Zinc status in athletes: relation to diet and exercise

Is Micronutrient Supplementation Helpful in Supporting the Immune System during Prolonged, High-Intensity Physical Training?

It is well known that during prolonged, high-intensity physical training, athletes experience a state of immunosuppression and that balanced nutrition can help maintain immunity. This review summarizes the effects (amplified by virus infection) of high-intensity, long-term exercise on immunity, critically presenting key micronutrients and supplementation strategies that can influence athletes' performance and their immune system. The main conclusion is that micronutrient supplementation with diet could help to protect the immune system from the stress effects induced by intense physical activities. The importance of personalized supplementation has been also recommended.

Zinc transporters expression profile in professional handball players supplemented with zinc

INTRODUCTION

Zinc (Zn) deficiency has been described not only on general human health but also within the sports context -as negatively affecting performance-. Thus, Zn status assessment is of great interest for athletes, especially in order to correct deficiency states of this mineral.

OBJECTIVE

The overall objective of this work was to assess Zn status in professional handball players during the competitive period (through plasma levels, dietary intake and gene expression of the Zn transporters), as well as to determine the effect of Zn supplementation.

METHODS

A total of twenty-two participants were recruited, -twelve belonged to the Control Group (CG) and ten male handball players comprised the experimental group (ATH-G)-, being monitored over a 2-month period with 2 evaluation moments: baseline (i.e., initial conditions) and follow-up (i.e., after 8 weeks of training and competition). Zn intake, plasma Zn levels, and gene expression of Zn transporters were obtained.

RESULTS

Plasma Zn levels were higher in ATH-G than in CG at the end of Zn intervention (p ≤ 0.010). Moreover, differences in the gene expression profile of Zn transporters were observed in ATH-G -with the down-regulation of several Zn transporters-, compared to the CG at baseline (p ≤ 0.05). Likewise, differences in the Zn transporters expression were observed in ATH-G at 8 weeks (all, p ≤ 0.001) -with ZnT2, ZnT5, ZIP3, ZIP5, ZIP11, ZIP13 and ZIP14 transporters being up-regulated-.

CONCLUSION

Handball players seemed to have different nutritional needs for Zn, with differences in the gene expression of Zn transporters compared to controls. Zn intervention in our athletes may have influenced the expression of Zn transporters, indicating a potential increase in Zn transporters expression to mobilize Zn at the cellular level at 8 weeks of Zn intervention.

Green strength: The role of micronutrients in plant-based diets for athletic performance enhancement

This review examines the correlation between plant-based diets and athletic performance, with a specific emphasis on the vital aspect of optimizing micronutrients for athletes. In light of the increasing prevalence of plant-based nutrition among athletes due to its perceived advantages in terms of health, ethics, and the environment, this study investigates the ability of these diets to satisfy the demanding nutritional requirements essential for achieving optimal performance and facilitating recovery. The article emphasizes the significance of essential micronutrients such as iron, vitamin B12, calcium, vitamin D, zinc, and omega-3 fatty acids and also addressing the challenges with their absorption and bioavailability from plant sources. The review consolidates existing scientific knowledge to propose strategies for improving micronutrient consumption, comparing the effects of supplements against whole foods, and highlighting the significance of enhancing bioavailability. The proposal supports the implementation of personalized meal planning, with the assistance of sports nutritionists or dietitians, and is substantiated by case studies showcasing the success of plant-based athletes. Future research directions examine the long-term effects of plant-based diets on micronutrient status and athletic performance, as well as developing nutritional trends and technology. The review concludes that plant-based diets can meet athletes' nutritional demands and improve peak performance while aligning with personal and ethical values with strategic planning and professional guidance. This study intends to help athletes, coaches, and nutritionists understand plant-based nutrition for enhanced athletic performance.

Optimizing the Gut Microbiota for Individualized Performance Development in Elite Athletes

The human gut microbiota can be compared to a fingerprint due to its uniqueness, hosting trillions of living organisms. Taking a sport-centric perspective, the gut microbiota might represent a physiological system that relates to health aspects as well as individualized performance in athletes. The athletes' physiology has adapted to their exceptional lifestyle over the years, including the diversity and taxonomy of the microbiota. The gut microbiota is influenced by several physiological parameters and requires a highly individual and complex approach to unravel the linkage between performance and the microbial community. This approach has been taken in this review, highlighting the functions that the microbial community performs in sports, naming gut-centered targets, and aiming for both a healthy and sustainable athlete and performance development. With this article, we try to consider whether initiating a microbiota analysis is practicable and could add value in elite sport, and what possibilities it holds when influenced through a variety of interventions. The aim is to support enabling a well-rounded and sustainable athlete and establish a new methodology in elite sport.

The Important Role of Zinc in Neurological Diseases

Zinc is one of the most abundant metal ions in the central nervous system (CNS), where it plays a crucial role in both physiological and pathological brain functions. Zinc promotes antioxidant effects, neurogenesis, and immune system responses. From neonatal brain development to the preservation and control of adult brain function, zinc is a vital homeostatic component of the CNS. Molecularly, zinc regulates gene expression with transcription factors and activates dozens of enzymes involved in neuronal metabolism. During development and in adulthood, zinc acts as a regulator of synaptic activity and neuronal plasticity at the cellular level. There are several neurological diseases that may be affected by changes in zinc status, and these include stroke, neurodegenerative diseases, traumatic brain injuries, and depression. Accordingly, zinc deficiency may result in declines in cognition and learning and an increase in oxidative stress, while zinc accumulation may lead to neurotoxicity and neuronal cell death. In this review, we explore the mechanisms of brain zinc balance, the role of zinc in neurological diseases, and strategies affecting zinc for the prevention and treatment of these diseases.

