MedWire News: People who regularly use the flavour enhancer monosodium glutamate in their food are more likely to be overweight and obese than those who do not use it, US researchers have found.

Obesity is associated with a significantly increased risk of a variety of conditions and diseases, including heart disease, diabetes, high blood pressure and some types of cancer.

"Animal studies have indicated for years that monosodium glutamate might be associated with weight gain," said researcher Dr Ka He, from the University of North Carolina in Chapel Hill. "Ours is the first study to show a link between monosodium glutamate use and weight in humans."

The team studied 750 men and women, aged between 40 and 59 years, from three rural villages in north and south China.

Most of the participants prepared their meals at home and did not use commercially processed foods. However, around 82% used monosodium glutamate in their food.

Participants who used monosodium glutamate in their food were divided into three groups based on the amount of the flavour enhancer they used.

After accounting for physical activity levels and total energy intake, the researchers found that monosodium glutamate intake was significantly related to body mass index.

Indeed, people in the group with the highest intake of the flavour enhancer were more than twice as likely to be overweight or obese as those who did not use monosodium glutamate.

"This research provides data that monosodium glutamate intake may be associated with increased risk of overweight independent of physical activity and total energy intake in humans," lead researcher Dr Jeremiah Stamler, from Northwestern University in Chicago, and team conclude in the journal Obesity.

Dr He added: ""The US Food and Drug Administration and other health organisations around the world have concluded that monosodium glutamate is safe, but the question remains - is it healthy?"