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The effects of lycopene supplementation on serum insulin-like growth factor 1 (IGF-1) levels and cardiovascular disease: A dose-response meta-analysis of clinical trials.
Xie, Z, Yang, F
Complementary therapies in medicine. 2021;:102632
Abstract
BACKGROUND The results of human studies assessing the efficacy of lycopene on insulin-like growth factor 1 (IGF-1) levels are inconsistent. Thus, we performed a systematic review and meta-analysis to examine the effects of lycopene supplementation on serum IGF-1 levels and cardiovascular disease. METHODS The literature published up to January 2020 was searched using the electronic databases Scopus, PubMed/Medline, Web of Science, Embase and Google Scholar. RESULTS Seven qualified trials were included in the current meta-analysis. IGF-1 levels were non-significantly decreased in lycopene group compared to the control (WMD: -6.74 ng/mL, 95 % CI: -23.01 to 9.52, p = 0.42; I2 = 94.3 %). Subgroup analysis revealed a significantly decrease in IGF-1 levels upon lycopene supplementation at doses ≥15 mg/d (WMD: -6.40 ng/mL), intervention period <12 weeks (WMD: -6.49 ng/mL), and subjects aged ≥60 years (WMD: -24.98 mg/dl). In addition, lycopene intake significantly reduced IGF-1 levels upon healthy conditions (WMD: -25.59 ng/mL) when compared with cancer patients (WMD: 0.35 ng/mL). In addition, the effect of lycopene supplementation was significant in patients diagnosed with cardiac disorders. CONCLUSION Overall, lycopene intake was not associated with reduced serum IGF-1 levels. However, association was significant when lycopene was administrated at doses >15 mg/d, for <12 weeks, as well as for healthy conditions and patients aged ≥60 years. In addition, lycopene supplementation exhibited potential health benefits in the management of patients with cardiac disorders.
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The role of physical exercise in modulating peripheral inflammatory and neurotrophic biomarkers in older adults: A systematic review and meta-analysis.
Titus, J, Bray, NW, Kamkar, N, Camicioli, R, Nagamatsu, LS, Speechley, M, Montero-Odasso, M
Mechanisms of ageing and development. 2021;:111431
Abstract
BACKGROUND Physiological cascades of neurotrophic factors and inflammatory cytokines may mediate the exercise-induced amelioration of cognition in older adults. However, there is limited understanding on how different exercise modalities improving cognition alter biomarkers. Our aim was to evaluate the effects of different exercise modalities on blood biomarker concentrations in cognitive clinical trials of older adults. METHODS A systematic review (SR) and meta-analysis (MA) were performed using the databases PubMed, EMBASE, and SCOPUS. After exclusions, 17 trials with 18 distinct exercise interventions were included. RESULTS Aerobic training increased (n = 2) or did not significantly change BDNF (n = 5), and resistance training increased (n = 2) or did not significantly change (n = 2) IGF-1. Multimodal training significantly increased (n = 1) or did not change (n = 3) BDNF. Interventions that recruited sex-specific cohorts showed an advantage in males for blood marker concentrations and cognitive performance outcomes (n = 3) compared to females (n = 3). Only one of three interventions decreased concentrations of CRP. Eight studies examining BDNF changes were suited for MA and showed that higher BDNF concentrations were reached post intervention, although not reaching statistical significance (p = .26, I2 = 44 %). DISCUSSION Our results suggest that exercise has potential to ameliorate cognitive decline in older adults with divergent, modality-specific, neurotrophic mechanisms.
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3.
The effect of resistance training on serum insulin-like growth factor 1(IGF-1): A systematic review and meta-analysis.
Jiang, Q, Lou, K, Hou, L, Lu, Y, Sun, L, Tan, SC, Low, TY, Kord-Varkaneh, H, Pang, S
Complementary therapies in medicine. 2020;:102360
Abstract
BACKGROUND Data about the effects of resistance exercise on level of IGF-1 in the serum are conflicting. To resolve this inconsistency, we performed a systematic review and meta-analysis to precisely examine the effects of resistance exercise on the levels of serum IGF-1. METHODS PubMed, Scopus, Web of Science, and Embase databases were systematically searched from their inceptions until 10 December 2019 for randomized controlled trials (RCTs) comparing individuals who underwent resistance training and control participants. We applied a random-effects model to calculate the weighted mean difference (WMD). RESULTS 33 trials reported IGF-1 level as an outcome measure. The pooled estimate demonstrated a significant increase in IGF-1 (WMD: 10.34 ng/ml, 95 % CI: 4.93, 15.74, p = 0.000, I2 = 90.3 %) after resistance training compared with the control group. Subgroup analysis demonstrated that the increase in IGF-1 levels following resistance training was only statistically significant in treatment duration ≤16 weeks (WMD: 8.04 ng/ml), participants aged more than 60 years old (WMD: 9.84 ng/ml); and in women (WMD: 17.27 ng/ml). Subsequent analysis of the relationship between participants' age with plasma IGF-1 alterations revealed a U shape correlation in non-liner dose response, in which resistance training resulted in a declined IGF-1 level up to 40 years of age. Beyond 40 years old, the IGF-1 level was increased following resistance training. CONCLUSION We have successfully demonstrated that resistance training was associated with an increased IGF-1 level among those who received the training for ≤16 weeks, among participants older than 60 years old, and among women. Further studies are warranted to clarify the mechanisms underlying the influence of resistance training on IGF-1.
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Effects of Dietary or Supplementary Micronutrients on Sex Hormones and IGF-1 in Middle and Older Age: A Systematic Review and Meta-Analysis.
