When a healthy individual eats, his stomach widens and sends a signal to the brain to send him a signal of satiety. These signals allow us to say, “I’m not hungry anymore!”
In the case of eating disorders, one or more of these detections or signalling mechanisms are deficient. They lead to an alteration in the feeling of postprandial satiety (after a meal), an unpleasant feeling of heaviness in the stomach, which can lead to nausea and bloating.
In obese individuals, the signals of satiety are less sensitive and the gastric emptying is faster, which incites them to eat in larger quantities, thus resulting in a greater energy intake
The article by Christine Feinle-Bisset and her colleagues explain the mechanisms linked to several eating disorders.
- In case of obesity, all the satiety mechanisms seem to be deficient. Indeed, studies show that overweight patients ingest higher amounts of food before feeling fullness. Gastric emptying in patients with obesity is faster than in healthy people. While more studies are needed, it appears that obese patients are less sensitive to lipid satiety signals. This result means that when they eat foods high in fat, they do not feel full as a non-obese person would.
- Functional dyspepsia is a multifactorial disorder characterized by nausea, heaviness, discomfort, bloating, and vomiting. Due to a higher sensitivity to stomach distension, it leads to a feeling of discomfort after meals. Patients also have a higher intestinal sensitivity to certain nutrients, which leads them to believe that they are gluten, and lactose intolerant but this requires further study. While between 60% and 70% of people declare hypersensitivity to lipid intake, other nutrients such as proteins, gluten and FODMAPs have not yet been investigated.
- We are talking about anorexia of aging when the food intake of an individual between 60 and 75 years of age drops. As a person ages, the efficiency of all of their organs decreases, often resulting in slower gastric emptying, which can cause a feeling of fullness due to abdominal distension, and slower absorption of nutrients. As a result, these people have less appetite, at an age when energy intake is a criteria of good health. Conversely, studies have shown that in the elderly, the satiating effect of protein is weaker, encouraging them to eat more. In some cases, and following the advice of a dietitian, a diet rich in or supplemented with protein would seem to be the best treatment for this eating disorder and for ensuring the maintenance of muscle mass.
In the future, it would be interesting to see research groups studying the link between intestinal microbiota and eating disorders
This article, included in the special issue of Nutrients “Food and diet for gut function and dysfunction”, shows that problems with food detection appear in several eating disorders. More studies are needed in this area to better understand the cause and effect relationship between deficient satiety systems and eating disorders such as obesity, dyspepsia and age-related anorexia.
Numerous GMFH News Watch publications show that the gut microbiota is linked to many health conditions, so it would be interesting in the future for research groups to study this link with eating disorders.
Hajishafiee, M.; Bitarafan, V.; Feinle-Bisset, C. Gastrointestinal Sensing of Meal-Related Signals in Humans, and Dysregulations in Eating-Related Disorders. Nutrients 2019, 11, 1298. Doi: 10.3390/nu11061298