Postprandial secretion of hormones and hunger sensation in elderly are influenced by meal fat content

The "anorexia of aging" is defined as a condition associated with reduced appetite and consequent decrease in food intake in apparently healthy elderly people; this may lead to malnutrition. It is still unclear if meal composition can affect this condition. The aim of this study was to evaluate satiety and hunger sensation as well as hormone concentrations after meals with different fat contents. Twelve aged healthy community-dwelling subjects and twelve younger controls were asked to score their hunger sensation, using a visual analogical scale, under fasting condition and at 30-min interval for up to 4 h after two 800-kcal meals, where 20% and 40% of the calories were derived from fats, respectively. Serum samples were collected at -30, 60, 120, and 240 min after meal to measure glucagon-like peptide 1 (GLP-1), acylated and desacylated ghrelin, triglycerides, glucose, and insulin. In the elderly group serum concentrations of GLP-1 were higher after the 40% fat meal than after the 20% fat meal. In this group, after the 40% fat meal a lower acylated to desacylated ghrelin ratio, higher triglycerides and a lower hunger sensation were also observed. In conclusion, in apparently healthy elderly people larger amounts of fat in meals increase the satiety signal from GLP-1 and lower the acylated to desacylated ratio of ghrelin, consequently decreasing hunger. These data may explain the reduction in calory intake often observed in elderly people and should be taken into account in planning their diet composition.