Tag Archives: health

teeth: miracle or weakness of evolution?

I’ve always thought that teeth might be the weakest point of the human body. Why did our teeth evolve to be made of calcium, which dissolves in acid, when pretty much all our food is acidic? Why do we have to strap metal torture devices to children’s teeth for years just for them to be reasonably straight? Why don’t animals seem to have these problems?

This article in Scientific American sings the praises of teeth. It argues that, like many of our other organs and systems, our modern lives just aren’t what they evolved to deal with. It basically comes down to the idea that our food is too sweet and too soft.

The evolutionary history of our teeth explains not only why they are so strong but also why they fall short today. The basic idea is that structures evolve to operate within a specific range of environmental conditions, which in the case of our teeth include the chemicals and bacteria in the mouth, as well as strain and abrasion. It follows that changes to the oral environment can catch our teeth off guard. Such is the case with our modern diets, which are unlike any in the history of life on our planet. The resulting mismatch between our biology and our behavior explains the dental caries (cavities), impacted wisdom teeth and other orthodontic problems that afflict us.

Scientific American

I admit, I don’t like working for my food – I like boneless, seedless, shell-less everything. My teeth may have paid the price.

the goal of social distancing

Vox has an informative article with some visuals on the goal of social distancing in an epidemic. If you can reduce the total number of infections that is a bonus, but the primary goal is to reduce the peak number of infections happening at any one time. You can do this by delaying cases and spreading them out of time, so that the capacity of the health care system is better able to deal with them. This looks very similar to a stormwater or flood control engineer – often, our goal is also to reduce and delay the peak. Reducing the volume is a bonus if you can manage it. The lesson is not that epidemics are like hydrology, it’s that there are certain fundamental system structures that lead to fundamental behaviors, and they are shared between systems. A couple more that come to mind along the lines of this basic model are congestion pricing to spread traffic out over time, and batteries to store solar and wind energy and trickle them back over time.

the Flynn effect and the reverse Flynn effect

When IQ tests are taken by each generation, they are always normalized so that the average is a score of 100. However, when people are asked to take tests from older generations, they tend to do better than the older generations did. This is the Flynn effect. It was very consistent throughout the second half of the 20th century and into the 21st, but a number of studies in Scandinavia indicate that it may have reversed more recently. Immigration is one controversial explanation that has been suggested, whether due to genetic or cultural reasons. But the study I link to here tested the effect within families against the effect across unrelated people, and found that it is just as strong within families. This suggests environmental factors such as education and nutrition as the culprits, although the article does still put “migration” in this category. I suppose if you had a society with a high quality of nutrition and education, and you then have an influx of new people with more bad habits (let’s say, a high rate of smoking), that could have an effect.

the stats on Bernie Sanders’s health risks

Slate has an interesting article on health risks for someone Bernie Sanders’s age with Bernie Sanders’s known health condition. The author points out that these estimates can be done for Bernie because he has released a fair amount of health information (although still not everything the author would like), while the other older candidates have not.

  • His 12-month risk of a heart attack, stroke, or death is about 6%.
  • His risk of being hospitalized for any reason between now and November is about 30-35%.
  • His odds of surviving a first presidential term are about 65%, and his odds of surviving a second about 40%.

the “best” health advice from 2019

The Week has cherry picked a few studies from 2019 as best. Although they did pick ones with large sample sizes, what would be “best” to me would be some kind of meta-analysis of all studies published and what they said on balance, with some kind of grading for quality and communication of the uncertainty involved. That would be awesome journalism, but I imagine it would be expensive. The great news is that if you add up all the percentages that doing this and that can reduce your chances of death, you can live forever! Anyway, here is my quick summary:

  • Exercise, fruits, vegetables, and whole grains just never go out of style. More whole foods (the thing, not the chain) and less processed foods in general seem to be a very good idea. Seriously, just orient your life style around these things and it is very unlikely the scientific consensus will change some day and tell you it was a bad idea.
  • Napping is good for you – this particular study says “five minutes to an hour once or twice a week”. I’m not surprised that rest is good for the heart, but I thought there was an emerging consensus that maintaining a consistent schedule on all days was good, and this seems to contradict that a bit.
  • Parents are stressed out while kids are young, then ultimately glad they had the kids later in life. This doesn’t surprise me since I am living through the stressed out part, but I do find it helpful to put myself in my future self’s shoes and ask if I would regret having children. In fact, my wife and I did that when we made the decision to have children, and the answer was and is no, we have no regrets. The distinction between happiness in the moment and overall life satisfaction also comes to mind.
  • Aspirin and ibuprofen seem to help your heart, but also raise your risk of internal bleeding. It’s probably best not to self-medicate.
  • Smoking and getting hit on the head, even gently, are not good for you.

sleep optimization

This article is about devices that can supposedly help you get more out of whatever hours of sleep you manage to get. It sound suspicious, but appears to be backed by at least some research and scientific/medical opinion.

One of the most promising techniques to do so works a bit like a metronome counting the brain into the correct rhythms. Experimental participants wear a headset that records their brain activity and notes when they have started to make those slow waves. The device then plays short pulses of gentle sound, beginning in sync with the brain’s natural slow waves, at regular intervals over the night. The sounds are quiet enough to avoid waking the participant, but loud enough to be registered, unconsciously, by the brain.

BBC

One of the devices commercially available is made by Phillips and costs around $370 (I do not get any sort of commission if you click on this link or buy one.)

bacteria, viruses, and fungi, oh my!

In the category of new diseases to worry about, and just in case you have not yet perused the latest issue of the Journal of Fungi, Candida auris is a really dangerous yeast fungus making the rounds in hospitals.

On the Origins of a Species: What Might Explain the Rise of Candida auris?

Candida auris is an emerging multidrug-resistant yeast first described in 2009 that has since caused healthcare-associated outbreaks of severe human infections around the world. In some hospitals, it has become a leading cause of invasive candidiasis. C. auris is markedly different from most other pathogenic Candida species in its genetics, antifungal resistance, and ability to spread between patients. The reasons why this fungus began spreading widely in the last decade remain a mystery. We examine available data on C. auris and related species, including genomic epidemiology, phenotypic characteristics, and sites of detection, to put forth hypotheses on its possible origins. C. auris has not been detected in the natural environment; related species have been detected in in plants, insects, and aquatic environments, as well as from human body sites. It can tolerate hypersaline environments and higher temperatures than most Candida species. We explore hypotheses about the pre-emergence niche of C. auris, whether in the environmental or human microbiome, and speculate on factors that might have led to its spread, including the possible roles of healthcare, antifungal use, and environmental changes, including human activities that might have expanded its presence in the environment or caused increased human contact.