18 research outputs found
Untersuchung der Dosis-Wirkungsbeziehung von Isomaltulose
No full textHintergrund: Der Einfluss von Kohlenhydraten auf die Leistung im Ausdauersport ist schon sehr genau untersucht. Die Isomaltulose ist ein natürlich vorkommendes Disaccharid, das aus einem Glukose- und einem Fruktosemolekül besteht. Im Gegensatz zu Saccharose und Maltose wird sie im Dünndarm sehr langsam hydrolisiert. Der Anstieg in der Blutglukose und im Insulin verläuft daher um Vergleich zu anderen Sacchariden flacher. Für Glukose gibt es bereits eine Dosis-Wirkungsbeziehung mit einer maximal empfohlenen Menge von 90 g/h. Solche Daten sind für die Isomaltulose jedoch noch ausständig.
Zielsetzung: Ziel der vorliegenden Arbeit war es, die Dosis-Wirkungsbeziehung von Isomaltulose zu untersuchen. Die Untersuchung sollte anhand der Messung von verschiedenen Leistungsfaktoren während einer zweistündigen Dauerbelastung am Rad und einem abschließenden Zeitfahren erfolgen. Aus den Ergebnissen abgeleitet sollten am Ende Trainingsempfehlungen für die Dosierung von Isomaltulose gegeben werden können.
Methodik: Für die empirische Arbeit wurde eine doppelblinde, randomisierte Cross-Over Studie mit zwölf Ausdauersportlern durchgeführt.
Resultate und Schlussfolgerung: Für Isomaltulosekonzentrationen zwischen 20 und 60 g/h konnte keine Dosis-Wirkungsbeziehung nachgewiesen werden. Es gibt zwischen den Konzentrationen weder einen Unterscheid in der Effizienz noch in den physiologischen Parametern oder der Substratverwendung. Auch in der Leistung beim abschließenden Zeitfahren gibt es keine signifikanten Unterschiede zwischen den Konzentrationen.Background: The influence of carbohydrates on performance in endurance sports has already been studied in great detail. Isomaltulose is a naturally occurring disaccharide consisting of a glucose and a fructose molecule. In contrast to sucrose and maltose, it is hydrolized very slowly in the small intestine. The increase in blood glucose and insulin is therefore flatter compared to other saccharides. For glucose there is already a dose-response relationship with a maximum recommended amount of 90 g/h. However, such data are still pending for isomaltulose.
Objective: The aim of this study was to investigate the dose-response relationship of isomaltulose. The investigation was to be carried out by measuring various power factors during a two-hour continuous cycling test and a final time trial. Based on the results, training recommendations for the dosage of isomaltulose should be given.
Methods: For the empirical work a double-blind, randomized cross-over study with twelve endurance athletes was conducted.
Results and conclusion: For isomaltulose concentrations between 20 and 60 g/h no dose- response relationship could be demonstrated. There is no difference between the concentrations in terms of efficiency, physiological parameters or substrate use. There are also no significant differences between the concentrations in the performance at the final time trial
Effects of carbohydrate periodisation on performance and fat oxidation in endurance sports
No full textThe study focuses on investigating the effects of diet periodisation adapted to training on endurance performance and fat oxidation. The aim is to identify long-term adaptations of the body to different diets with different carbohydrate contents and their combination, taking into account the current training goal. The primary aim is to maximise fat oxidation during a 4-week low-intensity endurance training session using a low-carbohydrate diet. Subsequently, a further 4-week training phase with higher intensity and a carbohydrate-rich diet is intended to increase performance at higher intensities.
The adapted diet in the various training phases should result in the athletes showing increased fat oxidation at the end of the trial period compared to the group without dietary adaptation. In addition, they are expected to show improved resilience during more intensive exercise compared to the control group with a low-carbohydrate diet. This assumption is based on the idea that the respective dietary adaptations have an additive effect that could increase the performance of the intervention group compared to the respective comparison groups
Effects of carbohydrate periodisation on performance and fat oxidation in endurance sports
No full textThe study focuses on investigating the effects of diet periodisation adapted to training on endurance performance and fat oxidation. The aim is to identify long-term adaptations of the body to different diets with different carbohydrate contents and their combination, taking into account the current training goal. The primary aim is to maximise fat oxidation during a 4-week low-intensity endurance training session using a low-carbohydrate diet. Subsequently, a further 4-week training phase with higher intensity and a carbohydrate-rich diet is intended to increase performance at higher intensities.
