Be warned: you are what your mother ate...

A growing body of evidence suggests that the foods mothers eat during pregnancy could have a profound impact on the health outcomes of their offspring in later life.

Professor Harry McArdle, head of policy and scientific studies at the Rowett Research Institute in Scotland, said: "You are what your mother ate - it's as simple as that."

He added: "Prenatal nutritional imbalance can lead to an increased risk of cardiovascular disease, type 2 diabetes and hypertension - ie. metabolic syndrome. It can also lead to impaired fertility that carries on to the next generation. The effects are long-term."

There was clear evidence that a maternal diet that is deficient in protein, iron, zinc and copper was a "recipe for high blood pressure" for the child in later life, said McArdle. "Nature is actually affected by nurture in this case - because we have seen that nutritional deficiencies are changing things like steroid metabolism, cytokine expression and DNA methylation. You are basically changing the way your DNA works."

The developing foetus was particularly vulnerable to poor diet in early pregnancy, he added. However, more research was needed to establish exactly how much protein, or minerals, were needed, during pregnancy, said Dr Kirsten Brandt, senior lecturer at the University of Newcastle. "Optimal intakes are not known. Take folate. Some people need more than others - depending on genotype. Too much could be a bad thing."

As for optimal nutrient intakes for 20 and 30 year olds, little was known, admitted Brandt. "Are moderate intakes of certain nutrients at 20 better than high intakes at 50? We just don't know."