Dietary fiber intake, depression, and anxiety: a systematic review and meta-analysis of epidemiologic studies.

BACKGROUND: Findings of previous studies on relationship between dietary fiber intake and depression were inconsistent. We performed a meta-analysis on the association of dietary fiber intake with depression and anxiety in epidemiologic studies. METHODS: We conducted a systematic search of electronic databases, up to May 2021. Data from 18 publications (12 cross-sectional, five cohort and one case-control studies) on dietary fiber consumption in relation to depression or anxiety were included. For depression, fifteen studies were conducted on adults and three others on adolescents. Anxiety was not included in the analysis, due to insufficient eligible studies. RESULTS: Total dietary fiber intake was associated with a 10% lower odds of depression (OR = 0.90; 95% confidence interval [CI]: 0.86, 0.95) in adults and a 57% lower odds (OR = 0.43, 95% CI: 0.32, 0.59) in adolescents. Dose-response meta-analysis revealed an inverse linear association between total dietary fiber intake and odd of depression in adults; such that each 5-g increase in total dietary fiber intake was associated with a 5% reduction in risk of depression (OR = 0.95; 95% CI: 0.94, 0.97). An inverse significant association was observed between intake of fiber from vegetables (OR = 0.73; 95% CI: 0.66, 0.82) and soluble fiber (OR = 0.80, 95% CI: 0.71, 0.91) and odds of depression. However, cereal fiber, fiber from fruits and insoluble fiber were marginally associated with a reduction in having depression. CONCLUSIONS: High intake of dietary fiber was protectively associated with depression in adults, in a dose-response fashion.

Effect of sugar-sweetened beverage taxation on sugars intake and dental caries: an umbrella review of a global perspective.

BACKGROUND: As part of the Global Strategy on Oral health, the World Health Organization (WHO) is exploring cost-effective interventions for oral health, including taxation on sugar-sweetened beverages (SSBs). To inform this process, this umbrella review aimed to identify the best available estimates pertaining to the impact of SSB taxation on the reduction of sugars intake, and the sugars-caries dose-response, such that estimates of the impact of SSB taxation on averting dental caries in both high (HIC) and low and middle (LMIC) countries be available. METHODS: The questions addressed were: (1) what are the effects of SSB taxation on consumption of SSBs and (2) sugars? (3) What is the effect on caries of decreasing sugars? and (4) what is the likely impact of a 20% volumetric SSB tax on the number of active caries prevented over 10 years? Data sources included PubMed, Embase, Web of Science, Scopus, CINAHL, Dentistry and Oral Sciences Source, Cochrane Library, Joanna Briggs Institute (JBI) Systematic Review Register, and PROSPERO. The review was conducted with reference to JBI guidelines. The quality of included systematic reviews was assessed using AMSTAR to identify best evidence. RESULTS: From 419 systematic reviews identified for questions 1 & 2, and 103 for question 3, 48 (Questions 1 & 2) and 21 (Question 3) underwent full text screening, yielding 14 and five included reviews respectively. Best available data indicated a 10% tax would reduce SSB intake by 10.0% (95% CI: -5.0, 14.7%) in HIC and by 9% (range -6.0 to 12.0%) in LMIC, and that a 20% tax would reduce free sugars intake on average by 4.0 g/d in LMIC and 4.4 g/d in HIC. Based on best available dose response data, this could reduce the number of teeth with caries per adults (HIC and LMIC) by 0.03 and caries occurrence in children by 2.7% (LMIC) and 2.9% (HIC), over a 10-year period. CONCLUSION: Best available data suggest a 20% volumetric SSB tax would have a modest impact on prevalence and severity of dental caries in both HIC and LMIC.

Dietary intake of total, animal and plant proteins and the risk of coronary heart disease and hypertension: a systematic review and dose-response meta-analysis of prospective cohort studies.

