[Effect of lipid intake in meals on the duodenojejunal and sigmoid motor responses in healthy volunteers].

OBJECTIVES

In man, fat induces a fed motor pattern in the small bowel and stimulates colonic motility. With a pure lipid meal, these motor effects are dose-related. However, animal studies have suggested that the motor effects of fat are reduced when lipids are mixed with proteins and carbohydrates. Our aim was to study in healthy volunteers the duodeno-jejunal and sigmoid motor responses after two 750-kcal meals, one containing 28%, the other 58% lipids.

METHODS

Combined duodeno-jejunal and sigmoid manometric sessions were performed in each volunteer during 3 hours after each test meal. Meal was always given 30 minutes after the occurrence of a phase III in the duodenum. The order of the two studies was randomly assigned with a minimal interval of 8 days between the two studies. The number of waves and the area under curve were calculated both on the overall and on each of the 6 successive half hours of the recording period.

RESULTS

Phases III were interrupted at least for 3 hours by both types of meals in each volunteer. The overall duodeno-jejunal motor response was not different after the two meals and, in all cases, a progressive decrease of the motor parameters with time was demonstrated. A lower response in the duodeno-jejunum during the first postprandial hour and a delayed onset of the maximal motor activity were observed with the high fat meal. In the sigmoid, a motor response to food was observed in all volunteers without any quantitative difference between the low and high fat meals.

CONCLUSION

A two-fold increase of the lipid fraction of a meal does not enhance the duodeno-jejunal and sigmoid motor responses to food. At variance, it reduces the first hour motor response and delays the peak of maximal activity in the duodeno-jejunum. Our data confirm that the specific motor effects of fat are modified by their combination with proteins and carbohydrates.