Got cold. Try zinc?

Having a cold is no fun.  Sore throat, runny nose, general feeling of all-around blechiness.  About the only good thing I can say about colds is that they don't last long, usually about a week.

We still don't have a cure for the common cold, but it's not for lack of trying.  For decades, Nobel laureate Linus Pauling promoted mega-doses of vitamin C as a way to prevent colds, but he turned out to be wrong on that one.  Somewhere in the neighborhood of 200 different viruses cause us to get colds, and we don't seem to be able to get rid of any of them.

In recent years, the most popular new remedy is zinc, usually in the form of a lozenge.  The evidence for zinc's effectiveness is not entirely clear, but a review published just last month, which looked at 13 different studies, concluded that zinc seems to help, just a little bit.  All 13 studies were randomized controlled trials, the gold standard of research, and collectively they included 966 people.

That sounds encouraging, but the benefit was disappointingly small: zinc seemed to shorten the duration of a cold by about one day.  So instead of being sick for 7 days, you might be sick for 6 days.

Or maybe not: Dr. Terence Davidson from UC San Diego argues that if you look at just the more rigorous studies, the effect vanishes entirely.

Chunks of elemental zinc

Then there are the worrisome reports that Zicam, a zinc-based cold remedy, causes people to lose their sense of smell.  (This may not sound so terrible, but some people reported a permanent loss.  Imagine never being able to smell fresh-baked bread again.)  In 2009, these reports led the FDA to issue a warning advising consumers to stop using three particular Zicam products.  In addition to over 130 reports directly to the FDA, Zicam's manufacturer had over 800 additional complaints about loss of sense of smell.

In an ironic twist, Zicam markets its products as homeopathic remedies, which means that the FDA cannot regulate them. It also means that they shouldn't contain any active ingredients, because homeopathic preparations are diluted until they contain nothing at all.  But Zicam does contain zinc, quite a lot of it, and the FDA's warning letter demanded that Zicam stop marketing these products because they had never demonstrated that they were safe and effective.

Zicam markets a wide range of zinc-containing products, and the FDA's warning only affected three of them.  Zicam's website today states that "there is no valid, scientific evidence showing a link between Zicam and anosmia [loss of sense of smell]."  Strictly speaking, this is correct, but there have been published reports suggesting a link, such as this one from 2006 and this one from 2009.  These studies looked at nasal sprays, not lozenges, suggesting that the risk (if any) comes from spraying the zinc product directly up your nose.

Aside: Zicam also claims that their products cure allergies too, for which there is not a shred of evidence.  Their website makes the sweeping claim that "all Zicam products are both effective and safe when taken as directed." I see no reason to trust these guys.

Conclusion: I'm not taking zinc.  The side effects might be minimal, but the benefit is very small and possibly zero.  I'll stick with hot tea, which at least makes my throat feel better.  Or chicken soup.  That can cure almost anything.

Evolution bugs me

Cover illustration for the forthcoming textbook
by Carl Zimmer and Douglas Emlen

This is a real photo.  It's the cover for a new biology textbook by Carl Zimmer and Douglas Emlen.  The photo shows three "walking leaves," or leaf insects, which have evolved to look just like the leaves around them.

These little bugs must be one of the best examples of natural selection ever.  The more closely they resemble a leaf, the more difficult it is for predators to find them.  Over the millenia, the bugs who evaded predators survived better, and eventually walking leaves looked like they do today.

In fact, these guys have been around for a long time, at least 47 million years, according to a fossil discovery published in 2006.  That paper described a fossilized leaf insect found in an ancient lake bed in Germany, which looks remarkably similar to its modern descendants.

Yes despite this amazing evidence, only 40% of Americans believe in evolution. State legislatures continue to pass bills attempting to teach children the creation myth that the world was created less than 10,000 years ago.  Just last week, a committee in Alabama's legislature proposed a new law that would give students credit for courses on creationism.  The bill's sponsor, local legislator Blaine Galliher, was very clear about his motivation:

"They teach evolution in the textbooks, but they don't teach a creation theory…. Creation has just as much right to be taught in the school system as evolution does." 