BACKGROUND & OBJECTIVES: Previous findings assessing the association between long-term protein intake and cardiovascular diseases (CVDs) are inconsistent. This study aimed to summarize previous investigations on the association between total, animal and plant proteins intake and the risk of coronary heart disease (CHD) and hypertension (HTN) in adults. METHODS: Related papers were found by searching through PubMed/Medline, Scopus, and Google Scholar up to April 2020. Prospective cohort studies examined the association between consumption of the dietary protein from different sources and the risk of CHD and HTN in general population, were included. The random-effects model was used to pool the reported relative risks (RR). Dose-response associations were modeled by restricted cubic splines. RESULTS: Thirteen prospective studies, in total, including 547,303 participants- 11,590 cases with total CHD and 5,620 with HTN- were included. Dietary intake of total protein was not significantly associated with the risk of total CHD (RR: 0.97; 95%CI: 0.90-1.05) and HTN (RR: 1.01; 95% CI: 0.90-1.14). Moreover, consumption of both dietary plant and animal protein was not related to the risk of total CHD and HTN. Dose-response analysis indicated that the risk of CHD and HTN did not change significantly with increasing dietary total protein intake from 10% to 25% of total calorie intake. CONCLUSIONS: Dietary protein intake from different sources had no significant association with risk of CHD and HTN. Further high-quality research is needed to examine the potential mechanistic links between dietary protein intake and health outcomes.

Suppression of Energy Intake by Intragastric l-Tryptophan in Lean and Obese Men: Relations with Appetite Perceptions and Circulating Cholecystokinin and Tryptophan.

BACKGROUND: l-Tryptophan reduces energy intake in healthy men. The underlying mechanisms, including appetite, plasma cholecystokinin (CCK), tryptophan (Trp), and the ratio of Trp to large neutral amino acids (Trp:LNAAs ratio), and whether responses differ in lean and obese individuals, are uncertain. OBJECTIVES: We evaluated the effects of intragastric Trp on energy intake (primary outcome) and their potential mechanisms, pre- and postmeal, in lean men and those with obesity. METHODS: Twelve lean men [mean ± SD age: 30 ± 3 y; BMI (in kg/m2): 23 ± 1] and 13 men with obesity (mean ± SD age: 31 ± 3 y; BMI: 33 ± 1) received, on 3 separate occasions, in double-blind, randomized order, 3 g ("Trp-3") or 1.5 g ("Trp-1.5") Trp, or control ("C"), intragastrically, 30 min before a buffet-meal. Energy intake from the buffet-meal, hunger, fullness, and plasma CCK and amino acid concentrations were measured in response to Trp alone and for 2 h postmeal. Data were analyzed using maximum likelihood mixed-effects models, with treatment, group, and treatment-by-group interaction as fixed effects. RESULTS: Trp alone increased plasma CCK, Trp, and the Trp:LNAAs ratio (all P < 0.001), with no difference between groups. Trp suppressed energy intake (P < 0.001), with no difference between groups (lean, C: 1085 ± 102 kcal, Trp-1.5: 1009 ± 92 kcal, Trp-3: 868 ± 104 kcal; obese, C: 1249 ± 98 kcal, Trp-1.5: 1217 ± 90 kcal, Trp-3: 1012 ± 100 kcal). Postmeal, fullness was greater after Trp-3 than after C and Trp-1.5 (all P < 0.05), and in men with obesity than in lean men (P < 0.05). Plasma Trp and the Trp:LNAAs ratio were greater after Trp-3 and Trp-1.5 than after C (all P < 0.001), and tended to be less in men with obesity than in the lean (P = 0.07) (Trp:LNAAs ratio: lean, C: 1.5 ± 0.2, Trp-1.5: 6.9 ± 0.7, Trp-3: 10.7 ± 1.4; obese, C: 1.4 ± 0.1, Trp-1.5: 4.6 ± 0.7, Trp-3: 7.8 ± 1.3). There were inverse correlations of energy intake with plasma Trp and the Trp:LNAAs ratio in both groups (lean, both r = -0.50, P < 0.01; obese, both r = -0.40, P < 0.05). CONCLUSIONS: Intragastric Trp has potent energy intake-suppressant effects, in both lean men and those with obesity, apparently related to the Trp:LNAAs ratio.

The effect of Alpha-lipoic acid supplementation on endothelial function: A systematic review and meta-analysis.

