Scientists have found out how fructose sweeteners in processed and packaged foods may be fueling America's obesity epidemic, discovered with the help of brain imaging studies.
Research from investigators at Oregon Health & Science University fructose sends different signals to the brain than the sweetener glucose that is important for controlling body weight.The authors say, “For consumers, our findings support current recommendations that people be conscious of sweeteners added to their drinks and meals and not overindulge on high-fructose, processed foods.”
Jonathan Purnell, M.D., an associate professor of medicine (endocrinology, diabetes and clinical nutrition) in the OHSU School of Medicine explains, "With newer technologies such as functional MRI, we can examine how brain activity in humans reacts when exposed to, say, carbohydrates or fats. What we've found in this case is that the brain's response to fructose is very different to the response to glucose, which is less likely to promote weight gain."
To find out why fructose may be fueling obesity, the researchers conducted functional MRI imaging studies on nine normal weight study participants during intravenous infusion of fructose, glucose or a saline solution,
They focused on two areas of the brain - the hypothalmus and the cortical brain area that control response to the way food tastes, smells and to pictures of food that can influence eating behaviors through food advertisements and brain response.
The findings on brain imaging showed fructose and glucose did not affect the hypothalmus that regulates food intake - but fructose did inhibit activity in the cortical brain area that was not seen with glucose.
Dr, Purnell says, "This study provides evidence in humans that fructose and glucose elicits opposite responses in the brain. It supports the animal research that shows similar findings and links fructose with obesity."
