Portion size affects food selection in an immersive virtual reality buffet and is related to measured intake in laboratory meals varying in portion size

A crucial step for validating the utility of an immersive virtual reality (iVR) buffet to study eating behavior is to determine whether variations in food characteristics such as portion size (PS) are relevant predictors of food selection in an iVR buffet. We tested whether manipulating PS in an iVR buffet affects the weight of food selected, and whether this response to PS is similar to participants' measured intake when PS varies at laboratory meals. In a randomized crossover design, 91 adults (18-71 y; 64 females; BMI = 25.3 ± 5.7) used their iVR remote to select lunch and dinner portions from an iVR buffet before consuming a standardized lab meal at two visits separated by one week. The PS in the iVR buffet and lab meals varied between a standard PS and a large PS. This design enabled comparisons of PS effects between iVR and lab settings, despite the scale difference in food weight between the environments. Portion size significantly affected food selection and food intake (p < 0.001). Subjects selected an additional 350 g in iVR and consumed an additional 154 g of food in the lab meals when offered the large portion compared to the small portion. The effect of PS showed a similar percentage increase in iVR (36.5%) and lab meals (39.2%). There was no significant difference in the effect of PS between iVR and lab meals after accounting for scale differences in food weight between the environments. The response to PS was not influenced by subject characteristics such as body mass index, sex, or age. These results demonstrate the utility of iVR for replicating real-world eating behaviors and enhancing our understanding of the intricate dynamics of food-related behaviors in a variety of contexts.

Macular pigment is inversely related to circulating C-reactive protein concentrations in school-aged children

Xanthophyll carotenoids (i.e., lutein and zeaxanthin) are plant pigments that selectively deposit in the macula of the eye and provide retinal tissue with protection against photooxidative stress. Although having greater xanthophylls in various tissues is related to lower inflammation in adulthood and infancy, this relationship is underinvestigated in childhood. Thus, this study aimed to elucidate the relationships between macular xanthophyll status and inflammation in school-aged children. We hypothesized that greater macular pigment would be associated with lower systemic concentrations of C-reactive protein (CRP). Forty children (aged 7-12 years) from the East-Central Illinois area were recruited. Data were collected in a convenience sample over multiple visits to the laboratory that occurred over 1 month, including all individuals who provided adequate blood samples for analyses. Macular pigment optical density (MPOD) was assessed using customized heterochromatic flicker photometry. Dietary lutein and zeaxanthin were determined using 7-day diet records. Capillary dried blood spot samples were analyzed for CRP concentrations via enzyme-linked immunosorbent assay. Whole-body percentage fat (%Fat) was measured using dual-energy x-ray absorptiometry. Two-step hierarchical linear regression modelling was used to assess relationships between MPOD and CRP, following adjustment of pertinent covariates and the removal of outliers (N = 3). MPOD was negatively associated with CRP concentrations, after controlling for a priori covariates of age, sex, %Fat, and dietary lutein and zeaxanthin (β = -0.58, ΔR² = 0.22, P = .004). Age, sex, dietary lutein and zeaxanthin, and %Fat did not significantly contribute to the model. This study provides novel evidence that macular pigment and peripheral inflammation are inversely related in childhood.

Neuroprotective influence of macular xanthophylls and retinal integrity on cognitive function among persons with multiple sclerosis

BACKGROUND

No studies to date have examined if macular xanthophyll accumulation and retinal integrity are independently associated with cognitive function in individuals with multiple sclerosis (MS). This study explored whether macular xanthophyll accumulation and structural morphometry in the retina were associated with behavioral performance and neuroelectric function during a computerized cognitive task among persons with MS and healthy controls (HCs).

METHODS

42 HCs and 42 individuals with MS aged 18-64 years were enrolled. Macular pigment optical density (MPOD) was measured using heterochromatic flicker photometry. Optic disc retinal nerve fiber layer (odRNFL), macular retinal nerve fiber layer, and total macular volume were assessed via optical coherence tomography. Attentional inhibition was assessed using an Eriksen flanker task while underlying neuroelectric function was recorded using event-related potentials.

RESULTS

Persons with MS had a slower reaction time, lower accuracy, and delayed P3 peak latency time during both congruent and incongruent trials compared with HCs. Within the MS group, MPOD explained variance in incongruent P3 peak latency, and odRNFL explained variance in congruent reaction time and congruent P3 peak latency.

CONCLUSIONS

Persons with MS exhibited poorer attentional inhibition and slower processing speed, yet higher MPOD and odRNFL levels were independently associated with greater attentional inhibition and faster processing speed among persons with MS. Future interventions are necessary to determine if improvements in these metrics may promote cognitive function among persons with MS.

User engagement with a popular food brand before, during and after a multi-day interactive marketing campaign on a popular live streaming platform

OBJECTIVE

To assess viewer engagement of a food advertising campaign on the live streaming platform Twitch.tv, a social media platform that allows creators to live stream content and communicate with their audience in real time.

DESIGN

Observational analysis of chat comments across the Twitch platform containing the word 'Wendy's' or 'Wendys' during a 5-day ad campaign compared with two 5-day non-campaign time periods. Comments were categorised as positive, negative or neutral in how their sentiment pertained to the brand Wendy's.

SETTING

Twitch chatrooms.

PARTICIPANTS

None.

RESULTS

There were significantly more chatroom messages related to the Wendy's brand during the campaign period. When considering all messages, the proportion of messages was statistically different (x2 = 1417·41, P < 0·001) across time periods, with a higher proportion of neutral and positive messages and a lower proportion of negative messages during the campaign compared with the comparison periods. Additionally, the proportion of negative messages following the campaign was lower than before the campaign. When considering only positive and negative messages, the proportion of messages was statistically different (x2 = 366·38, P < 0·001) across each time period with a higher proportion of positive messages and a lower proportion of negative messages during the campaign when compared with the other time periods. Additionally, there was a higher proportion of positive messages and a lower portion of negative messages following the campaign when compared with before the campaign.

CONCLUSIONS

This study demonstrates the impact and sustained impact of a fast-food brand ad campaign on brand engagement on the live streaming platform Twitch.

MIND Dietary Pattern Adherence Is Selectively Associated with Cognitive Processing Speed in Middle-Aged Adults

BACKGROUND

Most previous work has focused on a single-nutrient, bottom-up approach when examining the influence of diet on neurocognition. Thus, the impact of dietary patterns on cognitive health is underinvestigated.

OBJECTIVES

We aimed to investigate the relation between different diet indices [i.e., Mediterranean, Dietary Approaches to Stop Hypertension (DASH), Healthy Eating Index-2015 (HEI-2015), and Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND)] and attentional inhibition and neuroelectric function.

METHODS

We undertook a cross-sectional analysis of adults aged 34.1 ± 6.0 y (n = 207, 116 females) with a BMI of 18.5 to >40 kg/m2 who completed the Dietary History Questionnaire II (DHQII) FFQ (Past Month and Year with Serving Sizes) to assess adherence to different diet quality indices. Attentional inhibition was assessed using a modified Eriksen flanker task during which event-related potentials (ERPs) were recorded. The amplitude and latency of the P3/P300 ERP were used to index attentional resource allocation and information processing speed, respectively.

