An Advance in Breast Cancer Surgery

Breast cancer surgery began long before radiation therapy, chemotherapy or hormonal therapy existed. At that time surgery was the only available treatment. The standard of care was radical mastectomy – removal of the entire breast tissue with the underlying muscle and removal of all the lymph nodes from the arm pit. The surgery is terribly disfiguring and debilitating, but was the only thing standing between patients and a fatal illness. Radical mastectomy was first performed in the 1880s and remained the standard of care until the 1970s when it was replaced by lumpectomy.

Lumpectomy involves removing only the malignant tumor with some healthy tissue around it and sparing the remaining breast. It was found to be as effective as radical mastectomy but was still performed with the removal of lymph nodes from the arm pit.

For many women the consequences of the arm pit surgery are worse than those of the breast surgery. The lymph node removal can lead to discomfort and swelling in the arm and can predispose to infections. Nevertheless this surgery remained the standard of care as it was thought to be essential to stopping any microscopic cancer that had spread from the breast into the lymph nodes.

The next leap forward in minimizing the harm of surgery for breast cancer patients came in the 1990s. A technique called sentinel lymph node biopsy pioneered by Dr. Armando Giuliano allowed surgeons to identify the first lymph node that cancer cells are likely to reach when leaving the breast. The surgeon can then just remove that node (or two or three) and leave the rest. It was shown that if these sentinel nodes are free of cancer cells, the rest of the nodes in the underarm will also be cancer-free. This resulted in many women being spared removal of the lymph nodes.

This week, a new study will make many women’s breast cancer surgery even less invasive. A team led by Dr. Giuliano performed a study to test whether taking out all the underarm lymph nodes is helpful. The study was published in the Journal of the American Medical Association. The study randomized women with early stage breast cancer with positive (malignant) sentinel nodes. One group underwent surgery to remove all the lymph nodes from the underarm, the other group did not. All women underwent lumpectomy and radiation. Some women in both groups also had chemotherapy or hormonal therapy.

Both groups did equally well from their cancer with over 90% survival over 5 years. The women randomized to surgery, however, had many more complications related to arm pain, swelling and infections. So for women who match the specific criteria of the study, removal of all the lymph nodes is no longer necessary.

Learn more:

New York Times article: Lymph Node Study Shakes Pillar of Breast Cancer Care

New York Times Q. and A.: Breast Cancer and Lymph Nodes

Journal of the American Medical Association study: Axillary Dissection vs No Axillary Dissection in Women With Invasive Breast Cancer and Sentinel Node Metastasis

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Benzonatate: A Cough Suppressant So Dangerous, You’d Rather Just Cough

Benzonatate is a cough suppressant available by prescription as a generic medication or under the brand Tessalon. It is chemically related to medicines used as local anesthetics and works by numbing the nerves in the lungs which trigger a cough reflex. It was approved by the FDA in the 1950s.

A recent issue of The Medical Letter briefly highlighted an FDA warning about benzonatate. (Links to The Medical Letter review and the FDA warning are below.)

The FDA warning focused on accidental overdose in children under 10. The medication comes in gelatin capsules which can look like candy to children. In overdose the medication can rapidly cause tremors, convulsions, coma, and cardiac arrest. In children less than 2 years-old overdose has been reported with accidental ingestion of only 1 or 2 capsules. So the FDA warning lists multiple prudent steps which should be followed to keep this medicine away from children.

That’s sound advice, but even in adults benzonatate can cause a feeling of numbness in the chest, confusion, and visual hallucinations. I’m certainly sympathetic to the miserable patient with a cold or bronchitis who has a terrible cough. Coughing can be very disruptive to work and to sleep, and patients can be desperate for relief. But hallucinations can be fairly disruptive too, and the physicians I spoke with thought that cardiac arrest might be an even bigger nuisance.

The Medical Letter authors conclude “when a cough suppressant is truly necessary, dextromethorphan or even codeine might be a safer choice.” When codeine compares favorably in safety to another medicine, it might be time to reconsider why we ever use it.

