vitamin D


Calcium, Vitamin D For Osteoporosis: Are Recommendations Skewed By Conflicts Of Interest?

A photo illustration shows over-the-counter calcium supplements. (Bebeto Matthews/AP)

A photo illustration shows over-the-counter calcium supplements. (Bebeto Matthews/AP)

By Marina Renton
CommonHealth Intern

Might commercial influences be driving the widespread recommendation of calcium and vitamin D supplementation for the prevention and treatment of osteoporosis?

That’s the conclusion of an analysis published in the journal BMJ, written by Andrew Grey and Mark Bolland, endocrinologists and associate professors at the University of Auckland.

The analysis — strongly refuted by organizations that advocate for osteoporosis research — further complicates the already contentious issue of whether it’s a good idea to take the supplements and if so, at what dosage.

The Supplement Conundrum

Women over 50 are most likely to develop osteoporosis, a bone disease affecting millions of Americans that results in bone weakness and increased risk of fracture. Calcium and vitamin D supplements are widely recommended to prevent and treat the condition.

“But as we point out, the considerable body of randomized trial evidence doesn’t support that practice,” Grey, the study’s co-author, wrote in an email.  “We wondered why practice hasn’t changed to reflect the evidence.”

To promote bone health, over half of older Americans take calcium and vitamin D supplements, which can be prescribed by a doctor or purchased over the counter, the authors write.

The Institute of Medicine (IOM) recommends adults take in 1,000 mg of calcium per day (1,200 for adults 70+ and women 51-70) and 600 IU (international units) of vitamin D — 800 IU for the 70+ set.

As of 2013, the U.S. Preventive Services Task Force does not recommend daily calcium and vitamin D supplementation for non-institutionalized postmenopausal women to prevent fractures. This, they note, is not necessarily inconsistent with the IOM’s recommendations, which do not specifically discuss fracture prevention.

The supplements have been standard clinical practice in preventing or treating osteoporosis in older adults since the early 2000s. Since then, however, studies have emerged to contest their effectiveness, according to the paper. Continue reading

Debating Vitamin D: Leading Docs Still Wrangling On Best Dose For Patients

(Suzanne Schroeter/Flickr)

(Suzanne Schroeter/Flickr)

The message on vitamin D is pretty clear if you talk to Dr. JoAnn E. Manson, M.D., chief of the preventive medicine division at Brigham and Women’s Hospital in Boston, who is leading the largest clinical trial in the world investigating the potential health benefits of vitamin D. It boils down to this: Curb Your Enthusiasm. At least for the time being. Even in the midst of a hellish winter when you may be tempted to take an extra dose of the so-called “Sunshine Vitamin” for a boost.

In a commentary piece published this week in the Journal of the American Medical Association, Dr. Manson urges caution. She says that even though the public has become smitten with vitamin D, its growing popularity has led to mega-dosing that’s not backed by the current evidence. “More isn’t always better, more is sometimes worse,” Manson said in an interview. “We don’t yet have the answers, so we shouldn’t make assumptions.” But, she adds, in a couple of years, gold-standard evidence on whether higher doses of vitamin D are good for you should be out.

But get on the phone with Dr. Michael F. Holick, Ph.D., M.D., a leading vitamin D proponent, endocrinologist at Boston Medical Center and professor at Boston University School of Medicine, and you’ll get a totally different, but equally clear message. Vitamin D deficiency and insufficiency are far more widespread than certain professional medical groups suggest, Holick says, and dosing at higher levels shows “no evidence of toxicity.”

How did we get here and what’s a patient to do?

Here’s a little background:

In debates over nutrition, vitamin D is one of those supplements that’s drawn both passionate supporters and equally aggressive skeptics over the years. And, like coffee, chocolate and red wine, it’s often the subject of studies that can make your head spin: it’s good for you…until it’s not.

The current vitamin D guidelines from the Institute of Medicine recommend 600 IU’s per day for adults up to 70 years old and 800 IU’s per day for those over 70. “This,” writes Manson in her JAMA piece “is equivalent to 3 to 4 daily servings of fortified foods such as milk, yogurt, soy beverages, orange juice, or cereal, plus fatty fish twice per week. These amounts are adequate for at least 97.5% of U.S. and Canadian residents, she says, and it’s good even in the bleakest, darkest season, “even if you’re in Antartica in winter.” Continue reading

Study: Vitamin D Boosts Survival For Some Colon Cancer Patients

Suzanne Schroeter/flickr

Suzanne Schroeter/flickr

When it comes to vitamins, much of the recent news has been grim.  “Enough is enough: Stop wasting money on vitamin and mineral supplements” was the headline of a medical journal  editorial not so long ago.

One exception may be Vitamin D, aka the sunshine nutrient.

Vitamin D is no silver bullet, according to the research. But studies have shown that when your levels are too low, it can be bad for your health.

Now, a new study by researchers at the Dana-Farber Cancer institute finds that high levels of vitamin D increase survival in certain patients with colon cancer.

From the Dana-Farber news release:

… clinical trial patients with metastatic colorectal cancer who had high levels of vitamin D in their bloodstream prior to treatment with chemotherapy and targeted drugs, survived longer, on average, than patients with lower levels of the vitamin. Those findings were reported today at the 2015 American Society of Cancer Oncology (ASCO) Gastrointestinal Cancers Symposium in San Francisco.

…The research, based on data from more than 1,000 patients with metastatic colorectal cancer who enrolled in a phase 3 clinical trial of chemotherapy plus biologic therapies, adds to vitamin D’s already impressive luster as a potential cancer-inhibiting agent. In the study, patients with the highest blood levels of vitamin D survived for a median period of 32.6 months, compared to 24.5 months for those with the lowest levels…

The study’s lead researcher Kimmie Ng, MD, MPH, a medical oncologist at Dana-Farber said in an email to me:

“There is a lot of debate about what can be concluded from observational studies of vitamin D and colorectal cancer survival, with many believing that higher vitamin D levels may just be a proxy for better health or less aggressive disease. But this is where our study truly stands out from the rest – we had very detailed and comprehensive data on patient and tumor characteristics, survival, response to chemotherapy, and diet and lifestyle factors. Even after controlling for all of these variables in our analysis, our results did not change – higher plasma vitamin D was still associated with significantly better survival. Continue reading

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.