Extracellular and Intracellular Concentrations of Molybdenum and Zinc in Soccer Players: Sex Differences

Molybdenum (Mo) and zinc (Zn) play important roles in the process of adaptation to physical training. The aims of the present study were: (i) to analyze the differences in extracellular (plasma and urine) and intracellular (erythrocytes and platelets) Mo and Zn concentrations between sexes and (ii) to relate extracellular Zn concentrations with biomarkers of muscle damage and muscle mass. The present study involved 138 semi-professional soccer players divided according to sex: male (n = 68) and female (n = 70). Mo and Zn concentrations were determined by inductively coupled plasma mass spectrometry. Erythrocytes, platelets, creatine kinase (CK), and lactate dehydrogenase (LDH) values were also determined by automatic cell counter and spectrophotometric techniques. There were no sex differences in Mo and Zn intake. Male soccer players obtained higher values of erythrocytes, CK, and LDH (p < 0.05), and showed higher plasma and urinary concentrations of Mo and Zn (p < 0.05). Female soccer players showed relatively higher Zn concentrations in erythrocytes (p < 0.05). Finally, positive correlations were observed between extracellular Zn concentrations with CK, LDH and muscle mass. Extracellular concentrations of Mo and Zn were higher in male soccer players. However, the relative concentrations of Zn in relation to the number of erythrocytes were higher in female soccer players.

Mechanisms Underlying the Protective Effect of Maternal Zinc (ZnSO4 or Zn-Gly) against Heat Stress-Induced Oxidative Stress in Chicken Embryo

Environmental factors such as high temperature can cause oxidative stress and negatively affect the physiological status and meat quality of broiler chickens. The study was conducted to evaluate the effects of dietary maternal Zn-Gly or ZnSO4 supplementation on embryo mortality, hepatocellular mitochondrial morphology, liver antioxidant capacity and the expression of related genes involved in liver oxidative mechanisms in heat-stressed broilers. A total of 300 36-week-old Lingnan Yellow broiler breeders were randomly divided into three treatments: (1) control (basal diet, 24 mg zinc/kg); (2) inorganic ZnSO4 group (basal diet +80 mg ZnSO4/kg); (3) organic Zn-Gly group (basal diet +80 mg Zn-Gly/kg). The results show that maternal zinc alleviated heat stress-induced chicken embryo hepatocytes’ oxidative stress by decreasing the content of ROS, MDA, PC, 8-OHdG, and levels of HSP70, while enhancing T-SOD, T-AOC, CuZn-SOD, GSH-Px, CTA activities and the content of MT. Maternal zinc alleviated oxidative stress-induced mitochondrial damage in chick embryo hepatocytes by increasing mitochondrial membrane potential and UCP gene expression; and Caspase-3-mediated apoptosis was alleviated by increasing CuZn-SOD and MT gene expression and decreasing Bax gene expression and reducing the activity of caspase 3. Furthermore, maternal zinc treatment significantly increased Nrf2 gene expression. The results above suggest that maternal zinc can activate the Nrf2 signaling pathway in developing chick embryos, enhance its antioxidant function and reduce the apoptosis-effecting enzyme caspase-3 activities, thereby slowing oxidative stress injury and tissue cell apoptosis.

Manipulation of Dietary Intake on Changes in Circulating Testosterone Concentrations

Elevations in the circulating concentration of androgens are thought to have a positive effect on the anabolic processes leading to improved athletic performance. Anabolic-androgenic steroids have often been used by competitive athletes to augment this effect. Although there has been concerted effort on examining how manipulating training variables (e.g., intensity and volume of training) can influence the androgen response to exercise, there has been much less effort directed at understanding how changes in both macronutrient and micronutrient intake can impact the androgen response. Thus, the focus of this review is to examine the effect that manipulating energy and nutrient intake has on circulating concentrations of testosterone and what the potential mechanism is governing these changes.

Bioaccessibility and Bioavailability of Minerals in Relation to a Healthy Gut Microbiome

Adequate amounts of a wide range of micronutrients are needed by body tissues to maintain health. Dietary intake must be sufficient to meet these micronutrient requirements. Mineral deficiency does not seem to be the result of a physically active life or of athletic training but is more likely to arise from disturbances in the quality and quantity of ingested food. The lack of some minerals in the body appears to be symbolic of the modern era reflecting either the excessive intake of empty calories or a negative energy balance from drastic weight-loss diets. Several animal studies provide convincing evidence for an association between dietary micronutrient availability and microbial composition in the gut. However, the influence of human gut microbiota on the bioaccessibility and bioavailability of trace elements in human food has rarely been studied. Bacteria play a role by effecting mineral bioavailability and bioaccessibility, which are further increased through the fermentation of cereals and the soaking and germination of crops. Moreover, probiotics have a positive effect on iron, calcium, selenium, and zinc in relation to gut microbiome composition and metabolism. The current literature reveals the beneficial effects of bacteria on mineral bioaccessibility and bioavailability in supporting both the human gut microbiome and overall health. This review focuses on interactions between the gut microbiota and several minerals in sport nutrition, as related to a physically active lifestyle.

[Musculoskeletal laboratory diagnostics in competitive sport]

Hintergrund

Die labordiagnostische Untersuchung stellt eine wichtige Möglichkeit zur Beurteilung und Optimierung der Leistungs- und Regenerationsfähigkeit professioneller Athleten dar. Ferner ist sie für die Prävention, Diagnostik und Rehabilitation von Verletzungen und Überbelastungen von Bedeutung.

