Effects of red pepper on appetite and energy intake

Two studies were conducted to investigate the effects of red pepper (capsai cin) on feeding behaviour and energy intake. In the first study, the effect s of dietary red pepper added to high-fat (HF) and high-carbohydrate (HC) m eals on subsequent energy and macronutrient intakes were examined in thirte en Japanese female subjects. After the ingestion of a standardized dinner o n the previous evening, the subjects ate an experimental breakfast (1883 kJ ) of one of the following four types: (1) HF; (2) HF and red pepper (10 g); (3) HC; (4) HC and red pepper. Ad libitum energy and macronutrient intakes were measured at lunch-time. The HC breakfast significantly reduced the de sire to eat and hunger after breakfast. The addition of red pepper to the H C breakfast also significantly decreased the desire to eat and hunger befor e lunch. Differences in diet composition at breakfast time did not affect e nergy and macronutrient intakes at lunch-time. However, the addition of red pepper to the breakfast significantly decreased protein and fat intakes at lunch-time. In Study 2, the effects of a red-pepper appetizer on subsequen t energy and macronutrient intakes were examined in ten Caucasian male subj ects. After ingesting a standardized breakfast, the subjects took an experi mental appetizer (644 kJ) at lunch-time of one of the following two types: (1) mixed diet and appetizer; (2) mixed diet and red-pepper (6 g) appetizer . The addition of red pepper to the appetizer significantly reduced the cum ulative ad libitum energy and carbohydrate intakes during the rest Of the l unch and in the snack served several hours later. Moreover, the power spect ral analysis of heart rate revealed that this effect of red pepper was asso ciated with an increase in the ratio sympathetic: parasympathetic nervous s ystem activity. These results indicate that the ingestion of red pepper dec reases appetite and subsequent protein and fat intakes in Japanese females and energy intake in Caucasian males. Moreover, this effect might be relate d to an increase in sympathetic nervous system activity in Caucasian males.