Effects of acute arginine supplementation on neuroendocrine, metabolic, cardiovascular, and mood outcomes in younger men: A double-blind, placebo-controlled trial.

OBJECTIVES: Arginine is an amino-acid supplement and precursor for nitric-oxide synthesis, which affects various biologic processes. The objective of this study was to determine the effects of arginine supplementation on growth hormone (GH) and metabolic parameters. METHODS: Thirty physically active, healthy men (age 18-39 y; body mass index: 18.5-25 kg/m2) were randomized in a double-blind, placebo-controlled, crossover trial. Arginine (10 g) and placebo (0 g) beverages were consumed after an overnight fast. Blood samples were collected at baseline and 1.5, 3.0, and 24 h after supplementation. The primary outcomes were serum GH and metabolomics. Also, amino acids, glucose, insulin, triacylglycerols, thyroid hormones, testosterone, cortisol, dehydroepiandrosterone, and mood state were assessed. Individuals with detectable increases in GH were analyzed separately (responders: n = 16; < 0.05 ng/mL at 1.5 h). Repeated-measure analyses of variance estimated the treatment effects at each timepoint. RESULTS: Arginine levels increased at 1.5 h (146%) and 3.0 h (95%; P ≤ 0.001) and GH (193%) and thyroid-stimulating hormone (TSH; 10%) levels at 24 h (P < 0.05) after arginine versus placebo consumption. Arginine versus placebo increased glucose levels at 1.5 h (5%) and 3.0 h (3%; P ≤ 0.001). Arginine versus placebo did not affect other dependent measures, including mood state (P > 0.05), but changes in the urea, glutamate, and citric-acid pathways were observed. Among responders, arginine versus placebo increased GH at 1.5 h (37%), glucose at 1.5 h (4%) and 3.0 h (4%), and TSH at 24 h (9%; P < 0.05). Responders had higher levels of benzoate metabolites at baseline and 1.5 h, and an unknown compound (X-16124) at baseline, 1.5 h, and 24 h that corresponds to a class of gut microbes (P < 0.05). CONCLUSIONS: Arginine supplementation modestly increased GH, glucose, and TSH levels in younger men. Responders had higher benzoate metabolites and an unknown analyte attributed to the gut microbiome. Future studies should examine whether the increased prevalence of these gut microorganisms corresponds with GH response after arginine supplementation.

A Systematic Review of Dietary Supplements and Alternative Therapies for Weight Loss.

OBJECTIVE: Dietary supplements and alternative therapies are commercialized as a panacea for obesity/weight gain as a result of the minimal regulatory requirements in demonstrating efficacy. These products may indirectly undermine the value of guideline-driven obesity treatments. Included in this study is a systematic review of the literature of purported dietary supplements and alternative therapies for weight loss. METHODS: A systematic review was conducted to evaluate the efficacy of dietary supplements and alternative therapies for weight loss in participants aged ≥18 years. Searches of Medline (PubMed), Cochrane Library, Web of Science, CINAHL, and Embase (Ovid) were conducted. Risk of bias and results were summarized qualitatively. RESULTS: Of the 20,504 citations retrieved in the database search, 1,743 full-text articles were reviewed, 315 of which were randomized controlled trials evaluating the efficacy of 14 purported dietary supplements, therapies, or a combination thereof. Risk of bias and sufficiency of data varied widely. Few studies (n = 52 [16.5%]) were classified as low risk and sufficient to support efficacy. Of these, only 16 (31%) noted significant pre/post intergroup differences in weight (range: 0.3-4.93 kg). CONCLUSIONS: Dietary supplements and alternative therapies for weight loss have a limited high-quality evidence base of efficacy. Practitioners and patients should be aware of the scientific evidence of claims before recommending use.

Video chat technology to remotely quantify dietary, supplement and medication adherence in clinical trials.