Learn more:

FDA Drug Safety Communication: Death resulting from overdose after accidental ingestion of Tessalon (benzonatate) by children under 10 years of age

The Medical Letter brief: Benzonatate Warning

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Rattled by Rickets Resurgence

Rickets is a childhood bone disease caused by severe vitamin D deficiency. It causes bone pain, weak bones and bone deformities in growing children. In the 1920s the link between rickets and vitamin D was discovered and within a couple of decades rickets largely disappeared from the developed world.

Until now.

A flurry of articles in the media this week (links below) reports a resurgence of rickets in England, Scotland and Ireland. One hospital in Southampton is reported to have treated 40 children with rickets last year.

That’s worrisome enough, but even more alarming is that the articles (and the physicians interviewed) seem to misdiagnose the cause. The articles all blame the recent upsurge in rickets on the northern latitudes and the increasing use of sunscreen. That’s true but that’s like blaming gravity for a plane crash. England will not be tropical any time soon and children will continue to spend most of their time indoors.

Some of the doctors in the articles recommend 20 to 30 minutes of sun exposure daily, but that seems shortsighted on two fronts. First, sun exposure increases the risk of wrinkles and skin cancer. Second, recommending sun exposure is a sign that the British doctors have forgotten their own glorious history of conquering rickets. In the 1920s when vitamin D deficiency was found to cause rickets did they have all English children sunbathe every day? No. They recommended supplementing all children’s diet with foods very high in vitamin D. This spawned countless stories of English kids being forced by their nannies to ingest cod liver oil, and it banished rickets from England for over two generations.

Although the US is farther south than England and so gets more direct sunlight, we take another measure to prevent rickets – we add vitamin D to our milk. The English amassed a global empire without a single Brit ever getting a suntan. They would do well to remember the benefits of vitamin D supplementation.

Learn more:

Los Angeles Times article: Global Health Watch: Rickets showing up in some British children

BBC article: Rickets comeback due to ‘lack of sunshine exposure’

Irish Medical Times article: Re-emergence of rickets and vitamin D deficiency

My post from December reviewing the evidence about vitamin D: The Most Recent Celebrity Vitamin: D

Tangential miscellany:

This week in 2006 I decided that what the world really needed was one more doctor writing about health-related issues. Five years and 250 posts later I hope that some of my musings have informed, interested, or amused you. I remain very grateful for all the feedback I receive about my posts and for all the links to articles you send. I’ll try not to bore you for the next five years.

Lastly, there won’t be a post next week. Posting resumes in two weeks.

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Study Linking Vaccines to Autism not Just Wrong, Intentionally Fraudulent

In 1998 the British medical journal Lancet published a study led by Dr. Andrew Wakefield that changed public opinion about vaccination ever since. The study described twelve children with autism and colitis whose symptoms began shortly after they received the MMR vaccine. Public panic was immediate and sustained. Vaccination rates plummeted in England and measles incidence climbed thereafter. Measles is now endemic in England, meaning that there are enough unvaccinated children that the infection can continue to spread within the population. The anti-vaccine scare has since been transported globally. In the US the movement is being promoted by celebrities and some fringe pediatricians who promote themselves as being sensitive to parents’ concerns about vaccines.

The study never gained much scientific traction. First of all, a study casting doubt on a vaccine given to millions of children by citing twelve cases should raise nothing but skepticism. After all, I’m sure I can find 12 children whose first seizure coincided with their first Latin class. Multiple larger studies since then have failed to find any link between MMR and autism. Nevertheless distraught parents and anti-vaccine activists continue to swear by Wakefield and his study.

It should have been clear when Wakefield’s findings could not be reproduced that his study was wrong. But science is a human endeavor and as such often takes an irregular path to the truth. There are many wrong turns and dead ends simply because nature yields her secrets reluctantly. But this was not a simple case of well-intentioned science reaching the wrong conclusions. An article by Brian Deer published in BMJ last week (link below) lists multiple reasons to believe that the study was a deliberate fraud.  Below, I summarize just a few of the glaring inconsistencies Deer found.