RESULTS

P3 peak latency was inversely associated with greater adherence to the MIND dietary pattern during incongruent flanker trials (∆R2 = 0.02, β = -0.14, P = 0.043) but not during congruent trials. Adherence to the Mediterranean, DASH, and HEI-2015 patterns was not associated with P3 latency (P > 0.05). No associations were observed between the diet indices and attentional inhibition at the behavioral level (i.e., accuracy or reaction time) or P3 amplitude (all P values >0.05).

CONCLUSIONS

Greater adherence to the MIND diet was selectively associated with faster information processing speed in middle-aged adults with healthy to obese BMI. Further, the influence of the MIND diet for faster information processing speed might be particularly beneficial when cognitive control demands are increased. Future intervention trials testing the effects of consuming a MIND diet on cognitive function are warranted to help inform dietary recommendations for healthy cognitive aging.

Use of a brief, retrospective Comprehensive Feeding Practices Questionnaire in a bariatric-surgery seeking adult population

Parental feeding practices in childhood have been shown to contribute to childhood eating habits, behaviors, and weight status. Less understood is the longitudinal impact of parental feeding practices on these variables in adulthood. Therefore, the aim of the present work was to validate a modified, brief, Comprehensive Feeding Practices Questionnaire (CFPQ) reformatted to account for retrospective recollections of parental feeding practices experienced in childhood among a sample of adults with obesity. Adults (n = 719, mean age = 44.3 years, mean BMI = 47.1 kg/m²) completed a modified, brief, retrospective CFPQ containing seven pre-defined subscales of the original CFPQ. Exploratory Factor Analysis (EFA) and Confirmatory Factor Analysis (CFA) procedures were used to evaluate survey factor structure and associations with gender, BMI, and self-reported race. An EFA derived six-factor model demonstrated better model fit and reliability than the originally proposed seven-factor model. Gender and self-reported race were not correlated with subscales of the brief, retrospective, CFPQ, while BMI was positively correlated with the Food as Reward subscale. This six-factor, brief, retrospective, CFPQ can be used to provide insight into the potential origins of individual eating behaviors, and warrants use in future work attempting to clarify the relationships between parental feeding practices and eating behaviors in adulthood.

Remote iVR for Nutrition Education: From Design to Evaluation

While different crowdsourcing platforms promote remote data collection, experiments in the immersive Virtual Reality (iVR) research community are predominantly performed in person. The COVID-19 pandemic, however, has forced researchers in different disciplines, including iVR, to seriously consider remote studies. In this paper, we present a remote study using the Immersive Virtual Alimentation and Nutrition (IVAN) application, designed to educate users about food-energy density and portion size control. We report on the results of a remote experiment with 45 users using the IVAN app. In IVAN, users actively construct knowledge about energy density by manipulating virtual food items, and explore the concept of portion size control through hypothesis testing and assembling virtual meals in iVR. To explore the feasibility of conducting remote iVR studies using an interactive health-related application for nutrition education, two conditions were devised (interactive vs. passive). The results demonstrate the feasibility of conducting remote iVR studies using health-related applications. Furthermore, the results also indicate that regardless of level of interactivity learners significantly improved their knowledge about portion size control after using the IVAN (p &lt; 0.0001). Adding interactivity, however, suggests that the perceived learning experience of users could be partially affected. Learners reported significantly higher scores for immediacy of control in the interactive condition compared to those in the passive condition (p &lt; 0.05). This study demonstrates the feasibility of conducting an unsupervised remote iVR experiment using a complex and interactive health-related iVR app.

Consuming a Protein and Fiber-Based Supplement Preload Promotes Weight Loss and Alters Metabolic Markers in Overweight Adults in a 12-Week, Randomized, Double-Blind, Placebo-Controlled Trial

BACKGROUND

Higher protein and fiber diets promote weight management and metabolic health.

OBJECTIVES

This study aimed to determine if greater weight loss and positive changes in metabolic outcomes could be achieved with twice-daily consumption of a high-protein and fiber-based multi-ingredient nutritional shake (HPF) compared with an isocaloric low-protein, lower fiber-based placebo (LPF).

METHODS

Study procedures were conducted by an independent research organization under clinicaltrials.gov registration NCT03057873. Healthy overweight and obese adults [n = 206; BMI (kg/m2): 27-35; 70% female] were randomly assigned to HPF or LPF. All participants were prescribed an energy-restricted diet (500 kcal/d less than energy needs) and consumed a HPF (17 g protein, 6 g fiber) or LPF (1 g protein, 3 g fiber) shake 30 min before breakfast and lunch for 12 wk. Primary outcomes included body weight and total body fat percentage. Blood samples were collected at days (D) 0, 28, 56, and 84 for secondary analyses related to metabolic markers of health.

RESULTS

Although weight loss occurred in both groups, HPF had greater weight loss at D84 compared with LPF (-3.3 kg vs. -1.8 kg, P < 0.05). Percentage body fat decreased in both groups (HPF: -1.33%, LPF: -1.09%; P < 0.001) with no differences between groups. Serum total cholesterol, LDL cholesterol, and oxidized LDL decreased between -5.1% to -8.3%, whereas adiponectin increased over time in both groups; these changes occurred to a greater extent in HPF compared with LPF (all P < 0.05).

CONCLUSIONS

A multi-ingredient HPF nutritional supplement shake consumed as a preload before breakfast and lunch positively influenced weight management and metabolic outcomes in overweight adults compared with an LPF placebo. These findings suggest that specific nutrient factors (i.e., potentially including protein, fiber, and bioactive content) other than calorie reduction alone influence the success of a weight-loss regimen. This trial was registered at www.clinicaltrials.gov as NCT03057873.

Avocado Consumption, Abdominal Adiposity, and Oral Glucose Tolerance Among Persons with Overweight and Obesity

BACKGROUND

Although intake of Hass avocado has been cross-sectionally linked to lower abdominal obesity, knowledge of the effects of avocado consumption on abdominal adiposity and glycemic outcomes remains limited.

OBJECTIVE

The effects of avocado consumption on abdominal adiposity, insulin resistance, oral-glucose-tolerance test (OGTT), and estimated β-cell function were evaluated.

METHODS

A total of 105 adults aged 25-45 y (61% female) with BMI ≥25 kg/m2 were randomly assigned to an intervention (N = 53) that received a daily meal with 1 fresh Hass avocado or a control (N = 52) that received an isocaloric meal with similar ingredients without avocado for 12 wk. DXA was used to assess the primary outcomes of abdominal adiposity [visceral adipose tissue (VAT), subcutaneous abdominal adipose tissue (SAAT), and the ratio of VAT to SAAT (VS Ratio)]. Fasted glucose and insulin were used to assess the primary outcomes of insulin resistance (HOMA-IR), and insulin sensitivity (Matsuda index) and β-cell function (Insulinogenic index) were estimated using an OGTT. Changes between groups were compared using an ANCOVA. Secondary analyses were conducted based on sex.