Fragestellung

Ziel dieser Arbeit ist die Darstellung muskuloskelettaler laborchemischer Parameter, die relevante Erkenntnisse für die medizinische Betreuung von Leistungssportlern liefern.

Material und Methoden

Literaturrecherche und narratives Review.

Ergebnisse

Die Bestimmung des Vitamin-D-, Calcium- und Knochenstoffwechsels stellt die laborchemische Basisdiagnostik im Rahmen der Beurteilung des Skelettstatus mit zusätzlichem präventivem Nutzen bezüglich muskuloskelettaler Verletzungen dar. Ferner können muskuläre Serummarker, z. B. Laktatdehydrogenase (LDH), Kreatinkinase (CK), Myoglobin und Aspartat-Aminotransferase (ASAT), helfen, eine metabolische Adaptation an das physische Training festzustellen und Aussagen über die muskuläre Arbeitslast und mögliche Schädigungen zu gewinnen. Die Energieverfügbarkeit kann durch eine entsprechende Bilanzierung sowie die laborchemische Bestimmung der Makro- und Mikronährstoffe eingeschätzt und optimiert werden.

Schlussfolgerungen

Die labordiagnostische Untersuchung besitzt in der Betreuung von Athleten eine sportartenübergreifende klinische Relevanz. Sie dient der Erreichung einer höchstmöglichen Leistungsfähigkeit sowie optimalen Prävention von Knochen- und Muskelverletzungen, wobei sämtliche Mangelzustände (z. B. Vitamin D) ausgeglichen werden sollten. Durch eine Periodisierung der laborchemischen Untersuchungen, mit zumindest zwei Labordiagnostiken im Jahr, und Aufstellung individueller Variabilitäts- und Referenzbereiche kann ferner eine bessere Beurteilbarkeit erreicht werden.

Malnutrition in Orthopaedic Sports Medicine: A Review of the Current Literature

CONTEXT

Malnutrition is well-studied in various aspects of the orthopaedic literature, most commonly in relation to arthroplasty, spine surgery, and trauma. However, the management of nutritional deficiencies is commonly overlooked among orthopaedic sports medicine providers. The purpose of this article is to analyze the available sports medicine literature to review the associations between malnutrition and the management of orthopaedic sports medicine patients from a treatment and performance standpoint.

EVIDENCE ACQUISITION

PubMed was searched for relevant articles published from 1979 to 2019.

STUDY DESIGN

Clinical review.

LEVEL OF EVIDENCE

Level 4.

RESULTS

Few studies exist on the implications of macronutrient deficiencies specific to orthopaedic sports medicine procedures. Interestingly, micronutrient disorders-namely, hypovitaminosis D and iron deficiency-have been well studied and may lead to worse postoperative outcomes, injury rates, and athletic performance. Nutritional supplementation to correct such deficiencies has been shown to mitigate these effects, though further study is required.

CONCLUSION

Nutritional deficiencies are highly prevalent in orthopaedic sports medicine patients, and practitioners should be aware of their potential effects on treatment and performance outcomes. Management of such deficiencies and their effect on surgical patients remain an area of potential future research. Future studies are warranted in order to explore the potential therapeutic role of nutritional supplementation to prevent complications after common orthopaedic sports medicine procedures, improve athletic performance, and reduce injury rates.

Nutrition and Athlete Immune Health: New Perspectives on an Old Paradigm

Respiratory and gastrointestinal infections limit an athlete's availability to train and compete. To better understand how sick an athlete will become when they have an infection, a paradigm recently adopted from ecological immunology is presented that includes the concepts of immune resistance (the ability to destroy microbes) and immune tolerance (the ability to dampen defence yet control infection at a non-damaging level). This affords a new theoretical perspective on how nutrition may influence athlete immune health; paving the way for focused research efforts on tolerogenic nutritional supplements to reduce the infection burden in athletes. Looking through this new lens clarifies why nutritional supplements targeted at improving immune resistance in athletes show limited benefits: evidence supporting the old paradigm of immune suppression in athletes is lacking. Indeed, there is limited evidence that the dietary practices of athletes suppress immunity, e.g. low-energy availability and train- or sleep-low carbohydrate. It goes without saying, irrespective of the dietary preference (omnivorous, vegetarian), that athletes are recommended to follow a balanced diet to avoid a frank deficiency of a nutrient required for proper immune function. The new theoretical perspective provided sharpens the focus on tolerogenic nutritional supplements shown to reduce the infection burden in athletes, e.g. probiotics, vitamin C and vitamin D. Further research should demonstrate the benefits of candidate tolerogenic supplements to reduce infection in athletes; without blunting training adaptations and without side effects.

Effects of dietary supplements on selected hematological and biochemical parameters of Pakistani athletes

Background

CDC’s (Centers for Disease Control and Prevention) National Center for Health statistics recent reports have shown that an upsurge has occurred in the use of dietary supplements among age of 20 years since 1994 and this use shown regular increase. The purpose of our study was to investigate the effect of supplements on the reproductive health on male athletes in Pakistan.

Methods

A total of 150 adult male with mean age of 25.78 ± 0.56 years were included in this study and divided into four groups: Non-athlete control (n = 57), Non supplemental athlete control (n = 40), Supplemental athlete group I (n = 28) and supplemental athlete group II (n = 25). Blood (10 ml) was taken from each subject. Complete blood count was performed and 5 ml of blood was centrifuged to separate plasma and then analyzed for antioxidant enzyme (CAT, POD, GR and GSH) activities, Lipid peroxidation (TBARS), electrolyte, metal (sodium, potassium and zinc) and Luteinizing hormone (LH) concentration.