I feel sorry for the students in Alabama whose education might suffer thanks to the ignorance of their lawmakers.  But there is some hope: in the national poll showing that 40% of Americans overall accept evolution, among young adults that percentage was 49%, while among over-55 set it was just 31%, as shown in this graph:

So perhaps in another hundred years or so, Americans will start to "get" evolution.  But it might take longer: apparently 18% of Americans still believe that the sun revolves around the earth.  So it's taken us 500 years to get to 80% for that one.

Should a doctor fire an anti-vax patient?

The anti-vaccination movement continues to grow, despite the retraction and thorough discrediting of the 1998 scientific study that spurred much of its growth.  The stubborn persistence of anti-vaxxers shows how difficult it is to dispel misinformation once that information is out there, even after dozens of new studies and millions of dollars in research that demonstrate that vaccines are safe.

One of the most dangerous trends is the growing number of parents who refuse to vaccinate their kids, or who choose "alternative" vaccine schedules, such as the one promoted aggressively by Robert Sears (who goes by "Dr. Bob").  Sears appears to have simply invented this alternative schedule without bothering to conduct any scientific studies, in part to promote sales of his 2007 book, The Vaccine Book: Making the Right Decision for Your Child.  Vaccine expert Dr. Paul Offit explained, in a 2009 article in the journal Pediatrics, why Dr. Sears' schedule was a very poor choice for children and for the public health.  After thoroughly dismantling Sears' anti-science positions, Offit concludes, "Sears has a poor grasp of the scientific method."  That's an understatement.

Other doctors, perhaps jealous of all the attention that Sears has gained through his anti-vaccine writings and television appearances, have created their own alternative vaccine schedules.  One of them, Donald Miller, even goes so far as to say that vaccines cause childhood cancer, despite the complete lack of evidence for this wild claim.  Somehow Sears, Miller, and others like them have managed to convince many parents that their children don't need vaccines.

In response to parents who don't want to vaccinate, many of whom show up with Dr. Bob's schedule in hand, pediatricians have struggled to find an effective response.  Parents can be utterly convinced by the misinformation they find on the Internet, which is all too easy to find.  (For example, Googling "vaccine" brings up the National Vaccine Information Center, a hotbed of anti-vaccine propaganda and pseudoscience, on the first page of hits.)  By the time parents arrive with their babies for the first vaccine, convincing them to change their minds can be nearly impossible.

Perhaps in frustration, doctors have started to "fire" their patients if they refuse to vaccinate.  As reported by Shirley Wang in The Wall St. Journal last week, 20-30% of doctors in two different surveys, in Connecticut and the Midwest, reported having to kick patients out of their practices because of vaccine refusal.  These numbers have roughly doubled over the past ten years, according to the American Academy of Pediatrics.

Is firing a patient the right thing to do? It's a difficult question.  On the one hand, doctors should do everything they can to make sure kids are vaccinated.   If a doctor kicks a parent out, that parent may find another doctor who doesn't insist on vaccinating children, which ultimately harms the children.  Doctors have to spend more time educating parents about the tremendous benefit of vaccines, about the very strong evidence (based on tens of millions of doses) for vaccine safety, and about the frightening consequences of infection with meningitis, hepatitis, measles, polio, and other vaccine-preventable diseases.

On the other hand, unvaccinated children bring diseases into the pediatrician's office, where they can spread them to other children.  Some of these other children are too young to be vaccinated, and childhood infections can be extremely dangerous, even fatal, in the very young.  From this perspective, "firing" a patient might be the only responsible action, after first trying to convince the parents to vaccinate.  I know that I wouldn't want to bring my child to a doctor's office where unvaccinated children were in the same room.