Long before he began working on the Lancet study Wakefield had been retained by attorneys to support a lawsuit against vaccine manufacturers. These attorneys and other anti-MMR campaigners referred the parents of the patients in the study to Wakefield specifically because they reported the symptoms he was looking for. The source of the patients was not reported in the study, leaving it to appear that they were simply 12 interesting cases that the authors discovered.

All of the patients underwent a colonoscopy to demonstrate colitis. All of the biopsy results were normal and did not show any signs of colitis. Nine of the results were later changed in the paper to “non-specific colitis.”

Five of the twelve children had developmental problems documented in their medical records prior to their receipt of the MMR vaccine.

In review of preliminary drafts of the paper which were circulated by the authors prior to publication, the average time interval between the administration of the vaccine and the onset of symptoms shrank with each subsequent version of the study. That is, every time the paper was edited the apparent link between MMR and the onset of behavioral and intestinal problems grew stronger.

Deer summarizes

So that is the Lancet 12: the foundation of the vaccine scare. No case was free of misreporting or alteration. Taken together, NHS records cannot be reconciled with what was published.

A year ago, Lancet retracted the study. (I wrote about it then, link below.) Last May, Wakefield’s medical license in England was revoked. He remains unapologetic and denies wrongdoing.

Think of all the harm done – all the cases of measles in the UK and the US in the last decade, the funds spend on large trials to try to reproduce Wakefield’s findings, the funds that should have been spent finding the cause of autism which is still unknown, the anguished parents some of whom must now realize they were fooled.

Hopefully this false link between vaccines and autism is now dead and buried. Celebrities who attempt to resuscitate it or rally to Wakefield’s defense should be dragged through infectious disease wards in London to be reminded of the consequences of their lies.

Learn more:

BMJ article by Brian Deer: How the case against the MMR vaccine was fixed

Wall Street Journal editorial: The Autism Vaccine Hoax

MSNBC article: Doctor defends research tying vaccine to autism

CNN article: Retracted autism study an ‘elaborate fraud,’ British journal finds

My previous posts on the anti-vaccine movement and vaccine refusal:

Twelve Years Later, the Truth about Vaccines and Autism

Vaccines: Fighting Fear with Information

Vaccine Refusal: Turning Back Two Centuries of Progress

U.S. Measles Cases at Highest Numbers Since 2001

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Everything You Always Wanted to Know About Nasal Decongestants But Were Afraid to Ask

… Or, You Might Think That it’s Funny, But it’s Snot

As I mentioned last week, a miserable cold is striking lots of my patients, spreading grief across the land.  The typical symptoms are nasal congestion, cough and the mother of all malaise.  Since there is nothing proven to significantly decrease the duration of the common cold, the best doctors can do is treat the symptoms and encourage patience.

The mainstay of treating cold symptoms is a nasal decongestant.  Besides letting you actually breathe through your nose, a nasal decongestant may decrease the post-nasal drip that’s making you cough.  For people prone to sinus infections, it can keep your sinuses clear and prevent a sinus infection.  For people traveling by air it can keep the eustachian tubes clear so your ears can equilibrate when the plane takes off and lands.

Unfortunately, there is much confusion about nasal decongestants, and many patients baffled by the options at the drug store buy a product that won’t help at all.  So here’s a brief review of the nasal decongestants you should know about.  Their most well-known brand names are in parentheses, but you should feel free to buy the same ingredient in the cheaper store brand.

Oxymetazoline (Afrin) nasal spray

Afrin is the most potent over-the-counter nasal decongestant.  And you shouldn’t use it.  The reason you shouldn’t use it is that after two to three days of use it causes rebound congestion.  That means after you stop using it your nose gets more congested than before you start it.  For that reason I generally recommend that patients only take it for only one day at a time.  When is it at all useful to have a potent nasal decongestant for just one day?  On the days you fly.

Pseudoephedrine (Sudafed)

Pseudoephedrine is the next best thing to Afrin in terms of potency and it doesn’t cause rebound congestion.  The problem is that patients no longer know how to find it.  In California you have to show ID at the drug store counter and ask for it (though you don’t need a prescription).  Because it’s a chemical cousin of ephedrine, it’s a stimulant.  So some people feel too jittery on it or can’t sleep after taking it.  It should not be taken by people with high blood pressure or breast-feeding mothers. It can cause (temporary) prostate enlargement, so older men may have difficulty urinating after taking it.  Nevertheless, with all the above caveats, it’s probably the best thing to take during a cold to keep your nose and sinuses clear.