Results

Complete blood count results showed normal RBC, WBC, Platelets, Hemoglobin, Hematocrit, Mean corpuscular hemoglobin and Mean corpuscular hemoglobin concentration. Antioxidant enzymes (CAT, POD, GR, GSH) increased significantly in supplemental athletes as compared to control groups. Sodium and potassium showed significant increase (p < 0.001) in supplemental athlete group I, while TBARS also showed significant increase (p < 0.05) in supplemental group I and II as compared to non athlete control while non supplemental athletes showed significant increase (p < 0.05) in TBARS concentration as compared to non athlete control. LH concentration was found to be decreased significantly (p < 0.05) in supplemental group I and II as compared to control groups.

Conclusion

It is therefore concluded from the present results that oxidative stress was considerably elevated in response to supplement consumption among athletes which may affect their health haematological parameters and reproductive hormones.

Influence of an Acute Exercise Until Exhaustion on Serum and Urinary Concentrations of Molybdenum, Selenium, and Zinc in Athletes

The aim of the present study was to determine changes occurring in serum and urine concentrations of essential trace elements with proven essentiality (molybdenum, selenium, and zinc) as a result of performing an acute physical activity until exhaustion in middle- and long-distance runners who live in the same area of Extremadura (Spain). Twenty-one Spanish national middle- and long-distance runners and 26 sedentary students of a similar age were recruited for the study. Both groups ran on a treadmill until exhaustion, starting at a speed of 10 and 8 km/h, respectively, and increasing the speed at 1 km/h every 400 m, without modifying the slope, always within the recommended parameters. Serum and urine samples were obtained from all subjects before and after the tests. Analysis of trace metals was performed by inductively coupled plasma mass spectrometry (ICP-MS). Resting serum and urinary concentrations between groups were compared using the Student t test, and the Wilcoxon test was used to analyze the trends of changes before and after the effort. The results showed that molybdenum concentrations were significantly higher in athletes than in controls (p < 0.01). Selenium (p < 0.05) and zinc (p < 0.01) concentrations were significantly lower in athletes than in controls. When we compared the serum concentrations before and after the test in the controls, only in the case of selenium (p = 0.006), a significant increase was observed after the test. However, this signification disappears with the corrections for hematocrit. Athletes' serum concentrations of Se (p = 0.004) and Zn (p = 0.005) lowered at the end of the test. Also, the results showed that there were no statistical urinary concentration (expressed in μg/g creatinine) changes in Mo and Se. Zn urinary concentration increased at the end of exercise (p = 0.018), since an incremental exercise to exhaustion in middle- and long-distance elite athletes produces a decrease in Se and Zn serum concentrations but Zn urinary concentration increased. In conclusion, athletes show higher serum concentrations of molybdenum and lower serum concentrations of selenium and zinc than sedentary subjects. Additionally, a treadmill test until exhaustion provokes a decrease in serum concentration of selenium and zinc and a higher excretion of urinary zinc. Serum concentrations of Se and Zn should be carried out in order to avoid any possible deficit cases and to establish the optimal supplementation.

Serum concentration of cobalt, molybdenum and zinc in aerobic, anaerobic and aerobic-anaerobic sportsmen

BACKGROUND

The aim of the present study was to determine changes in the serum concentrations of trace elements Cobalt (Co), Molybdenum (Mo) and Zinc (Zn) among high-level sportsmen.

METHODS

Eighty professional athletes of different metabolic modalities (aerobic, anaerobic and aerobic-anaerobic), were recruited before the beginning of their training seasons. Thirty-one sedentary participants of the same geographic area constituted the control group. Co, Mo and Zn analysis was performed by Inductively Coupled Plasma Mass Spectrometry (ICP-MS).

RESULTS

Serum concentration of Mo (p < 0.001) was higher among sportsmen compared to the control group values. Separated by modalities, the concentrations of Co in the aerobic-anaerobic athletes were lower (p < 0.01) than in the control group as well as than in the other athletes. The highest Mo concentration was found in anaerobic sportsmen (p < 0.001), followed by aerobic-anaerobic (p < 0.001) being both statistically higher in comparison with the control group. In relation to Zn, it was observed that aerobic-anaerobic (p < 0.001) and anaerobic (p < 0.001) sportsmen showed higher concentrations than the control participants. However, aerobic sportsmen showed lower concentrations (p < 0.01) than controls.

CONCLUSION

This data manifest that long-term, daily physical training may induce variations in serum concentrations of several essential elements among sportsmen in comparison to untrained men and that these changes seems to be related to the sports modality practiced.

Enhanced aerobic exercise performance in women by a combination of three mineral Chelates plus two conditionally essential nutrients

BACKGROUND

Certain essential and conditionally essential nutrients (CENs) perform functions involved in aerobic exercise performance. However, increased intake of such nutrient combinations has not actually been shown to improve such performance.

METHODS

For 1 mo, aerobically fit, young adult women took either a combination of 3 mineral glycinate complexes (daily dose: 36 mg iron, 15 mg zinc, and 2 mg copper) + 2 CENs (daily dose: 2 g carnitine and 400 mg phosphatidylserine), or the same combination with generic mineral complexes, or placebo (n = 14/group). In Trial 1, before and after 1 mo, subjects were tested for 3 mile run time (primary outcome), followed by distance covered in 25 min on a stationary bike (secondary outcome), followed by a 90 s step test (secondary outcome). To test reproducibility of the run results, and to examine a lower dose of carnitine, a second trial was done. New subjects took either mineral glycinates + CENs (1 g carnitine) or placebo (n = 17/group); subjects were tested for pre- and post-treatment 3 mile run time (primary outcome).

