2016 has just begun but it has already been a fantastic week for science news. Researchers have discovered an ancient stomach bug in the remains of Otzi the Iceman, the creators of the popular “brain training” Lumosity were fined $2 million for unsubstantiated claims, and doubts have been cast on the old adage that you are composed of a 10:1 ratio of bacteria to, well, you. Those three stories and more are described further below, along with links to some of my favorite science reads from around the web last week.
Challenging the Over-quoted Statistic
Microbiologists love quoting the statistic that the bacterial cells in and on our bodies outnumber our own cells 10 to 1…and I am certainly guilty of using this factoid to initiate more than one conversation about the microbiome with a friend.
The old 10:1 estimate is what scientists would call an “order of magnitude” difference. The new study suggests that the ratio is within the same order of magnitude, more along the lines of 1.3 bacteria per every human cell. The authors conclude that “the numbers are similar enough that each defecation event may flip the ratio to favor human cells over bacteria.” (Yes,it was hard to quote that with a straight face.) This possibility is easily explained since the highest concentration of bacteria (1011/ml) and largest number of bacteria (1014) are located in the colon of the large intestine, the final stop along the digestive track before the rectum.
The new numbers are still estimates. One important factor that the authors recognize is human variability. Their paper uses the “average man,” coming in at 170 cm in height, 70 kg in weight, and 20-30 years of age, as the baseline. Of course, the numbers would be expected to change based on sex and body size, but the authors say that “the paper conclusions are relevant for the general human population” because these differences would be accounted for within the uncertainty of their estimates.
Another important distinction comes from estimating the numbers of bacteria compared to the microbiome, which consists of all microscopic organisms including bacteria but also fungi, archaea, single-celled eukaryotes, and viruses (we’ll let the technicalities of whether a virus is an organism or not slide for this one). The current study only counted bacteria, so the ratio of of non-human cells to human cells would still be larger.
And just because there are not quite as many bacteria in the human body as once thought doesn’t mean they are any less important. The explosion of research on the microbiome, and its effects on human health and disease motivated the researchers to find a more accurate statistic for what has become an uncontested fact. And since such statistics can be difficult to estimate, we can expect follow-up work to this study in the future.
Four “New” Elements Fill in the Periodic Table
The existence of four new elements has official been verified according to the International Union of Pure and Applied Chemistry. The elements with atomic numbers 113, 115, 117, and 118 have had placeholder names on the periodic table for years, but can now be given official names by their discoverers. All elements numbered 1 through 118 have now been described, but scientists hope to create conditions possible to observe elements 119 and 120, which would add a new row to the table. Elements with an atomic number 121 or higher may be too unstable to exist.
Lumosity “Brain Training” Asked to Pay Up
70 million people have used Lumosity’s “brain training” games which are allegedly backed by neuroscience to help stave off age-related cognitive impairments. At $15 a month, or $300 for a lifetime subscription, you can do the math to see that Lumosity is no small business. But this week the Federal Trade Commission charged Lumos Labs, the creator of Lumosity, a $2 million fine for deceiving customers with unfounded claims.
The creators of Lumosity say the game can improve everyday cognitive performance, including tasks relevant for work, school, and sports. Perhaps even more controversially, they say that their game helps protect against age-related memory loss, including Alzhiemer’s, and can reduce impairments of health conditions including PTSD, ADHD, and stroke.
The FTC actually fined Lumos Labs $50 million, but this judgment was suspended due to their “financial condition.” Lumos Labs will be required to notify subscribers on an automatic renewal plan about the FTC’s actions and provide a way for subscribers to cancel their auto-renewal. Lumos Labs still stands by its product and scientific claims however, saying that the problem was one of the marketing language rather than actual results.
US Nutrition Guidelines Updated
Every five years the federal government issues new health recommendations, and the latest installment was released last week. As expected, Americans are urged to eat more vegetables and consume less sodium. Noteworthy changes include an emphasis that the cholesterol in eggs should not be as big of a worry as it is often made out to be, and a shift in protein consumption for males. The report says, “Some individuals, especially teen boys and adult men, also need to reduce overall intake of protein foods by decreasing intakes of meats, poultry, and eggs and increasing amounts of vegetables or other underconsumed food groups.”
5,300 Year-Old Stomach Bug
How would you like to have the “stomach bug” for 5,300 years?
That seems to have been the fate of Otzi the “Iceman” who was murdered with an arrow to the back 5,300 years ago in the Tyrolean Alps of Italy. Otzi remained buried in the ice and snow until some hikers stumbled across his body in 1991, and scientists have been studying him ever since. But recently they noticed something they had missed before: his stomach.
Otzi the Iceman was discovered in 1991, but scientists are still gleaning new discoveries from his body 24 years later. Image Credit: Wikipedia Commons
After extracting bits of ancient stomach and its contents, which has since degraded into a sand-like substance, the researchers found a treasure trove of DNA belonging to Heliobacter pylori. The bacteria H. pylori is most famously known for causing stomach ulcers, although there is some evidence that H. pylori may not be all bad. The bacteria is found in many people’s stomachs with no ill effects, and may even reduce the risk of some immune disorders including asthma.
Otzi’s H. pylori didn’t look like modern European H. pylori however. The DNA more closely resembled that of the Asian H. pylori strain. The modern European H. pylori is thought to be a blend between the Asian and African strains. These details could provide insights into human migration, since it seems to imply that the African H. pylori strain had not yet reached Europe around 5,300 years ago.
Some scientists have been critical of the extrapolation of the story to human migration though, saying that a lot more 5,300 year-old stomachs would need to be examined to reach those conclusions. But regardless of what Otzi can tell us about human migration, the signs of inflammation in his stomach led researchers to believe that just like some of us today, Otzi was suffering from H. pylori-related ailments.
Great Reads from around the Web:
- Vox has put together a great article called “The hidden drugs in your favorite supplements,” describing the dangers of the unregulated and renegade components of hundreds of dietary supplements. They’ve even included an interactive and searchable table describing illegal drug components in 851 supplements.
- Christie Aschwanden’s article “You Can’t Trust What You Read About Nutrition” published on FiveThirtyEight last week is a great dive into the spurious statistics so often associated with health studies. She found statistical evidence for a relationship between consuming steak with trimmed fat and a lack of belief in god…but as she explains, that doesn’t mean that the two are actually related. Read on for more humorous and informative wanderings into the statistics of health and diet studies.
- From The New York Times Magazine, comes the story of Rob Bilott, a corporate defense attorney who is “The Lawyer Who Became DuPont’s Worst Nightmare.” Undeniable evidence of DuPont’s chemical pollution in the small town of Parkersburg, West Virginia, would led Bilott to take a unexpected turn in his career.
Thank you for reading, and stay tuned for more great science news in next week’s “Science Week in Review.”