There is evidence that alpha-lipoic acid (ALA) supplementation plays an important role in preventing cardiovascular diseases. However, its effect, specifically, on endothelial function (EF) is unclear. Therefore, this systematic review and meta-analysis aimed to evaluate the effects of ALA supplementation on EF. Databases including PubMed/Medline, Scopus, and ISI Web of Science were searched to identify eligible publications from inception up to April 2020. Randomized controlled trials assessing the effect of ALA supplementation on flow-mediated dilation (FMD) levels in adults were included. The pooled results were obtained using the random-effects model and are expressed as weighted mean differences (WMD) with 95% confidence intervals (CI). Five studies including six effect sizes and 300 participants were included. ALA supplementation significantly increased FMD levels by 2.36% (95% CI: 1.21-3.51; p < .001), compared with the control. Subgroup analyses suggested that the effects of ALA on FMD could be changed by age and health status of the participants. Dose-response analysis also showed that ALA dosage had a significant non-linear effect on FMD levels. The results showed that ALA supplementation appears to improve the EF. However, the role of ALA supplementation in improving other biomarkers of EF requires further research.

Clinical effectiveness of zinc supplementation on the biomarkers of oxidative stress: A systematic review and meta-analysis of randomized controlled trials.

BACKGROUND: Oxidative stress plays an important role in the occurrence of chronic diseases. Zinc supplementation is also known to be an antioxidant agent. While, there is no review on the effects of zinc supplementation on oxidative stress, this study aimed to systematically summarize randomized clinical trials (RCTs) which have evaluated the impacts of zinc supplementation on oxidative stress biomarkers. METHODS: Systematic searches were performed using the PubMed/Medline, Scopus, and Google Scholar databases, up to April 2020. All RCTs assessed the effect of oral zinc supplementation on serum malondialdehyde (MDA), total antioxidant capacity (TAC), glutathione (GSH), and nitric oxide (NO) levels, were included. For each variable, mean differences (MD) and standard deviations (SDs) were combined using the random-effects model, and the fractional polynomial model was used to implement the dose-response analysis. RESULTS: Ten RCTs were included. The pooled analysis of data showed that zinc supplementation significantly reduced MDA levels (MD: -0.42 µmol/L; 95 % CI: -0.71 to -0.13), increased serum TAC (MD: 225.96 mmol/L; 95 % CI: 68.42-383.5) and GSH levels (MD: 49.99 µmol/L; 95 % CI: 2.25 t 97.73), compared with the placebo group. In contrast, no significant changes were seen in NO levels following zinc supplementation (MD: -1.66 µmol/L; 95 % CI: -5.89 to 2.57). Dose-response analysis showed a significant non-linear relationship between zinc supplementation dosage and serum levels of MDA (p < 0.01), but not other biomarkers. CONCLUSIONS: The current study showed that zinc supplementation would significantly decrease MDA and increase TAC and GSH, but not NO levels. Thus, it encourages the use of zinc supplementation in oxidative stress-related diseases.

Anti-hypertensive effects of cinnamon supplementation in adults: A systematic review and dose-response Meta-analysis of randomized controlled trials.

Background & Objectives: Despite controversies, no earlier study has systematically summarized findings from earlier studies on the effect of cinnamon supplementation on blood pressure. Therefore, current systematic review and meta-analysis was done on the effect of cinnamon supplementation on systolic blood pressure (SBP) and diastolic blood pressure (DBP) in adults.Methods: Relevant studies published up to July 2019 were searched through PubMed/Medline, Scopus, ISI Web of Science, Embase and Google Scholar. All randomized clinical trials investigating the impact of oral cinnamon supplementation on any of the blood pressure parameters including SBP or/and DBP were included.Results: Out of 469 citations, 9 trials that enrolled 641 subjects were included. Cinnamon supplementation resulted in significant reduction in SBP (Weighted Mean Differences (WMD): -6.23 mmHg, 95% CI: -10.69 to -1.77, P = 0.006) and DBP (WMD: -3.93 mmHg, 95% CI: -6.33 to -1.52, P = 0.001). Greater effects on SBP were detected in trials using ≤2 g cinnamon, lasted ≥12 weeks and participants aged <50 years' old. DBP was also reduced by using lower doses. However, no significant non-linear associations were found between cinnamon supplementation dosage and study duration with both SBP (For dosage: Pnon-linearity = 0.35, for duration: Pnon-linearity = 0.21) and DBP (For dosage: Pnon-linearity = 0.27, for duration: Pnon-linearity = 0.41).Conclusions: We found a significant reduction in both SBP and DBP following cinnamon supplementation in adults. It could be proposed as a hypotensive supplement in hypertension management.

