Massimo Negro

Human Skeletal Muscle Aging and the Oxidative System: Cellular Events

As we age, the aerobic and functional capacities of our major physiological systems progressively decline. In the case of the neuromuscular system, reductions in strength and mobility cause a deterioration in motor performance and in turn a greater tendency to fall (with increased risk of fractures), impaired mobility, disability and loss of independence in the elderly. Given the increase in our life expectancy and the consequent growth in the elderly population, these conditions will have an increasing impact on modern healthcare systems, and their prevention and attenuation needs to be addressed. Several intervention strategies have been used to improve motor performance among the aging. At the cellular level, aging is caused by a progressive decline in mitochondrial function that results in the accumulation of reactive oxygen species (ROS) generated by the addition of a single electron to the oxygen molecule As the level of oxidative stress in skeletal muscle increases with age, the production of some antioxidant enzymes increases adaptively to compensate in part. The aging process is characterized by an imbalance between an increase in the production of reactive oxygen species in the organism and the antioxidant defences as a whole. The goal of this review is to examine the results of existing studies on oxidative stress in aging human skeletal muscles, taking into account different physiological factors (sex, fiber composition, muscle type and function).

Supplementation with a fish protein hydrolysate (Micromesistius poutassou): effects on body weight, body composition, and CCK/GLP-1 secretion

Background Fish protein hydrolysates (FPHs) have been reported as a suitable source of proteins for human nutrition because of their balanced amino acid composition and positive effect on gastrointestinal absorption. Objective Here, we investigated the effect of a FPH, Slimpro®, obtained from blue whiting (Micromesistius poutassou) muscle by enzymatic hydrolysis, on body composition and on stimulating cholecystokinin (CCK) and glucagon-like peptide-1 (GLP-1) secretion. Design A randomized clinical study was carried out on 120, slightly overweight (25 kg/m2 ≤ BMI<30 kg/m2), male (25%) and female (75%) subjects. FPH was tested in a food supplement at two doses (1.4 and 2.8 g) to establish if a dose–effect relationship exists. Product use was associated with a mild hypocaloric diet (−300 kcal/day). Body composition (body weight; fat mass; extracellular water; and circumference of waist, thighs, and hips) and CCK/GLP-1 blood levels were measured at the beginning of the study and after 45 and 90 days of product use. CCK/GLP-1 levels were measured since they are involved in controlling food intake. Results Treated subjects reported an improvement of body weight composition and an increased blood concentration of both CCK and GLP-1. No differences were found between the 1.4 and 2.8 g FPH doses, indicating a plateau effect starting from 1.4 g FPH. Conclusions Both 1.4 and 2.8 g of FPH were effective in improving body composition and in increasing CCK and GLP-1 blood levels.

Protein Supplementation with Low Fat Meat after Resistance Training: Effects on Body Composition and Strength

Beef is a nutrient-rich, high-quality protein containing all the essential amino acids in proportions similar to those found in human skeletal muscle. In order to investigate the efficacy of a beef supplementation strategy on strength and body composition, we recruited 26 young healthy adults to participate in a resistance-training program of eight weeks, based on the use of isotonic machines and free weights at 75% of one repetition maximum. Subjects were randomly divided into two groups, food group and control group, of 12 and 14 subjects respectively. Food group were supplemented after resistance training with a 135 g serving of lean beef (tinned meat), providing 20 g of protein and 1.7 g of fat. No supplementation was provided to control group. Fat mass, fat free mass, lean mass, assessed by bioelectrical impedance analyzer, and muscle strength, assessed by one repetition maximum test, were evaluated in all subjects both at the beginning (week 0) and at the end (week 8) of the study. Pre- and post-training differences were evaluated with paired t-tests while group differences for each outcome parameter was evaluated with independent t-tests. At the end of the study the food group showed a significantly decrease in fat mass (week 0: 15.0 ± 6.7 kg; week 8: 13.1 ± 7.6 kg; Δ: −1.9 ± 2.9 kg; p < 0.05) and a significantly increase in fat free mass (week 0: 52.8 kg ± 9.4; week 8: 55.1 kg ± 10.9; Δ: 2.3 ± 2.5 kg; p < 0.01). No significant differences in lean mass were found in either food group or control group. No significant differences in one repetition maximum tests were found between food group and control group. Tinned meat can be considered a nutrition strategy in addition to other proteins or amino acid supplements, but as with any other supplementation strategy, a proper nutrition plan must be coupled.

Association between Dietary Patterns of Meat and Fish Consumption with Bone Mineral Density or Fracture Risk: A Systematic Literature

This systematic review aimed to investigate the association of fish and sea fish dietary patterns (FishDiet) and meat or processed meat dietary patterns (MeatDiet) with bone mineral density (BMD) and/or risk of fractures (RF). This review includes 37 studies with a total of 432,924 subjects. The results suggest that MeatDiet and FishDiet did not affect BMD or RF in 48.2% of the subjects with MeatDiet and in 86.5% of the subjects with FishDiet. Positive effects on bone were found in 3% of subjects with MeatDiet and in 12% with FishDiet. Negative effects on bone were observed in 2.7% of FishDiet and in 47.9% of MeatDiet. Major negative effects of MeatDiet were found in subjects located in the Netherlands, Greece, Germany, Italy, Norway, UK and Spain who do not sustain a Mediterranean diet (92.7%); in Korea (27.1%); in Brazil and Mexico (96.4%); and in Australia (62.5%). This study suggests that protein intake from fish or meat is not harmful to bone. Negative effects on bone linked to FishDiet are almost null. Negative effects on bone were associated to MeatDiet in the setting of a Western Diet but not in Mediterranean or Asian Diets.

