A Spray Tan That Really Gives You a Tan

It turns out redheads held the secret of how tanning works.

As any redhead will tell you – they don’t tan in the sun, they just burn. Understanding why turned out to be the key to producing a new compound that really gets your skin to tan – even if you’re a redhead.

Tanning happens when a skin receptor called melanocytes responds to signals to create more melanin in your skin, in response to increased UV exposure. By studying the redhead equivalent of mice, researchers at Massachusetts General Hospital in Boston realized their melanocytes do not respond to these signals – and it’s due to how melanocytes are encoded in the redhead version of the gene MC1R.

Further research revealed that a protein called salt-inducible kinase (SIK) is what acts as the “off switch” for melanin production in redheads. All that was left to do was order up a molecule known to inhibit SIK, apply it in liquid form on a redheaded mouse, and see what happens. Sure enough, the mouse’s skin turned almost jet black in response!

They proceeded to try it on a patch of human skin, which turned a nice shade of brown.

This isn’t just a cosmetic breakthrough – unlike today’s spray tans, this gives you a real tan – one that can help protect you against UV radiation and offer up some resistance to skin cancer. And if it keeps some people out of tanning booths, that too will reduce skin cancer.

It has yet to go through clinical trials, so you probably won’t see this on the shelves anytime soon. But it’s a really great story of an interesting breakthrough, and one that can make redheads around the world proud!

Image credit: iStock.com/kzenon

Even Moderate Alcohol Consumption Causes Brain Damage (or does it?)

Even one or two drinks a day can cause brain damage to your hippocampus, according to a recent study in the British Medical Journal. But, how much faith should we put into these findings?

I’ve pointed out the flaws in studies that try to link benefits to supposedly bad behavior, such as the study that says eating cheese is good for you, or that chocolate is good for your heart. The former was funded by cheese and dairy industry groups, and the latter was not a controlled study that had lots of statistical limitations. We should subject this paper to the same scrutiny – and not just because it’s a message we don’t want to hear.

The BMJ is the same journal that published that “chocolate is good for your heart” study, and upon closer examination you’ll find that this one has many of the same caveats.

The study involved 550 Londoners who filled out surveys about their drinking habits and had an MRI every 5 years for 30 years. The paper concludes that one drink per week is associated with a 0.01 percent decline in the size of your hippocampus, which is associated with memory and navigation.

You don’t need to be a statistician to see the problems here:

  • This study reports only on correlation; it is not a double-blind experiment and so we can say nothing about causation.
  • 550 people, all of whom are part of the same social group and in London, probably aren’t representative of all humans to begin with.
  • 0.01% is a very small change to detect, especially given this sample size. For comparison, your hippocampus shrinks 0.02% per year on its own, just due to aging.
  • There is the potential of selection bias, as participants in the study had to have the means and willingness to travel to Oxford from London to undergo these periodic tests.
  • Here’s the real kicker – for some reason, this change was only statistically significant for the right hemisphere of the hippocampus. It makes no sense that alcohol would affect it in such a selective manner. What would make more sense is that the arbitrary threshold chosen for “significance” just happened to be right on the cusp of the results for the right hemisphere observations – but “statistical significance” does not mean the effect is real!

In fact, a different way to report on this study is “having 8-12 drinks per week actually isn’t that bad for your brain.” If there is an effect, it’s barely detectable. That’s a more honest way to report these results. But it’s also true that claims of moderate drinking being beneficial are also probably sketchy.

To be fair, the authors are quite up front and transparent about these caveats, as they were in the chocolate study. But not all press coverage really presented these findings in their full context.

Hang on while I get a beer.

Image credit: iStock.com / Ezhukov

Is Chocolate Really Good for your Heart? Well, Maybe.

The British Medical Journal published a new study that claims eating chocolate can reduce your risk for irregular heart rhythms. You can expect to see a bunch of hype on the Internet today about how chocolate is good for you! So, is it time to have chocolate bars for dinner? Hold on a minute.

The quality of science in the medical field is a bit of a pet peeve of mine. It’s not entirely the fault of the scientists; I mean, a real controlled experiment that involves life or death can be tricky to say the least. ¬†But there are real problems:

  • Lying with statistics – experiments often suffer from small sample sizes, or are not controlled. If it’s not a double-blind study, or it’s not a study with a large number of participants, the results must be taken with a grain of salt. All too often, the media reports on studies published from journals that don’t have high standards for experimental design.
  • Funding bias / conflict of interests – all too often, a sensational scientific claim turns out to be funded by an organization that stands to benefit from it. A recent study about how cheese isn’t bad for you made the rounds on the Internet, but it was funded by the Global Dairy Platform and the Dairy Research Institute.
  • The reproducibility crisis or replication crisis – over half of published studies cannot be replicated, and in some fields it’s much higher.
  • Publication bias – researchers publish because they want tenure, and have a bias to only publish successful experiments as a result. We never hear about negative results.

These are huge issues that threaten the credibility of science as a whole. So what’s a person to do when faced with a claim like “chocolate’s good for your heart?”

Well, it’s on us to apply critical thinking and dig into the details. Let’s ask a few questions about this study:

Are they lying with statistics? This paper claims a 10% risk reduction in people who eat chocolate. 10% isn’t that big of a number, so I’d expect to see a large sample size (how many people were studied) before taking that seriously. Turns out this study had 55,000 participants, so a 10% difference does seem significant. You don’t need a degree in statistics to understand this – even if you rigorously measure statistical confidence, in the end it’s still a judgment call – statistics can only say how likely a measured effect is to be real; it never says it’s real conclusively.

Is there a conflict of interests? In this case, no. This study wasn’t funded by anyone who stands to benefit from increased sales of chocolate. This test also checks out on this study.

Has it been reproduced? No, but that’s not unusual for new research. However, if you really plan on increasing your chocolate consumption as a result of this study, it would be prudent to wait a few months and see if anyone has attempted to reproduce these findings (or proven unable to do so.) If I were a betting man, I’d say it won’t happen. Thanks to publication bias, it may take quite a bit of digging to find these results on your own.

Was it a controlled experiment? No, and the authors of the paper freely admit this. It was not a “double-blind” study; it merely looked for correlations between people who ate chocolate and those who didn’t with irregular heart rhythms. Correlation does not imply causality – there may have been some other underlying difference between these two groups that occurred randomly. Or perhaps there is some connection between eating chocolate and the real cause of the difference – perhaps chocolate-eaters are more likely to be physically active, in an effort to burn off that extra fat. This is the main issue with this particular study, and why you should take it with a huge grain of salt. Salted chocolate, as it were.

In the end, I wouldn’t call this particular study “bad science,” but its results should be taken with a good helping of skepticism¬†– and the study’s authors admit as much, which good scientists should do. It’s not a controlled experiment, the results aren’t overly dramatic, and it hasn’t been reproduced yet.

Still, a chocolate bar sounds pretty good right now.

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