Hormones in the intestines make food look better

An article in the May issue of Cell Metabolism (a edition of Cell Press) suggests that there is a hormone in the intestine that makes people crave food by making food look better. Researching images in the brain of each person, scientists found that the reward center of the brain in people who received the ghrelin hormone had a stronger reaction when viewing food images.

The study found two signaling diets - digestive signals and 'want to eat' signals that are closely linked internally.

Alain Dagher of the Montreal Neurology Institute at McGill University said: 'When we go to the supermarket hungry, everything looks better. Our brains pose a price compared to the benefits of each type of food. We have now found that it is ghrelin that acts on the brain to make food look more appealing. '

Dagher added that this behavior could occur in a lack of calories or nutrition as a adaptive advantage of humans. However, in the rich environment of our food and drink, it seems to be an important factor in obesity and related diseases.

There is a hormone in the intestine that makes people crave food by making food look better.

Ghrelin levels increase before meals and fall soon afterwards . This suggests that it causes hunger and stimulates eating. According to Dagher, in fact both lean and obese people with ghrelin eat a significantly higher calorie intake when eating buffet meals compared to placebo users. In general, long-term nutritional status affects the circulatory concentration of hormones.

Ghrelin stimulates eating by acting on the hypothalamus brain region - where ghrelin receptors are concentrated. However, ghrelin also has a certain effect on many brain regions that are rewarding and stimulating.

In the new study, the scientists used functional magnetic resonance imaging (fMRI) to measure the brain's response to food photographs and other subject photos after blind ghrelin infusions. application. Twelve people saw pictures before and after using ghrelin, eight others who did not use ghrelin watched the same pictures in two equal blocks. (All participants were told they might receive ghrelin infusion.)

Ghrelin stimulates a reaction to a photo of food in some areas of the brain that cause a feeling of irritation, interest in things observed; These include amygdala (the area of ​​the brain that controls emotions and instincts), the ocular frontal region (orbitofrontal cortex), the anterior cerebral lobe, the visual area and the striatum.

Dagher said: ' Ghrelin has a very wide impact. It not only affects one or two brain regions, but also the system . After ghrelin infusion, photos of food became more appealing to us. Hormones not only affect the visual processing process but also the memory. We will remember better food photos if ghrelin levels are high. '

Treatments that block ghrelin can promise a cure for obesity. But because this hormone affects the brain's excitement center, Dagher is concerned that treatment may have side effects on the mood of the patient.

He adds that, however, the research has certain implications for public health.

The brain reward center associated with ghrelin also works in addicts. 'It shows that it is reasonable to think that high-calorie food has potential for research,' Dagher said. If so, research results could provide the basis for plans to target fast food like cigarettes, such as banning the sale of fast food in the cafeteria.