Snacking Behavior and Obesity among Female Adolescents in Isfahan, Iran.

BACKGROUND AND OBJECTIVE: The high prevalence of obesity in the pediatric age groups draws attention to lifestyle factors including diet and physical activity. Data on obesity in adolescents and their snacking behavior are conflicting. This study aimed to assess the association of snacking behavior and obesity among female adolescents in Isfahan, Iran. SUBJECTS AND DESIGN: This cross-sectional study was carried out on 265 female Isfahanian students who were chosen by systematic cluster random sampling. Dietary intake was assessed using a validated self-administered semiquantitative food frequency questionnaire that included 53 food items. Snacking behavior was defined by healthy snack score in combination with the frequency of snack intake. RESULTS: Individuals who consumed more healthy snacks and those with snacking frequency of 4 times a day or more had significantly lower weight, body mass index (BMI), and waist circumference (p < 0.001). Decreased consumption of healthy snacks was significantly associated with a greater chance of being overweight, generally obese, and abdominally obese among adolescents (odds ratio [OR] = 1.98; 95% confidence interval [CI], 1.00-3.14, ptrend = 0.04 and OR = 2.10; 95% CI, 1.01-3.13, ptrend = 0.04, respectively). Frequency of snack intake was inversely related to overweight, general obesity, and abdominal obesity (OR = 3.23; 95% CI, 1.73-5.61, ptrend = 0.03 and OR = 1.84; 95% CI, 1.05-3.20, ptrend = 0.04, respectively). Healthy snack score in combination with frequency of snacking showed that those in the lowest tertile of snacking who consumed snacks less than 4 times/day had the highest risk of obesity compared to other categories (OR = 2.09, 95% CI, 1.11-3.20, p < 0.001). CONCLUSION: More frequent consumption of healthy snacks is associated with decreased prevalence of overweight, general obesity, and abdominal obesity in adolescents. Further studies, in particular of a prospective nature, are required to examine this association in other populations.

Cereal fibre intake and risk of mortality from all causes, CVD, cancer and inflammatory diseases: a systematic review and meta-analysis of prospective cohort studies.

Dietary fibre intake has been associated with a lower risk of mortality; however, findings on the association of different sources of dietary fibre with mortality are conflicting. We performed a systematic review and meta-analysis of the prospective cohort studies to assess the relation between cereal fibre intake and cause-specific mortality. Medline/PubMed, SCOPUS, EMBASE, ISI web of Science and Google scholar were searched up to April 2015. Eligible prospective cohort studies were included if they provided hazard ratios (HR) or relative risks (RR) and corresponding 95 % CI for the association of cereal fibre intake and mortality from all causes, CVD, cancer and inflammatory diseases. The study-specific HR were pooled by using the random-effects model. In total, fourteen prospective studies that examined the association of cereal fibre intake with mortality from all causes (n 48 052 death), CVD (n 16 882 death), cancer (n 19 489 death) and inflammatory diseases (n 1092 death) were included. The pooled adjusted HR of all-cause mortality for the highest v. the lowest category of cereal fibre intake was 0·81 (95 % CI 0·79, 0·83). Consumption of cereal fibre intake was associated with an 18 % lower risk of CVD mortality (RR 0·82; 95 % CI 0·78, 0·86). Moreover, an inverse significant association was observed between cereal fibre intake and risk of death from cancer (RR 0·85; 95 % CI 0·81, 0·89). However, no significant association was seen between cereal fibre intake and inflammation-related mortality. This meta-analysis provides further evidence that cereal fibre intake was protectively associated with mortality from all causes, CVD and cancer.

Adherence to Alternative Healthy Eating Index in relation to depression and anxiety in Iranian adults.