I understand how nervous a parent can be about vaccinations.  I will never forget the day my older daughter got her first vaccine: the needle looked huge compared to her tiny leg, and she screamed when the doctor gave her the shot.  But she was fine a few minutes later, and she'll be protected against a dangerous infection for her entire life.  Vaccines have been so successful at eliminating childhood infections that parents no longer see these infections as a threat.  Ironically, the very success of vaccines has allowed the anti-vaccine movement to sway so many people.

Doctors may have to keep firing the parents of their young patients, but I hope they'll first make every effort to educate them.  They need to explain that vaccines do not cause autism, nor do the ingredients in vaccines, and that scientific studies involving hundreds of thousands of patients support these conclusions.  They should also explain that many of the anti-vaccination claims on the Internet started when Andrew Wakefield published one small study of 12 patients, now retracted, claiming a link between the MMR vaccine and autism.  Investigations later revealed that he was paid by lawyers to recruit patients for a lawsuit against vaccine makers, that he didn't reveal these payments to his co-authors or the patients, and that he manipulated the data.  Since then, the anti-vaccine movement has exploded and we've experienced multiple outbreaks of measles, mumps, and other illnesses linked directly to unvaccinated children.

Doctors interviewed by the Wall St. Journal reported that they had convinced at least some parents to follow the recommended vaccine schedule.  Perhaps that's the best we can hope for.  If we're going to avoid a return to the era when children routinely died from infections, we must keep trying.

An Alzheimer's disease breakthrough?

We all hope to get old one day.  But if we do, our chances of getting Alzheimer's disease increase dramatically as we move into our 80s.  As many as 50% of people over age 85 may be affected.  Much progress has been made in understanding the disease, which appears to be caused by "plaques" forming in the brain, but we have no treatment and no cure.

But maybe - just possibly - a dramatic new study offers the first real hope for a treatment.  In a paper published today in the journal Science, a team of researchers led by Gary Landreth at Case Western University and his graduate student Paige Cramer found that an orphan drug called bexarotene has a remarkable affect on mice afflicted with a condition similar to Alzheimer's in humans.  These mice have similar plaques in their brains, compose of beta-amyloid proteins, and they show behavioral and cognitive impairment similar to some of the problems experienced by Alzheimer's patients.

Within just hours of administering bexarotene to these mice, the plaques started to clear.  If that weren't amazing enough, within a few days the mice also recovered cognitive abilities that they had lost.  In particular, they regained the ability to make nests, a behavior that normal mice have and that the Alzheimer's mice had lost.  They also regained at least some of their sense of smell.

Bexarotene (Targretin^TM) is an orphan drug that is approved for use in humans to treat cutaneous T-cell lymphoma, a rare skin cancer.  It works by inhibiting a gene, RXR, that is involved in the production of beta-amyloid proteins.  Cramer, Landreth, and colleagues hypothesized that because bexarotene can cross the blood-brain barrier, it might just help to clear out the plaques associated with Alzheimer's.  It seems that they may be right.

A huge caveat here is that many promising drugs seem to work in mice but fail when used in humans.  This drug is different, at least in the sense that it is already approved for human use, but no one has tested it on Alzheimer's patients.  Studies are likely to begin very very soon, but it will take time - possibly years - before we know if it can slow the progress of Alzheimer's.  But for a disease that affects a huge percentage of the population, with no current treatment, this could be a huge breakthrough.

Indiana's clumsy attempt at theocracy

An edible FSM

Those state legislators are meddling with science again.  This time it's Indiana, trying to promote their religious views in public schools by dictating what science teachers will teach.  As usual when legislators try to do science, they messed up badly.

What happened?  Just a few days ago, the Indiana state Senate passed a bill, sponsored by Republican Dennis Kruse, that required the teaching of creationism.  Actually, the original bill called for schools to teach "creation science," but then the Senate amended it to make it much funnier.  Thanks Indiana!

