vitamin D


Study: Vitamin D May Cut Risk Of Type 1 Diabetes

A new study by researchers at the Harvard School of Public Health adds to growing evidence that vitamin D plays a critical role in maintaining overall health.

The new government-funded study, published online in the American Journal of Epidemiology, suggests that a simple intervention — having adequate levels of vitamin D during young adulthood — may cut the risk of developing adult-onset, type 1 diabetes by as much as 50 percent.



Here’s some of the Harvard news release:

This study provides the strongest findings to date to suggest that vitamin D may be protective against type 1 diabetes.

In type 1 diabetes (once called juvenile-onset or insulin-dependent diabetes), the body’s immune system attacks and permanently disables the insulin-making cells in the pancreas. About 5% of the estimated 25.8 million people in the United States with diabetes have type 1, according to the American Diabetes Association. Although it often starts in childhood, about 60% of type 1 diabetes cases occur after age 20.

Previous studies have suggested that a shortage of vitamin D might boost type 1 diabetes risk, although those studies mostly examined the link between vitamin D levels in pregnancy or childhood and the risk of type 1 diabetes in children. Other research, in young adults, uncovered an association between high vitamin D levels and a lowered risk of multiple sclerosis—an autoimmune disease genetically and epidemiologically related to type 1 diabetes—suggesting that inadequate vitamin D in adulthood may be an important risk factor for autoimmune diseases in general…

The researchers conducted a prospective case-control study of U.S. military personnel on active duty, Continue reading

Latest Vitamin D Study: Little Effect In Older Women; Body Fat May Be Key

Dr. Charles Eaton of Brown University

I agree absolutely with all the people who denounce health coverage as an endlessly flip-flopping see-saw going back and forth between “Eat more X,” and “Don’t eat X.” Drink wine. No, don’t. Fat is bad. No, carbs are bad. Vitamins are good for you. No, they may be bad. I could go on.

But such is the nature of the kind of epidemiological research that yields many of the findings that are translated into health recommendations. It’s messy, complex, difficult work that tries to lurch toward some kind of consensus, and we follow its results like the audience at a baseball game, seeing the score at the end of each inning but not knowing what the final count will be.

All of which is a long-winded preamble to the fact that I published this post about a prime proponent of Vitamin D last week, and now would like to pass along new findings by researchers from Brown University and elsewhere that are less enthusiastic about Vitamin D’s potential broad health effects.

From Brown:

“A study of postmenopausal women found no significant mortality benefit from vitamin D after controlling for health risk factors such as abdominal obesity. The only exception was that thin-waisted women with low vitamin D levels might face some risk. The results, based on data in the Women’s Health Initiative and published online in the American Journal of Clinical Nutrition, agree with advice issued last year by the Institute of Medicine that cautioned against vitamin D having a benefit beyond bone health.”

The press release, which is here, begins:

PROVIDENCE, R.I. [Brown University] — Doctors agree that vitamin D promotes bone health, but a belief that it can also prevent cancer, cardiovascular disease and other causes of death has been a major health controversy. Continue reading

10 Points About Vitamin D From A Prime Proponent

From: The Journal of D-I-Y Medical Research (which I just made up).
Number of subjects: 1.
Intervention: 2,000 units of Vitamin D per day over one month, after I heard a primary care doctor attest that since he’d started taking more Vitamin D, his aches and pains of middle age had largely disappeared.
Outcome: Subject (yours truly) no longer has to walk stiffly down the stairs in the mornings like a toddler, planting both feet onto each stair before moving on to the next one. Foot and ankle pain mostly gone.
Conclusions: None. You can’t conclude anything from a study with an “n” of 1. But the results were intriguing enough to make me attend a lecture today by Dr. Michael Holick, director of the Vitamin D, Skin and Bone Research Laboratory at Boston University. It was titled, “The Solution For Good Health: Rx Vitamin D.”

