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Effect of green tea and lycopene on the insulin-like growth factor system: the ProDiet randomized controlled trial.
Biernacka, KM, Holly, JMP, Martin, RM, Frankow, A, Bull, CJ, Hamdy, FC, Donovan, JL, Neal, DE, Metcalfe, C, Lane, A
European journal of cancer prevention : the official journal of the European Cancer Prevention Organisation (ECP). 2019;28(6):569-575
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Prostate cancer (PCa) is a leading cause of morbidity and mortality. Nutrition, in particular adopting a western lifestyle, is thought to be an important contributor to prostate carcinogenesis. The primary role of insulin-like growth factor (IGF) ligands (IGF-I, IGF-II) is to regulate prenatal and postnatal growth with binding proteins modulating their action. The aim of this study was to investigate the influence of lycopene or green tea on circulating IGF peptides in men at elevated risk of PCa. The ProDiet trial was nested within the Prostate testing for Cancer and Treatment trial of treatments for localised PCa for men aged 50–69 years. Participants were randomly assigned to receive one of three lycopene interventions: lycopene-rich diet, lycopene capsules or matched placebo capsules and one of the green tea interventions: green tea drink, green tea-derived capsules or matched placebo capsules. Results indicate that increased tomato intake, lycopene supplementation, green tea drink or green tea supplementation did not influence the measured IGF ligands. Authors conclude that their study did not provide clear evidence that lycopene or green tea supplementation may influence serum levels of IGF which may contribute to the increased risk of PCa in men.
Abstract
Whether prostate cancer (PCa) may be preventable by dietary interventions can be assessed in randomized trials using intermediate biomarkers of cancer risk or progression. We investigated whether lycopene or green tea modify circulating insulin-like growth factor (IGF) peptides in men at increased risk of PCa. Participants (aged 50-69 years) in one centre in the UK wide PCa testing and treatment trial (ProtecT) with prostate specific antigen between 2.0 and 2.95 ng/ml or negative biopsies, were randomized to daily lycopene (n = 44 assigned 15 mg capsules/day; 44 assigned a lycopene-rich diet; 45 assigned placebo) and green tea (n = 45 assigned 600 mg/day epigallocatechin gallate; 45 assigned green tea drink; 43 assigned placebo) for 6 months. The interventions significantly elevated the primary outcomes, serum epigallocatechin gallate and lycopene at 6 months of follow-up. We report here an exploratory analysis in which serum IGF-I, IGF-II, IGF binding protein (BP)-2 and IGFBP-3 were measured at baseline and 6 months of postintervention. A total of 133 men were randomized (34% of eligible men approached) and 130 had follow-up IGF peptides (98%). In intention-to-treat analyses, there was only weak evidence that lycopene or green tea influenced some aspects of serum IGF-I, IGF-II, IGFBP-2 or IGFBP-3. In men randomized to lycopene supplements, IGFBP-2 was nonsignificantly (50.9 ng/ml; 95% confidence interval: -51.2-152.9, P = 0.3) higher in comparison to placebo, whereas in men randomized to green tea supplements, IGFBP-3 was nonsignificantly (205.2 ng/ml; 95% confidence interval: -583.3-172.9, P = 0.3) lower than with placebo. In this small, pilot randomized controlled trial, there was little evidence that lycopene or green tea interventions influenced serum levels of IGF-I, IGF-II, IGFBBP-3 and IGFBP-2. However, the effects were imprecisely estimates and some observed trends may justify larger trials.
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Mechanisms Underlying Metabolic Syndrome-Related Sarcopenia and Possible Therapeutic Measures.
Rubio-Ruiz, ME, Guarner-Lans, V, Pérez-Torres, I, Soto, ME
International journal of molecular sciences. 2019;20(3)
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Sarcopenia is a multifactorial process in which losses occur in both muscle mass and function. Although several studies indicate an association between sarcopenia and metabolic syndrome (MetS), the connection has not been extensively reviewed. The aim of this study is to examine the relationship between sarcopenia and MetS to better understand the mechanisms underlying disease and assess current therapeutic options. According to the existing literature, this study found insulin resistance, inflammation and obesity to be major underlying factors of MetS-related sarcopenia. Based on this information, the authors suggest the best option for managing MetS-related sarcopenia is preventative lifestyle change around diet and exercise until a consensus on a therapeutic treatment can be established.