The amended bill, which was approved 28-22, says:

"The governing body of a school corporation may offer instruction on various theories of the origin of life. The curriculum for the course must include theories from multiple religions, which may include, but is not limited to, Christianity, Judaism, Islam, Hinduism, Buddhism, and Scientology."

Holy cow!  I can't wait to see what Indiana students will be spouting when they go on to college.  Maybe they'll learn Scientology, which is one of the religions listed in the new law.  Scientologists believe that life on Earth started 75 million years ago, when an evil galactic warlord named Xenu brought 13.5 trillion of his people to Earth in a spaceship, stacked them around volcanoes, and vaporized most of them with hydrogen bombs.  (No, I'm not making this up.)

If I were teaching in Indiana schools, I'd be sure to cover the Church of the Flying Spaghetti Monster, which has a wonderful theory about the origin of life:

"We believe the Flying Spaghetti Monster created the world much as it exists today, but for reasons unknown made it appear that the universe is billions of years old (instead of thousands) and that life evolved into its current state (rather than created in its current form). Every time a researcher carries out an experiment that appears to confirm one of these “scientific theories” supporting an old earth and evolution we can be sure that the FSM is there, modifying the data with his Noodly Appendage. We don’t know why He does this but we believe He does, that is our Faith."

Now that's a theory you can sink your teeth into.

Finally, a little bit of science education for Indiana's legislators.  The next time you write a law trying to force the teaching of creationism instead of evolution, get the wording right.  You see, you wrote the bill incorrectly, because evolution is not a theory of the origin of life, as any good high school science teacher could have told you.  (Note to Indiana teachers: I've no doubt that you tried to teach these legislators back when they were in school. Apparently they're still not listening.)  Instead, evolution is a theory that explains how species arise: how a single species can evolve into many, through the process of natural selection.  You might have guessed this from the title of Darwin's book: The Origin of Species.  Scientists do have theories about the origin of life, but evolution isn't one of them.

Two years ago, South Dakota's legislature declared that astrology can explain global warming, which gave the rest of the country a bit of entertainment. Last week, it was Indiana's turn to look foolish.  After a huge flurry of embarrassing publicity, it appears that Indiana's legislature has changed its mind, and the bill will not become law.  But if they try again, I'd be happy to send them some materials on the Flying Spaghetti Monster.

[Note: I also recommend the blog posts by PZ Myers at Pharyngula and Jen McCreight at BlagHag.]

Embryonic stem cells: can we really restore vision to the blind?

Restoring sight to the blind is, literally, a miracle.  For centuries, men have told stories of miracles in which a blind person suddenly was able to see again.

In modern times, there have been cases of vision restored thanks to corneal transplants and cataract surgery.  These are amazing treatments themselves, and they have become almost routine in the developed world.  But when the cells inside the eye are damaged, there is nothing we can do.

Until now.  In an amazing advance, scientists at Advanced Cell Technology reported this week in The Lancet that they used embryonic stem cells to restore partial vision to 2 patients who were legally blind.  One patient had macular degeneration, a very common but incurable eye disease, and the second had Stargardt disease.  Both diseases are progressive and usually lead to blindness.

Both diseases also affect internal eye cells known as retinal pigment epithelium (RPE) cells.  The research team, led by Robert Lanza, took human embryonic stem cells and coaxed them into becoming RPE cells.  They tested the RPE cells extensively for any signs of contamination by viruses or bacteria, and once they confirmed that the cell cultures were pure, they injected them into the eyes of these first two patients.  (Earlier studies were done in mice and rats before trying the therapy on humans.)

After four months, both patients showed improvements in vision.  This is an amazing result for macular degeneration, which has been, until now, irreversible.  The cells appeared to "take" in both patients, attaching to other cells in the eye and replacing damaged areas.  As Rob Stein and David Brown reported in the Washington Post

"One of them no longer needs a large magnifying glass to read and can reportedly thread a needle. The other has begun to go shopping on her own."