Phenylephrine (Sudafed PE)

Phenylephrine is not a very effective nasal decongestant. Avoid it.  Lots of patients end up buying it because (in California) it’s the only option on the shelf and they don’t know to ask at the counter for pseudoephedrine.

Ipratropium (Atrovent) nasal spray

Last but not least, Atrovent nasal spray is a prescription alternative that has very few side effects.  It may be slightly less effective than pseudoephedrine but it’s the perfect solution for those who can’t take pseudoephedrine because of all the side-effects listed above.  The reason that Atrovent nasal spray requires a prescription despite being much safer than pseudoephedrine, which doesn’t, is mysterious to me, though I am confident that our drug regulations are otherwise perfectly rational.

Now you can decongest a nose as well as the pros.

Learn more:

My review from last year about how to diagnose and manage The Common Cold

Tangential miscellany:

If you’re flying US Airways in January, make sure to grab a copy of the in-flight magazine.  They’ve reprinted my post Sleep Deprivation Sabotages Dieting.  And please make a nuisance of yourself on the plane by pointing out to other passengers how cool your doctor is.  Thanks.

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Echinacea Still Unproven for the Common Cold

Many of my patients have come down with a nasty cold in the last two weeks – runny nose, cough, hoarseness, sore throat and the kind of fatigue that makes lifting your head off the pillow seem unnecessarily ambitious.  And just in time the Annals of Internal Medicine published a study to give them valuable advice.

The effects of echinacea on the common cold have been studied many times previously, though never as rigorously as in this study.  A definitive benefit has never been proven.

This study enrolled over 700 people who had just developed a cold.  They were randomized into four groups.  One group took no pill.  A second group took echinacea daily and was told that they were taking echinacea.  The last two groups took either a placebo pill or echinacea but were not told which they were taking.  They recorded the severity of their symptoms twice a day.

The results were positively meh.  The average duration of symptoms in the group knowingly taking echinacea was 6.8 days.  In those unknowingly taking echinacea it was 6.3 days.  Those taking placebo felt sick for an average of 6.9 days, and those taking nothing for 7.0 days.  Note that this shows a slight decrease in duration of symptoms between the two echinacea groups and the other two groups.  This difference was so small it was likely to have been due to chance (that is to say, the difference was not statistically significant).  But even if the difference is real it would amount to decreasing the misery of a cold that lasts a week by only several hours.

So this trial suggests that echinacea either doesn’t help in treating the common cold or it has a very small benefit.

Remember, nothing has been proven to decrease the duration of the common cold yet.  The best that you (and your doctor) can do is to make the symptoms less miserable until you recover.

I wish all of us a healthy, joyous and prosperous 2011.

Learn more:

Annals of Internal Medicine Summaries for Patients:  Echinacea for the Common Cold

LA Times Booster Shots:  Echinacea for a cold? Eh, don’t bother, study concludes

NPR Health News Blog:  If Echinacea Does Anything For Colds, It Isn’t Much

And lest echinacea have hurt feelings, Vitamin C doesn’t help in treating colds either.

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Flu Incidence on the Rise

(Please excuse this short post during this short week.  If you feel deprived of health education, I’ve listed some educational links for you below.)

You better watch out.  The flu is coming to town, and it doesn’t care if you’ve been naughty or nice.  It looks like flu season is starting later this year than usual, but both the CDC data and Google Flu Trends suggest that illnesses due to the flu are increasing nationwide.

The best way to protect yourself is with a flu shot.  And if you do get sick, call your doctor right away.  Antiviral medicines can help shorten the duration of the flu but only if they are started in the first 48 hours of symptoms.

Merry Christmas to everyone who is celebrating!  Stay healthy.

Learn more:

Google Flu Trends is the coolest way to track flu activity.  You can look at individual states, and now also major cities.  Check it out in time to warn Grandma in Milwaukee!

