Nutrient Formula contain 1,000 IU of vitamin D. In 2007, we increased the amount in our formulas from 600 IU to 1,000 IU, in response to research indicating that the RDA for vitamin D is far too low for most adults.

In recent years, as disappointing research cast a dark cloud over the hyped benefits of some vitamins and nutrients, vitamin D has been a ray of sunshine.

It’s partly because vitamin D is naturally produced in our skin when exposed to the sun’s ultraviolet rays.

But, it’s also because its reputation as a bone builder and disease fighter has been borne out by increasingly solid evidence.

“More studies are showing that vitamin D in the body is more diverse and more important than what we had thought,” says Cheryl Rock, a registered dietitian and professor of nutrition at the University of California San Diego Medical School. “We’ve known that it’s crucial for the absorption of calcium, but now we think it may relate to cancer because its biochemical activity is so diverse.”

In 2007, researchers from UCSD’s Moores Cancer Center found that people with high blood levels of vitamin D had half the risk of breast and colon cancer of those with low levels.

A review of dozens of studies and research in the American Journal of Public Health says that women with the lowest vitamin D levels are five times more likely to get breast cancer than those with the highest levels, and the vitamin slows the progression of the disease. Low levels of vitamin D also correlate with up to a 70 percent increase in the risk for prostate cancer and double the risk of colon cancer.

And in a Harvard School of Public Health study in 2006, researchers found that people who took in the highest amounts of vitamin D cut their risk of pancreatic cancer almost in half compared with those with the lowest intakes.

What’s the cancer link? Research has shown that vitamin D helps regulate cell growth, a fundamental biological process that goes haywire in cancer.

But it may be more than just cancer risk and bone health that benefit from increased vitamin D.

In a study published earlier this year, researchers at Harvard Medical School found a strong link between vitamin D deficiency and cardiovascular disease. Researchers followed more than 1,700 members of the Framingham Offspring Study (children or grandchildren of the original participants in the 1948 Framingham Heart Study) for more than five years. They found the rate of cardiovascular disease events such as heart attacks, strokes and heart failure were from 53 percent to 80 percent higher in people with low levels of vitamin D in their blood.

A study in the June 2007 edition of Archives of Internal Medicine found a “significantly higher” prevalence of hypertension, diabetes and high triglyceride levels in individuals with lower levels of vitamin D.

Scientists are not sure what mechanisms connect vitamin D with reduced risk of heart disease and diabetes, but some studies have shown that the vitamin can lower inflammation by increasing levels of anti-inflammatory messengers.

Researchers are careful to point out that this study does not prove that taking vitamin D supplements reduces heart attacks and strokes. That can only be done with a large clinical trial in which vitamin D is compared with a placebo.

A deficiency of the vitamin is also believed to weaken the immune system. Some research shows that increased vitamin D may also protect against multiple sclerosis and rheumatoid arthritis, in which the immune system attacks the body’s own healthy tissue.

Vitamin D functions a bit differently from other vitamins. The inactive form of vitamin D, made by our skin as a result of sun exposure or obtained from food, is like a reservoir of raw material stored in our livers, fat tissues, muscles and blood. When needed, it’s converted to an active form, actually a hormone, that tells various parts of the body what to do.

While much of the research presents a positive and hopeful picture of how the sunshine vitamin can benefit us, it only works if we get enough of it. And, according to some medical and nutrition experts, many of us don’t.

One-third to one-half of otherwise healthy, middle-aged to older adults have low levels of vitamin D in the United States, Harvard researchers say. A University of California San Diego study found that the average U.S. adult intake of vitamin D is only 230 international units (IU) daily. The government’s current recommendation for vitamin D is 200 IUs a day for people up to age 50, 400 IUs to age 70, and 600 IUs for people over 70.

Many experts say the government guidelines are too low, because we’re not getting enough of the vitamin from the sun or our food.

Although the conscientious use of sunscreen has successfully filtered out the harmful cancer-causing UV rays, it’s also reduced the amount of vitamin D we’d normally get from the sun. During winter when the sun is low and people are not outdoors as often, people’s vitamin D levels drop significantly.

The problem is particularly serious in colder parts of the world, in people with dark skin, the elderly and those who are diligent about avoiding sun exposure.

Some researchers say we need at least 800 to 1,000 units of vitamin D daily, probably taken in the form of a supplement, to reap the health benefits. The studies that showed a link between the vitamin and reduced cancer and cardiovascular disease risk used at least 1,000 units of vitamin D every day.

Not everyone agrees that the recommended dosage be increased. The American Cancer Society favors keeping the current recommendation of 200 to 600 IUs for now, cautioning that more than 2,000 units is viewed in the government nutritional guidelines as potentially dangerous.