RESULTS

In Trial 1, the mineral glycinates + CENs decreased 3 mile run time (25.6 ± 2.4 vs 26.5 ± 2.3 min, p < 0.05, paired t-test) increased stationary bike distance after 25 min (6.5 ± 0.6 vs 6.0 ± 0.8 miles, p < 0.05, paired t-test), and increased steps in the step test (43.8 ± 4.8 vs 40.3 ± 6.4 steps, p < 0.05, paired t-test). The placebo significantly affected only the biking distance, but it was less than for the glycinates-CENs treatment (0.2 ± 0.4. vs 0.5 ± 0.1 miles, p < 0.05, ANOVA + Tukey). The generic minerals + CENs only significantly affected the step test (44.1 ± 5.2 vs 41.0 ± 5.9 steps, p < 0.05, paired t-test) In Trial 2, 3 mile run time was decreased for the mineral glycinates + CENs (23.9 ± 3.1 vs 24.7 ± 2.5, p < 0.005, paired t-test), but not by the placebo. All changes for Test Formula II or III were high compared to placebo (1.9 to 4.9, Cohen's D), and high for Test Formula II vs I for running and biking (3.2 & 3.5, Cohen's D).

CONCLUSION

In summary, a combination of certain mineral complexes plus two CENs improved aerobic exercise performance in fit young adult women.

Adverse effects of parental zinc deficiency on metal homeostasis and embryonic development in a zebrafish model

The high prevalence of zinc deficiency is a global public health concern, and suboptimal maternal zinc consumption has been associated with adverse effects ranging from impaired glucose tolerance to low birthweights. The mechanisms that contribute to altered development and poor health in zinc deficient offspring are not completely understood. To address this gap, we utilized the Danio rerio model and investigated the impact of dietary zinc deficiency on adults and their developing progeny. Zinc deficient adult fish were significantly smaller in size, and had decreases in learning and fitness. We hypothesized that parental zinc deficiency would have an impact on their offspring's mineral homeostasis and embryonic development. Results from mineral analysis showed that parental zinc deficiency caused their progeny to be zinc deficient. Furthermore, parental dietary zinc deficiency had adverse consequences for their offspring including a significant increase in mortality and decreased physical activity. Zinc deficient embryos had altered expression of genes that regulate metal homeostasis including several zinc transporters (ZnT8, ZnT9) and the metal-regulatory transcription factor 1 (MTF-1). Zinc deficiency was also associated with decreased expression of genes related to diabetes and pancreatic development in the embryo (Insa, Pax4, Pdx1). Decreased expression of DNA methyltransferases (Dnmt4, Dnmt6) was also found in zinc deficient offspring, which suggests that zinc deficiency in parents may cause altered epigenetic profiles for their progeny. These data should inform future studies regarding zinc deficiency and pregnancy and suggest that supplementation of zinc deficient mothers prior to pregnancy may be beneficial.

Nutritional implications for ultra-endurance walking and running events

This paper examines the various nutritional challenges which athletes encounter in preparing for and participating in ultra-endurance walking and running events. Special attention is paid to energy level, performance, and recovery within the context of athletes' intake of carbohydrate, protein, fat, and various vitamins and minerals. It outlines, by way of a review of literature, those factors which promote optimal performance for the ultra-endurance athlete and provides recommendations from multiple researchers concerned with the nutrition and performance of ultra-endurance athletes. Despite the availability of some research about the subject, there is a paucity of longitudinal material which examines athletes by nature and type of ultra-endurance event, gender, age, race, and unique physiological characteristics. Optimal nutrition results in a decreased risk of energy depletion, better performance, and quicker full-recovery.

The influence of physical activity on hair toxic and essential trace element content in male and female students

The primary aim of the current study is to estimate the effect of different physical activity levels on hair trace element content in male and female students. A total of 113 students (59 women and 54 men) of P. G. Demidov Yaroslavl State University (Yaroslavl, Russia) took part in the current investigation. According to the level of the physical activity, all students were divided into three groups: high, medium, and low physical activity. Essential and toxic metal content (μg/g) in hair samples was assessed by inductively coupled plasma mass spectrometry using NexION 300D + NWR213 (Perkin-Elmer, USA). The obtained data show that hair iodine, zinc, arsenic, nickel, and tin levels are not related to physical activity in male and female students. At the same time, increased physical activity is associated with decreased hair copper, vanadium, bismuth, and mercury content in comparison to the low physical activity groups. Students with higher physical activity are also characterized by significantly higher hair cobalt, iron, manganese, selenium, cadmium, lithium, and lead concentrations. Finally, statistical analysis has revealed maximal gender differences in hair trace element content in the high physical activity groups, whereas in the low activity groups, the hair metal concentrations were nearly similar in females and males.