My post about who should and should not receive a flu shot.

Is it a cold or the flu?  Here’s my post about identifying and treating the common cold.

The Centers for Disease Control and Prevention Flu Activity and Surveillance (written for doctors more than for patients)

Finally, we should not allow the holidays to make us complacent about the constant zombie threat.

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NDM-1: No Drug Matters

My longtime readers know that I’m not one to panic when the media does.  I wasn’t very worried about anthrax in the mail.  I didn’t think swine flu was going to be a big deal.  (See link below.)  And I’m not concerned about the health effects of airport X-ray back-scatter machines.

But there’s plenty of stuff that worries me.  Most of it is scary on time scales longer than the typical media attention span.  What scares me is stuff that will hurt us decades from now.  For example, I’m very worried about stuff like the inevitable but not imminent collapse of Medicare, the fact that world population will peak on about 2075 and then decline, and the unavoidable zombie apocalypse.  OK, I’m just kidding about that last one.

This week’s New England Journal of Medicine published a perspective article about a topic that is sure to become an increasingly dangerous problem.  As far as I can tell it received no media attention.  The article described a new bacterial gene for antibiotic resistance.

The gene is called NDM-1, which stands for New Delhi metallo-beta-lactamase 1.  It deserves our concern for two reasons.  The first reason is that this gene codes for an enzyme that gives a bacterium resistance to almost all current antibiotics.  That’s bad.

To explain the second reason for concern, I first need to explain how genes normally get around.  Say you have a really nice gene, the gene for brown eyes as an example.  Say that you’d like to give that gene to someone else.  The only way for humans to do that naturally is to make another human.  You have to find a mate, procreate, and voila!  Nine months later you have an offspring with your brown eyes.  Genetic engineers have figured out ways to take genes from one living thing and put it into another, but nature typically works by having genes move only from parents to progeny.  You can’t give your tall stature to your neighbor or your natural red hair to your friend.  You can only transmit your genes to your kids.

Well, bacteria long ago have circumvented this limitation, essentially inventing their own genetic engineers.  They have most of their genes on a chromosome that is passed just to the descendents of each bacterium.  But some genes are on a tiny loop of DNA called a plasmid that can leave one bacterium and enter another.  If a chromosome is like a hard drive of genetic information, a plasmid is like a flash drive – tiny and portable.  NDM-1 is coded on a plasmid and has already been identified in several different kinds of disease-causing bacteria.  That means it can spread itself to different bacteria species.  (The equivalent genetic trick would be giving your brown eyes to your dog.)

To put it all in perspective, these bacteria carrying NDM-1 aren’t more infectious and don’t cause worse diseases than their non-NDM-1 cousins.  An E. coli with NDM-1 will cause a bladder or kidney infection that is no worse than a standard E. coli infection.  The disaster is that virtually no antibiotics will work for it.

NDM-1 was first discovered in 2008 and for now seems to be concentrated in the Indian subcontinent, though recent travelers to India have been found to be infected with NDM-1 in many other countries.

Is there anything for us to do?  Doctors should be constantly reminded about the danger of emerging antibiotic resistance and should be urged to use antibiotics rationally.  We should all keep an eye on the story of antibiotic resistance as it unfolds over the next years.  It is entirely possible that antibiotics, after serving us for about a century, will become ineffective.

Learn more:

New England Journal Medicine article:  NDM-1 — A Cause for Worldwide Concern

My post in 2007 about increasing antibiotic resistance:  Serious MRSA Infections More Common

My post from April 2007 when H1N1 flu first made news:  Swine Flu: Unlikely to End the World

It’s never too late to prepare for the zombie apocalypse, until it is.

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Animated about Aspirin

Aspirin was hailed as a wonder-drug in the 1800s when it was first purified – the first anti-inflammatory medication that did not have the severe side effects of steroids.  More recently aspirin’s benefits in stroke and heart attack prevention have been proven.  This week another possible benefit of aspirin has been uncovered.