Janjuha, R, Bunn, D, Hayhoe, R, Hooper, L, Abdelhamid, A, Mahmood, S, Hayden-Case, J, Appleyard, W, Morris, S, Welch, A
Nutrients. 2020;(5)
Abstract
Observational research suggests that micronutrients may be protective for sarcopenia, a key health issue during ageing, potentially via effects on hormone synthesis and metabolism. We aimed to carry out a systematic review of RCTs investigating effects of increasing dietary or supplemental micronutrient intake on sex hormones and IGF-1 in individuals aged 45 years or older. We searched MEDLINE, EMBASE and Cochrane databases for RCTs reporting the effects of different micronutrients (vitamins A, C, D, or E; carotenoids; iron; copper; zinc; magnesium; selenium; and potassium) on sex hormones or IGF-1. Of the 26 RCTs identified, nine examined effects of vitamin D, nine of multi-nutrients, four of carotenoids, two of selenium, one of zinc, and one of vitamin E. For IGF-1 increasing vitamin D (MD: -0.53 nmol/L, 95% CI: -1.58, 0.52), multi-nutrients (MD: 0.60 nmol/L, 95% CI -1.12 to 2.33) and carotenoids (MD -1.32 nmol/L; 95% CI -2.76 to 0.11) had no significant effect on circulating concentrations. No significant effects on sex hormones of other micronutrients were found, but data were very limited. All trials had significant methodological limitations making effects of micronutrient supplementation on sex hormones unclear. Further high quality RCTs with physiological doses of micronutrients in people with low baseline intakes or circulating concentrations, using robust methodology, are required to assess effects of supplementation adequately.
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Effect of calorie restriction or protein intake on circulating levels of insulin like growth factor I in humans: A systematic review and meta-analysis.
Kazemi, A, Speakman, JR, Soltani, S, Djafarian, K
Clinical nutrition (Edinburgh, Scotland). 2020;(6):1705-1716
Abstract
Calorie restriction (CR) and reductions in protein intake in rodents result in increased lifespan and reduced levels of IGF-1. However, the changes in IGF-1 in humans in response to CR and elevated protein intake are confused. We conducted a systematic review and meta-analysis to investigate the effect of Calorie restriction (CR) or increase in protein intake on IGF-1 in humans. The systematic review protocols have been developed based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement guidelines. Two separate systematic searches were undertaken: first for the effect of CR and second on the effect of increase in protein intake on IGF-1. PubMed, SCOPUS and ISI Web of Science databases were searched. In the meta-analysis of the calorie restriction studies, twelve studies met the inclusion criteria (8 clinical trials and 4 observational studies). The meta-analysis of both clinical trials and observational studies revealed no significant effect of CR on IGF-1 (clinical trials: standardized mean difference (SMD) = 0.002 ng/ml, 95% CI -0.14 to 0.14 ng/ml, p = 0.98; observational studies (SMD = -1.14 ng/ml, 95% CI -1.9 to -0.38 ng/ml, p = 0.003). In the meta-analysis of protein intake studies (six studies), a significant increase in circulating IGF-1 levels in response to increases in dietary protein was revealed (SMD = 0.4 ng/ml, 95% CI 0.18-0.61 ng/ml, p < 0.001). In conclusion, in humans, CR was not associated with a significant change in circulating IGF-1. However an increase in protein intake was associated with increased levels of circulating IGF-1. PROTOCOLS REGISTRATION NUMBER CRD42017073149 for the protein intake meta-analysis and CRD42016046260 for CR meta-analysis.
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The influence of fasting and energy restricting diets on IGF-1 levels in humans: A systematic review and meta-analysis.
Rahmani, J, Kord Varkaneh, H, Clark, C, Zand, H, Bawadi, H, Ryan, PM, Fatahi, S, Zhang, Y
Ageing research reviews. 2019;:100910
Abstract
BACKGROUND Fasting and energy restricting diets have a potential means of delaying or preventing the onset of a range of age-related metabolic and neoplastic diseases. Consistently at the centre of this effect appears to be a significant reduction in circulating IGF-1 levels. The aim of the current systematic review and meta-analysis was to determine the influence of fasting and energy restriction on IGF-1 levels in human subjects. METHODS A comprehensive systematic search was conducted from onset of the database to February 2019 in Embase, MEDLINE/PubMed, and SCOPUS to identify randomized clinical trials that investigating the impact of fasting or energy restriction circulating IGF-1 levels. Effect size was reported as weighted mean difference (WMD) and 95% confidence intervals (CI) using a random-effects models. Subgroup analysis was performed to identify the probable source of heterogeneity among trials. RESULTS Total pooling of fasting and energy restriction randomised controlled trials in WMD analysis revealed no significant effect on circulating IGF-1 levels (WMD: -16.41 ng/ml, 95% CI: -35.88, 3.07). Sub grouped analysis fasting regimens appeared to substantially reduce IGF-1 (WMD: -28.87 ng/ml, 95% CI: -43.69, -14.05, I2 = 00%), energy restricting regimens failed to do the same (WMD: -10.98 ng/ml, 95% CI: -33.08, 11.11, I2 = 90%). Within this final subgrouping, it was observed that only energy restriction regimens of 50% or greater of normal daily energy intake were capable of significantly reducing IGF-1 levels (WMD: -36.57 ng/ml, 95% CI: -59.19, -13.95, I2 = 00%). Finally, a meta regression were noted in which the percentage restriction of daily energy intake inversely correlated with plasma IGF-1 levels (p = 0.04). CONCLUSION This study uncovered that fasting significantly reduced levels of IGF-1, while energy restriction diets were successful only when intake was reduced by 50% or more.