Pregnant women do not tip over, and the reason has a lot to do with an evolutionary curve, researchers say

By JOHN SCHWARTZ (Seen in the New York Times)
Published: December 13, 2007

Anthropologists studying the human spine have found that women’s lower vertebrae evolved in ways that reduce back pressure during pregnancy, when the mass of the abdomen grows by nearly a third and the center of mass shifts forward considerably.
Even without the benefit of advanced study in biomechanics, women tend to deal with the shift — and avoid tumbling over like a bowling pin — by leaning back. But the solution to one problem creates another, since leaning puts even more pressure on the spine and muscles.
And that, report researchers from Harvard and the University of Texas in the current issue of the journal Nature, is where evolution enters the story.
Anthropologists have long known that the lower spine in humans developed a unique forward curve to help compensate for the strains that arose when the primate ancestors began walking upright. Researchers looked for a mechanism that compensated for pregnancy’s additional burden as well.
What they found, said Katherine K. Whitcome, a post-doctoral fellow at Harvard and the lead author of the paper, was evidence that evolution had produced a stronger and more flexible lower spine for women.
After studying 19 pregnant subjects, Dr. Whitcome found that the lumbar, or lower back, curve in women extends across three vertebrae, as opposed to just two in men. And the connecting points between vertebrae are relatively larger in women and shaped differently in ways that make the stack more stable and less prone to shifting or breaking.
Since the engine of evolution runs on the passage of genes from one generation to the next, pregnancy is a critical moment. Without that adaptation, Dr. Whitcome said, females would have been in considerably greater pain during pregnancy and might not have been able to forage effectively or escape predators, ending the pregnancy and the genetic line as well.
Working at the University of Texas with Dr. Liza Shapiro, an associate professor of anthropology, Dr. Whitcome found that the differences between male and female spines do not show up in chimpanzees. That suggested that the changes occurred in response to the pressures of walking upright.
When she moved on to Harvard and started working with Daniel Lieberman, an anthropologist with expertise in primate fossils, she was able to examine two sets of fossilized vertebrae. Of the two samples, she found the three-vertebra arrangement in one sample and not in the other. Separate evidence suggested that the extra-curvy spine belonged to a female and the other to a male. “It was very exciting” to have the fossilized puzzle fall into place, Dr. Whitcome said.
As solutions go, the extra flexibility is only partly successful, Professor Shapiro said, since women still commonly complain of back trouble during pregnancy. And that is the difference between the way that evolution works and the way that actual designers do their job, Dr. Whitcome said: nature tinkers. For natural selection to favor one feature over another, “It doesn’t have to be an ideal solution,” she said. “It just has to be better.”
Karen R. Rosenberg, an associate professor and chairwoman of the anthropology department at the University of Delaware, characterized Dr. Whitcome’s work as “way cool.” Dr. Rosenberg, who studies the evolution of childbirth, said the paper was the first published research that asked whether pregnancy caused evolutionary changes in the skeleton. “In hindsight,” she said, “Duh, of course it does.”

NEW STUDY: Honey is better than cough medicine for kids' coughs....

Honey works best to calm kids' coughs, study finds
Source: Reuters

By Michael Conlon
CHICAGO, Dec 3 (Reuters) - A spoonful of buckwheat honey quells a child's nighttime chest cold coughing better than the most common cough suppressant in nonprescription medicines, researchers said on Monday.
"Honey may be a preferable treatment for the cough and sleep difficulty associated with childhood upper respiratory tract infection," a team of investigators from Pennsylvania State University said.
Their study, paid for by the National Honey Board, an industry-funded U.S. Agriculture Department agency, compared honey to dextromethorphan -- or DM -- the most common cough suppressant in over-the-counter remedies.
Honey is not recommended for children under the age of one. Buckwheat honey is a dark variety that tends to have more compounds associated with honey's antioxidant properties, the researchers said. In addition, they said honey can sooth the throat and thus help control coughing.
The report said that neither the American Academy of Pediatrics nor the American College of Chest Physician backs the use of DM for childhood cough.
In addition the substance has been implicated in drug abuse among teenagers who use cough medicine to get high.
The study, published in the Archives of Pediatric and Adolescent Medicine, comes just weeks after a government advisory panel recommended that many nonprescription cough and cold medicines in use for decades should not be given to children under 6 until their efficacy can be proven.
That move came after a group of pediatricians and public health officials petitioned the U.S. Food and Drug Administration to restrict sales for children younger than 6 because of reports of deaths, seizures, hallucinations and other problems.
Makers have said the products are safe and effective, when given as directed, to children aged 2 and older.
The new study involved 105 youngsters age 2 to 18 who had been battling upper respiratory tract infections for seven days or less. Some were given 10 milliliters -- about one tablespoon -- of buckwheat honey 30 minutes before bedtime, others got DM and others nothing at all.
Honey was found to make the best improvements in cough control and sleep followed by DM, while doing nothing showed the least improvement.
"Parents rated honey most favorably for symptomatic relief of their children's nocturnal cough and sleep difficulty," the study concluded.
"While our findings and the absence of contemporary studies supporting the use of DM continue to question its effectiveness for the treatment of cough associated with upper respiratory tract infections, we have now provided evidence supporting honey, which is generally regarded as safe for children older than 1 year, as an alternative," the authors said. (Editing by Andrew Stern and Eric Walsh)