I am not surprised that an excess of fat may have a damaging effect

Professor David Phillips, Medical Research Council

Two separate groups of pregnant rats were given a diet in which either 12%, or 35% of calories came from fat.

Scientists say that 12% represents a normal, healthy diet, and 35% a high-fat diet.

Similarly, some were given 35% of their calorie intake in ethanol alcohol.

When the rats reached adulthood, at 14 months old, their offspring were studied to see if their metabolisms had been altered by their experiences in the womb.

Metabolic changes

They found that in the high-alcohol group, rats had lasting changes to the way their muscle tissue helped regulate blood sugar levels, and reduced sensitivity to the hormone insulin, a key hormone in this process.

Rats whose mothers had been given the high-fat diet displayed similarly altered metabolism.

The inability to harness the hormone insulin to help keep blood sugar levels at the right level, known as insulin resistance, is widely regarded as an early warning sign of diabetes.

This disease, if undetected, can cause serious complications, such as long-term raised blood pressure, which can lead to heart disease.

Dr Pennington said: "The current results are useful as they shed more light on the link between diabetes in adult offspring and maternal dietary fat and alcohol consumption."

Brain food

British expert Professor David Phillips, from the Medical Research Council Environmental Epidemiology Unit at the University of Southampton, said there was growing evidence that deficiencies in maternal diet had knock-on effects on the health of the child.

He said: "Obviously, there must be some fat in the diet. The foetus needs to develop a brain, and fatty acids may well be a part of this process.

"However, I am not surprised that an excess of fat may have a damaging effect."

The research was published in the Journal of Endocrinology.