Marginal zinc deficiency negatively affects recovery from muscle injury in mice

The aim of the present study was to elucidate whether the recovery from muscle injury is impaired in marginal zinc deficiency. C57BL/6 male mice were fed a marginally zinc-deficient diet (MZD: 8 mg Zn/kg diet), a zinc-adequate diet (ZA: zinc 35 mg Zn/kg diet), and a zinc-high diet (ZH: 190 mg Zn/kg diet) for 4 weeks. Muscle injury was induced in the gastrocnemius muscles using cardiotoxin. The gastrocnemius muscles of these mice were harvested at 3, 5, 7, 10, 14, and 20 days after injury. We evaluated the regeneration of the skeletal muscle with hematoxylin and eosin staining and developmental myosin heavy-chain (dMHC: implicated in regeneration) immunostaining. The rate of dMHC-positive cells was significantly low in MZD mice compared with ZA mice at 3 days after cardiotoxin injection. The peak dMHC expression was found at 3 days after injection in ZA mice, 5 days in ZH mice, and 7 days in MZD mice. These results suggest that recovery from muscle injury might be partly impaired and delayed in MZD mice. Therefore, we strongly suggest the appropriate zinc intake to prevent the impairment of skeletal muscle regeneration.

Influence of training frequency on serum concentrations of some essential trace elements and electrolytes in male swimmers

Elemental fluctuations during physical performances have been a point of interest. This study was designed to investigate the effect of swimming frequency on serum concentrations of some trace elements (chromium, iron, copper, zinc, selenium) and electrolytes (sodium, magnesium, potassium, calcium). Three groups of different-level male swimmers were included in the study, as elite swimmers (n = 14), amateur swimmers (n = 11), and sedentary individuals (n = 10). Elite and amateur swimmer groups followed a 3-week training program. At the end of the period, all volunteers were subjected to a controlled swimming test, and blood samples were collected at the beginning of (pre-test), immediately after (post-test), and 1 h after this activity. Element concentrations were determined by inductively coupled plasma mass spectrometry using a dilute and shoot procedure. Apart from the swimming test applied, pre-test calcium and potassium levels were higher in elite swimmers compared to amateurs and controls. The difference in pre-test levels of these elements can be associated with adaptive mechanisms emerged by the frequent training. Regarding the test applied, changes in magnesium, calcium, copper, zinc, and selenium levels exhibited a common pattern in all study groups, with higher post-test serum concentrations. Another point of note was a drop of copper, zinc, and selenium levels at 1 h after the test in elite swimmers. The decrease in serum zinc was also observed in the other groups. Results highlight the value of regular control of elemental status to provide insight into transient effects and deficiencies.

Effects of high-intensity training and resumed training on macroelement and microelement of elite basketball athletes

The purpose of this study was to assess the effects of high-intensity training and resumed training in hot and humid environment on plasma macro- and microelements levels of elite Han Chinese basketball players. Ten well-trained elite basketball athletes' plasma macroelements (chlorin, sodium, potassium, and calcium), creatine kinase (CK), and creatine kinase-MB (CK-MB) were measured before and after a 2-h high-intensity training, and microelements (zinc, copper, iron, and selenium) were determined before and after a 1-week high-intensity training and after a 1-week resumed training. The blood CK and CK-MB levels of the elite basketball athletes were significantly increased (P < 0.05) after high-intensity basketball training. The macroelements (chlorin, sodium, and calcium) levels of blood increased significantly except potassium after high-intensity basketball training. No significant differences (P > 0.05) were found in zinc and copper levels; nevertheless, the levels of plasma selenium and plasma iron were significantly lower (P < 0.05) after a 1-week high-intensity training. After a 1-week resumed training, except zinc, all of microelements measured had a trend toward original levels. These results implicated that high-intensity training would provoke the change of macroelements which would lead to electrolyte disturbance. In addition, the present study suggested that a 1-week high-intensity training would have an impact on microelement levels, especially for selenium and iron.

Effects of exercise and zinc supplementation on cytokine release in young wrestlers

The present study aims to examine the effect of zinc supplementation on the release of some cytokines in young wrestlers actively involved in wrestling. A total of 40 male subjects of the same age group were included in the study: half were wrestlers and the other half were not involved in sports. The subjects were equally divided into four groups and treated during an 8-week period as follows: group 1, zinc-supplemented athletes; group 2, non-supplemented athletes; group 3, zinc-supplemented sedentary subjects, and group 4, non-supplemented sedentary group. Blood samples were taken from each subject at the beginning and at the end of the study period. The serum tumor necrosis factor-α (TNF-α), interleukin-2 (IL-2), and interpheron-γ levels (IFN-γ) were determined using the enzyme-linked immunosorbent assay method. At the beginning of the study, there were no significant differences of the measured parameters between the four study groups. At the end of the study, the levels of TNF-α, IL-2, and IFN-γ were significantly higher in the two zinc-supplemented groups compared to those that did not receive supplementation, regardless of the activity status (p < 0.01).

Aspectos sobre a relação entre exercício físico, estresse oxidativo e zinco

Este trabalho visa a contribuir com informações sobre a relação entre exercício físico, estresse oxidativo e zinco. A formação de espécies reativas de oxigênio durante o exercício pode contribuir para danos tissulares e celulares, prejudicando o desempenho do atleta. Podem amenizar esses efeitos alguns minerais, como o zinco, que atuam como cofator da enzima superóxido dismutase e na regulação da síntese da metalotioneína, proteínas importantes no sistema de defesa antioxidante. No exercício físico, ocorrem distúrbios na compartimentalização do zinco, com alterações da concentração desse mineral em compartimentos celulares. No entanto, os mecanismos envolvidos no comportamento metabólico do zinco bem como a participação do mineral na melhora do desempenho físico ainda não estão totalmente esclarecidos. Dessa forma, conclui-se que a distribuição do zinco em organismos submetidos ao estresse oxidativo e os efeitos da deficiência desse mineral na capacidade antioxidante durante o exercício ainda devem ser pesquisados mais profundamente.

