Nutraceutical Improves Blood Glucose, Peripheral Serotonin and Reduce Body Fat

Serotonin (5 hydroxytryptamine; 5 HT) is generally associated with its actions in the central nervous system (CNS) as a neurotransmitter involved in activities such as mood regulation, food consumption, sleep, sexual activity and pain [1]. However, CNS serotonin represents only a small proportion of our body's total 5-HT. The other amount, peripheral serotonin, is produced in the intestine, through enterochromaffin cells, acting specifically in this tissue, as well as in other peripheral tissues. The concept that central and peripheral 5 HT are distinct sets is supported by the idea that the blood-brain barrier is relatively impermeable to 5 HT. This means that serotonin produced outside the CNS does not cross the CNS blood vessels to reach neurons [2]. Peripheral serotonin plays important roles in many diseases. It has been found that serotonin has marked pro-inflammatory and pro-oxidation functions in diseases linked to inflammation [3-5]. Serotonin influences the functions of brown and beige adipocytes, which are involved in thermoregulation. Serotonin levels are elevated in the brown adipose tissue of obese mice, and this leads to decreased thermogenesis and energy dissipation by brown adipocytes, probably by suppressing β-adrenergic-induced expression of Upc1 [6]. Another study showed that under high-fat diets in mice, inhibition of 5-HT synthesis in adipocytes reduced weight gain, improved glucose tolerance and decreased lipogenesis in white adipose tissue. Furthermore, in a diet-induced type 2 diabetes model, decreased serotonin levels improve glucose tolerance [7]. Based on the metabolic effects of peripheral serotinin, the present study aimed to verify the effect of nutraceutical supplementation on glycemic parameters, plasma serotinin levels and body fat.