Earlier studies have shown a protective association between adherence to healthy eating guidelines and mental disorders in Western nations; however, data in this regard are limited from the understudied region of Middle East. We examined the association between adherence to healthy eating guidelines, as measured by Alternative Healthy Eating Index (AHEI)-2010, and prevalence of anxiety and depression in a large sample of Iranian adults. In this cross-sectional study, data on dietary intakes of 3363 adult participants were collected using a validated dish-based 106-item semi-quantitative FFQ. Adherence to healthy eating was quantified using AHEI-2010, as suggested by earlier publications. The Iranian validated version of Hospital Anxiety and Depression Scale was used to assess anxiety and depression in study participants. Data on other covariates were gathered using a pre-tested questionnaire. Overall, the prevalence of anxiety and depression was 15·2 % (males 10·8 % and females 18·3 %) and 30·0 % (males 22·9 % and females 35·1 %), respectively. After controlling for potential confounders, those in the top quartile of AHEI-2010 had a 49 % lower chance of anxiety (OR 0·51; 95 % CI 0·35, 0·72) and a 45 % lower odds of depression (OR 0·55; 95 % CI 0·42, 0·72), compared with those in the bottom quartile. Stratified analysis by sex revealed that women in the highest categories of AHEI-2010 had a 49 % lower odds of having anxiety and depression, after adjustment for confounders, but no significant association was found in men. In addition, among individuals who were 40 years old or younger, those with high adherence to AHEI-2010 were 58 and 51 % less likely to have anxiety and depression, compared with those with less adherence. Adherence to healthy eating was inversely associated with a lower chance of anxiety and depression in Iranian adults. Prospective studies are required to confirm these associations in Middle-Eastern populations.

Hippocampal subfield volumes predict treatment response to oral ketamine in people with suicidality.

Ongoing stress results in hippocampal neuro-structural alterations which produce pathological consequences, including depression and suicidality. Ketamine may ameliorate stress related illnesses, including suicidality, via neuroplasticity processes. This novel study sought to determine whether oral ketamine treatment specifically affects hippocampal (whole and subfield) volumes in patients with chronic suicidality and MDD. It was hypothesised that oral ketamine treatment would differentially alter hippocampal volumes in trial participants categorised as ketamine responders, versus those who were non-responders. Twenty-eight participants received 6 single, weekly doses of oral ketamine (0.5-3 mg/kg) and underwent MRI scans at pre-ketamine (week 0), post-ketamine (week 6), and follow up (week 10). Hippocampal subfield volumes were extracted using the longitudinal pipeline in FreeSurfer. Participants were grouped according to ketamine response status and then compared in terms of grey matter volume (GMV) changes, among 10 hippocampal regions, over 6 and 10 weeks. Mixed ANOVAs were used to analyse interactions between time and group. Post treatment analysis revealed a significant main effect of group for three left hippocampal GMVs as well in the left and right whole hippocampus. Ketamine acute responders (Week 6) showed increased GMVs in both left and right whole hippocampus and in three subfields compared to acute non-responders, across all three timepoints, suggesting that pre-treatment increased hippocampal GMVs (particularly left hemisphere) may be predictive biomarkers of acute treatment response. Future studies should further investigate the potential of hippocampal volumes as a biomarker of ketamine treatment response.

Exploring the physiological factors relating to energy balance in women with polycystic ovary syndrome: a scoping review.

Polycystic ovary syndrome (PCOS) occurs in 8%-13% of reproductive-aged women and is associated with reproductive, metabolic, and psychological dysfunction. Overweight and obesity are prevalent and exacerbate the features of PCOS. The aim of this review is to evaluate the extent of evidence examining the physiological factors affecting energy homeostasis, which may impact weight gain, weight loss, and weight maintenance in PCOS, and identify research gaps and recommendations for future research. Literature searches using MEDLINE, EMBASE, PsycInfo, AMED, CINAHL, and Cochrane Central Register of Controlled Trials were conducted up to June 22, 2022. Abstracts, non-English-language articles, and reviews were excluded. A total of n = 78 (n = 55 energy intake and n = 23 energy expenditure) primary research papers were included. Papers with multiple outcomes of interest were counted as separate studies. Energy-intake studies (n = 89) focussed on assessing food, nutrient, or supplements stimuli and were grouped into the outcomes of gastrointestinal appetite hormones (n = 43), adipokines (n = 34), subjective appetite (n = 9), functional brain imaging (n = 3), and neuropeptides (n = 0). Energy-expenditure studies (n = 29) were grouped into total energy expenditure (n = 1), resting energy expenditure (n = 15), meal-induced thermogenesis (n = 3), nutrient oxidation (n = 5), and metabolic flexibility (n = 5). Across both energy-intake and -expenditure papers, 60% of the studies compared outcome responses in women with PCOS with a control group. Results were inconsistent, with 57% reporting no differences and 43% reporting altered responses in PCOS compared with controls, including blunted appetite hormone responses, metabolic inflexibility, and reduced energy expenditure. The authors identified that there is inconsistent, yet preliminary, evidence of possible altered physiological factors, which may impact energy balance and weight management. Further work is needed to act on the identified clinical and research gaps to support women with PCOS and health professionals in informing and achieving realistic weight-management goals for women with PCOS. Systematic Review Registration: The protocol was prospectively registered on the Open Science Framework on February 16, 2021 (https://osf.io/9jnsm).