Plasma trace elements levels are not altered by submaximal exercise intensities in well-trained endurance euhydrated athletes

The purpose of this study was to assess the effect of relative exercise intensity on various plasma trace elements in euhydrated endurance athletes. Twenty-seven well-trained endurance athletes performed a cycloergometer test: after a warm-up of 10 min at 2.0 W kg⁻¹, workload increased by 0.5 W kg⁻¹ every 10 min until exhaustion. Oxygen uptake, blood lactate concentration ([La⁻](b)), and plasma ions (Zn, Se, Mn and Co) were measured at rest, at the end of each stage, and 3, 5 and 7 min post-exercise. Urine specific gravity (U(SG)) was measured before and after the test, and subjects drank water ad libitum. Fat oxidation (FAT(OXR)), carbohydrate oxidation (CHO(OXR)), energy expenditure from fat (EE(FAT)), from carbohydrates (EE(CHO)) and total EE (EE(T)) were estimated using stoichiometric equations. A repeated measure (ANOVA) was used to compare plasma ion levels at each exercise intensity level. The significance level was set at P<0.05. No significant differences were found in U(SG) between, before, and after the test (1.014±0.004 vs. 1.014±0.004 g cm⁻³) or in any plasma ion level as a function of intensity. There were weak significant correlations of Zn (r=0.332, P<0.001) and Se (r=0.242, P<0.01) with [La⁻](b), but no relationships were established between [La⁻](b), VO₂, FAT(OXR), CHO(OXR), EE(FAT), EE(CHO), or EE(T) and plasma ion levels. Acute exercise at different submaximal intensities in euhydrated well-trained endurance athletes does not provoke a change in plasma trace element levels, suggesting that plasma volume plays an important role in the homeostasis of these elements during exercise.

Effect of zinc supplementation on antioxidant activity in young wrestlers

This study aims to examine the effect of zinc supplementation on free-radical formation and antioxidant system in individuals who are actively engaged in wrestling as a sport. The study registered a total of 40 male subjects, of whom 20 were wrestlers and 20 were sedentary individuals. The subjects were equally allocated to four groups: group 1, zinc-supplemented sportsmen group; group 2, sportsmen group without supplementation; group 3, zinc-supplemented sedentary group; group 4, sedentary group without supplementation. Blood samples were collected from all subjects twice, once at the beginning of the study and once again at the end of 8-week procedures. The blood samples collected were analyzed to determine the levels of malondialdehyde (MDA), serum glutathione (GSH), serum glutathione peroxidase (GPx) activity, serum superoxide dismutase (SOD) activity (ELISA colorimetric method) and zinc (colorimetric method). No difference was found between MDA levels of the study groups in the beginning of the study. The highest MDA value at the end of the study was obtained in group 4 (p < 0.01). MDA levels in group 2 were established to be significantly higher than those in groups 1 and 3 (p < 0.01). GSH level, GPx, and SOD activities and zinc level measured in the beginning of the study were not different between groups. Measurements performed at the end of the study showed that groups 1 and 3 (zinc-supplemented groups) had the highest GSH level, GPx, and SOD activities and zinc level (p < 0.01). These parameters were not different in the groups without supplementation (groups 2 and 4). Results obtained at the end of the study indicate that zinc supplementation prevents production of free radicals by activating the antioxidant system. In conclusion, physiologic doses of zinc supplementation to athletes may beneficially contribute to their health and performance.

Effects of acute swimming exercise on some elements in rats

The objective of the present study is to explore the effects of acute swimming exercise on plasma levels of some elements in rats, immediately after the exercise, and 24 and 48 h later. The study included 40 adult male rats of Spraque Dawley species, which were equally allocated to four groups. Group 1: General Control Group; Group 2: Swimming Group, the group that was decapitated immediately after 30-min acute swimming exercise; Group 3: Swimming Group, the group that was decapitated 24 h after 30-min acute swimming exercise; Group 4: Swimming Group, the group that was decapitated 48 h after 30-min acute swimming exercise. Plasma copper (Cu), iron (Fe), magnesium (Mg), phosphorus (P), selenium (Se), zinc (Zn) levels were determined according to atomic emission method in the blood samples collected from the animals by decapitation method. Measurements conducted immediately after acute swimming exercise (group 2) showed a significant decrease in Se and Zn levels (p < 0,01) and a significant increase in P levels (p < 0,01), when compared to group 1. Measurements carried out 24 h after the exercise (group 3) demonstrated a significant increase in all parameters except for Mg, in comparison to groups 1 and 2 (p < 0,01). It was seen in the measurements made 48 h after the exercise (group 4) that all parameters were restored to control values. The results of our study show that acute swimming exercise significantly changes plasma Cu, Fe, P, Se, and Zn levels.

Zinco no plasma e eritrócito de atletas profissionais de uma equipe feminina brasileira de voleibol

OBJETIVO: Avaliar o estado nutricional relativo ao zinco de 12 atletas profissionais do voleibol feminino. MÉTODOS: Determinou-se a concentração de zinco plasmático e eritrocitário por espectrofotometria de absorção atômica, e avaliou-se a ingestão dietética por meio de registro alimentar de três dias, de 12 atletas profissionais do sexo feminino, integrantes de uma equipe de voleibol de Curitiba, PR, na faixa etária de 18 a 24 anos, no ano de 2003. RESULTADOS: Todas as atletas apresentaram valores normais de zinco plasmático. Quanto ao zinco eritrocitário, 100,00% apresentaram valores abaixo da normalidade. Em relação à ingestão dietética de zinco, 83,33% apresentaram adequação. Decréscimos no conteúdo de zinco eritrocitário podem representar o efeito agudo de exercícios prolongados pela utilização enzimática da superóxido dismutase ou anidrase carbônica. CONCLUSÃO: O estado nutricional das atletas relativo ao zinco parece estar inadequado, pois, apesar dos valores normais para a concentração de zinco plasmático, a concentração eritrocitária esteve abaixo da faixa de normalidade para todas as atletas.