An important study published in The Lancet attempted to find any effect of aspirin on cancer prevention.  I’ve written frequently about the myriad substances that are falsely claimed to prevent cancer after an observational trial shows that people who take X get cancer less frequently then people who don’t take X.  These studies are all meaningless since the only way to test the effects of X is to randomize some patients to take X and others to take placebo.  That’s what’s so tantalizing about this week’s study – it’s a review of randomized trials.

The investigators reviewed all randomized trials which randomized patients to aspirin versus placebo for at least four years.  These studies happened back in the 1970s and 80s and were designed to test aspirin’s ability to prevent strokes and heart attacks.  The investigators looked at individual patient data from this handful of studies and extracted information about cancer deaths.  They counted the number of patients who died of various cancers in the aspirin group and the control group.  The results were impressive.

During the trials themselves, the patients in the aspirin group had significantly fewer deaths due to cancer than the placebo group.  For every about 150 patients who took aspirin rather than placebo for several years, one cancer death was prevented.  This effect was large enough that the mortality from all causes was smaller in the aspirin group.  For every approximately 110 patients who took aspirin, one death from any cause was prevented.  Interestingly the benefit only became apparent 5 years after randomization.  This time delay suggests that that the effect of aspirin is not on cancers that are already present but that aspirin either prevents cells from becoming cancerous or kills very small numbers of malignant cells.

The investigators then followed up on cancer deaths in these patients in the subsequent decades since the end of the trials.  These results were even more striking.  The benefit of aspirin in preventing death from cancer persisted over time even though many of the patients discontinued aspirin back in the 80s when the trials stopped.  There were some consistent patterns across the data.  The benefit of aspirin for cancer mortality prevention was present in each of the trials and was greater with the trial duration.  That is, the longer that people took aspirin rather than placebo, the greater reduction in cancer death risk.  Death from esophageal, stomach and colorectal cancer were most affected.  Deaths from other cancers however, such as leukemias, were not decreased.  Also, interestingly, the benefit was independent of the dose of aspirin, suggesting that a “baby” dose of 81 mg daily is sufficient.

So should we all start taking daily aspirin?  Should we just put it in the water supply?

Not yet.

First of all, children should not take aspirin because of the risk of Reye’s syndrome.  Second, the trials reviewed in this study involved almost exclusively men, so we have no idea if the results can be generalized to women.  (And, importantly, we don’t know the effects of aspirin on cancers that affect women exclusively – breast, ovarian, and uterine cancer.)

Aspirin also has some risks, the most serious being intestinal bleeding and hemorrhagic stroke (bleeding in the brain).  But numerically, these risks seem to be much smaller in magnitude than the benefit of cancer mortality prevention.  Prior to this study these risks had to be balanced against the benefits of aspirin in preventing strokes and heart attacks.  In people with no risk factors for stroke or heart attack the risks outweighed the benefits.

But now, at least for adult men, the idea of daily low dose aspirin for cancer prevention seems compelling.  Lots of experts in the media are cautioning that more information is needed, but what better information could we hope for?  This study is using 20 years of follow up.  Better information will take decades more.

I’m not making any recommendations as of now, and obviously each of you should discuss this with your doctor.  I’m going to discuss this paper with trusted colleagues over the next weeks.  My initial hunch is that we may have reached the tipping point in favor of daily aspirin in adult men.

Learn more:

New York Times article:  Aspirin Helps in Reducing Cancer Deaths, a Study Finds

Los Angeles Times article:  Baby aspirin linked to reduced cancer deaths

The Lancet article:  Effect of daily aspirin on long-term risk of death due to cancer: analysis of individual patient data from randomised trials

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The Most Recent Celebrity Vitamin: D

Every now and then some vitamin or dietary supplement becomes all the rage.  A couple of generations ago vitamin C was the miracle drug that could prevent all diseases, despite lots of evidence to the contrary.  Lots of my patients still take it for colds, demonstrating its persistent mythology.  Vitamin B12 became the wonder-drug a few decades ago, leading to a whole generation of patients getting monthly injections for reasons that remain scientifically mysterious.  And many lesser stars can be added to this grab bag, including glucosamine, folic acid, zinc and selenium, all of whom were taken for all sorts of putative benefits which were later debunked.