“In excess, vitamin D can be very toxic,” says Rock, who admits that the recommendation may need to be increased to 800 units daily. “Taking 2,000 IUs is the highest dosage in which you don’t see adverse effects. Any more than that and all bets are off.”

Some medical/nutrition experts advocate going to the source for more vitamin D.

“Just 10 to 15 minutes of sun on your face, arms or back twice a week is enough to keep your blood levels of vitamin D up. As we get older, we make the conversion less efficiently, so as we age we may need to get a little more sun exposure, maybe 20 minutes instead of 15,” says Rock, who notes that people with dark skin don’t convert the sun to vitamin D as readily, so they may also need more sun time.

Researchers from UCSD point out that people living closer to the equator have lower incidences of some cancers, including colon, lung, breast, ovary and prostate.

“Just don’t get carried away,” Rock says, noting that prolonged sun exposure increases the risk of skin cancer significantly. “You don’t need to spend hours in the sun and look like Malibu Barbie to get enough vitamin D.”

Relying on food for an adequate supply of vitamin D isn’t as easy, because not that many foods contain the vitamin.

Oily fish like sardines, salmon, mackerel and tuna all have vitamin D. So does cod liver oil. And eggs have a little bit.

“The good news is that many more foods are fortified with vitamin D. Milk has been fortified with vitamin D by law (since the 1930s to prevent the bone-deforming disease rickets). Many cereals are fortified and so are some cheeses and margarines and orange juice,” Rock says.

It’s important to try to get the right kind of vitamin D.

The vitamin has two main forms, D-2 and D-3. Vitamin D-2 is from plant sources and is the type often contained in many multivitamins and fortified foods. Vitamin D-3 is from meat sources and is considered to be the more potent and accessible. It’s what we make when our skin is exposed to sunlight.

“D-2 is not as bio-available as D-3, and our body doesn’t absorb it as well. So, if you take 400 IUs of D-2, you might not be getting all 400 units,” says Linda Copp, a registered dietitian and instructor of nutrition at San Diego State University.

Word is getting out to the supplement and food industry that vitamin D-3, or cholecalciferol, is the preferred form, and more of them are starting to offer it in their products, noting it boldly on the label.

How do you know if you’re lacking in vitamin D? You probably don’t know for sure. But if you rarely get any time in the sun and don’t eat or drink foods containing or enriched with the vitamin, or if your skin color is dark, chances are you may not be getting enough.

However, instead of guessing and haphazardly increasing your vitamin D dosage, Rock suggests having a blood test, which usually runs $100 to $200.

“It’s possible to measure the amount of vitamin D you have in your blood. Your health insurance probably won’t pay for it, but it’s not that expensive. And if you’re really concerned, it probably is a good idea to ask your doctor about being tested,” Rock says.

Beth Wood contributed to this article.

Epidemiological data show an inverse relationship between vitamin D levels and breast cancer incidence. This study investigates the relationship of modeled and measured serum 25-hydroxyvitamin D [25(OH)D] levels with age-standardized incidence rates of breast cancer in 107 countries.

The hypothesis being tested is that breast cancer incidence is inversely related to geographically-dependent cutaneous [skin] sunlight exposure. A multiple regression approach was used to examine the contributions of ultraviolet B (UVB) irradiance to age-standardized incidence rates of breast cancer in the 107 countries with data on these covariates - total column ozone thickness, per capita intake of alcohol and energy from animal and vegetable sources, cigarettes, proportion of female population overweight, and total fertility.

Age-standardized incidence rates were substantially higher at latitudes distant from the equator (R2 = 0.43, p < 0.0001). The dose–response gradient between modeled serum 25(OH)D levels and incidence rates of breast cancer followed a standard inverse dose–response curve Increasing increments in serum 25(OH)D in the range above 22 ng/mL were associated with incrementally lower incidence rates of breast cancer.

According to multiple regression, UVB irradiance adjusted for cloud cover was inversely associated with incidence rates (p = 0.04) after controlling for covariates.

Intake of energy from animal sources was also positively associated with incidence rates (p < 0.01). The overall coefficient of determination, R2, was 0.81 (p < 0.0001).

There was a protective effect of UVB irradiance on risk of breast cancer that was independent of fertility rate, proportion of the population overweight, alcohol intake, animal energy intake, and other covariates.

Source: The Breast Journal, May/June 2008, 14(3) pp. 255-260. PMID: 18422861 by Mohr SB, Garland CF, Gorham ED, Grant WB, Garland FC. Department of Family and Preventive Medicine, University of California San Diego, La Jolla; and Sunlight, Nutrition, and Health Research Center, San Francisco, California, USA [E-mail: cgarland@ucsd.edu]