The adapted diet in the various training phases should result in the athletes showing increased fat oxidation at the end of the trial period compared to the group without dietary adaptation. In addition, they are expected to show improved resilience during more intensive exercise compared to the control group with a low-carbohydrate diet. This assumption is based on the idea that the respective dietary adaptations have an additive effect that could increase the performance of the intervention group compared to the respective comparison groups
Effects of carbohydrate periodisation on performance and fat oxidation in endurance sports
No full textThe study focuses on investigating the effects of diet periodisation adapted to training on endurance performance and fat oxidation. The aim is to identify long-term adaptations of the body to different diets with different carbohydrate contents and their combination, taking into account the current training goal. The primary aim is to maximise fat oxidation during a 4-week low-intensity endurance training session using a low-carbohydrate diet. Subsequently, a further 4-week training phase with higher intensity and a carbohydrate-rich diet is intended to increase performance at higher intensities.
The adapted diet in the various training phases should result in the athletes showing increased fat oxidation at the end of the trial period compared to the group without dietary adaptation. In addition, they are expected to show improved resilience during more intensive exercise compared to the control group with a low-carbohydrate diet. This assumption is based on the idea that the respective dietary adaptations have an additive effect that could increase the performance of the intervention group compared to the respective comparison groups
Longer-Term Effects of the Glycaemic Index on Substrate Metabolism and Performance in Endurance Athletes
No full textNutrition has a decisive influence on athletic performance. However, it is not only the nutrient intake during exercise that is important, but the daily diet must also be adapted to the requirements of physical activity in order to optimally promote training adaptations. The goal of prolonged endurance training is to enhance fat oxidation, to maintain aerobic performance at a higher intensity while sparing limited carbohydrate stores. The targeted modification of macronutrient intake is a common method of influencing substrate metabolism, fuel selection, and performance. However, it is not well established whether the glycaemic index of carbohydrates in our daily diet can improve endurance performance by influencing carbohydrate or fat oxidation during training. Therefore, the aim of the following review is to elucidate the possible influence of the glycaemic index on substrate utilization during exercise and to clarify whether the consumption of a long-term high-carbohydrate diet with different glycaemic indices may have an influence on substrate metabolism and endurance performance
Impact of collagen peptide supplementation together with long-term resistance training on maximal strength and muscle size in healthy adults – A systematic review and meta-analysis
No full textIntroduction & Purpose
Of late, numerous studies have investigated the use of collagen peptides (CP) as an ergogenic aid to boost sports performance, although CP is frequently referred to as low-quality protein. Given the high content of glycine, proline, and hydroxyproline in collagen proteins, the current rationale behind the potential impact of CP supplementation may revolve around the incorporation of these amino acids into muscle and tendon tissues (Holwerda & van Loon, 2022). There have been reports of a notable increase in the uptake of these specific amino acids within two hours after the ingestion of 15 g gelatine, coupled with six minutes of rope skipping, as observed in human serum (Shaw et al., 2017). The combination of resistance training (RT) with immediate CP administration seems to serve as a potent stimulus for enhancing anabolic pathways such as phosphatidylinositol 3 - kinase - protein kinase B (PI3k - Akt), mitogen-activated protein kinase (MAPK) and the mechanistic target of rapamycin (mTOR) to induce myofibrillar hypertrophy and collagen synthesis (Centner et al. 2022). Some studies have already demonstrated increased muscle mass gains following CP intake together with exercise interventions (Balshaw et al., 2023), but not all (Centner et al., 2019). Since maximal strength is highly associated with muscular size (Balshaw et al., 2021) several trials have also investigated strength outcomes in various exercises accompanied with CP administration with equivocal results (Jendricke et al., 2019; Zdzieblik et al., 2021). Based on aforementioned findings and the fact that no systematic review and/or meta-analysis has examined the impact of long-term CP supplementation linked with RT on muscular adaptation and strength yet, a meta-analysis is conducted to figure out whether regular CP intake with RT is associated with improvements in maximal strength and increased muscle size.
