Oral administration of nasturtium affects peptide YY secretion in male subjects

Scope: Nasturtium plants contain the glucosinolate glucotropaeolin and its corresponding breakdown product benzyl isothiocyanate (BITC), the latter being intensively studied with regard to cancer chemoprevention and anti-inflammatory properties. In addition, recent research has shown that isothiocyanates are able to activate the release of several gut hormones in vitro and in rodent studies. Here, we tested the effects of a dietary nasturtium administration on circulating levels of gut hormones in humans. Methods and results: Metabolically healthy males (n = 15) received a single oral dose of 10 g freeze-dried nasturtium leaf material suspended in water or only water (control). Blood samples were taken every hour and serum concentrations of insulin, C-peptide, glucagon-like peptide 1 (GLP-1), glucose-dependent insulinotropic peptide (GIP), and peptide (PYY) were analyzed. Oral nasturtium intake resulted in an increased release of PYY over a time period of 6 h whereas circulating levels of other hormones were not changed. Conclusion: Given the finding that nasturtium consumption enhances secretion of PYY, a key hormone involved in energy regulation, special diets containing nasturtium, or supplementation with nasturtium or BITC might be considered in the treatment of obesity.