RESULTS

The control group exhibited a greater reduction in SAAT [-54.5 ± 155.8 g (control) compared with 17.4 ± 155.1 g (treatment), P = 0.017] and increase in VS Ratio [0.007 ± 0.047 (control) compared with -0.011 ± 0.044 (treatment), P = 0.024]. Among females, the treatment group exhibited a greater reduction in VAT [1.6 ± 89.8 g (control) compared with -32.9 ± 81.6 g (treatment), P = 0.021] and VS Ratio [0.01 ± 0.05 (control) compared with -0.01 ± 0.03 (treatment), P = 0.001]. Among males, there was no significant difference between groups in changes in abdominal adiposity or glycemic outcomes.

CONCLUSIONS

Daily consumption of 1 fresh Hass avocado changed abdominal adiposity distribution among females but did not facilitate improvements in peripheral insulin sensitivity or β-cell function among adults with overweight and obesity.This study was registered at clinicaltrials.gov as NCT02740439.

Sedentary time is related to deficits in response inhibition among adults with overweight and obesity: An accelerometry and event-related brain potentials study

Excessive sedentariness has been related to poorer cognitive control in adults. Sedentariness may compound obesity-related impairments in response inhibition, but its relationship to response inhibition remains poorly understood. This study investigated the relationship between accelerometer-measured sedentary time (ST, min/day), performance on the Oddball and NoGo tasks, N2 and P3-ERP indices of response inhibition and attentional control in 80 adults with overweight and obesity (55 females, M_age  = 35.2 ± 5.8 years, BMI = 32.8 ± 5.3 kg/m² ). ST was not related to performance on the Oddball task. However, more sedentary adults had larger P3b amplitude to targets. Higher ST was also related to increased attentional resource allocation during NoGo target and nontarget trials as indicated by higher P3b amplitudes across centroparietal sites (C1, Cz, C2, CP1, CPz, CP2; ps ≤ .03). ST was negatively indirectly related to target accuracy on NoGo trials through its association with faster response times to nontargets (95% percentile bootstrap CI for a standardized effect: -0.182, -0.014). ST was not related to N2 amplitude on either Oddball or NoGo target trials. Adjustment for moderate-to-vigorous physical activity (MVPA; all models), age (models with P3b NoGo target amplitude, N2 NoGo target amplitude and latency), and % fat mass (models with target NoGo accuracy and N2 NoGo target amplitude) did not modulate behavioral findings. MVPA did not significantly predict P3b amplitude. Our results suggest suboptimal response inhibition due to trading accuracy for speed and despite the upregulation of attentional resources among more sedentary adults with overweight and obesity.

Introducing bedaquiline: experiences from the Challenge TB Project

BACKGROUND: Drug-resistant tuberculosis (DR-TB) remains a global public health crisis. In 2013, the World Health Organization recommended the introduction of bedaquiline (BDQ) for eligible DR-TB patients.METHODS: We conducted a retrospective review and analyses of project reports from 2016 to mid-2019 on the processes, activities implemented, available results on enrolment and interim treatment outcomes, across the 23 Challenge TB (CTB) supported countries.RESULTS: Initial introduction of BDQ-containing regimens in the 23 CTB-supported countries took on average 2 years, with subsequent nation-wide scale-up achieved in Ethiopia and Kyrgyzstan within a short time period. Successful implementation required critical interventions including advocacy, revision of policies and guidelines, capacity building of health care workers, and strengthening of laboratory networks. The number of countries providing BDQ increased from 9 to 23; 9398 patients were enrolled on bedaquiline containing regimens; 71% were culture-negative after 6 months of treatment; and the number of countries reporting serious adverse events increased (from 5 to 18). Major challenges included limited in-country coordination with drug regulatory agencies, unrealistic quantification and drug ordering, weak laboratory networks and reporting systems for drug safety.CONCLUSION: BDQ introduction required a systematic and programmatic approach. The initial time investment helped achieve initial introduction and scale-up of coverage, ownership and sustainability by National TB Programmes.

Systemic inflammation mediates the negative relationship between visceral adiposity and cognitive control

Elevated visceral adipose tissue (VAT) has been associated with cardiometabolic risk factors including chronic systemic low-grade inflammation. Whereas the cognitive implications of inflammation have been extensively studied in preclinical models, the influence of inflammatory cytokines on cognitive function in humans is unclear. This study aimed to investigate the relations among VAT, inflammatory cytokines, and cognitive control. We hypothesized that inflammatory markers would mediate the negative influence of VAT on selective attention. Participants between 25 and 46 years (N = 115, 43 females) underwent a DXA scan to estimate VAT. A modified Eriksen Flanker task was used to assess attentional inhibitory control while event-related potentials were recorded. ELISA was used to quantify plasma C-reactive protein (CRP) and Interleukin-6 (IL-6) concentrations. Mediation modeling while controlling for diet quality and education level revealed that CRP concentrations significantly mediated the relationship between VAT and incongruent trial accuracy (indirect effect 95% CI {-0.24, -0.01}). Further, IL-6 concentrations had a significant mediation effect on the relationship between VAT and incongruent P3 peak latency (indirect effect 95% CI {0.05, 1.39}). These results suggest that mechanisms by which visceral adiposity exerts a negative influence on cognitive function includes systemic inflammation.

Weight Status and Visceral Adiposity Mediate the Relation between Exclusive Breastfeeding Duration and Skin Carotenoids in Later Childhood

BACKGROUND

Breastfeeding is associated with healthier weight and nutrient status in early life. However, the impact of breastfeeding on carotenoid status beyond infancy, and the influence of adiposity, are unknown.

OBJECTIVES

The aim of the study was to retrospectively investigate the relation between breastfeeding and carotenoid status, and the mediating effect of weight status and adiposity on this relation, among school-age children.

METHODS

This was a secondary analysis of baseline data collected from a randomized-controlled clinical trial. Children 7-12 y old (n = 81) were recruited from East-Central Illinois. DXA was used to assess visceral adipose tissue (VAT) and whole-body total fat percentage (%Fat; i.e., whole-body adiposity). Weight was obtained to calculate children's BMI percentiles. Skin carotenoids were assessed via reflection spectroscopy. Macular carotenoids were assessed as macular pigment optical density (MPOD). Dietary, birth, and breastfeeding information was self-reported by parents.

RESULTS

Skin carotenoids were inversely related to %Fat (P < 0.01), VAT (P < 0.01), and BMI percentile (P < 0.01). VAT and BMI percentile significantly mediated this relation between exclusive breastfeeding duration and skin carotenoids, after adjustment for dietary carotenoids, energy intake, and mother education.

CONCLUSIONS

Weight status and adipose tissue distribution mediate the positive correlation between exclusive breastfeeding duration and skin carotenoids among children aged 7-12 y. The results indicate the need to support breastfeeding and healthy physical growth in childhood for optimal carotenoid status.This trial was registered at clinicaltrials.gov as NCT03521349.

Dietary lutein plus zeaxanthin and choline intake is interactively associated with cognitive flexibility in middle-adulthood in adults with overweight and obesity

BACKGROUND

The xanthophyll carotenoids lutein+zeaxanthin and the dietary component choline have been linked to benefits in cognition. However, knowledge on the interactive influence of these dietary components on cognitive function is sparse.

