Salivary lipase and α-amylase activities are higher in overweight than in normal weight subjects: Influences on dietary behavior

- Salivary lipase and α-amylase activities were investigated in humans.
- Enzyme activities were higher in overweight than in normal weight subjects.
- Lipase correlated with BMI, preference for high-fat foods and dietary fats.
- Habitual diet did not influence salivary α-amylase activity in overweight subjects.
- The low salivary zinc in overweight subjects might reduce taste perception.

Mounting evidence shows that hedonic eating, leading to overeating just for pleasure, can be driven by oro-sensory factors through the activation of reward processing and learning in the brain. Foods rich in sugars and fats are potent rewards and saliva composition influences oral taste, texture and aroma perception. A role for salivary α-amylase and lipase in the gustatory system and a link between salivary α-amylase activity and dietary habits were recently hypothesized.The objective of this study was to verify the relationship among salivary lipase and α-amylase activities as well as zinc concentration with food preference and choice of people with different body mass indices.Forty-two (23 normal weight and 19 overweight) healthy subjects participated in the study. Data showed that α-amylase and lipase were 1.8 and 2.4 folds higher in overweight than in normal weight subjects, respectively. On the other hand, overweight subjects showed a 33% reduced salivary zinc concentration compared to normal weight subjects. Only lipase activity positively correlated with individual preference for high-fat foods and with fat content of the diets.All in all data suggested that high salivary lipase activity in overweight subjects could be an adaptive response to the low fat-taste perception related to the reduced zinc concentration. It cannot be ruled out that other factors but diet might influence salivary α-amylase activity in overweight subjects.