Pregnant women who routinely consume fatty foods could be predisposing their children to a lifetime of overeating and obesity, according to a surprising study.
The new research demonstrates that a mother's diet can influence fetal development, essentially hard-wiring the brain so the child instinctively craves fat.
"Exposure to a high-fat diet in utero produces permanent neurons in the fetal brain that later increase the appetite for fat," said the senior author of the study, Sarah Leibowitz of Rockefeller University in New York City.
The experiment was conducted on rats, allowing the researchers to precisely measure the type of brain cells produced in the offspring.
Some of the pregnant rodents were fed a diet that contained 50 per cent fat. Others were given a more normal, or balanced, diet in which only 25 per cent of the calories were derived from fat.
The study showed that the high-fat diet led to a proliferation of neurons that generate appetite-simulating chemicals - especially for fat.
As a result, "the rat pups that were born to the mothers who consumed the high-fat diet, even after the diet had been removed at birth, ate more, weighed more throughout life and began puberty earlier than those born to mothers who ate a balanced diet," the researchers said in a statement released with the study published in the Journal of Neuroscience.
Although the study involved laboratory animals, Dr. Leibowitz is convinced the same biological processes are at work in people and the findings may help explain the growing number of overweight children and adults.
"We must look in the womb to understand what is producing today's obesity," she said in an interview.
Dr. Leibowitz speculated that the offspring are being physiologically prepared to survive on the same type of diet as the mother. "The point is we want our youngsters to be able to eat and metabolize the diet ... that the mother will likely feed them," she explained. "So they are being born with a preference ... for fat."
She noted that "our diet has changed over the past 50 years," with a significant proportion of the population consuming an increasing amount of fatty and sugary foods.
"Obesity has increased with each generation ... and I believe [dietary fat] is affecting the development of [appetite-stimulating] neurons in our children's brains."
MD exam time
Is your doctor staying up-to-date with the latest medical advances so you receive the best health care possible?
According to the Canadian Medical Association's code of ethics, physicians have a responsibility "to engage in lifelong learning to maintain and improve their professional knowledge, skills and attitudes."
But an editorial in the current issue of the Canadian Medical Association Journal questions whether adequate measures are in place to guarantee that doctors keep on top of their game. Right now, the onus rests mainly with the doctors themselves to do so.
Wendy Levinson, author of the editorial and chairwoman of the department of medicine at the University of Toronto, points out that physicians in numerous countries, including the United States, must periodically write requalification exams to maintain their medical licences.
Dr. Levinson was recently required to answer a multiple-choice test because she is also a member of the American Board of Internal Medicine.
"I studied for four months and was worried that I would fail. I would never have made the effort if not faced with an examination," she acknowledged in the editorial.
She argues that medical regulators in Canada should consider introducing similar retesting - especially following the recent examples of pathology errors that led to cases of breast cancer being misdiagnosed in New Brunswick and Newfoundland.
"Ultimately, we must be able to assure our colleagues and the public that we are living up to our professional responsibilities," she says.
AIDS vaccine tests begin
University of Western Ontario researchers say tests are about to begin on their experimental HIV/AIDS vaccine.
It was developed by Chil-Yong Kang and his team at UWO's Schulich School of Medicine and Dentistry. The vaccine uses a killed whole sample of HIV - similar to the Salk polio vaccine.
But HIV is a crafty, constantly mutating microbe. That makes it extremely challenging to produce an effective and lasting vaccine. Many previous efforts have ended in failure.
Even so, Sumagen Canada Inc., which holds the vaccine licence, plans to move forward with trials, first doing toxicity tests in animals.
If those are successful, the vaccine will be tried on people who are already infected with HIV but have not yet developed the symptoms of AIDS.