DESIGN

80 middle-aged adults with overweight and obesity (Body Mass Index: (BMI) ≥25.0 kg/m²), completed 7-day diet records, venous blood draws, heterochromatic flicker photometry, assessment of intelligence quotient (IQ), and a cognitive flexibility task while undergoing electroencephalographic recording for event-related potential (ERP) extraction. Multiplicative interaction terms and hierarchical linear regressions, controlling for age, BMI, sex, annual household income, and IQ were utilized to assess independent and interactive contributions of dietary and biomarker data on Switch task outcomes.

RESULTS

Higher intake of lutein+zeaxanthin and choline was associated interactively, but not independently, with faster reaction time (RT), after controlling for pertinent covariates. Dietary intake of lutein+zeaxanthin and choline was associated with serum lutein concentrations, but not with plasma choline metabolites nor macular pigmentation. Plasma phosphatidylcholine (PC) concentrations were associated with higher accuracy in Switch trials, while no other biomarkers were associated with cognitive outcomes. Dietary intake and biomarker data were not related to the N2 nor P3 ERP component.

CONCLUSIONS

Among a sample of adults with overweight and obesity, greater intake of choline and lutein+zeaxanthin was associated with faster performance on a cognitive flexibility task. Future work examining methods of increasing consumption of both of these dietary components as a possible means of improving or maintaining cognitive flexibility among adults with overweight and obesity is therefore warranted.

Hydration Biomarkers Are Related to the Differential Abundance of Fecal Microbiota and Plasma Lipopolysaccharide-Binding Protein in Adults

INTRODUCTION

Prevalence of chronic hypohydration remains elevated among adults in the USA; however, the health effects of hypohydration in regards to human gut health have not been explored.

METHODS

This study examined the relationship between total water intake, hydration biomarkers (first-morning urine specific gravity [FMUsg], first-morning urine volume [FMUvol], and plasma copeptin), fecal microbiota, and plasma lipopolysaccharide-binding protein (LBP) in adults (25-45 years, 64% female). Fecal microbiota composition was assessed using 16S rRNA gene sequencing (V4 region). Immunoassays quantified plasma copeptin and LBP in fasted venous blood samples. Dietary variables were measured using 7-day food records. Linear discriminant analysis effect size (LEfSe) analyzed differentially abundant microbiota based on median cutoffs for hydration markers. Multiple linear regressions examined the relationship between LBP and copeptin.

RESULTS

LEfSe identified 6 common taxa at the genus or species level that were differentially abundant in FMUsg, total water (g/day), or plasma copeptin (µg/mL) groups when split by their median values. Uncultured species in the Bacteroides, Desulfovibrio, Roseburia, Peptococcus, and Akkermansia genera were more abundant in groups that might indicate poorer hydration status. Multivariate linear analyses revealed a positive relationship between plasma copeptin and LBP when controlling confounding variables (F(6,52) = 4.45, p = 0.002, R2 = 0.34).

CONCLUSIONS

Taxa common between markers are associated with the intestinal mucus layer, which suggests a potential link between hydration status and intestinal mucus homeostasis. The relationship between LBP and copeptin indicates that copeptin may be sensitive to metabolic endotoxemia and potentially gut barrier function.

Genetic Variants in Lipid Metabolism Pathways Interact with Diet to Influence Blood Lipid Concentrations in Adults with Overweight and Obesity

INTRODUCTION

The effect of various types of dietary fat on cardiometabolic health continues to be debated, due in part to the high heterogeneity of results following clinical trials investigating the effects of saturated (SFA) and unsaturated fat intake. This variability may be due to genetic differences. Individuals with obesity are at an increased risk for adverse cardiometabolic health and dyslipidemia, and often present with the combined phenotype of elevated triglyceride (TG) and decreased high-density lipoprotein (HDL) cholesterol concentrations. Studying genetic variants relevant to lipid and lipoprotein metabolism can elucidate the mechanisms by which diet might interact with genotype to influence these phenotypes. The objective of this study was to determine relationships of genetic variation, dietary fat intake, and blood lipid concentrations in adults with overweight and obesity.

METHODS

Genomic DNA, blood lipid concentrations (HDL and TG), and 7-day diet records were obtained from 101 adults (25-45 years of age) with overweight or obesity. Resting energy expenditure (REE) was measured using indirect calorimetry and used to determine implausible intakes using a modified Goldberg method (kilocalories/REE). Genetic variants included 23 single-nucleotide polymorphisms (SNPs) from 15 genes in lipid metabolism pathways. Variants were analyzed with dietary fat intake (total fat, SFA, monounsaturated fat [MUFA], and polyunsaturated fat [PUFA]) via regression analyses. All models were adjusted for age, sex, ancestry, visceral adipose tissue mass, and total kilocalorie intake. The Bonferroni correction was applied for multiple comparisons.

RESULTS

Two interactions were detected for TG concentrations. Five gene-diet interactions were associated with HDL concentrations. There was a significant interaction detected between the rs5882 variant of cholesterol-esterase transfer protein (CETP) and MUFA intake to associate with TG concentrations (interaction p = 0.004, R2 = 0.306). Among carriers of the CETP-rs5882 major allele (G), TG concentrations were significantly lower in individuals consuming more than the median MUFA intake (31 g/day) than in those with an intake below the median. Total dietary fat intake interacted with the rs13702 polymorphism of lipoprotein lipase (LPL) to associate with HDL concentrations (interaction p = 0.041, R2 = 0.419), by which individuals with the risk allele (G) had significantly higher HDL concentrations when consuming a higher-fat diet (>92 g/day) than those with a lower-fat diet (56 ± 3 vs. 46 ± 2 mg/dL, p = 0.033).

CONCLUSIONS

Interactions between dietary intake and genes in lipid metabolism pathways were found to be associated with blood lipid concentrations in adults with overweight and obesity. Fatty acid intake may not modulate blood lipid concentrations uniformly across all individuals. Additional research is needed to determine the biological causes of individual variability in response to dietary intake. Understanding the influence of nutrigenetic interactions on dyslipidemia can aid in the development and implementation of personalized dietary strategies to improve health.

Avocado Consumption Alters Gastrointestinal Bacteria Abundance and Microbial Metabolite Concentrations among Adults with Overweight or Obesity: A Randomized Controlled Trial

BACKGROUND

Avocados are rich in dietary fiber and monounsaturated fatty acids (MUFAs), nutrients that have been independently connected to metabolic health benefits and the gastrointestinal microbiota.

OBJECTIVES

We aimed to evaluate the impact of avocado consumption on the gastrointestinal microbiota and microbial metabolites, secondary outcomes of the Persea americana for Total Health (PATH) study, and conduct exploratory analyses to assess relations between the fecal microbiota, fecal metabolites, and health markers.

METHODS

Adults [n = 163, 25-45 y, BMI (kg/m2) ≥ 25.0] were enrolled in the PATH study, a 12-wk investigator-blinded trial where participants were batch randomized to match the 2 groups by age, sex, visceral adiposity, and fasting glucose concentrations. Participants consumed isocaloric meals with or without avocado (175 g, men; 140 g, women) once daily for 12 wk. The fecal microbiota was assessed with 16S ribosomal RNA gene (V4 region) sequencing and analysis using DADA2 and QIIME2. Fecal fatty acid and bile acid concentrations were quantified using GC and LC-MS. Per-protocol (≥80% meal consumption) and intent-to-treat analyses were conducted using univariate ANOVA and Mann-Whitney U tests. Bivariate correlations were conducted between fecal microbiota, fecal metabolites, and health measures.