According to the study, neither patient has shown any signs of rejecting the cells.

The Lancet study, which you can read here, was funded entirely by private funds due to U.S. government restrictions on embryonic stem cell research.

This is only an early result from a very small study, but coming on the heels of reports just a few months ago, in which adult stem cells restored heart function to patients with advanced heart failure, the promise of stem cells again got just a bit brighter.

So yes, maybe we really can make the blind see again.

A surprising triumph in the fight against polio

Source: polioeradication.org

The last case of polio in India occurred exactly one year ago, on January 13, 2011.  In the decades-long battle against this devastating disease, this is one of the best pieces of news in a long time.  Just two years ago, health officials counted 741 polio infections in India, and it seemed that the battle was far from over.  It may yet be, but in 2010 the cases dropped dramatically, to just 42, and last year there was only one, on January 13.


As recently as the 1950s, polio was a dreaded, incurable disease that killed or paralyzed millions of children each year.  The U.S. alone had 58,000 cases in 1952. Then came the invention of a vaccine by Jonas Salk, one of the great medical breakthroughs of the 20th century.  By the 1960s, widespread vaccination campaigns had virtually eliminated polio from Europe and the U.S.  Polio lingered in the U.S., mainly in the Amish population who refused to accept vaccinations, but it finally disappeared in 1979.

The worldwide campaign to eliminate polio started in 1988, when 350,000 infections were recorded.  Polio is extremely difficult to control, because a large majority of infected people show no symptoms, but they can still spread the virus.  Vaccination campaigns need to treat everyone who comes in contact with an infected individual in order to break the cycle of transmission.  This is especially hard to do in remote areas of poor countries, especially when the populace is suspicious and uncooperative.

The greatest challenge in India came in the desperately poor, crowded regions of the north, where health care, hygiene, and education are all very poor.  The vaccination efforts were made even more difficult by conspiracy theories among the Muslim population.  As Simon Denyer wrote in the Washington Post this week:

"Rumors spread among the region's numerous Muslims that the polio vaccination campaign was an American conspiracy to wipe them out, by making their sons impotent and their daughters infertile.... Vaccinators were stoned as they approached Muslim neighborhoods. 'The general mind-set was that the immunization campaign was aimed at ending our lineage,' said Anwar Ahmad, the head of a madrassa in a Muslim neighborhood in the city of Meerut."

The campaign turned around after UNICEF and Rotary international launched a major education effort that first convinced Muslim leaders, and then everyone else, that the vaccine would benefit their communities.  With this success in India, polio is now endemic in only three countries in the world: Afghanistan, Pakistan, and Nigeria.  The same rumors and conspiracy theories that plagued India have spread within Muslim populations in these countries as well, but India shows that the misinformation - and polio - can be defeated.

Unfortunately, even here in the U.S. we have our own conspiracy theorists: the anti-vaccination zealots over at Age of Autism, where Dan Olmsted and Mark Blaxill recently posted a series of articles claiming that polio is "a harmless intestinal bug" that only causes disease when triggered by pesticides or by arsenic.  Never mind that there is no evidence to back this truly wacky assertion; these two anti-vaxxers seem happy to invent facts to support their single-minded campaign against all vaccines, even when the vaccines are demonstrably saving tens of thousands of lives.

Polio is still with us, and it could return.  Besides the 3 countries with endemic polio, 9 other countries continue to suffer polio cases that were imported from endemic countries.  Without widespread vaccination in those countries, polio could re-establish itself in any of them.

If polio stays out of India, we can thank the thousands of health care workers who traveled to remote villages, in extremely difficult conditions, to dispense lifesaving vaccines.  Their heroic efforts have paid off for everyone.  We should also thank the combined efforts of the WHO, UNICEF, Rotary International, the Gates Foundation, and the CDC, all of whom are backing the worldwide effort to eradicate polio.  Let's root for humanity to win this one.