High-fat pregnancy diet causes obesity-promoting changes in fetal brain

New research suggests that eating a high-fat diet during pregnancy may cause changes in the fetal brain that promote the development of obesity.

Dr Sarah Leibowitz and colleagues at Rockefeller University compared the offspring of rats fed a high-fat diet with those fed a normal diet containing moderate amounts of fat. Results showed that the offspring of rats fed a high-fat diet ate more, weighed more throughout their lives, and began puberty earlier than the offspring of rats fed a normal diet.

Furthermore, the rats born to mothers who ate a high-fat diet also had higher levels of triglycerides and orexigenic, or appetite-promoting, peptides at birth and as adults. Further examination revealed that feeding the mother rats a high-fat diet caused changes in the brain of their fetal offspring which left the unborn rats with a significantly higher than normal number of orexigenic peptide-producing neurons. In comparison, the offspring of rats fed a normal diet had far less of the specialized neurons, and they did not appear until after the rats had been born.

“We’ve shown that short-term exposure to a high-fat diet in utero produces permanent neurons in the fetal brain that later increase the appetite for fat. This work provides the first evidence for a fetal program that links high levels of fats circulating in the mother’s blood during pregnancy to the overeating and increased weight gain of offspring after weaning,” said Dr Leibowitz in a news release. “We believe the high levels of triglycerides that the fetuses are exposed to during pregnancy cause the growth of the neurons earlier and much more than is normal. We’re programming our children to be fat.”

Chang GQ, Gaysinskaya V, Karatayev O, Leibowitz SF. Maternal High-Fat Diet and Fetal Programming: Increased Proliferation of Hypothalamic Peptide-Producing Neurons That Increase Risk for Overeating and Obesity. The Journal of Neuroscience. 2008;28:12107-12119. doi:10.1523/JNEUROSCI.2642-08.2008

News release: Fatty diet during pregnancy produces new neurons in fetal brain. Rockefeller University. November 10th 2008.

Abdominal fat dramatically increases risk of death

Abdominal fat significantly increases a person’s risk of premature death, even if their overall weight is within normal limits, say researchers.

Researchers examined the association between BMI, waist circumference, and the risk of death using data collected from 359,387 participants enrolled in the European Prospective Investigation into Cancer and Nutrition (EPIC) study.

Results showed that there was a significant association between BMI and risk of death, with higher risks of death observed in the lower and upper BMI categories than in the middle categories – the lowest risk of death was observed in men with a BMI of 25.3 and women with a BMI of 24.3.

The results also showed that waist circumference and waist-to-hip ratio were a “powerful indicator” of risk of death, regardless of BMI. Men with waists exceeding 47″ (119cm) were twice as likely to die early compared with those with waists of less than 31.5″ (80 cm), in women, those with waists over 39″ (99 cm) had double the risk of premature death compared to those of less than 25.5″ (64.7 cm). For people with the same BMI each extra 2″ (5 cm) raised the risk of early death by 17% for men and 13% for women.

The researchers concluded: “The current results underscore the importance of assessing the distribution of body fat even among persons of normal weight and challenge the use of cutoff points to define abdominal obesity, at least when they are used to predict the risk of death. Our finding of a positive association between waist circumference and the risk of death among participants of normal weight may also explain why studies have been unable to show a linear relationship between BMI and the risk of death across the entire range of BMI values.

Pischon T, Boeing H, Hoffman K, et al. General and Abdominal Adiposity and Risk of Death in Europe. NEJM 2008;359:2105-2120.