RESULTS

The avocado treatment increased ɑ diversity and enriched Faecalibacterium, Lachnospira, and Alistipes between 26% and 65% compared with the control group. The avocado group had 18% greater fecal acetate, 70% greater stearic acid, and 98% greater palmitic acid concentrations than the control group, while the concentrations of the bile acids cholic and chenodeoxycholic acid were 91% and 57% lower, respectively.

CONCLUSIONS

Daily avocado consumption resulted in lower fecal bile acid concentrations, greater fecal fatty acid and SCFAs, and greater relative abundances of bacteria capable of fiber fermentation, providing evidence that this nutrient-dense food affects digestive physiology, as well as the composition and metabolic functions of the intestinal microbiota. This trial was registered at www.clinicaltrials.gov as NCT02740439.

Single Nucleotide Polymorphisms Related to Lipoprotein Metabolism Are Associated with Blood Lipid Changes following Regular Avocado Intake in a Randomized Control Trial among Adults with Overweight and Obesity

BACKGROUND

Avocados are rich in unsaturated fat and fiber; clinical trials have investigated their effects on metabolic disease. There is high variability in individual changes following avocado consumption, which may be in part due to individual genetic differences.

OBJECTIVE

Secondary analyses of the Persea americana for Total Health (PATH) Study were used to examine how single nucleotide polymorphisms (SNPs) impact blood lipid changes following a daily meal containing avocado compared with control.

METHODS

Adults (n = 115, 37% male) aged 25-45 y with overweight and obesity were randomly assigned to receive a daily isocaloric meal with (intervention) or without (control) a standardized amount (males: 175 g; females: 140 g) of avocado for 12 wk. Control meals were higher in saturated fat (17% of energy compared with 7%) and lower in fiber (4 g compared with 16 g) than intervention meals. Whole venous blood was taken at baseline and 12 wk to determine total cholesterol (TC), high-density lipoprotein (HDL) cholesterol, and triglyceride (TG) concentrations. Seventeen SNPs in 10 genes related to lipoprotein metabolism were genotyped. Effects of SNP, diet, and SNP-diet interactions were determined using general linear models.

RESULTS

No group-by-time effects were detected for changes in TC (P = 0.96), HDL cholesterol (P = 0.28), or TG (P = 0.06) over 12 wk. Three SNP-diet interactions were associated with final TC concentrations: ANGPTL3-rs10889337 (P = 0.01), ANGPTL4-rs2278236 (P = 0.02), and CD36-rs10499859 (P = 0.01). SNPs in GCKR and LPL were associated with TC changes (P = 0.01). The interaction between GCKR-rs1260326 and diet was such that C-homozygotes receiving avocado (n = 23) had final TC concentrations that were significantly lower than the C-homozygotes in the control group (n = 20) (P = 0.02).

CONCLUSIONS

Results from these exploratory analyses indicate that avocado consumption may help manage dyslipidemia in adults with overweight and obesity; however, effectiveness may differ by genetic profile. Understanding the role of genetic variation in variability following dietary intervention can potentially inform personalized nutrition recommendations.

Hydrogen sulphide production by Saccharomyces cerevisiae UCD 522 in a synthetic grape juice medium deficient of thiamin (vitamin B1 ) and/or pyridoxine (vitamin B6 )

The impacts of thiamin and pyridoxine along with YAN on alcoholic fermentation and hydrogen sulphide production by Saccharomyces cerevisiae were studied. Using a synthetic grape juice medium, three fermentation trials were conducted; (i) 2 × 3 factorial design with thiamin (0, 0·2, or 0·5 mg l^-1 ) and YAN (60 or 250 mg l^-1 ) as variables, (ii) 2 × 3 factorial design with pyridoxine (0, 0·25, or 0·5 mg l^-1 ) and YAN (60 or 250 mg l^-1 ) as variables, and (iii) 3 × 3 factorial design with thiamin (0, 0·2 or 0·5 mg l^-1 ) and pyridoxine (0, 0·25 or 0·5 mg l^-1 ) as variables in media containing 60 mg l^-1 YAN. Although the progress of fermentations was affected by thiamin or pyridoxine, YAN had a larger impact than either vitamin. H₂ S production was significantly lower with increasing amounts of thiamin in those fermentations under low YAN (60 mg l^-1 ) while even lower amounts (<30 µg l^-1 ) were produced under high YAN (250 mg l^-1 ) with or without the vitamin. The highest amounts of H₂ S were synthesized in those fermentations without any pyridoxine (>110 µg l^-1 ), with the lowest production in media with pyridoxine and high YAN (<20 µg l^-1 ). SIGNIFICANCE AND IMPACT OF THE STUDY: Concentrations of thiamin, pyridoxine and yeast assimilable nitrogen (YAN) influenced the synthesis of hydrogen sulphide (H₂ S) by Saccharomyces cerevisiae in a synthetic grape juice medium. With a few exceptions, an increase in the concentration of either vitamin or YAN resulted in less H₂ S released. This is the first report to demonstrate that both thiamin and pyridoxine along with YAN affected H₂ S production, emphasizing the need to assess yeast nutrients to lower risks of off-odours during fermentation.

Dietary choline is related to neural efficiency during a selective attention task among middle-aged adults with overweight and obesity

Objectives: Obesity is associated with poorer brain health and cognitive function. However, it is not clear whether specific dietary factors may provide neuroprotective effects among individuals with overweight and obesity. The aim of this study was to examine the impact of choline intake on neurophysiological markers of attentional control among young and middle-aged adults with overweight or obesity.Methods: 146 adults with BMI ≥25 kg/m² (34.0 ± 5.9 years, 57 males) participated in the study. Behavioral performance (accuracy and reaction time) and neuroelectric indices (event-related brain potentials [ERPs]) of attentional inhibition were assessed during a Flanker task. Specifically, the amplitude and latency of the P3 waveform in a central-parietal region of interest (ROI) were used to index attentional resource allocation and information processing speed, respectively. Choline intake and overall diet quality (Healthy Eating Index [HEI-2015]) were assessed using 7-day diet records. Intelligence Quotient was assessed using the Kaufman-Brief Intelligence Test. Regression analyses were conducted to examine the relationship between habitual dietary choline intake and cognitive outcomes following adjustment of demographic factors, IQ, HEI-2015, and BMI.Results: Choline intake was selectively associated with a lower peak amplitude of the P300 waveform during incongruent trials (β = -0.25, p = <0.01). No significant relationships were observed for accuracy or reaction time.Discussion: Higher choline intake is associated with more efficient neural processing among adults with overweight and obesity. Intervention are necessary to determine whether choline consumption provides neuroprotective effects for executive function among individuals with elevated weight status.

School Lunch Timing and Children's Physical Activity During Recess: An Exploratory Study

OBJECTIVE

To examine the relationship between school lunch timing (before vs after recess) on physical activity (PA) during recess and energy balance and food intake at lunch.