Methods
The systematic review and meta-analysis was conducted based on PERSiST (implementing Prisma in Exercise, Rehabilitation, Sport medicine and SporTs science) guidelines. Studies investigating healthy adults (≥ 18 years of age, male & female) with a body mass index of 18.5 to 31 kg/m² were included. Both low and professional training status of subjects were suitable for inclusion. Participants had to ingest CP (as treatment group) daily at least for eight weeks, the control group a calorie or non-calorie matched placebo (PLA). Only studies with an accompanying RT of at least two times a week were included. Manuscripts had to be human randomized controlled trials (RCT). Studies adding creatine or caffeine as fortification were excluded. Literature search was carried out in March 2024 in PubMed, Scopus, CINAHL and SPORTDiscus without any restrictions. The following search string was applied in all databases: “collagen AND (peptide OR peptides OR supplement OR supplementation OR hydrolysate) AND (muscle strength OR architecture OR size) [AND (only added in Scopus)] NOT (disease OR skin OR osteoporosis OR osteoarthritis)”. References of included studies and Google Scholar were also screened (forward & backward search) and if eligible, handpicked. The following parameters of studies were chosen for each item: Muscle size: volume (cm³) of quadriceps (and also rectus femoris, vastus intermedius, lateralis and medialis alone), gluteus maximus & hamstrings; CSA (cm²) of the thighs; thickness (cm) of medial gastrocnemius, vastus lateralis, intermedius and rectus femoris. Maximal strength: maximal voluntary contraction and one-repetition maximum of both upper- and lower-body exercises. The Physiotherapy Evidence Database (PEDro) scale was used to assess risk of bias. Meta-analysis was conducted in Jamovi 2.4.11 using the standardized mean difference (SMD) of change scores (post – pre values, resulting in Δ mean and Δ SD) and a random effects model. Certainty of evidence was assessed using the GRADE (Grading of Recommendations Assessment, Development and Evaluation) approach.
Results
After duplicate removal, 847 studies were screened. Seventeen seemed to meet eligibility criteria. Due to some limitations such as missing and too short training interventions as well as an insufficient control group design, nine studies, all of them being RCT’s, were included. Six records sourced from website searches and citation investigations ultimately resulted in exclusion due to reasons mentioned earlier. 385 subjects, aged ~18 – 65, participated in the included studies. CP and PLA were administered daily ranging from 5 g (n = 2) to 15 g (n = 7) for at least 8 weeks. Three and six studies supplemented either maltodextrin or a non-caloric PLA, respectively. Dietary protein intake have not changed significantly throughout the trials. Training status of subjects varied, from either untrained to resistance trained (being able to squat 100% of the individual body weight) before study commencements. All nine studies prescribed a RT regimen of three times a week. None of the included studies achieved a total score below “good” (6 - 8), which implicates low risk of bias overall. Muscle size was investigated in 175 subjects in five studies using either MRI or sonography. CP intake led to a statistical significant pooled estimate (ES = 0.35, p = .002, I² = 0%, CI [0.13, 0.57], Figure 1). Nine studies including 385 subjects resulted in a significantly higher maximal strength following CP supplementation (ES = 0.23, p < .01, I² = 0.01%, CI [0.13, 0.57], Figure 1) compared to placebo. Overall, certainty of evidence for both parameters was low due to wide confidence intervals and varying training status of subjects.
Discussion
To the best of our knowledge, this is the first systematic review and meta-analysis examining the effects of long-term CP supplementation alongside regular RT on maximal strength and muscle size in healthy adults. Our findings suggest that prolonged (≥ 2 months) CP intake may significantly improve muscle size accrual and maximal strength, albeit with a low level of evidence. Similar to leucine, a single bolus of CP has been shown to evoke a higher upregulation of key anabolic pathways (PI3K - Akt, MAPK) involved in myofibrillar protein synthesis four hours following RT (Centner et al., 2022). Additionally, an in-vitro experiment treating C2C12 cells with the dipeptide hydroxyprolyl - glycine inducing phosphorylation of p70S6k, mTOR and Akt, suggesting myogenic differentiation (Kitakaze et al., 2016). CP also positively impacted maximal strength concurrently with muscle size. Among other factors, muscle fiber composition, muscle architecture, neural activation and specific tension also contribute to muscle strength. Significantly higher evoked contractile twitch peak torque but no quadriceps tension, muscle architectural differences and lack of muscle fiber type adaptation occurred in long-term trials, thus assuming a probable adaptation of passive tissue components (Balshaw et al., 2023; Kirmse et al., 2019).
Conclusion
A several-week regimen of CP supplementation alongside RT seems to offer advantages to healthy, active adults aiming to enhance both maximal strength and muscle size. A daily intake of 15 g CP seems to induce these adaptations. Future trials are encouraged to identify the optimal CP dosage, composition, absorption and incorporation into collagenous tissues.
