Endogenous Ghrelin Levels and Perception of Hunger: A Systematic Review and Meta-Analysis.

BACKGROUND: Ghrelin is an orexigenic hormone primarily released by the stomach and has 2 isoforms: acylated ghrelin (AG) and de-acylated ghrelin (DAG), that appear to have different functions in humans. OBJECTIVES: To perform a systematic review and meta-analysis of the association between plasma concentrations of total ghrelin (TG), AG, and DAG and perceptions of hunger in healthy adults. METHODS: The following criteria were used for inclusion: 1) sample contained adults ≥18 y of age, 2) body mass index [BMI kg/m2] was ≥18.5, 3) ghrelin was sampled through blood, 4) subjective hunger was measured on a validated scale, 5) study reported a Pearson product correlation of ghrelin or had relevant figure(s) for data extraction, 6) participants were healthy with no overt disease, 7) protocols contained no physical activity or weight loss medication that suppressed appetite, 8) interventions were conducted without environmental manipulations. Moderators assessed were age, BMI, percentage of body fat (%BF), macronutrient content of test meals, energy intake (kcals), sex, and ghrelin isoform (AG, DAG, or TG). RESULTS: The analysis included 47 studies (110 trials, n = 1799, age: 31.4 ± 12.0 y, BMI: 26.0 ± 4.75 kg/m2) and measured AG (n = 47 trials), DAG (n = 12 trials), and TG (n = 51 trials). The overall model indicated that ghrelin concentrations and perceptions of hunger were moderately correlated (r = 0.43, P < 0.001), and ghrelin isoform significantly moderated this relationship (AG: r = 0.60, P < 0.001; TG: r = 0.215, P = 0.01; DAG: r = 0.53, P = 0.695). Other significant moderators included age (b = -0.02, P = 0.01), BMI (b = -0.03, P = 0.05), %BF (b = -0.03, P = 0.05), energy intake (b = 0.0003, P = 0.04), and percentage of carbohydrates of test meals (b = 0.008, P = 0.05). CONCLUSIONS: Ghrelin is associated with perceptions of hunger in humans, and this relationship is strengthened when AG is isolated; thus, AG may have a large impact on hunger signals in various populations. Future research should attempt to understand the role of DAG in hunger sensations.

Preschool- and childcare center-based interventions to increase fruit and vegetable intake in preschool children in the United States: a systematic review of effectiveness and behavior change techniques.

BACKGROUND: Fruit and vegetable (FV) consumption in children in the United States (US) is very low. Adequate FV consumption is required for proper development during childhood, and dietary habits are established during preschool-age and tend to persist into adulthood. As most U.S. preschool-aged children attend childcare or preschool, this may be an opportune time and setting to conduct interventions to improve FV intake. These interventions should be based in theory and use behavior change techniques (BCTs) to explain mechanisms for expected change. To date, no published reviews have examined the effectiveness of childcare- or preschool-based FV interventions in preschoolers and their use of theoretical frameworks and BCTs. METHODS: This systematic review was completed adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Inclusion criteria were randomized controlled trials (RCTs) published between 2012 and 2022 of interventions to improve diet or FV intake in preschoolers (aged 2-5 years) in childcare or preschool-settings. A search of four databases was conducted between in September 2022 using search terms pertaining to the study's primary aim (FV consumption), age group (preschool-aged), settings (US childcare or preschool settings), and study design (RCT). Additional criteria were objective measures of FV consumption or skin carotenoids, as a proxy for FV intake. Included studies were narratively synthesized based on intervention type, measured effect, and use of theory and BCTs. RESULTS: The search resulted in six studies that reported on nine interventions. Overall, six interventions increased FV intake, of which five used nutrition education and one manipulated the feeding environment. Among the three interventions with no measured effect, two manipulated the feeding environment and one used peer modeling. Effective studies used at least three BCTs, though no pattern was observed between use of theory or BCTs and intervention effect. CONCLUSIONS: While several studies have shown promising results, the limited number of studies identified in this review highlights key gaps in this field: there is a need for studies to test FV interventions in US childcare settings that use objective measures of FV intake, directly compare intervention components and BCTs, are theory-based, and assess long-term behavior change.

Diet Quality and Dietary Inflammatory Index Score among Women's Cancer Survivors.

The purpose of this study was to investigate Healthy Eating Index 2015 (HEI-2015) and Energy-Adjusted Dietary Inflammatory Index (E-DIITM) scores in women's cancer survivors and to examine socio-economic (SES) characteristics associated with these two diet indices. In this cross-sectional study, survivors of women's cancers completed a demographic questionnaire and up to three 24-h dietary recalls. HEI-2015 and E-DII scores were calculated from average intakes. One-way ANOVA was used to examine the association of various demographic factors on HEI-2015 and E-DII scores. Pearson Correlation was used to calculate the correlation between the two scores. The average HEI-2015 score was 55.0 ± 13.5, lower than the national average, and average E-DII was -1.14 ± 2.24, with 29% of women having a more pro-inflammatory and 71% a more anti-inflammatory diet. Diets with higher HEI-2015 scores were associated with more anti-inflammatory diets (r = -0.67, p < 0.001). Those having a graduate degree (F(2,49) = 3.6, p = 0.03) and completing cancer treatment > 4 years ago (F(2,49) = 4.8, p = 0.01) had higher HEI-2015 scores. There were no associations between SES and E-DII scores. The diet quality of women's cancer survivors is comparatively low, but many achieved an anti-inflammatory diet; a promising avenue for preventing recurrence. There is an urgent need to involve health care professionals in the guidance of women's cancer survivors to improve diet quality and prevent cancer recurrence.

Changes in Learning Outcomes after Dietary Intervention in Preschoolers: A Pilot Study.

The executive functioning skill set, which includes working memory, cognitive flexibility, and inhibitory control, begins developing in early life and continues into adulthood. Preschoolers' abilities to perform those skills may be influenced by diet. The purpose of this study was to explore the acute effects of consuming a low-GI diet compared to the usual childcare diet on preschoolers' self-reported feelings of hunger and fullness and their performance on learning-associated tasks. This study was a prospective feeding trial in n = 20 children 3-4 years of age, completed in a laboratory setting where children attended "day camps" and consumed two days of usual diet (CON) and two days of low-GI (INT) diet. Learning outcomes were evaluated using select learning assessments including the Kansas Reflection-Impulsivity Scale for Preschoolers (KRISP), Track-it, Peg Tapping, and Happy/Sad. Repeated measures, full-factorial analysis of covariance revealed that diet was significantly related to impulsivity (p > 0.05), and univariate analysis of variance indicated that feelings of hunger and fullness differentially affected cognitive constructs in that feeling full improved impulsivity and attention, while feeling hungry improved inhibitory control. These findings highlight that the connection between diet and learning-related skills of children are independently mediated by both diet composition and feelings of hunger and fullness.