METHODS

A cross-sectional study design was used to examine lunch intake and PA during recess among fourth- and fifth-graders (n = 103) over 5 school days. Lunch and PA were measured using a weighted plate waste technique and accelerometry, respectively.

RESULTS

Children who received lunch before recess accumulated lower residual energy (ie, energy intake at lunch minus energy expenditure during recess) and consumed a greater proportion of milk servings. No timing effects were observed for other lunch and PA variables.

CONCLUSIONS AND IMPLICATIONS

Lunch intake and activity during recess are related to lunch timing policy. Findings warrant further examination using experimental and quasi-experimental studies to better understand the impact of timing on health behaviors.

Serum Lutein is related to Relational Memory Performance

Dietary carotenoids, plant pigments with anti-oxidant properties, accumulate in neural tissue and are often found in lower concentrations among individuals with obesity. Given previous evidence of negative associations between excess adiposity and memory, it is possible that greater carotenoid status may confer neuroprotective effects among persons with overweight or obesity. This study aimed to elucidate relationships between carotenoids assessed in diet, serum, and the macula (macular pigment optical density (MPOD)) and relational memory among adults who are overweight or obese. Adults aged 25-45 years (N = 94) completed a spatial reconstruction task. Task performance was evaluated for accuracy of item placement during reconstruction relative to the location of the item during the study phase. Dietary carotenoids were assessed using 7-day diet records. Serum carotenoids were measured using high-performance liquid chromatography. Hierarchical linear regression analyses were used to determine the relationship between carotenoids and task performance. Although initial correlations indicated that dietary lutein, beta-carotene, and serum beta-carotene were positively associated with memory performance, these relationships were not sustained following adjustment for age, sex, and BMI. Serum lutein remained positively associated with accuracy in object binding and inversely related to misplacement error after controlling for covariates. Macular carotenoids were not related to memory performance. Findings from this study indicate that among the carotenoids evaluated, lutein may play an important role in hippocampal function among adults who are overweight or obese.

Dietary Fiber Is Independently Related to Blood Triglycerides Among Adults with Overweight and Obesity

BACKGROUND

Metabolic syndrome (MetS), a cluster of visceral adiposity-related risk factors, affects approximately 35% of the United States population. Although improvement in diet quality is an important approach to reducing MetS risk, the role of particular dietary components remains unclear, especially among younger adults. Individual dietary components have been implicated in ameliorating or exacerbating MetS risk; however, the extent to which these factors contribute to MetS prevention has received little attention.

OBJECTIVE

This cross-sectional study aimed to assess relations between diet and individual MetS components in young to middle-aged adults who are overweight and/or obese.

METHODS

Participants aged 25-45 y (N = 117) with overweight and obesity, but no other diagnosed metabolic disease, recorded dietary intake over 7 d. MetS components (waist circumference, blood pressure, glucose, triglycerides [TGs], and high-density lipoprotein cholesterol [HDL]) were measured. Visceral adipose tissue was measured by dual-energy X-ray absorptiometry. Linear regression was used to assess relations between diet and MetS risk factors, adjusting for age, sex, and visceral adipose tissue.

RESULTS

MetS prevalence in this sample was 32%. Energy-adjusted total fiber intake (β = -0.21, P = 0.02) was inversely associated with TG concentrations. No significant relations were observed between other dietary factors and MetS components. These findings indicate that among MetS components, TG concentrations are potentially sensitive to fiber consumption.

CONCLUSIONS

These results provide cross-sectional evidence supporting the protective influence of dietary fiber on MetS components among young to middle-aged adults. Additional, well-designed clinical trials are needed to assess the causal relations between various types of dietary fiber and metabolic disease.

Retinal Morphometric Markers of Crystallized and Fluid Intelligence Among Adults With Overweight and Obesity

Objective: To investigate the relationship between retinal morphometric measures and intellectual abilities among adults with overweight and obesity. Methods: Adults between 25 and 45 years (N = 55, 38 females) with overweight or obesity (BMI ≥ 25.0 kg/m2) underwent an optical coherence tomography (OCT) scan to assess retinal nerve fiber layer (RNFL) volume, ganglion cell layer (GCL) volume, macular volume, and central foveal thickness. Dual-Energy X-ray absorptiometry was used to assess whole-body adiposity (% Fat). The Kaufman Brief Intelligence Test-2 was used to assess general intelligence (IQ), fluid, and crystallized intelligence. Hierarchical linear regression analyses were performed to examine relationships between adiposity and intelligence measures following adjustment of relevant demographic characteristics and degree of adiposity (i.e., % Fat). Results: Although initial bivariate correlations indicated that % Fat was inversely related to fluid intelligence, this relationship was mitigated by inclusion of other demographic factors, including age, sex, and education level. Regression analyses for primary outcomes revealed that RNFL was positively related to IQ and fluid intelligence. However, only GCL was positively related to crystallized intelligence. Conclusion: This work provides novel data linking specific retinal morphometric measures - assessed using OCT - to intellectual abilities among adults with overweight and obesity. Clinical Trial Registration: www.clinicaltrials.gov, identifier NCT02740439.

Oral Glucose Tolerance is Associated with Neuroelectric Indices of Attention Among Adults with Overweight and Obesity

OBJECTIVE

This study aimed to elucidate the relationship between glucose levels and insulin resistance and sensitivity obtained from oral glucose tolerance tests and neurophysiological indices of attention among adults with overweight and obesity.

METHODS

Forty adults with overweight or obesity (BMI ≥ 25 kg/m² ) underwent dual-energy x-ray absorptiometry to assess visceral adipose tissue. Repeated venous blood samples were collected during an oral glucose tolerance test to measure insulin resistance (homeostatic model assessment of insulin resistance) and indices of insulin sensitivity (Matsuda index and Stumvoll metabolic clearance rate). Attention was assessed using event-related brain potentials recorded during a visual oddball task. Amplitude and latency of the P3 wave form in a central-parietal region of interest were used to index attentional resource allocation and information processing speed.

RESULTS

Following adjustment for visceral adipose tissue, reduced values of Matsuda index and Stumvoll metabolic clearance rate (indicating poor insulin sensitivity) were correlated with longer peak latency, whereas insulin area under the curve was positively related to peak latency, indicating slower information processing. Individuals with decreased insulin sensitivity (Matsuda index < 4.3) had significantly longer P3 latencies compared with individuals with normal insulin sensitivity.

CONCLUSIONS

Higher fasting glucose, but not homeostatic model assessment of insulin resistance, and reduced indices of glucose sensivity are associated with decrements in attention characterized by slower reaction time and slower information processing speed among adults with overweight and obesity.