References
Balshaw, T. G., Funnell, M. P., McDermott, E., Maden-Wilkinson, T. M., Abela, S., Quteishat, B., Edsey, M., James, L. J., & Folland, J. P. (2023). The effect of specific bioactive collagen peptides on function and muscle remodeling during human resistance training. Acta Physiologica, 237(2), Article e13903. https://doi.org/10.1111/apha.13903
Balshaw, T. G., Maden-Wilkinson, T. M., Massey, G. J., & Folland, J. P. (2021). The human muscle size and strength relationship: Effects of architecture, muscle force, and measurement location. Medicine & Science in Sports & Exercise, 53(10), 2140–2151. https://doi.org/10.1249/MSS.0000000000002691
Centner, C., Jerger, S., Mallard, A., Herrmann, A., Varfolomeeva, E., Gollhofer, S., Oesser, S., Sticht, C., Gretz, N., Aagaard, P., Nielsen, J. L., Frandsen, U., Suetta, C., Gollhofer, A., & König, D. (2022). Supplementation of specific collagen peptides following high-load resistance exercise upregulates gene expression in pathways involved in skeletal muscle signal transduction. Frontiers in Physiology, 13, Article 838004. https://doi.org/10.3389/fphys.2022.838004
Centner, C., Zdzieblik, D., Roberts, L., Gollhofer, A., & König, D. (2019). Effects of blood flow restriction training with protein supplementation on muscle mass and strength in older men. Journal of Sports Science & Medicine, 18(3), 471–478.
Holwerda, A. M., & van Loon, L. J. C. (2022). The impact of collagen protein ingestion on musculoskeletal connective tissue remodeling: A narrative review. Nutrition Reviews, 80(6), 1497–1514. https://doi.org/10.1093/nutrit/nuab083
Jendricke, P., Centner, C., Zdzieblik, D., Gollhofer, A., & König, D. (2019). Specific collagen peptides in combination with resistance training improve body composition and regional muscle strength in premenopausal women: A randomized controlled trial. Nutrients, 11(4), Article 892. https://doi.org/10.3390/nu11040892
Kirmse, M., Oertzen-Hagemann, V., de Marées, M., Bloch, W., & Platen, P. (2019). Prolonged collagen peptide supplementation and resistance exercise training affects body composition in recreationally active men. Nutrients, 11(5), Article 1154. https://doi.org/10.3390/nu11051154
Kitakaze, T., Sakamoto, T., Kitano, T., Inoue, N., Sugihara, F., Harada, N., & Yamaji, R. (2016). The collagen derived dipeptide hydroxyprolyl-glycine promotes C2C12 myoblast differentiation and myotube hypertrophy. Biochemical and Biophysical Research Communications, 478(3), 1292–1297. https://doi.org/10.1016/j.bbrc.2016.08.114
Shaw, G., Lee-Barthel, A., Ross, M. L., Wang, B., & Baar, K. (2017). Vitamin C-enriched gelatin supplementation before intermittent activity augments collagen synthesis. The American Journal of Clinical Nutrition, 105(1), 136–143. https://doi.org/10.3945/ajcn.116.138594
Zdzieblik, D., Jendricke, P., Oesser, S., Gollhofer, A., & König, D. (2021). The influence of specific bioactive collagen peptides on body composition and muscle strength in middle-aged, untrained men: A randomized controlled trial. International Journal of Environmental Research and Public Health, 18(9), Article 4837. https://doi.org/10.3390/ijerph1809483
Anti-obesity effects of prolonged collagen peptide supplementation in rodents - A systematic review with meta-analysis of animal studies
No full textSeveral studies conducted in animals, particularly in rodents, have investigated potential anti-obesity effects of long-term collagen peptide intake
Effects of long-term periodized carbohydrate intake on body composition, substrate metabolism and running performance in recreational active men: A pilot trial
No full textIntroduction & Purpose
It is important to consider the impact of nutrition on training adaptations and performance outcomes (Jeukendrup, 2017). The present study was therefore conducted with the objective of determining whether long-term periodizing carbohydrate (CHO) intake during an eight-week endurance training plan has any benefit in comparison to a traditional high-CHO or low-CHO diet in terms of running performance, substrate metabolism and body composition in recreational active males.
