New way to burn off calories

A new study in the September issue of Cell Metabolism, a publication of Cell Press, points to a new method for burning off all those irresistible extra calories-by turning on an energy-draining, but otherwise futile, cycle of protein synthesis and breakdown.

Christopher Lynch of The Pennsylvania State University College of Medicine and his colleagues found that they could drive such heightened protein turnover in mice by disrupting an enzyme involved in the metabolism of some amino acids, the building blocks of proteins. The enzyme-deficient animals showed elevated blood levels of the essential amino acid leucine, an important nutrient signal, and became slimmer than normal mice despite eating more food. They also showed "remarkable" improvements in glucose and insulin tolerance, and resistance to becoming obese on a high-fat diet.

"The mice on the outside look normal, just skinnier and smaller," Lynch said. "After looking at their metabolism, we found that for the same activity, they were using more energy."

Moreover, the researchers found that the animals that ate the most food also expended the most energy. "That would be ideal for people who are overweight," Lynch said. "They could continue to eat and just waste the energy and be thin."

Abundant food supplies and a sedentary lifestyle have contributed to the current epidemic of obesity in Western nations, the researchers said. Obesity results when people consume more energy in their diet than they expend. In both short-term and relatively long-term studies, high-protein and low-fat diets have been found to increase energy expenditure, they noted, while short-term protein intake helps stave off hunger.

The effects of dietary protein are thought to be driven at least in part by leucine and perhaps other so-called branched-chain amino acids (BCAAs). Yet it has remained unclear whether leucine supplementation actually improves or worsens obesity, Lynch said.

In the current study, the researchers generated mice lacking the enzyme BCATm, critical for the first step in BCAA breakdown, which caused their leucine levels to rise by more than 10-fold. As a result of the enzyme deficiency, the animals ate more food but were lean in comparison to normal mice. The researchers traced the effect to an energy-demanding increase in protein turnover that appeared to be directly related to the amount of food the mice ate.

"Unfortunately for dieters, it appears unlikely that the tactic used by the [mutant mice] to avoid weight gain, i.e., a big increase in protein turnover, can be achieved by merely ingesting high-protein diets or leucine supplements," said Susan Fried and Malcolm Watford in an accompanying commentary. An earlier study found that eating leucine can only increase its levels to twice the normal concentration, they noted. And unlike the enzyme disruption, dietary leucine stimulates protein synthesis while it slows protein breakdown.

Nonetheless, the scientists all agree that the findings could lead to new weight-loss therapies. "It is possible that revving up protein turnover by manipulating BCATm activity through pharmacological means is worth exploring as a treatment for obesity in humans," Fried and Watford said.

http://www.cellpress.com/

Psychiatrists are the least religious of all physicians

A nationwide survey of the religious beliefs and practices of American physicians has found that the least religious of all medical specialties is psychiatry.

Among psychiatrists who have a religion, more than twice as many are Jewish and far fewer are Protestant or Catholic, the two most common religions among physicians overall.

The study, published in the September 2007 issue of Psychiatric Services, also found that religious physicians, especially Protestants, are less likely to refer patients to psychiatrists, and more likely to send them to members of the clergy or to a religious counselor.

"Something about psychiatry, perhaps its historical ties to psychoanalysis and the anti-religious views of the early analysts such as Sigmund Freud, seems to dissuade religious medical students from choosing to specialize in this field," said study author Farr Curlin, MD, assistant professor of medicine at the University of Chicago. "It also seems to discourage religious physicians from referring their patients to psychiatrists."

"Previous surveys have documented the unusual religious profile of psychiatry," he said, "but this is the first study to suggest that that profile leads many physicians to look away from psychiatrists for help in responding to patients' psychological and spiritual suffering."

"Because psychiatrists take care of patients struggling with emotional, personal and relational problems," Curlin said, "the gap between the religiousness of the average psychiatrist and her average patient may make it difficult for them to connect on a human level."

In 2003, to learn about the contribution of religious factors on physicians' clinical practices, Curlin and colleagues surveyed 1,820 practicing physicians from all specialties, including an augmented number of psychiatrists; 1,144 (63%) physicians responded, including 100 psychiatrists.

The survey contained questions about medical specialties, religion, and measures of what the researchers called intrinsic religiosity-the extent to which individuals embrace their religion as the "master motive that guides and gives meaning to their life."

Although 61 percent of all American physicians were either Protestant (39%) or Catholic (22%), only 37 percent of psychiatrists were Protestant (27%) or Catholic (10%). Twenty-nine percent were Jewish, compared to 13 percent of all physicians. Seventeen percent of psychiatrists listed their religion as "none," compared to only 10 percent of all doctors.

Curlin's survey also included this brief vignette, designed to present "ambiguous symptoms of psychological distress" as way measure the willingness of physicians to refer patients to psychiatrists.

"A patient presents to you with continued deep grieving two months after the death of his wife. If you were to refer the patient, to which of the following would you prefer to refer first" (a psychiatrist or psychologist, a clergy member or religious counselor, a health care chaplain, or other)."

Overall, 56 percent of physicians indicated they would refer such a patient to a psychiatrist or psychologist, 25 percent to a clergy member or other religious counselor, 7 percent to a health care chaplain and 12 percent to someone else.

Although Protestant physicians were only half as likely to send the patient to a psychiatrist, Jewish physicians were more likely to do so. Least likely were highly religious Protestants who attended church at least twice a month and looked to God for guidance "a great deal or quite a lot."

"Patients probably seek out, to some extent, physicians who share their views on life's big questions," Curlin said. That may be especially true in psychiatry, where communication is so essential. The mismatch in religious beliefs between psychiatrists and patients may make it difficult for patients suffering from emotional or personal problems to find physicians who share their fundamental belief systems.

http://www.uchospitals.edu/