Now it’s vitamin D’s turn in the spotlight.  Vitamin D has been receiving increasing attention in the last few years as its role in bone health has been better understood and as more people are found who are deficient in vitamin D.  Unfortunately, with more understanding comes more hoopla, and there are now shaky claims that vitamin D helps prevent myriad diseases.  This week, the Institute of Medicine (IOM), the government body that decides how much of each nutrient we need, revisited their recommendations for vitamin D.  (See the link below for their report.)  This received much (frequently confusing) media attention and a whole bunch of my patients (thanks!) emailed me links to various articles about this story.

Let’s parse this issue and separate what is known from what is speculated.

Benefits of vitamin D

Vitamin D has only two proven benefits.  The first is that vitamin D is essential to maintain strong bones.  Another way to say this is that vitamin D deficiency eventually predisposes to osteoporosis.  The only other benefit of vitamin D which has been proven in randomized trials is that vitamin D supplementation in men and women over 60 helps decrease the frequency of falls.  How does it do that?  Does it help balance?  Does it help muscle strength?  Does it turn off gravity?  No one knows, but I’m pretty sure it doesn’t affect gravity.

Many other supossed benefits of vitamin D are frequently mentioned, from prevention of heart disease to prevention of cancer.  None of these claims are supported by a shred of evidence from randomized trials, so for now we should assume that they are false.  Anecdotally, many patients (including my patients) report a dramatic reduction in aches and pains and improvement in energy after starting vitamin D supplements.

How much vitamin D is enough?

This is where the IOM made waves.  They increased the daily recommended amount of vitamin D from 200 IU to 600 IU.  But many doctors (including me) have already been recommending daily supplementation of 1,000 or 2,000 IU.  So why is the IOM taking such baby steps?  Or, conversely, why are doctors prescribing so much more than the IOM?  The heart of the dispute is a disagreement about what vitamin D levels are normal.  The IOM defines a vitamin D blood level of over 20 nanograms per milliliter (ng/ml) as normal.  By that definition most North Americans have normal levels and 600 IU daily is all that most people need to achieve those levels.

But the Endocrine Society and the International Osteoporosis Foundation have concluded that a level of 30 ng/ml is necessary for optimum bone health.   They call levels above 30 ng/ml normal, levels between 20 and 30 as “vitamin D insufficiency”, and levels below 20 “vitamin D deficiency”.  They have some data that supports their conclusion involving hormonal markers of osteoporosis improving until vitamin D levels climb to 30 ng/ml.  By this more strict definition, many more people have low vitamin D levels (as many of my patients know) and to reach this higher level of 30 ng/ml 600 IU is frequently inadequate.

Risks of vitamin D

What happens if you take too much vitamin D?  Again, many of the reported risks are as unfounded as the reported benefits.  There are loose associations with all sorts of possible diseases, but none of these are from randomized trials, so they should be ignored.  The known risks of vitamin D toxicity all relate to causing abnormally high calcium levels and include kidney stones and decreased kidney function.

How much vitamin D is too much?

The simplest way to answer that question is to have your vitamin D level checked.  The risks listed above occur with vitamin D levels above 80 ng/ml.  Levels that high are very hard to reach with 2,000 IU of vitamin D daily.

So the take-home message is that there is no reason to believe that vitamin D will prevent cancer, make you famous, or lower interest rates.  It will keep your bones healthy and decrease your likelihood of falling when you’re older than 60.  The most accurate way to assess whether you are deficient and how much vitamin D you should take is to have your doctor check your vitamin D level.  Daily supplementation with 1,000 to 2,000 IU daily is unlikely to be harmful.

Learn more:

Institute of Medicine report:  Dietary Reference Intakes for Calcium and Vitamin D

Wall Street Journal article:  Triple That Vitamin D Intake, Panel Prescribes

MSNBC article:  How much vitamin D is enough? Report sets new levels

New York Times article:  Report Questions Need for 2 Diet Supplements

The best recent review I’ve seen in the medical literature about vitamin D deficiency is a New England Journal of Medicine article from 2007:  Vitamin D Deficiency

Tangential miscellany: Happy Hanukkah!

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