Anti-inflammatory Dietary Interventions and Supplements to Improve Performance during Athletic Training

Despite the numerous positive effects of physical exercise, some negative physiological changes occur in long-lasting heavy training with transient dysfunction of the immune system, increased inflammation, and oxidative stress. This is the case of elite athletes, who train intensively to compete at the highest levels. However, these athletes can counteract the negative effects of heavy training, reducing acute and chronic inflammations and supporting the immune system, with nutritional and supplementation countermeasures. For this purpose, macronutrient manipulation with an appropriate use of certain supplements can be considered as an intervention to reduce exercise-induced immune changes and inflammatory risk. For example, branched-chain amino acid (BCAA) supplementation may promote such immune responses in skeletal muscle. Furthermore, micronutrients play an important role in immune function; in particular, the antioxidant capacity of several dietary micronutrients (e.g., tocopherols, docosahexaenoate, and flavonoids) is very interesting to support the endogenous antioxidant defense systems of the athletes, counterbalancing the negative effects of oxidative damage due to free radicals. Some of these nutrients have potential anti-inflammatory properties as assessed by the attenuated levels of interleukin-6 (IL-6) and C-reactive protein (CRP). Key Teaching Points• Long-lasting heavy training plan and competition can lead to chronic immune suppression in athletes, increasing infection risk.• Chronic exercise increases mobilization of neutrophils, decreases mobilization of lymphocytes, and decreases the absolute and relative numbers of neutrophils at rest.• Nutritional deficiencies alter the immuno-system and increase infection risk.• Nutrition can influence exercise-induced immune suppression.• Elite athletes competing at the highest levels can benefit from nutritional and supplementation support to improve immunity and reduce acute and chronic inflammations.

Essential Amino Acids (EAA) Mixture Supplementation: Effects of an Acute Administration Protocol on Myoelectric Manifestations of Fatigue in the Biceps Brachii After Resistance Exercise

Background: The purpose of this study was to investigate the acute effects of a single oral administration of an essential amino acids enriched mixture (EAA) on myoelectric descriptors of fatigue and maximal force production after a resistance exercise protocol (REP). Methods: Twenty adult males (age: 27 ± 6 years; body mass: 72.7 ± 7.50 kg; height: 1.76 ± 0.06 m) were enrolled in a double-blind crossover placebo-controlled study. Subjects were randomized to receive EAA mix (0.15 g/kg BM) or a placebo (PLA) in two successive trials 7 days apart. In both trials subjects completed a REP 2 h after the ingestion of the EAA mix or PLA. Before ingestion and after REP subjects performed isometric contractions of the dominant upper limb with the elbow joint at 120 degrees: (1) two maximal voluntary contractions (MVCs) for 2–3 s; (2) at 20% MVC for 90 s; (3) at 60% MVC until exhaustion. Mean values of MVC, conduction velocity initial values (CV), fractal dimension initial values (FD), their rates of change (CV slopes, FD slopes) and the Time to perform the Task (TtT) were obtained from a multichannel surface electromyography (sEMG) recording technique. Basal blood lactate (BL) and BL after REP were measured. Results: Following REP a significant decrease of MVC was observed in PLA (P < 0.05), while no statistical differences were found in EAA between pre-REP and post-REP. After REP, although a significant increase in BL was found in both groups (P < 0.0001) a higher BL Δ% was observed in PLA compared to EAA (P < 0.05). After REP, at 60% MVC a significant increase of CV rate of change (P < 0.05) was observed in PLA but not in EAA. At the same force level TtT was longer in EAA compared to PLA, with a significant TtT Δ% between groups (P < 0.001). Conclusion: Acute EAA enriched mix administration may prevent the loss of force-generating capacity during MVC following a REP. During isometric contraction at 60% MVC after REP the EAA mix may maintain CV rate of change values with a delay in the TtT failure.

Opinion paper: scientific, philosophical and legal consideration of doping in sports

The term doping is generally used to indicate practices based on the use of performance-enhancing drugs (PEDs) or the abuse of medical therapies. Mostly analysed by doctors and officials, doping nevertheless also requires a philosophical consideration to avoid being simplistically portrayed as an isolated practice. To do this, we need to pay attention to the contradictions and paradoxes in the modern approach to doping in sport. In this context, doping is not only relevant to the health of an individual involved in the violation of World Anti-Doping Agency (WADA) criteria, but it actually represents a double-edged phenomenon containing ethical and legal points of view. Several philosophical items affect the ethics of doping. While, indeed, through a deontological vision it is easy to morally condemn an athlete who takes the decision to turn to doping, the same condemnation becomes difficult when the practice of doping is compared with the strong social demand of winners in every field of life. This point must be considered to prevent doping from becoming accepted as a daily practice to excel at all costs and regarded not only as normal but as a necessity for those participating in sport at both an amateur and professional level. Furthermore, a complete discussion on doping has to consider not only the philosophy of performance-enhancing drug abuse, but also the widespread practice of an inappropriate and excessive intake of certain dietary supplements with the unique and obsessive purpose (similar to doping) of increasing physical or mental performance. Based on the above, the aim of this paper is to provide a critical opinion of the doping problem and its related practices and analyze possible solutions considering issues that go beyond the impact of doping on health and reflect on whether it is right or not that an athlete does all he can to improve his performance.Graphical Abstract