Facial Expressions May be Genetic

TUESDAY, Oct. 17 (HealthDay News) — Did your mother ever tell you to stop making a funny face because it might “freeze” that way?

Well, in a way, she was right. New research shows that facial expressions may be “frozen” by your genes.

Comparing the expressions of blind people to other family members, Israeli researchers discovered there’s probably a genetic component to facial expressions and that human faces may be programmed from the start to look, and act, the same as those of their parents and siblings.

“There is evidence for a hereditary basis for facial expressions,” said the study’s lead author, Gili Peleg, a doctoral candidate at the University of Haifa in Israel. “This study paves the way for discovering genes that influence facial expressions, understanding their evolutionary significance, and elucidating repair mechanisms for syndromes characterized by lack of facial expression, such as autism,” the researcher said.

“This is an interesting study that raises yet another question about those qualities that we have thought of as having a purely emotional basis,” commented Dr. Charles Goodstein, a psychoanalyst and professor of psychiatry at New York University Medical Center. “Many more qualities may be based on physiology and genetics than we’ve realized.”

He said that having families share similar facial expressions might perform some evolutionary function. “If you have the genetically linked capacity to emulate the facial expressions of your parents, in terms of evolution, you’d probably be the most likely to survive,” he said. “There’s evolutionary value to having similar facial expressions; you may be more likely to gain the care, love, and attention of your parents.”

Results of the study were published in this week’s issue of the Proceedings of the National Academy of Sciences.

Peleg, under the supervision of professors Eviatar Nevo and Gadi Katzir at the International Graduate Center of Evolution at the University of Haifa, compared the facial expressions of 21 people who were blind from birth to the expressions of 30 of their relatives.

The facial expressions of congenitally blind people could not have been influenced by their environment, the researchers pointed out, since they remain visually unaware of their relatives’ faces.

Each study volunteer was interviewed individually and all experienced sadness, anger and joy at some point during the interview. Facial expressions were photographed and indexed.

In most cases, families did exhibit a unique family facial expression “signature,” according to the researchers. In fact, in about 80 percent of cases, family members could be accurately linked to individual participants, based on their range of facial expressions.

“We found that the frequency of a facial movement of a congenitally blind subject in his family is significantly higher than that outside his family,” said Peleg.

“There will always be debate about what traits are nature vs. nurture,” said Goodstein. “This study eliminates an important consideration, however: What could have been envisioned by the child.”

Environment could still play a role in the development of facial expressions, even in blind children, he added. Goodstein theorized that when a child first smiles, a parent might recognize the expression and be pleased by it.

“What if the parent rewards the baby’s smile and pats the baby? That smile is more likely to become a habitual smile,” noted Goodstein.

“Facial expressions may be hardwired at birth, but they may not,” he added.

To read more about facial expressions, visit the American Psychological Association.

— Serena Gordon, HealthDay News

Lack of sleep linked with childhood obesity

THURSDAY, Oct. 19 (HealthDay News) — A yawning child is more likely to be an overweight child, a new British study finds.

In fact, one researcher says poor sleep may be a prime reason behind the growing epidemic of obesity among kids.

According to Dr. Shahrad Taheri of the University of Bristol, sleeping less disturbs normal metabolism, which may contribute to obesity, insulin resistance, diabetes and cardiovascular disease. Even two to three nights of shortened sleep can have profound effects, he said.

“While obesity occurs because of imbalance between energy intake (calories consumed) and energy expenditure (physical activity), we know very little about the factors that influence each side of the energy balance equation,” Taheri said.

Sleep could be an important factor, altering metabolic hormones in such a way that people eat more and also choose the wrong kind of foods. In addition, lack of sleep can cause fatigue, which can reduce physical activity, Taheri said.

In addition, research shows that levels of leptin — a hormone produced by fat tissue when energy stores are low — were more than 15 percent lower in those sleeping five hours per night compared with those sleeping up to eight hours. And another hormone, ghrelin — released by the stomach to signal hunger — was almost 15 percent higher in those with a five-hour sleep schedule, the British researcher noted.

His report, which reviews the current data on sleep and obesity, was published in the October issue of the Archives of Disease in Childhood.

In one study that included over 13,000 British children followed since birth in Bristol (The Avon Longitudinal Study of Parents and Children), long periods of TV-watching was associated with shorter sleep, Taheri said. Shorter sleep is also associated with spending less time being outdoors and active, he added.

“We also observed that short sleep duration at age 30 months is associated with obesity at age 7 years,” Taheri said. “So, sleep is likely to be an important factor for both energy intake and expenditure.”

Taheri says the increasing availability of computers, mobile phones, TVs and other gadgets is chipping away even further at the time children have for sleep.

“Obesity is rising alarmingly. We need to urgently address it through preventive measures,” Taheri said. “We can easily ensure that distractions to sleep are removed from bedrooms of children. Ensuring adequate sleep in children in combination with healthy diet and physical activity is likely to help prevent obesity,” he said.

One expert agreed that sleep might be a big factor in obesity.

“An important point mentioned by Taheri is that data linking restricted sleep and obesity exists for children,” said Dr. Robert Daniel Vorona, an associate professor of internal medicine at Eastern Virginia Medical School. “In fact, this data in youngsters might be stronger than similar data in adults.”

Those studies do not establish a causal relationship between lack of sleep and obesity, however. But Vorona said alterations in hormones such as leptin and ghrelin could cause increased food intake, and thus be the link between less sleep and obesity.

“Even if sleep loss is much less important than caloric intake and lack of exercise in causing the epidemic of obesity, it still makes sense for physicians to encourage children and adults alike to obtain sufficient sleep,” Vorona said.

There’s more on helping kids get good sleep at the National Sleep Foundation.

— Steven Reinberg, HealthDay News