Interactive effects between total SO2 , ethanol and storage temperature against Brettanomyces bruxellensis

Although Brettanomyces bruxellensis continues to be a problem during red winemaking due to formation of off-odours and flavours, few interactions between intrinsic and extrinsic conditions that would limit spoilage have been identified. Using a commercially prepared Merlot wine, a 3 × 2 × 2 complete factorial design was implemented with total SO₂ (0, 60 or 100 mg l^-1 ), ethanol (13% or 14·5% v v^-1 ) and storage temperature (15° or 18°C) as variables. Populations of two strains of B. bruxellensis isolated from Washington wines (I1a and F3) were monitored for 100 days before concentrations of 4-ethylphenol, 4-ethylguaiacol and volatile acidity were measured. In wines with 13% v v^-1 ethanol and stored at 15°C, addition of 100 mg l^-1 total SO₂ resulted in much longer lag phases (>40 days) compared with wines without sulphites. At 14·5% v v^-1 ethanol, culturability did not recover from wines with 100 mg l^-1 total SO₂ regardless of the storage temperature (15° or 18°C). A few significant interactions were noted between these parameters which also affected synthesis of metabolites. Thus, SO₂ , ethanol concentration and storage temperature should be together used as means to reduce infections by B. bruxellensis.

SIGNIFICANCE AND IMPACT OF THE STUDY

The potential for utilizing SO₂ along with the ethanol and storage temperature was studied to inhibit the spoilage yeast, Brettanomyces bruxellensis, during cellar ageing of red wines. This report is the first to identify the existence of interactions between these parameters that affect growth and/or metabolism of the yeast (i.e., synthesis of 4-ethylphenol, 4-ethylguaiacol and volatile acidity). Based on current and past findings, recommendations are presented related to the use of potential antimicrobial synergies between SO₂ , ethanol concentration and storage temperatures.

The Role of Retinal Carotenoids and Age on Neuroelectric Indices of Attentional Control among Early to Middle-Aged Adults

One apparent consequence of aging appears to be loss of some aspects of cognitive control. This loss is measurable as early as mid-adulthood. Since, like many aspects of cognition, there is wide variance among individuals, it is possible that behavior, such as one’s diet, could drive some of these differences. For instance, past data on older humans and non-human primates have suggested that dietary carotenoids could slow cognitive decline. In this study, we tested how early such protection might manifest by examining a sample (n = 60) of 25–45 year olds. Carotenoid status was assessed by directly measuring macular pigment optical density (MPOD) which has shown to be highly correlated with the primary carotenoid in brain, lutein. Cognitive control was measured using event-related potentials during the performance of cognitive control tasks designed to tap into different aspects of attentional (i.e., selective attention, attentional inhibition, and response inhibition) control. Our results showed that, across participants, MPOD was related to both age and the P3 component of participants’ neuroelectric profile (P3 amplitude) for attentional, but not response, inhibition. Although younger adults exhibited larger P3 amplitudes than their older adult counterparts, older subjects with higher MPOD levels displayed P3 indices similar to their younger adult counterparts in amplitude. Furthermore, hierarchical regression analyses showed that age was no longer a significant predictor of P3 amplitude when MPOD was included as a predictor in the model, suggesting that MPOD may partially contribute to the relationship between age and P3 amplitude. In addition, age and MPOD were shown to have independent associations with intraindividual variability of attentional control, such that younger individuals and individuals with higher MPOD showed less intraindividual variability. These results show a relationship between retinal carotenoids and neuroelectric indices underlying cognitive control. The protective role of carotenoids within the CNS may be evident during early and middle adulthood, decades prior to the onset of older age.

Advances in the control of wine spoilage by Zygosaccharomyces and Dekkera/Brettanomyces

Understanding the characteristics of yeast spoilage, as well as the available control technologies, is vital to producing consistent, high-quality wine. Zygosaccharomyces bailii contamination may result in refermentation and CO2 production in sweet wines or grape juice concentrate, whereas Brettanomyces bruxellensis spoilage often contributes off-odors and flavors to red wines. Early detection of these yeasts by selective/differential media or genetic methods is important to minimize potential spoilage. More established methods of microbial control include sulfur dioxide, dimethyl dicarbonate, and filtration. Current research is focused on the use of chitosan, pulsed electric fields, low electric current, and ultrasonics as means to protect wine quality.

The influence of nitrogen and biotin interactions on the performance of Saccharomyces in alcoholic fermentations

AIM

To study the impact of assimilable nitrogen, biotin and their interaction on growth, fermentation rate and volatile formation by Saccharomyces.

METHODS AND RESULTS

Fermentations of synthetic grape juice media were conducted in a factorial design with yeast assimilable nitrogen (YAN) (60 or 250 mg l(-1)) and biotin (0, 1 or 10 microg l(-1)) as variables. All media contained 240 g l(-1) glucose + fructose (1 : 1) and were fermented using biotin-depleted Saccharomyces cerevisiae strains EC1118 or UCD 522. Both strains exhibited weak growth and sluggish fermentation rates without biotin. Increased nitrogen concentration resulted in higher maximum fermentation rates, while adjusting biotin from 1 to 10 microg l(-1) had no effect. Nitrogen x biotin interactions influenced fermentation time, production of higher alcohols and hydrogen sulfide (H(2)S). Maximum H(2)S production occurred in the medium containing 60 mg l(-1) YAN and 1 microg l(-1) biotin.

CONCLUSIONS

Nitrogen x biotin interactions affect fermentation time and volatile production by Saccharomyces depending on strain. Biotin concentrations sufficient to complete fermentation may affect the organoleptic impact of wine.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study demonstrates the necessity to consider nutrient interactions when diagnosing problem fermentations.

Nonstarter lactic acid bacteria and aging temperature affect calcium lactate crystallization in cheddar cheese

The occurrence of unappetizing calcium lactate crystals in Cheddar cheese is a challenge and expense to manufacturers, and this research was designed to understand their origin. It was hypothesized that nonstarter lactic acid bacteria (NSLAB) affect calcium lactate crystallization (CLC) by producing D(-)-lactate. This study was designed to understand the effect of NSLAB growth and aging temperature on CLC. Cheeses were made from milk inoculated with Lactococcus lactis starter culture, with or without Lactobacillus curvatus or L. helveticus WSU19 adjunct cultures. Cheeses were aged at 4 or 13 degrees C for 28 d, then half of the cheeses from 4 and 13 degrees C were transferred to 13 and 4 degrees C, respectively, for the remainder of aging. The form of lactate in cheeses without adjunct culture or with L. helveticus WSU19 was predominantly L(+)-lactate (> 95%, wt/wt), and crystals were not observed within 70 d. While initial lactate in cheeses containingL. curvatus was only L(+)-lactate, the concentration of D(-)-lactate increased during aging. After 28 d, a racemic mixture of D/L-lactate was measured in cheeses containing L. curvatus; at the same time, CLC was observed. The earliest and most extensive CLC occurred on cheeses aged at 13 degrees C for 28 d then transferred to 4 degrees C. These results showed that production of D(-)-lactate by NSLAB, and aging temperature affect CLC in maturing Cheddar cheese.

Fermentative activity and production of volatile compounds by Saccharomyces grown in synthetic grape juice media deficient in assimilable nitrogen and/or pantothenic acid

AIMS

To understand the impact of assimilable nitrogen and pantothenic acid on fermentation rate and synthesis of volatile compounds by Saccharomyces under fermentative conditions.