Methods
In a controlled, randomised, parallel-group and free-living design, recreationally active runners (n = 24, VO2 peak: 51 ± 8 mL·min-1·kg-1) completed 8 weeks of an ad-libitum dietary intervention (LCHF[low CHO, high fat]/CHO: 4-week regimen with ≤ 50 g CHO per day directly followed by a 4-week regimen comprising 50-60% of daily energy intake from CHO, n = 8; CHO/CHO: 8-week regimen comprising 50-60% of daily energy intake from CHO, n = 9; LCHF/LCHF: 8-week regimen with ≤ 50 g CHO per day, n = 7) together with 5 prescribed sessions of an endurance training program. Dietary recalls were conducted 3 times a week. Body composition, performance and substrate metabolism were assessed 3 times during the study (T -0, T -1 and T -2) using bioelectric impedance and a graded exercise test on a treadmill starting at 6 km·h−1 with increasing speed by 1.5 km·h−1 every 3 minutes until exhaustion. Data were analysed using a 2-way mixed ANOVA and are presented as mean ± STD. Significance was set at p < .05.
Results
Peak running speed (PRS) and time to exhaustion (TTE) demonstrated an increase over time, with no additional benefit observed in relation to any group. Total fat oxidation and maximum fat oxidation (MFO) increased in the first half of the LCHF/CHO diet and decreased during the CHO rich diet (p < .001). In LCHF/LCHF fat oxidation and MFO increased from T -0 to T -1 (p < .001) and remained unchanged at T -2. In CHO/CHO no changes in fat oxidation or MFO were observed (p > .05). Total fat oxidation and MFO were significantly higher at T -1 in LCHF/CHO and LCHF/LCHF compared to CHO/CHO (p < .05). However, at T -2 fat oxidation and MFO were significantly higher in LCHF/LCHF compared to LCHF/CHO and CHO/CHO (p < .05). Significant reductions in weight, BMI, and absolute fat mass were observed in LCHF/CHO from T -0 to T -1 (p < .05) without any further changes until T -2. For LCHF/LCHF weight and BMI were significantly reduced in the first four weeks (p < .001) and even further reduced in the second half (p < .05). For CHO/CHO no significant changes in body composition were observed (p > .05).
Discussion & Conclusion
As previously noted, a high-fat diet resulted in a greater reliance on fat oxidation during exercise (Cao et al., 2021). Here, long-term periodisation of CHO according to the preferred training adaptation leads to changes in substrate metabolism during exercise in terms of improved fat oxidation during a LCHF diet and restoration of CHO oxidation during a CHO-rich diet. Despite the observed improvements in PRS and TTE over the course of the study, no significant advantage was demonstrated by any of the groups in comparison to the other trial groups.
References
Cao, J., Lei, S., Wang, X., & Cheng, S. (2021). The effect of a ketogenic low-carbohydrate, high-fat diet on aerobic capacity and exercise performance in endurance athletes: A systematic review and meta-analysis. Nutrients, 13(8), Article 2896. https://doi.org/10.3390/nu13082896
Jeukendrup, A. E. (2017). Periodized nutrition for athletes. Sports Medicine, 47(S1), 51-63. https://doi.org/10.1007/s40279-017-0694-
The pH induced sol-gel transition in skim milk revisited. a detailed study using time-resolved light and X-ray scattering experiments
No full textWe present a detailed study of the evolution of the size, structure and stability of casein micelles upon acidification of skim milk typically applied in yogurt-making processes using a combination of time-resolved light and small-angle X-ray scattering experiments. While most of the available light scattering studies on casein acidification have been restricted to transparent and therefore highly diluted samples, we now profit from a newly developed multiangle 3D light scattering instrument, which allows for time-resolved measurements in highly turbid samples. Our experiments clearly demonstrate the presence of two parallel pH-dependent processes, micellar reassembly and aggregation. Using a systematic investigation of the effect of casein concentration, acidification rate, and ionic strength, we are able to decouple these two processes and obtain detailed information about the pH-induced restructuration of the casein micelle structure that occurs prior to destabilization. Moreover, our experiments also unambiguously demonstrate that these micellar reassembly processes are highly concentration dependent, and that typical light scattering studies conducted under highly diluted conditions are resulting in findings that may not be relevant for the situation encountered in industrial processes at higher concentrations. Experiments conducted with covalently cross-linked micelles, where the pH-induced reassembly has been suppressed, further confirm our findings
Influence of collagen peptide supplementation on biomechanical adaptations, muscle & tendon remodeling, functional recovery and fat-free mass in healthy adults
No full textImpact of collagen peptide supplementation in combination with long-term physical training on strength, musculotendinous remodeling, functional recovery and body composition in healthy adults – A systematic review with meta-analysis of 19 randomized controlled trial
