ECSS Paris 2023: OP-PN02
INTRODUCTION: (Poly)phenols may mitigate exercise-induced muscle damage (EIMD), ostensibly due to their antioxidant and anti-inflammatory properties. However, such research is limited to high doses of (poly)phenols in singular foods or compounds, such as tart cherry juice or curcumin. Indeed, there is a paucity of research on whether interventions containing a range of (poly)phenolic foods can attenuate symptoms of EIMD, such as muscle function loss, and delayed onset of muscle soreness (DOMS). Providing a range of (poly)phenol-rich foods could elicit synergistic effects, enhancing the efficacy of (poly)phenol interventions, and offer an alternative to concentrated supplements. Thus, the aim of this study was to examine whether a (poly)phenol-rich diet could attenuate markers of EIMD. METHODS: Thirty (n=18 males, n=12 females) recreationally strength trained individuals (age 23±3 y; height 1.74±0.11 m; mass 71.3±11.5 kg) were randomly assigned to a (poly)phenol unrestricted (U-POL) or (poly)phenol restricted (R-POL) diet for 10 days. The U-POL diet was further supplemented with high (poly)phenol foods (40 g/day of dark chocolate and walnuts) and the R-POL diet with low (poly)phenol foods (40 g/day of milk chocolate and peanuts). On day 8 of their diet, participants completed 200 eccentric knee extensions at 60°s-1 on an isokinetic dynamometer. Pre (PRE), post (POST), 24 h-post (24H), 48 h-post (48H), and 72 h-post-exercise (72H), maximum isometric voluntary force of the knee extensors (MIVF), DOMS (0-200mm VAS), and via femoral nerve stimulation, voluntary activation (VA), rate of twitch development within 0-50 ms (RTD.50), time to peak twitch (CT), and half relaxation time (0.5RT) were assessed. At PRE, POST and 48H, white blood cell (WBC), neutrophil (NEU), and lymphocyte (LYM) counts were measured. Mixed-model ANOVAs were used to examine for group x time-point interactions; Bonferroni adjustments were applied for post-hoc tests. RESULTS: Energy intake, macronutrient intake, and total work completed during exercise did not differ between groups (P≥0.293). The U-POL group consumed more (poly)phenol-rich foods in total than the R-POL group (+322 g/day; P<0.001), including more fruits, vegetables, herbs and spices (+158 g/day; P<0.001), and wholegrains (+69 g/day; P=0.004). MIVF was reduced by ~31% post-exercise and remained ~12% below baseline at 72H (P<0.001). Exercise increased DOMS, which peaked at 48H (+148%; P<0.001). VA, CT, RTD.50, and 0.5RT were reduced at POST (P≤0.019), and at 24H for VA and RTD.50 (P≤0.043). NEU were elevated at POST (P<0.001), and LYM were reduced at POST and 48H (P<0.001). No significant group (P≥0.432) or interaction (P≥0.160) effects were observed for any variable. CONCLUSION: A (poly)phenol-rich diet for 10 days did not significantly influence MIVF, DOMS, neuromuscular function, or WBC counts in the 72-h following 200 eccentric muscle contractions, possibly due to an insufficient dose and/or the inherent inter-individual variability in EIMD responses.