Effects of intragastric administration of L-tryptophan on the glycaemic response to a nutrient drink in men with type 2 diabetes - impacts on gastric emptying, glucoregulatory hormones and glucose absorption.

BACKGROUND: The rate of gastric emptying and glucoregulatory hormones are key determinants of postprandial glycaemia. Intragastric administration of L-tryptophan slows gastric emptying and reduces the glycaemic response to a nutrient drink in lean individuals and those with obesity. We investigated whether tryptophan decreases postprandial glycaemia and slows gastric emptying in type 2 diabetes (T2D). METHODS: Twelve men with T2D (age: 63 ± 2 years, HbA1c: 49.7 ± 2.5 mmol/mol, BMI: 30 ± 1 kg/m2) received, on three separate occasions, 3 g ('Trp-3') or 1.5 g ('Trp-1.5') tryptophan, or control (0.9% saline), intragastrically, in randomised, double-blind fashion, 30 min before a mixed-nutrient drink (500 kcal, 74 g carbohydrates), containing 3 g 3-O-methyl-D-glucose (3-OMG) to assess glucose absorption. Venous blood samples were obtained at baseline, after tryptophan, and for 2 h post-drink for measurements of plasma glucose, C-peptide, glucagon and 3-OMG. Gastric emptying of the drink was quantified using two-dimensional ultrasound. RESULTS: Tryptophan alone stimulated C-peptide (P = 0.002) and glucagon (P = 0.04), but did not affect fasting glucose. In response to the drink, Trp-3 lowered plasma glucose from t = 15-30 min and from t = 30-45 min compared with control and Trp-1.5, respectively (both P < 0.05), with no differences in peak glucose between treatments. Gastric emptying tended to be slower after Trp-3, but not Trp-1.5, than control (P = 0.06). Plasma C-peptide, glucagon and 3-OMG increased on all days, with no major differences between treatments. CONCLUSIONS: In people with T2D, intragastric administration of 3 g tryptophan modestly slows gastric emptying, associated with a delayed rise, but not an overall lowering of, postprandial glucose.

Intragastric administration of leucine and isoleucine does not reduce the glycaemic response to, or slow gastric emptying of, a carbohydrate-containing drink in type 2 diabetes.

AIMS: In healthy individuals, intragastric administration of the branched-chain amino acids, leucine and isoleucine, diminishes the glycaemic response to a mixed-nutrient drink, apparently by stimulating insulin and slowing gastric emptying, respectively. This study aimed to evaluate the effects of leucine and isoleucine on postprandial glycaemia and gastric emptying in type-2 diabetes mellitus (T2D). METHODS: 14 males with T2D received, on 3 separate occasions, in double-blind, randomised fashion, either 10 g leucine, 10 g isoleucine or control, intragastrically 30 min before a mixed-nutrient drink (500 kcal; 74 g carbohydrates, 18 g protein, 15 g fat). Plasma glucose, insulin and glucagon were measured from 30 min pre- until 120 min post-drink. Gastric emptying of the drink was also measured. RESULTS: Leucine and isoleucine stimulated insulin, both before and after the drink (all P < 0.05; peak (mU/L): control: 70 ± 15; leucine: 88 ± 17; isoleucine: 74 ± 15). Isoleucine stimulated (P < 0.05), and leucine tended to stimulate (P = 0.078), glucagon before the drink, and isoleucine stimulated glucagon post-drink (P = 0.031; peak (pg/mL): control: 62 ± 5; leucine: 70 ± 9; isoleucine: 69 ± 6). Neither amino acid affected gastric emptying or plasma glucose (peak (mmol/L): control: 12.0 ± 0.5; leucine: 12.5 ± 0.7; isoleucine: 12.0 ± 0.6). CONCLUSIONS: In contrast to health, in T2D, leucine and isoleucine, administered intragastrically in a dose of 10 g, do not lower the glycaemic response to a mixed-nutrient drink. This finding argues against a role for 'preloads' of either leucine or isoleucine in the management of T2D.

