Obese women may affect great-grandchildren

A woman's obesity may put her future great-grandchildren at high risk of metabolic problems such as type 2 diabetes and heart disease, even before she becomes pregnant, a study has found.

While previous studies have linked a woman's health in pregnancy to her child's weight later in life, the new study published this week in the US journal Cell Reports showed the risk does not end only with the first generation, Xinhua news agency reported.

Obesity-caused genetic abnormalities, it said, and can be passed through the female bloodline to at least three generations, even if these offspring eat healthy.

"Our findings indicate that a mother's obesity can impair the health of later generations," said senior author Kelle Moley, professor of obstetrics and gynaecology at the Washington University School of Medicine in St. louis.

"This is particularly important because more than two-thirds of reproductive-age women in the US are overweight or obese," Moley said.

In the new study, the researchers fed mice a high-fat, high-sugar diet comprised of about 60 per cent fat and 20 per cent sugar, which mimics more of the Western diet and was "like eating fast food every day", from six weeks prior to conception until weaning.

Their offspring then were fed a controlled diet of standard rodent chow, which is high in protein and low in fat and sugar.

Despite the healthy diet, the pups, grand pups and great-grand pups developed insulin resistance and other metabolic problems.

Abnormalities in mitochondria, which often are referred to as the powerhouses of cells because they supply energy for metabolism and other biochemical processes and are inherited only from mothers, not fathers, were found in muscle and skeletal tissue of the mice.

The research showed that a mother's obesity -- and its associated metabolic problems -- may be inherited through mitochondrial DNA present in the unfertilised oocyte, or egg.

"It's important to note that in humans, in which the diets of children closely mirror those of their parents, the effects of maternal metabolic syndrome may be greater than in our mouse model," Moley said.

She urged people to eat nutritiously, although more research is needed to determine if a consistent diet low in fat and sugar, as well as regular exercise, may reverse genetic metabolic abnormalities.

"Over the decades, our diets have worsened, in large part due to processed foods and fast foods. We're seeing the effects in the current obesity crisis," Moley said. 

"Research points to poor maternal nutrition and a predisposition to obesity."