Abstract
Although there are several reviews that report the interrelationship between sarcopenia and obesity and insulin resistance, the relation between sarcopenia and the other signs that compose the metabolic syndrome (MetS) has not been extensively revised. Here, we review the mechanisms underlying MetS-related sarcopenia and discuss the possible therapeutic measures proposed. A vicious cycle between the loss of muscle and the accumulation of intramuscular fat might be associated with MetS via a complex interplay of factors including nutritional intake, physical activity, body fat, oxidative stress, proinflammatory cytokines, insulin resistance, hormonal changes, and mitochondrial dysfunction. The enormous differences in lipid storage capacities between the two genders and elevated amounts of endogenous fat having lipotoxic effects that lead to the loss of muscle mass are discussed. The important repercussions of MetS-related sarcopenia on other illnesses that lead to increased disability, morbidity, and mortality are also addressed. Additional research is needed to better understand the pathophysiology of MetS-related sarcopenia and its consequences. Although there is currently no consensus on the treatment, lifestyle changes including diet and power exercise seem to be the best options.
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Effects of eight weeks of time-restricted feeding (16/8) on basal metabolism, maximal strength, body composition, inflammation, and cardiovascular risk factors in resistance-trained males.
Moro, T, Tinsley, G, Bianco, A, Marcolin, G, Pacelli, QF, Battaglia, G, Palma, A, Gentil, P, Neri, M, Paoli, A
Journal of translational medicine. 2016;14(1):290
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Time-restricted feeding (TRF) allows subjects to consume ad libitum energy intake within a defined window of time, which means a fasting window of 12–21 h per day is employed. The aim of the present study was to investigate the effects of an isoenergetic TRF protocol on body composition, athletic performance, and metabolic factors during resistance training in healthy resistance trained males. The study enrolled thirty-four resistance-trained males. The participants were randomly assigned to a TRF group (n = 17) or standard diet group (n = 17). Training was standardized for both groups. Results indicate that after 8 weeks, a significant decrease in fat mass was observed in the TRF group, while fat-free mass was maintained in both groups. The same trend was observed for arm and thigh muscle cross-sectional area. Leg press maximal strength increased significantly, but no difference was present between treatments. Authors conclude that TRF can maintain muscle mass, reducing body fat, and reducing inflammation markers and anabolic hormones. This kind of regimen could be adopted by athletes during maintenance phases of training in which the goal is to maintain muscle mass while reducing fat mass.
Abstract
BACKGROUND Intermittent fasting (IF) is an increasingly popular dietary approach used for weight loss and overall health. While there is an increasing body of evidence demonstrating beneficial effects of IF on blood lipids and other health outcomes in the overweight and obese, limited data are available about the effect of IF in athletes. Thus, the present study sought to investigate the effects of a modified IF protocol (i.e. time-restricted feeding) during resistance training in healthy resistance-trained males. METHODS Thirty-four resistance-trained males were randomly assigned to time-restricted feeding (TRF) or normal diet group (ND). TRF subjects consumed 100 % of their energy needs in an 8-h period of time each day, with their caloric intake divided into three meals consumed at 1 p.m., 4 p.m., and 8 p.m. The remaining 16 h per 24-h period made up the fasting period. Subjects in the ND group consumed 100 % of their energy needs divided into three meals consumed at 8 a.m., 1 p.m., and 8 p.m. Groups were matched for kilocalories consumed and macronutrient distribution (TRF 2826 ± 412.3 kcal/day, carbohydrates 53.2 ± 1.4 %, fat 24.7 ± 3.1 %, protein 22.1 ± 2.6 %, ND 3007 ± 444.7 kcal/day, carbohydrates 54.7 ± 2.2 %, fat 23.9 ± 3.5 %, protein 21.4 ± 1.8). Subjects were tested before and after 8 weeks of the assigned diet and standardized resistance training program. Fat mass and fat-free mass were assessed by dual-energy x-ray absorptiometry and muscle area of the thigh and arm were measured using an anthropometric system. Total and free testosterone, insulin-like growth factor 1, blood glucose, insulin, adiponectin, leptin, triiodothyronine, thyroid stimulating hormone, interleukin-6, interleukin-1β, tumor necrosis factor α, total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and triglycerides were measured. Bench press and leg press maximal strength, resting energy expenditure, and respiratory ratio were also tested. RESULTS After 8 weeks, the 2 Way ANOVA (Time * Diet interaction) showed a decrease in fat mass in TRF compared to ND (p = 0.0448), while fat-free mass, muscle area of the arm and thigh, and maximal strength were maintained in both groups. Testosterone and insulin-like growth factor 1 decreased significantly in TRF, with no changes in ND (p = 0.0476; p = 0.0397). Adiponectin increased (p = 0.0000) in TRF while total leptin decreased (p = 0.0001), although not when adjusted for fat mass. Triiodothyronine decreased in TRF, but no significant changes were detected in thyroid-stimulating hormone, total cholesterol, high-density lipoprotein, low-density lipoprotein, or triglycerides. Resting energy expenditure was unchanged, but a significant decrease in respiratory ratio was observed in the TRF group. CONCLUSIONS Our results suggest that an intermittent fasting program in which all calories are consumed in an 8-h window each day, in conjunction with resistance training, could improve some health-related biomarkers, decrease fat mass, and maintain muscle mass in resistance-trained males.