We conducted two studies to test the validity, reliability, feasibility and acceptability of using video chat technology to quantify dietary and pill-taking (i.e. supplement and medication) adherence. In study 1, we investigated whether video chat technology can accurately quantify adherence to dietary and pill-taking interventions. Mock study participants ate food items and swallowed pills, while performing randomised scripted 'cheating' behaviours to mimic non-adherence. Monitoring was conducted in a cross-over design, with two monitors watching in-person and two watching remotely by Skype on a smartphone. For study 2, a twenty-two-item online survey was sent to a listserv with more than 20 000 unique email addresses of past and present study participants to assess the feasibility and acceptability of the technology. For the dietary adherence tests, monitors detected 86 % of non-adherent events (sensitivity) in-person v. 78 % of events via video chat monitoring (P=0·12), with comparable inter-rater agreement (0·88 v. 0·85; P=0·62). However, for pill-taking, non-adherence trended towards being more easily detected in-person than by video chat (77 v. 60 %; P=0·08), with non-significantly higher inter-rater agreement (0·85 v. 0·69; P=0·21). Survey results from study 2 (n 1076 respondents; ≥5 % response rate) indicated that 86·4 % of study participants had video chatting hardware, 73·3 % were comfortable using the technology and 79·8 % were willing to use it for clinical research. Given the capability of video chat technology to reduce participant burden and outperform other adherence monitoring methods such as dietary self-report and pill counts, video chatting is a novel and promising platform to quantify dietary and pill-taking adherence.

Examination of the reliability and validity of the Mindful Eating Questionnaire in pregnant women.

OBJECTIVE: Mindfulness is theorized to affect the eating behavior and weight of pregnant women, yet no measure has been validated during pregnancy. METHODS: This study qualitatively and quantitatively evaluated the reliability and validity of the Mindful Eating Questionnaire (MEQ) in overweight and obese pregnant women. Participants completed focus groups and cognitive interviews. The MEQ was administered twice to measure test-retest reliability. The Eating Inventory (EI) and Mindful Attention Awareness Scale (MAAS) were administered to assess convergent validity, and the Neighborhood Environment Walkability Scale (NEWS) assessed discriminant validity. RESULTS: Participants were 20 ± 8 weeks gestation (mean ± SD), 30 ± 2 years old, and 55% were obese. The MEQ total score had good test-retest reliability (r = .85). The total score internal consistency reliability was poor (Cronbach's α = .56). The external cues subscale (ECS) was not internally consistent (α = .31). Other subscales ranged from α = .59-.68. When the ECS was excluded, the MEQ total score internal consistency was acceptable (α = .62). Convergent validity was supported by the MEQ total score (with and without ECS) correlating significantly with the MAAS and the EI disinhibition and hunger subscales. Discriminant validity of the MEQ was supported by the MEQ and NEWS total scores and subscales not being significantly correlated. The quantitative results were supported by the qualitative context and content analysis. CONCLUSION: With the exception of the ECS, the MEQ's reliability and validity was supported in pregnant women, and most of the subscales were more robust in pregnant women than in the original sample of healthy adults. The MEQ's use with overweight and obese pregnant women is supported.

Hexosamine biosynthetic pathway activity in leptin resistant sucrose-drinking rats.

Rats offered 30% sucrose solution in addition to chow and water become leptin resistant therefore we investigated the effect of sucrose solution consumption on leptin signaling. In Experiment 1 rats were resistant to 3rd ventricle injections of1.5 µg leptin after 36 days of sucrose and western blot indicated that resistance was associated with increased basal levels of signal transducer and activator of transcription 3 phosphorylation (pSTAT3). In Experiment 2 rats were resistant to a peripheral injection of 2mg leptin/kg after 26 days of sucrose. Immunohistochemistry indicated that increased basal pSTAT3 was limited to the medial and lateral arcuate nucleus of the hypothalamus. Increased availability of glucose and fructose can stimulate the hexosamine biosynthetic pathway (HBP) which O-GlcNAc-modifies proteins. This has the potential to change protein bioactivity. We tested whether this pathway could account for the leptin resistance. There was no increase in the expression of HBP enzymes in tissues from sucrose rats in Experiment 1, however, direct activation of the HBP with a 3h intravenous infusion of 30 µmol/kg/min glucosamine significantly increased hypothalamic pSTAT3. Although sucrose consumption and activation of the HBP both increase hypothalamic pSTAT3 experiments described here did not provide evidence of a direct link between sucrose consumption, HBP activity and leptin resistance. Unexpectedly, we found that the HBP enzyme glutamine fructose-6-phosphate amidotransferase (GFAT) in liver and O-GlcNAcase in hypothalamus were increased 30min after leptin injection in leptin responsive animals, implying a complex interaction between activity of the HBP and leptin responsiveness.