Read CV Emily HansellECSS Paris 2023: OP-PN02
INTRODUCTION: The incorporation of omega-3 polyunsaturated fatty acids (n-3 PUFA) into the phospholipid membrane of human skeletal muscle cells modulates muscle protein turnover. However, differential effects of n-3 PUFA ingestion on gene expression in young and older adults are yet to be fully understood and may contribute, in part, to age-related differences in n-3 PUFA impact on skeletal muscle. We sought to determine the influence of n-3 PUFA ingestion on global gene expression profiles in skeletal muscle of young and older adults. METHODS: Thirteen young (23±3 y, 7 female) and eleven older (67±6 y, 7 female) adults supplemented their diet, in capsule form, with 1.26g/day n-3 PUFA (720mg EPA + 540mg DHA) over 12 wk. Muscle biopsies were obtained at baseline and after 12 wk of supplementation for analysis of n-3 PUFA phospholipid membrane composition using gas chromatography, and global gene expression using microarrays. Gene category enrichment was determined using the Molecular Signatures Hallmark gene sets and data were analysed using R. Lean and fat mass was quantified via dual-energy X-ray absorptiometry, physical activity status monitored with ActiGraph GT3X+, and handgrip strength assessed using a Takei handgrip dynamometer. RESULTS: The percent of n-3 PUFA relative to total fatty acids increased in muscle phospholipid membranes of young (+1.4 ± 0.2%) and older (+1.5 ± 0.5%) adults after 12 wk with no significant age-related differences (P>0.05). In young adults, n-3 PUFA ingestion downregulated two pathways related to bioenergetics (Ox Phos and ROS) and four pathways related to tissue regeneration (MYC targets, DNA repair, IFN-α, IFN-γ), while one pathway linked to tissue regeneration (Mitotic spindle) was upregulated. In older adults, three pathways related to tissue regeneration (Epithelial mesenchymal transition, Angiogenesis, IFN-γ) were upregulated, while one gene set related to bioenergetics (Ox Phos) was downregulated. Differential regulation of IFN-α, and IFN-γ gene sets was observed between age groups (upregulation in older adults, downregulation in young adults). Although physical activity increased from 39 ± 6% to 42 ± 6% of recorded time, there was no significant difference between age groups (P>0.05). No significant effect of n-3 PUFA ingestion on lean mass or strength was observed in young or older adults (P>0.05). CONCLUSION: To conclude, the incorporation of n-3 PUFA into skeletal muscle membranes differentially alters gene sets involved in skeletal muscle regeneration and bioenergetics in young and older adults. These effects were unrelated to changes in physical activity status, lean mass, and strength over the 12-wk supplementation period. This study highlights the potential clinical application of n-3 PUFA supplementation in remodelling skeletal muscle across the lifespan.
Read CV Milena BanicECSS Paris 2023: OP-PN02
INTRODUCTION: Resistance training (RT) and time-restricted eating (TRE) are established lifestyle modalities for enhancing body composition. Yet, their combined effect has yet to be determined. This study aimed to determine the effects of RT with either TRE or normal diet (ND) on fat mass (FM) and fat-free mass (FFM) in obese men with metabolic syndrome (MetS). METHODS: In this randomized controlled trial, 32 obese men with MetS (aged 49.1±5.8y, BMI 31.0±4.0kg/m2, body fat 33.7±4.6%) were randomly assigned to TRE of 8 hours of eating and 16 hours of fasting (n=16) or ND (n=16) for ten weeks. Both groups consumed an isocaloric diet and underwent the same supervised whole-body RT three times per week. Body composition changes were assessed using dual-energy X-ray absorptiometry (DXA) scans pre- and post-intervention. A 2-way repeated measures ANOVA evaluated the within- and between-group differences and interaction. RESULTS: After 10 weeks of intervention, body weight significantly decreased for the TRE group (-1±1.4 kg, p=0.02) and slightly increased (0.3±1.8 kg) for the ND group. Both dietary interventions decrease FM (TRE: -2.3±1.2 kg, ND: -2.2±1.7 kg, p<0.001 for both), with no significant differences between the groups. Although both groups showed a considerable improvement in FFM (TRE: 1.3±1.1 kg, p=0.001, ND: 2.5±0.9 p=0.001), the increase was more substantial in the ND group (p=0.003), indicating a differential effect of diet on muscle mass gains in combination with RT. CONCLUSION: Both TRE and ND, along with RT, improve body composition in obese men with MetS, but ND was more effective in enhancing FFM. This suggests that meal timing and duration can influence muscle mass.
Read CV Roi YavetzECSS Paris 2023: OP-PN02