An intron variant of the GLI family zinc finger 3 (GLI3) gene differentiates resistance training-induced muscle fiber hypertrophy in younger men.

We examined the association between genotype and resistance training-induced changes (12 wk) in dual x-ray energy absorptiometry (DXA)-derived lean soft tissue mass (LSTM) as well as muscle fiber cross-sectional area (fCSA; vastus lateralis; n = 109; age = 22 ± 2 y, BMI = 24.7 ± 3.1 kg/m2 ). Over 315 000 genetic polymorphisms were interrogated from muscle using DNA microarrays. First, a targeted investigation was performed where single nucleotide polymorphisms (SNP) identified from a systematic literature review were related to changes in LSTM and fCSA. Next, genome-wide association (GWA) studies were performed to reveal associations between novel SNP targets with pre- to post-training change scores in mean fCSA and LSTM. Our targeted investigation revealed no genotype-by-time interactions for 12 common polymorphisms regarding the change in mean fCSA or change in LSTM. Our first GWA study indicated no SNP were associated with the change in LSTM. However, the second GWA study indicated two SNP exceeded the significance level with the change in mean fCSA (P = 6.9 × 10-7 for rs4675569, 1.7 × 10-6 for rs10263647). While the former target is not annotated (chr2:205936846 (GRCh38.p12)), the latter target (chr7:41971865 (GRCh38.p12)) is an intron variant of the GLI Family Zinc Finger 3 (GLI3) gene. Follow-up analyses indicated fCSA increases were greater in the T/C and C/C GLI3 genotypes than the T/T GLI3 genotype (P < .05). Data from the Auburn cohort also revealed participants with the T/C and C/C genotypes exhibited increases in satellite cell number with training (P < .05), whereas T/T participants did not. Additionally, those with the T/C and C/C genotypes achieved myonuclear addition in response to training (P < .05), whereas the T/T participants did not. In summary, this is the first GWA study to examine how polymorphisms associate with the change in hypertrophy measures following resistance training. Future studies are needed to determine if the GLI3 variant differentiates hypertrophic responses to resistance training given the potential link between this gene and satellite cell physiology.

Ordered Eating and Its Effects on Various Postprandial Health Markers: A Systematic Review.

OBJECTIVE: Aberrations in glucose, insulin, and other postprandial (PP) markers are common in obesity and cardiometabolic disorders. One potentially simple lifestyle/dietary modification to manage these issues is to change the order in which foods are consumed within meals. Carbohydrate exerts the largest effect on PP glucose, and there is some evidence that ingesting dietary fat or protein before carbohydrate delays gastric emptying of carbohydrate and reduces PP glucose. Additionally, certain dietary proteins may augment insulin release if ingested with carbohydrate, thereby improving blood glucose clearance. This review aimed to systematically evaluate evidence from acute experiments that modified the order in which foods were consumed in isocaloric meals. METHODS: Outcomes of interest were PP glucose and insulin (including area under the curve for both), C-peptide, gut hormones, and perceptual responses. Three databases were searched (PubMed, Cochrane CENTRAL, Web of Science) in February 2022. Additionally, reference lists of identified reports were searched, and an author of several studies was consulted to verify that relevant literature was included. The review included acute interventions that administered isocaloric meals of the same foods but with foods eaten in different orders. Studies were not excluded based on participant characteristics. RESULTS: Eleven reports were identified. All reports that assessed glucose and insulin showed a tendency toward lower levels, at least over parts of the PP period, by consuming carbohydrates last. GLP-1 tended to be higher in carbohydrate-last conditions, though this was only measured in a few studies. Perceptual responses (hunger, fullness, etc.) were not consistently different between conditions in two studies, but the certainty of evidence was very low. CONCLUSIONS: Findings indicate that, at least acutely, there may be benefits to eating carbohydrate after vegetable and/or protein-rich foods. The most consistent effect (judged as moderate certainty) is that carbohydrate-last meal orders tend to lower blood glucose and insulin excursions.

Trunk-to-leg-volume ratio is not associated with bone density or fracture risk in middle-aged adults: results from the National Health and Nutrition Examination Survey.

Unlike a high body mass index or waist circumference, a high trunk-to-leg-volume ratio does not associate with a lower risk of osteopenia/osteoporosis at the femoral neck. While elevated TLVR showed a suggestive association with a history of wrist fracture in women, additional research is needed to confirm this suggestion. PURPOSE: Body mass index (BMI) and waist circumference (WC) are commonly used to predict bone health, which is typically assessed via bone mineral density (BMD). Trunk-to-leg-volume ratio (TLVR), a relatively novel measure, predicts cardiometabolic outcomes, but its relationships with BMD and fracture remain unstudied. This study evaluated these anthropometric measures' associations with BMD and fracture in Americans aged 40-60 years. METHODS: Analyses of middle-aged adults from the 2013-2014 to 2017-2018 National Health and Nutrition Examination Survey were conducted. Whole-body, dual-energy X-ray absorptiometry was used to quantify TLVR as well as BMD at the lumbar spine, while a femur-specific scan was used to quantify femoral neck BMD. Fracture history was self-reported. Linear and logistic regression models were constructed with age, diabetes, smoking, race/ethnicity, education, and physical activity as confounding variables. RESULTS: TLVR was generally not associated with BMD, while WC and BMI showed positive associations with femoral neck BMD. Odds of osteopenia/osteoporosis at the femoral neck were ~ 65-80% lower among participants in the highest tertile of BMI and WC versus the lowest (p < 0.001). There were no statistically significant associations between anthropometric predictors and fracture. Women in tertiles 2 or 3 of TLVR (p = 0.097 and 0.079, respectively) did have 2.66 times the odds of wrist fracture than women in tertile 1, but this was not significant. CONCLUSION: As shown in previous research, BMI and WC show positive associations with femoral BMD. In contrast, the more novel anthropometric marker TLVR shows no association with femoral BMD, and no clear association with fracture.

Anxiety and visceral sensitivity relate to gastrointestinal symptoms in runners but not pre- or during-event nutrition intake.

BACKGROUND: Previous research has shown anxiety to relate to gastrointestinal (GI) symptoms in endurance athletes, but it remains unclear whether competition-related fueling is impacted by anxiety. This study examined whether general anxiety, pre-race anxiety, and visceral sensitivity were associated with nutritional intake before and during endurance running races. METHODS: A total of 149 (86 female, 63 male) runners participated in this cross-sectional survey study. Assessments, which were carried out at a median of eight hours after races finished, included the State-Trait Inventory for Cognitive and Somatic Anxiety (STICSA)-Trait, Visceral Sensitivity Index (VSI), perceived pre-race anxiety (0-10), during-race GI symptoms (total, upper, and lower), and intakes of energy, macronutrients, fluid, and caffeine for the pre-race period (4 h before) and during races. Spearman's correlations were used to examine associations between variables. A two-sided P value ≤0.01 was used as the threshold for significance. RESULTS: Median race durations were 139.5 and 126.9 min for women and men, respectively. VSI scores were positively correlated with total during-race GI symptoms, while STICSA-Trait scores were positively correlated with total and upper during-race GI symptoms (ρ=0.22-0.25; P<0.01). No significant correlations were observed between measures of anxiety/visceral sensitivity and nutrient intakes before or during races. CONCLUSIONS: In a sample of primarily recreational runners, greater anxiety and visceral sensitivity did not translate to lower intakes of energy, macronutrients, fluid, etc. around competition. Further work is needed in other settings, especially with high-level athletes, to understand the impact of competition anxiety on fueling choices.