Healthy lifestyle score and irritable bowel syndrome: A cross-sectional study in adults.

BACKGROUND: Lifestyle modifications play an important role in the management of irritable bowel syndrome (IBS), but there is limited information on any associations of combined lifestyle-related factors with IBS in Middle Eastern populations. We, therefore, assessed the associations of a "lifestyle score," in analogy to lifestyle scores applied in studies of other disorders, with IBS in adults. METHODS: In a cross-sectional study on 3363 Iranian adults, a healthy lifestyle score (HLS) was constructed using information about dietary habits, dietary intake, physical activity, smoking status, and psychological distress, which was collected using validated questionnaires. A modified version of the Rome III questionnaire (in Persian) was used to diagnose IBS and its subtypes. KEY RESULTS: Individuals with the highest HLS had a 65% lower odds of having IBS compared with those in the lowest category (OR: 0.35; 95% CI: 0.26-0.48). Participants with healthy dietary habits, including regular meal pattern, slow/moderate eating rate, moderate intra-meal fluid consumption, moderate/long meal-to-sleep interval, and low/moderate consumption of fatty foods, had significantly lower odds of having IBS compared with those with unhealthy dietary habits (OR: 0.81; 95% CI: 0.69-0.96). Moreover, individuals with lower levels of psychological distress, compared with those with higher levels of distress, had significantly lower odds of IBS (OR: 0.49; 95% CI: 0.40-0.60). CONCLUSIONS AND INFERENCES: Our data suggest that having an overall "healthy lifestyle" is related to substantially reduced odds of IBS, suggesting that adhering to a healthy lifestyle pattern, including dietary habits, diet quality, physical activity, smoking, and psychological distress, can be considered as a key management strategy for IBS.

Effects of intragastric tryptophan on acute changes in the plasma tryptophan/large neutral amino acids ratio and relationship with subsequent energy intake in lean and obese men.

Circulating tryptophan/large neutral amino acids (tryptophan/LNAA) ratio, an indicator of brain serotonin levels, may be important in appetite regulation, together with gastrointestinal (gastric emptying, plasma cholecystokinin) mechanisms. We have compared effects of intragastric tryptophan ('Trp') on the plasma tryptophan/LNAA ratio in lean and obese men, and the associations of the tryptophan/LNAA ratio, gastric emptying and CCK concentrations with energy intake. Lean and obese male participants (n = 16 each) received 3 g Trp or volume-matched control intragastrically, 15 min before a mixed-nutrient drink (300 mL, 400 kcal) (t = 0 min) in randomised, double-blind fashion. Plasma amino acid (for calculation of the plasma tryptophan/LNAA ratio) and CCK concentrations were measured from t = -20-60 min. Gastric emptying was assessed from t = 0-60 min, and ad-libitum energy intake from a standardised buffet-style meal from t = 60-90 min. The increase in the plasma tryptophan/LNAA ratio was less in obese, than lean, participants (P < 0.05), and greater in lean participants who reduced their energy intake (by >0 kcal) after Trp compared with those who did not (by ≤0 kcal) (P < 0.05). Moreover, in participants who reduced their energy intake, the ratio was lower in obese, than in lean (P < 0.05). There was a trend for an inverse correlation between energy intake with the plasma tryptophan/LNAA ratio in lean (r = -0.4, P = 0.08), but not in obese, participants. There was no significant difference in gastric emptying or CCK between participants who reduced their energy intake and those who did not. In conclusion, the plasma tryptophan/LNAA ratio appears to be a determinant of the suppression of energy intake in response to tryptophan in normal-weight people, but not in those with obesity. The role of the plasma tryptophan/LNAA ratio to regulate energy intake, and potential changes in obesity, warrant evaluation in prospective studies.

Gastrointestinal Sensing of Meal-Related Signals in Humans, and Dysregulations in Eating-Related Disorders.

