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.

Bioavailability and metabolism of benzyl glucosinolate in humans consuming Indian cress (Tropaeolum majus L.).

SCOPE: Benzyl isothiocyanate (BITC), which occurs in Brassicales, has demonstrated chemopreventive potency and cancer treatment properties in cell and animal studies. However, fate of BITC in human body is not comprehensively studied. Therefore, the present human intervention study investigates the metabolism of the glucosinolate (GSL) glucotropaeolin and its corresponding BITC metabolites. Analyzing BITC metabolites in plasma and urine should reveal insights about resorption, metabolism, and excretion. METHODS AND RESULTS: Fifteen healthy men were randomly recruited for a cross-over study and consumed 10 g freeze-dried Indian cress as a liquid preparation containing 1000 µmol glucotropaeolin. Blood and urine samples were taken at several time points and investigated by LC-ESI-MS/MS after sample preparation using SPE. Plasma contained high levels of BITC-glutathione (BITC-GSH), BITC-cysteinylglycine (BITC-CysGly), and BITC-N-acetyl-L-cysteine (BITC-NAC) 1-5 h after ingestion, with BITC-CysGly appearing as the main metabolite. Compared to human plasma, the main urinary metabolites were BITC-NAC and BITC-Cys, determined 4-6 h after ingestion. CONCLUSION: This study confirms that consumption of Indian cress increases the concentration of BITC metabolites in human plasma and urine. The outcome of this human intervention study supports clinical research dealing with GSL-containing innovative food products or pharmaceutical preparations.

Determination of benzyl isothiocyanate metabolites in human plasma and urine by LC-ESI-MS/MS after ingestion of nasturtium (Tropaeolum majus L.).

A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated to determine the concentration of benzyl isothiocyanate (BITC) metabolites in human plasma and urine. In this study, the following BITC metabolites have been considered: BITC-glutathione, BITC-cysteinylglycine, BITC-cysteine, and BITC-N-acetyl-L-cysteine. The assay development included: (1) synthesis of BITC conjugates acting as reference substances; (2) sample preparation based on protein precipitation and solid-phase extraction; (3) development of a quantitative LC-MS/MS method working in the multiple-reaction monitoring mode; (4) validation of the assay; (5) investigation of the stability and the reactivity of BITC conjugates in vitro; (6) application of the method to samples from a human intervention study. The lower limits of quantification were in the range of 21-183 nM depending on analyte and matrix, whereas the average recovery rates from spiked plasma and urine were approximately 85 and 75 %, respectively. BITC conjugates were found to be not stable in alkaline buffered solutions. After consumption of nasturtium, containing 1,000 µM glucotropaeolin, the primary source of BITC, quantifiable levels of BITC-NAC, BITC-Cys, and BITC-CysGly were found in human urine samples. Maximum levels in urine were determined 4 h after the ingestion of nasturtium. With regard to the human plasma samples, all metabolites were determined including individual distributions. The work presented provides a validated LC-MS/MS method for the determination of BITC metabolites and its successful application for the analysis of samples collected in a human intervention study.

Predictive modelling of interventions to improve iodine intake in New Zealand.

OBJECTIVE: The potential effects of four interventions to improve iodine intakes of six New Zealand population groups are assessed. DESIGN: A model was developed to estimate iodine intake when (i) bread is manufactured with or without iodized salt, (ii) recommended foods are consumed to augment iodine intake, (iii) iodine supplementation as recommended for pregnant women is taken and (iv) the level of iodization for use in bread manufacture is doubled from 25-65 mg to 100 mg iodine/kg salt. SETTING: New Zealanders have low and decreasing iodine intakes and low iodine status. Predictive modelling is a useful tool to assess the likely impact, and potential risk, of nutrition interventions. SUBJECTS: Food consumption information was sourced from 24 h diet recall records for 4576 New Zealanders aged over 5 years. RESULTS: Most consumers (73-100 %) are predicted to achieve an adequate iodine intake when salt iodized at 25-65 mg iodine/kg salt is used in bread manufacture, except in pregnant females of whom 37 % are likely to meet the estimated average requirement. Current dietary advice to achieve estimated average requirements is challenging for some consumers. Pregnant women are predicted to achieve adequate but not excessive iodine intakes when 150 µg of supplemental iodine is taken daily, assuming iodized salt in bread. CONCLUSIONS: The manufacture of bread with iodized salt and supplemental iodine for pregnant women are predicted to be effective interventions to lift iodine intakes in New Zealand. Current estimations of iodine intake will be improved with information on discretionary salt and supplemental iodine usage.

Eating behaviour and eating disorders in students of nutrition sciences.

OBJECTIVE: Sometimes the suspicion is put forward that nutrition students show more disordered eating patterns, which may be among the motivating factors to study nutrition. At the same time, it is not clear whether the students' increasing knowledge about diet and nutrition is associated with a more healthy eating behaviour or with an unhealthy obsession with food choices. DESIGN: Cross-sectional comparison of nutrition students from German universities during the first year of their studies (n 123) and during higher semesters (n 96), with a control group from other study programmes (n 68 and n 46, respectively). Dietary restraint, disinhibition, the tendency towards orthorexia nervosa and healthy food choices were assessed using a questionnaire. RESULTS: Nutrition students showed higher levels of dietary restraint than the control group. Disinhibition and orthorexia nervosa did not differ between nutrition students and controls. Orthorexic tendencies were lower in the more advanced nutrition students. Healthy food choices did not differ among students in the first year. More advanced nutrition students showed healthier food choices, whereas the corresponding controls showed slightly more unhealthy food choices. CONCLUSIONS: Nutrition students, more than other students, tend to restrict their food intake in order to control their weight, but they do not have more disturbed or disordered eating patterns than other students. Moreover, during the course of their studies, they adopt slightly more healthy food choices and decrease their tendency to be obsessive in their eating behaviour.

Protein intake in the first year of life: a risk factor for later obesity? The E.U. childhood obesity project.

Effective strategies for primary prevention are urgently needed to combat the rapidly increasing prevalence of childhood obesity. Evidence accumulates that early nutrition programmes later obesity risk. Breast feeding reduces the odds ratio for obesity at school age, adjusted for biological and sociodemographic confounding variables, by some 20-25%. We propose that the protective effect of breast feeding is related in part by the induction of a lower weight gain in infancy, which is related to differences in substrate intake. Protein intake per kg bodyweight is some 55-80% higher in formula fed than in breast fed infants. We hypothesize that high early protein intakes in excess of metabolic requirements enhance weight gain in infancy and increase later obesity risk (the "early protein hypothesis"). The European Childhood Obesity Programme tests this hypothesis in a randomized double blind intervention trial in 1150 infants in five European centres. Infants that are not breast fed are randomized to formulae with higher or lower protein content and followed up to school age. If an effect of infant feeding habits on later obesity risk should be established, there is great potential for effective preventive intervention with a significant potential health benefit for the child and adult population.