METHODS AND RESULTS

A 2 x 3 factorial experimental design was employed with the concentrations of yeast assimilable nitrogen (YAN) (60 and 250 mg l(-1)) and pantothenic acid (10, 50 and 250 microg l(-1)) as variables. In media containing 250 microg l(-1) pantothenic acid, H2S production by two different species of Saccharomyces decreased when YAN was increased from 60 to 250 mg l(-1). Conversely, H2S production was significantly higher when the concentration of assimilable nitrogen was increased if pantothenic acid was deficient (10 or 50 microg l(-1)). Yeast synthesis of other volatile compounds were impacted by both assimilable nitrogen and pantothenic acid.

CONCLUSIONS

While growth and fermentative rate of Saccharomyces was more influenced by nitrogen than by pantothenic acid, complicated interactions exist between these nutrients that affect the synthesis of volatile compounds including H2S.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study has important implications for the winemaking industry where a better understanding of the nutritional requirements of Saccharomyces is necessary to reduce fermentation problems and to improve final product quality.

Lactobacillus nagelii sp. nov., an organism isolated from a partially fermented wine

A Gram-positive rod was isolated from a commercial grape wine undergoing a sluggish/stuck alcoholic fermentation. The organism produced DL-lactic acid from glucose without gas formation, produced dextran from sucrose, hydrolysed aesculin and fermented galactose, D-glucose, D-fructose, D-mannose, L-sorbose, rhamnose, mannitol, sorbitol, methyl alpha-D-glucoside, N-acetylglucosamine, amygdalin, salicin, cellobiose, maltose, sucrose, trehalose and beta-gentiobiose. 16S rRNA gene sequence analysis revealed that the isolate was phylogenetically a member of the genus Lactobacillus and formed a distinct subline within the Lactobacillus casei cluster of species. On the basis of phenotypic and phylogenetic evidence, Lactobacillus nagelii sp. nov. ATCC 700692T is proposed as a new species.

Lactobacillus kunkeei sp. nov.: a spoilage organism associated with grape juice fermentations

A Gram-positive rod was isolated from a commercial grape wine undergoing a sluggish/stuck alcoholic fermentation. The organism produced L-lactic acid from glucose, possessed weak catalase activity, and fermented relatively few carbohydrates, i.e. glucose, fructose, sucrose, raffinose (weakly) and mannitol. The 16S rRNA gene sequence analysis revealed that the isolate was phylogenetically a member of the genus Lactobacillus and formed a distinct subline within the Lact. casei cluster of species. Based on phenotypic and phylogenetic evidence, a new species is proposed, Lact. kunkeei. The type strain of Lact. kunkeei is ATCC 700308.

Evaluation of Four Pea ( Pisum sativum ) Cultivars in PE-2 Medium for the MPN Enumeration of Anaerobic Spore-Forming Organisms

Untreated 'Alaska' seed peas have traditionally been used to prepare PE-2 medium, a medium used to recover anaerobic bacteria. Three cultivars of seed peas, 'Columbian', 'Yellow', and 'Scotch' were compared to the cultivar 'Alaska' peas in PE-2 for recovery of Clostridium butyricum ATCC 860, Clostridium sporogenes ATCC 7955/NCA 3679, and Thermoanerobacterium thermosaccharolyticum ATCC 25773 determined by using the most probable number (MPN) technique. Organisms were grown in cooked meat medium (CMM) and enumerated by the three-tube MPN method in PE-2 media incubated at 37°C for 48 h. Recovery of C. butyricum and T. thermosaccharolyticum grown in homogenates of commercial cream-style corn and vegetable beef soup were also evaluated. Similar recovery of organisms from stock cultures or from foodstuffs were observed in PE-2 prepared with three of the pea cultivars ('Alaska', 'Columbian', and 'Yellow'). While the 'Scotch' cultivar PE-2 medium yielded recoveries comparable to PE-2 prepared with the other pea cultivars, turbid tubes were occasionally observed from which viable microorganisms could not be recovered. This cultivar is therefore not recommended due to the probability of yielding false positives in the MPN technique.

Thresholds for short-latency auditory-evoked potentials to tones in notched noise in normal-hearing and hearing-impaired subjects

The thresholds for the short-latency auditory evoked potentials (SLAEPs) to short-duration tones presented in notched-noise masking were evaluated in 20 normal-hearing and 20 hearing-impaired subjects. The differences (dB) between these thresholds (dB nHL) and the pure-tone behavioral thresholds (dB HL) across all 40 subjects were 11.6, 6.1, 6.3 and 0.8 dB for 500, 1,000, 2,000 and 4,000 Hz, respectively. These differences were significantly smaller for the hearing-impaired subjects than for the normal-hearing subjects. Ninety-eight percent of the SLAEP threshold estimations were within 30 dB of the subjects' pure-tone behavioral thresholds and 91% were within 20 dB.

Inducing malolactic fermentation in wines

Malolactic fermentation (MLF) in wine can be accomplished by relying on the natural microflora or by inducing through inoculation of a specific strain(s) of malolactic bacteria, primarily strains of Leuconostoc oenos. Problems with inducing MLF include intrinsic factors of the grape must such as pH, presence of sulfur dioxide, and ethanol in addition to antagonism of malolactic bacteria by wine yeast. Current methods and new technology to improve the predictability of MLF are discussed.

Total Sulfur Dioxide Residuals in Fresh Mushrooms Washed in Sulfite Solutions 1

Freshly-harvested, cultivated mushrooms ( Agaricus bisporus ) were washed in 1000 ppm solutions of sodium sulfite and stored in ventilated, polyvinylchloride film-overwrapped packages at 5 and 15°C. Total sulfur dioxide of the mushrooms was measured by the modified Monier-Williams procedure numerous times during a 48-h storage period. Initial SO₂ averaged 48.1 ppm and subsequently declined at a logarithmic rate. Total SO₂ fell below detectable levels (<10 ppm) at about 11.8 and 15.6 h at 15 and 5°C, respectively.

Brainstem electric-response audiometry in infants of a neonatal intensive care unit

Brainstem electric-response audiometry was used to assess the auditory function of 600 infants from a neonatal intensive care unit. Two groups of children were tested, one group as inpatients prior to discharge with a mean age at test of 39.4 weeks and one group as outpatients with a mean age at test of 55.4 weeks. Our results indicate that testing infants when they are older will reduce the incidence of failure on the initial evaluation and will reduce the identification of transient hearing losses which resolve spontaneously. Our results also indicate that a threshold of 30 dB nHL or less is probably normal and that some infants with a threshold of 40 dB nHL at first test require otological or audiological management.

Neonatal auditory brain stem responses from ipsilateral and contralateral recording montages

Ipsilateral and contralateral auditory brain stem responses were recorded from both ears of 10 neonates between 37 and 43 weeks from conception with normal auditory brain stem function. The most prominent component of the contralateral response was a forehead positive deflection occurring 0.3 millisecond before the ipsilateral wave III followed by two forehead negative waves, the latter present at the same latency as the ipsilateral wave V. The amplitude of the contralateral response was small: at 30 dB nHL only 7 of the 20 ears showed clear responses from this montage. The morphology of the neonatal contralateral response is thus considerably different than the ipsilateral, unlike the adult. A neonate could be mistakenly diagnosed as hearing impaired or neurologically involved if the interpretation is based on the contralateral recording.