Effects of whey protein alone or as part of a multi-ingredient formulation on strength, fat-free mass, or lean body mass in resistance-trained individuals: A meta-analysis

BACKGROUND: Even though the positive effects of whey protein-containing supplements for optimizing the anabolic responses and adaptations process in resistance-trained individuals have been supported by several investigations, their use continues to be controversial. Additionally, the administration of different multi-ingredient formulations where whey proteins are combined with carbohydrates, other protein sources, creatine, and amino acids or derivatives, has been extensively proposed as an effective strategy to maximize strength and muscle mass gains in athletes. OBJECTIVE: We aimed to systematically summarize and quantify whether whey protein-containing supplements, administered alone or as a part of a multi-ingredient, could improve the effects of resistance training on fat-free mass or lean body mass, and strength in resistance-trained individuals when compared with other iso-energetic supplements containing carbohydrates or other sources of proteins. METHODS: A structured literature search was conducted on PubMed, Science Direct, Web of Science, Cochrane Libraries, US National Institutes of Health clinicaltrials.gov, SPORTDiscus, and Google Scholar databases. Main inclusion criteria comprised randomized controlled trial study design, adults (aged 18 years and over), resistance-trained individuals, interventions (a resistance training program for a period of 6 weeks or longer, combined with whey protein supplementation administered alone or as a part of a multi-ingredient), and a calorie equivalent contrast supplement from carbohydrates or other non-whey protein sources. Continuous data on fat-free mass and lean body mass, and maximal strength were pooled using a random-effects model. RESULTS: Data from nine randomized controlled trials were included, involving 11 treatments and 192 participants. Overall, with respect to the ingestion of contrast supplements, whey protein supplementation, administered alone or as part of a multi-ingredient, in combination with resistance training, was associated with small extra gains in fat-free mass or lean body mass, resulting in an effect size of g = 0.301, 95% confidence interval (CI) 0.032-0.571. Subgroup analyses showed less clear positive trends resulting in small to moderate effect size g = 0.217 (95% CI -0.113 to 0.547) and g = 0.468 (95% CI 0.003-0.934) in favor of whey and multi-ingredient, respectively. Additionally, a positive overall extra effect was also observed to maximize lower (g = 0.316, 95% CI 0.045-0.588) and upper body maximal strength (g = 0.458, 95% CI 0.161-0.755). Subgroup analyses showed smaller superiority to maximize strength gains with respect to the contrast groups for lower body (whey protein: g = 0.343, 95% CI -0.016 to 0.702, multi-ingredient: g = 0.281, 95% CI -0.135 to 0.697) while in the upper body, multi-ingredient (g = 0.612, 95% CI 0.157-1.068) seemed to produce more clear effects than whey protein alone (g = 0.343, 95% CI -0.048 to 0.735). LIMITATIONS: Studies involving interventions of more than 6 weeks on resistance-training individuals are scarce and account for a small number of participants. Furthermore, no studies with an intervention longer than 12 weeks have been found. The variation regarding the supplementation protocol, namely the different doses criteria or timing of ingestion also add some concerns to the studies comparison. CONCLUSIONS: Whey protein alone or as a part of a multi-ingredient appears to maximize lean body mass or fat-free mass gain, as well as upper and lower body strength improvement with respect to the ingestion of an iso-energetic equivalent carbohydrate or non-whey protein supplement in resistance-training individuals. This enhancement effect seems to be more evident when whey proteins are consumed within a multi-ingredient containing creatine

International Conference on Advances in Radiation Oncology (ICARO): Outcomes of an IAEA Meeting

The IAEA held the International Conference on Advances in Radiation Oncology (ICARO) in Vienna on 27-29 April 2009. The Conference dealt with the issues and requirements posed by the transition from conventional radiotherapy to advanced modern technologies, including staffing, training, treatment planning and delivery, quality assurance (QA) and the optimal use of available resources. The current role of advanced technologies (defined as 3-dimensional and/or image guided treatment with photons or particles) in current clinical practice and future scenarios were discussed

Second primary cancers after radiation for prostate cancer: a review of data from planning studies

A review of planning studies was undertaken to evaluate estimated risks of radiation induced second primary cancers (RISPC) associated with different prostate radiotherapy techniques for localised prostate cancer. A total of 83 publications were identified which employed a variety of methods to estimate RISPC risk. Of these, the 16 planning studies which specifically addressed absolute or relative second cancer risk using dose–response models were selected for inclusion within this review. There are uncertainties and limitations related to all the different methods for estimating RISPC risk. Whether or not dose models include the effects of the primary radiation beam, as well as out-of-field regions, influences estimated risks. Regarding the impact of IMRT compared to 3D-CRT, at equivalent energies, several studies suggest an increase in risk related to increased leakage contributing to out-of-field RISPC risk, although in absolute terms this increase in risk may be very small. IMRT also results in increased low dose normal tissue irradiation, but the extent to which this has been estimated to contribute to RISPC risk is variable, and may also be very small. IMRT is often delivered using 6MV photons while conventional radiotherapy often requires higher energies to achieve adequate tissue penetration, and so comparisons between IMRT and older techniques should not be restricted to equivalent energies. Proton and brachytherapy planning studies suggest very low RISPC risks associated with these techniques. Until there is sufficient clinical evidence regarding RISPC risks associated with modern irradiation techniques, the data produced from planning studies is relevant when considering which patients to irradiate, and which technique to employ

Preservation of the rat parotid gland function after radiation by prophylactic pilocarpine treatment: Radiation dose dependency and compensatory mechanisms

Purpose: To study the ability of a prophylactic pilocarpine administration to preserve the rat parotid gland function after unilateral irradiation with graded doses of X-rays. Methods: The right parotid gland of male albino Wistar rats was irradiated with single doses of X-rays (10-30 Gy, at 1.5 Gy min(-1)). Pilocarpine (4 mg/kg) was administered intraperitoneally, 1 hour prior to irradiation. Saliva samples of both left and right parotid gland were collected by means of miniaturized Lashley cups 4 days before and 3, 7, 10, and 30 days after irradiation. The parotid salivary flow rate (mu l/min) was used as a parameter for the assessment of parotid gland function. Results: Our data confirm that a single prophylactic treatment of pilocarpine can attenuate radiation-induced loss of gland function. Surprisingly, the effect of pilocarpine was not restricted to the irradiated gland only. Pilocarpine also enhanced the how rate in the contralateral, nonirradiated gland. The latter effect was found for all doses above 10 Gy and became apparent around 7 days after the radiation treatment. The effectiveness of pilocarpine to attenuate function loss in the irradiated gland decreased with increasing dose and was lost after single doses of 30 Gy. Conclusions: Our data provide direct evidence that increasing the compensatory potential of the nondamaged gland, at least in part, underlies the "radioprotective effect" of pilocarpine in case of unilateral radiation. The ability of pilocarpine to ameliorate the early radiation-induced impairment of the parotid gland function in the irradiated gland may therefore be dependent on the remaining number of functional cells, and thus on the volume of the gland that lies within the radiation portal. (C) 1999 Elsevier Science Inc