Calcium, dairy products, and energy balance in overweight adolescents: a controlled trial.

BACKGROUND: Dairy product and calcium consumption have been associated with modifying body fat and body weight in children and adults. OBJECTIVE: In overweight adolescent boys and girls, we aimed to determine the effect of the doubling of habitual calcium intake to the recommended intake from dairy or calcium carbonate on energy balance and purported mechanisms including fecal fat excretion, macronutrient use, and parathyroid hormone suppression. DESIGN: Twenty-five girls with a mean (±SD) BMI (in kg/m(2)) of 33 ± 5 and 17 boys with a BMI of 28 ± 5, aged 12-15 y, participated in two 3-wk controlled feeding sessions that used a crossover design in random order as a summer research camp. In one session, 756 mg Ca/d was consumed; in the other session, an additional 650 mg Ca/d was provided as dairy or calcium carbonate supplements that were matched to the control in macronutrient content. Total energy and macronutrient intakes were controlled and were the same for the 2 sessions for each subject. Primary outcome measures were energy balance, fecal fat excretion, lipid oxidation, and postprandial energy expenditure. RESULTS: There were no effects of quantity or source of calcium on energy or fat balance, despite calcium-induced increases (P <0.01) in postprandial serum parathyroid hormone suppression. CONCLUSION: These data lend little evidence to support the proposed mechanisms for the relation between an increase in calcium intake from calcium carbonate or dairy and weight loss or weight maintenance in children. This trial was registered at clinicaltrials.gov as NCT00592137.

Effects of food form on food intake and postprandial appetite sensations, glucose and endocrine responses, and energy expenditure in resistance trained v. sedentary older adults.

Limited research has suggested that the food form of nutritional supplements (FFNS) and resistance training (RT) influence ingestive behaviour and energy balance in older adults. The effects of the FFNS and RT on acute appetitive, endocrine and metabolic responses are not adequately documented. The present study assessed the effects of the FFNS and RT on postprandial appetite sensations (hunger and fullness), endocrine responses (plasma insulin, cholecystokinin, ghrelin and glucagon-like peptide-1 (GLP-1)), metabolism (glucose, energy expenditure and RER) and food intake (satiation) in older adults. On separate days, eighteen sedentary (Sed) and sixteen RT healthy adults (age 62-84 years) consumed 12·5 % of their energy need as an isoenergetic- and macronutrient-matched solid or beverage. Postprandial responses were assessed over 4 h. No RT × FFNS interactions were observed for any parameter. Fasting cholecystokinin was higher in the RT v. Sed group (P < 0·05). RT did not influence fullness, but fullness was higher following the solid v. beverage intake (P < 0·01). Neither RT nor FFNS influenced hunger. Glucose and insulin were higher after the solid v. beverage intake (P < 0·01). Ghrelin, GLP-1 and energy expenditure were not different between the RT and FFNS groups. Postprandial cholecystokinin was higher in the RT v. Sed group (P < 0·01) and for solid v. beverage (P < 0·05). RER was lower for solid v. beverage (P < 0·001). Neither RT nor FFNS independently or interactively influenced food intake 2 h after post-nutritional supplements. In conclusion, RT had little influence on ingestive behaviour. The appetitive and endocrine responses suggested the solid-promoted satiety; however, the FFNS did not alter subsequent food intake.