For context, Dr. Holick is clearly a controversial figure. He tends to be hated by some dermatologists because he advocates (moderate, carefully calibrated) sun exposure. He discloses an array of financial ties with various companies — as well as NIH support — and has written two books on Vitamin D, the latest called “The Vitamin D Solution.”

But he is not a fringe figure. He remains a professor of medicine, physiology and biophysics at B.U., and he led the Endocrine Society team that issued new practice guidelines on Vitamin D this summer. (They recommended more than a 2010 Institute of Medicine report, which had tripled the recommended levels.)

Here in Boston, our bodies make virtually no Vitamin D from November to February no matter how long we stay outside.

I must confess, I had Linus Pauling on my mind when I went to see Dr. Holick speak. For all Pauling’s Nobel-winning chemistry brilliance, time appears to have proven him wrong on his great enthusiasm for Vitamin C.

But lately, time seems to be on Dr. Holick’s side. Evidence of a broad array of health benefits — and lack of harm — from appropriate doses of Vitamin D has been accumulating, and more studies are in the works. I quake when I pass along recommendations of a vitamin that can have toxic effects if overdone — and the dangers are very real, as the Wall Street Journal’s Health Blog reported here. But here are two recent positive signs: Continue reading

Vitamin D Instead Of A Flu Shot?

Last week, the outspoken backers of hefty doses of Vitamin D got a scientific thrashing by a panel that determined those big doses are not only unnecessary, but may also be harmful.

This week, The Wall Street Journal reports that those super-sized Vitamin D doses may actually have a benefit: fighting off upper respiratory infections. Laura Johannes writes:

Based on early research results, some doctors are recommending high doses to help stave off the upper respiratory infections, with some even speculating it could be a substitute to the annual flu shot…

Until recently, scientists have blamed the higher prevalence of flu cases during winter to the tendency of humans to congregate inside or the low humidity of cold weather, which makes viruses survive in the air longer. Increasingly, scientists are exploring another possible explanation: During the wintertime, we are outside less, resulting in lower vitamin D absorption from the sun…

In an observational study published in June, Dr. Sabetta and colleagues followed 195 people during winter and found that people with a blood serum concentration of 38 nanograms per milliliter of vitamin D had half the risk of getting an upper respiratory tract infection as those with levels below that threshold. The people with higher vitamin D levels hadn’t gotten any more flu shots and weren’t taking more of other vitamins than those with lower levels, according to the study. The study, however, didn’t rule out the possibility that the group with higher vitamin D also had better overall nutrition.

New Vitamin D Recommendations: Skeptics Remain

Vitamin D: Is less now best? Not everyone agrees.

Every major media outlet covered today’s news from the Institute of Medicine that most people apparently don’t need the high doses of vitamin D and calcium that have been promoted in recent years (but we do need more of those vitamins than current recommendations call for.)

According to NPR: “After two years of study and debate, the panel says children and most adults need 600 international units of vitamin D a day. People older than 70 need 800. That’s more than the previous targets, set 13 years ago, of 200 units a day for young adults, 400 for those older than 50.”

But some skeptics remain. Later in the piece, NPR quotes one vitamin D expert who says he won’t change his advice to patients:.

Dr. Michael Holick of Boston University, who discovered the active form of vitamin D 40 years ago and is a leading proponent of high doses, isn’t backing away from his conviction that most people need at least 3,000 units a day. That’s what he takes, and what he recommends to his patients. Sometimes he prescribes 50,000 units of vitamin D a week.

“My recommendation is very simple,” Holick says. “I don’t see any downside to increasing your vitamin D intake. When I’ve been recommending for the past decade that people take more than the [officially recommended] 200 units, there was a lot of skepticism. Now they’re recommending three times what we recommended in 1997.

“I suspect a decade from now that they’ll be recommending another three- or fourfold higher increase,” Holick predicts.

I emailed Dr. Holick to ask more about why he remains so certain about the health benefits of vitamin D given the evidence. I’ll let you know what he says.