Fat loss reduces fertility in mothers. Dr. Bruce Murphy, director of the Centre de recherche en reproduction animale (CRRA), the animal reproduction research center at the Université de Montréal, made this discovery this while studying breeding animals during their reproductive cycle. In a more recent study, Dr. Murphy noted, for example, that if sow second litters are "lower-performance" (fewer pigs, born in poorer condition) than the first, part of the cause is a drop in fatty tissue.

"We believe that the genes resulting in fatty tissues play a regulatory role in pig reproduction, and, therefore, in all mammals," says Dr. Murphy, who has just been awarded over half a million dollars to study this hypothesis.

Dr. Murphy takes the conclusion even further. He maintains that poor weight leads directly to infertility. Is this problem a cause for concern for women, especially where obsessions for keeping slim are a widespread problem? "There's definitely a parallel to be established with human beings," he says. "Not only anorexics. When, for example, a woman marathon runner in training makes draconian cuts to her fat intake she runs the risk of halting her menstrual cycle, and the whole reproductive system will be affected. We often see this."

Laboratory studies have shown that at molecular levels the fatty tissues play a role as "endocrine organs" that influence the hypothalamus and ovaries.

In veterinary medicine, Dr. Murphy's research has major economic impact. If weight loss can be successfully limited in pigs or cattle after the females give birth to their young, the economic value of animal breeding will be much higher.

The CRRA studies could also yield important results for human medicine. "The presence of fat in the organism has given birth to a research explosion in the past decade," the head of the veterinary faculty says. "Its harmful effects have been clearly shown in disorders like obesity, cardiovascular disease and diabetes. But we mustn't forget that fat also plays a useful role."

Researcher: Bruce Murphy
Phone: (450) 773-8521, Local 8221 or (514) 343-6111, local 8382
Funding: Natural Sciences and Engineering Research Council of Canada (NSERC)