The upper gastrointestinal (GI) tract plays a critical role in sensing the arrival of a meal, including its volume as well as nutrient and non-nutrient contents. The presence of the meal in the stomach generates a mechanical distension signal, and, as gastric emptying progresses, nutrients increasingly interact with receptors on enteroendocrine cells, triggering the release of gut hormones, with lipid and protein being particularly potent. Collectively, these signals are transmitted to the brain to regulate appetite and energy intake, or in a feedback loop relayed back to the upper GI tract to further adjust GI functions, including gastric emptying. The research in this area to date has provided important insights into how sensing of intraluminal meal-related stimuli acutely regulates appetite and energy intake in humans. However, disturbances in the detection of these stimuli have been described in a number of eating-related disorders. This paper will review the GI sensing of meal-related stimuli and the relationship with appetite and energy intake, and examine changes in GI responses to luminal stimuli in obesity, functional dyspepsia and anorexia of ageing, as examples of eating-related disorders. A much better understanding of the mechanisms underlying these dysregulations is still required to assist in the development of effective management and treatment strategies in the future.

Soy product consumption and association with health characteristics and dietary quality indices in Isfahan, Iran.

BACKGROUND: To determine the average intake of soy products and its association with socio-demographic, general and health characteristics, and dietary quality indices among the population of Isfahan, Iran. METHODS: In this descriptive cross-sectional study conducted on 491 subjects in 2013-2014, grocery stores, nuts stores, chain stores, and supermarkets from different areas of Isfahan Municipality were visited. Shop owners were asked to report the amounts of soy products sales (soy nut, processed soy protein, soy milk and soy yogurt). Furthermore, a food frequency questionnaire was completed from 496 customers by an experienced nutritionist. Mean sales and intake of soy products and dietary intakes including dietary quality indices and mean adequacy ratio (MAR) as well as anthropometric and socio-demographic variables were assessed. RESULTS: Soy protein and soy yogurt are the highest [673 ± 81 (g/month)] and lowest [420 ± 148 (g/month)] purchased soy products, respectively. While soy nut [63 ± 10 (g/month)] was consumed to the lowest amount, soy protein [236 ± 39 (g/month)] was the most consumed soy product. Subjects with higher consumption of soy products were older and had higher intake of protein, vitamin C, zinc and iron, and lower intake of whole grains, legumes, and vegetables as well as greater values of MAR and dietary diversity score as well as nutrient adequacy ratio for vitamin C. CONCLUSION: Soy protein is the most purchased and consumed soy product among people living in Isfahan. More intakes of whole grains and vegetables among those with higher consumption of soy foods could define greater quantities of zinc, iron and vitamin C in the diet. Soy consumption had a reverse correlation with body mass index.

Consumption of spicy foods and the prevalence of irritable bowel syndrome.

AIM: To explore the association between consumption of spicy foods and prevalence of irritable bowel syndrome (IBS) among Iranian adults. METHODS: In this cross-sectional study, data from 4763 Iranian adult participants were used. Consumption of spicy foods was estimated using a dietary habits questionnaire that included a question on spicy foods consumption: "how frequently do you use spicy foods (pepper, curry, ginger, cinnamon and turmeric) during a week?" Participants could respond to the question by choosing one of these choices: never, 1-3 times, 4-6 times, 7-9 times, or more than 10 times per week. A modified Persian version of the Rome III questionnaire was used to determine the prevalence of IBS. RESULTS: IBS was prevalent in 21.7% (18.6% of men and 24.1% of women) of the study population. After controlling for potential confounders including dietary behaviors, those consuming spicy foods ≥ 10 times per week were 92% more likely to have IBS compared with those who never consumed spicy foods (OR = 1.92; 95%CI: 1.23-3.01, P trend < 0.01). The association remained significant even after taking lactose intolerance into account (OR = 1.85; 95%CI: 1.18-2.90, P trend < 0.01). Stratified analysis by gender revealed that the association between consumption of spicy foods and IBS was not significant in men; however, a significant association was found among women after taking potential cofounders, including meal regularity and lactose intolerance, into account. Women who consumed spicy foods ≥ 10 times per week were two times more likely to have IBS compared with those who never consumed spicy foods (OR = 2.03; 95%CI: 1.09-3.77, P trend = 0.02). CONCLUSION: Consumption of spicy foods is directly associated with IBS, particularly in women. Further, prospective studies are warranted to (1) examine this association in other populations; and (2) evaluate whether dietary interventions, for example a reduction in spice consumption, would improve IBS symptoms.