Preventive effects of Spirulina platensis on skeletal muscle damage under exercise-induced oxidative stress

The effects of spirulina supplementation on preventing skeletal muscle damage on untrained human beings were examined. Sixteen students volunteered to take Spirulina platensis in addition to their normal diet for 3-weeks. Blood samples were taken after finishing the Bruce incremental treadmill exercise before and after treatment. The results showed that plasma concentrations of malondialdehyde (MDA) were significantly decreased after supplementation with spirulina (P < 0.05). The activity of blood superoxide dismutase (SOD) was significantly raised after supplementation with spirulina or soy protein (P < 0.05). Both of the blood glutathione peroxidaes (GPx) and lactate dehydrogenase (LDH) levels were significantly different between spirulina and soy protein supplementation by an ANCOVA analysis (P < 0.05). In addition, the lactate (LA) concentration was higher and the time to exhaustion (TE) was significantly extended in the spirulina trail (P < 0.05). These results suggest that ingestion of S. platensis showed preventive effect of the skeletal muscle damage and that probably led to postponement of the time of exhaustion during the all-out exercise.

Nutrition and student performance at school

This article reviews research from published studies on the association between nutrition among school-aged children and their performance in school and on tests of cognitive functioning. Each reviewed article is accompanied by a brief description of its research methodology and outcomes. Articles are separated into 4 categories: food insufficiency, iron deficiency and supplementation, deficiency and supplementation of micronutrients, and the importance of breakfast. Research shows that children with iron deficiencies sufficient to cause anemia are at a disadvantage academically. Their cognitive performance seems to improve with iron therapy. A similar association and improvement with therapy is not found with either zinc or iodine deficiency, according to the reviewed articles. There is no evidence that population-wide vitamin and mineral supplementation will lead to improved academic performance. Food insufficiency is a serious problem affecting children's ability to learn, but its relevance to US populations needs to be better understood. Research indicates that school breakfast programs seem to improve attendance rates and decrease tardiness. Among severely undernourished populations, school breakfast programs seem to improve academic performance and cognitive functioning.

Dietary supplements and sports performance: minerals

Minerals are essential for a wide variety of metabolic and physiologic processes in the human body. Some of the physiologic roles of minerals important to athletes are their involvement in: muscle contraction, normal hearth rhythm, nerve impulse conduction, oxygen transport, oxidative phosphorylation, enzyme activation, immune functions, antioxidant activity, bone health, and acid-base balance of the blood. The two major classes of minerals are the macrominerals and the trace elements. The scope of this article will focus on the ergogenic theory and the efficacy of such mineral supplementation.

Effects of dietary intake and life style on bone density in patients with diabetes mellitus type 2

OBJECTIVE

The aim of our study was to investigate the relation among glycemic control, lifestyle and dietary intake with bone mineral density in patients with diabetes mellitus type 2.

DESIGN

Cross-sectional study.

SETTING

Tertiary care hospital.

PARTICIPANTS

A cross-sectional study in a tertiary care hospital was performed. Ninety-two patients attending our diabetes service (56 females/36 males) with diabetes mellitus type 2 were enrolled in a consecutive way. The inclusion criteria were diabetes diagnosed >40 years of age, with type 2 diabetes defined in accordance with the criteria of the American Diabetes Association and no use of dietary supplements. Body mass index, waist-to-hip ratio, glucose level, and HbA1c levels were assessed in all patients. X-ray densitometry of the calcaneal region and a 3-days written food record keeping, and a qualitative questionnaire of lifestyle were also performed.

RESULTS

A total of 21.7% of patients had osteoporosis (T score <2.5 SD). Patients were overweight with a high BMI and a medium glucose control. Patients with osteoporosis were older than those without osteoporosis (67.8 +/- 6.9 vs. 62.1 +/- 9.2 years; p < 0.05). Significant differences were detected between patients without and with osteoporosis in calcium intake (1,219.37 +/- 387 vs. 839 +/- 251 mg/day; p < 0.05) and zinc intake (9.23 +/- 3.5 vs. 13.3 +/- 6.9 mg/day; p < 0.05), respectively. No differences were detected in other dietary dairy intakes. In correlation analysis age (r = -0.23; p < 0.05) and BMI (r = 0.48; p < 0.05) was correlated with BMD. In univariate analysis with dicotomic variables, only exercise was positive associated with osteoporotic status (87.5% exercise habit in patients without osteoporosis and 25% exercise habit in patients with osteoporosis; p < 0.05). In a logistic model with the dependent variable (osteoporosis), remained in the final model dietary dairy intake of calcium and zinc, BMI, age and exercise. Exercise, calcium intake and BMI were protective factors. Zinc intake, and age were risk factors.

CONCLUSIONS

Exercise, calcium intake, body mass index had a protective role in bone mineral density in patients with diabetes mellitus type 2. Zinc intake and age were risk factors in our population.

Persistence of nutritional deficiencies after short-term weight recovery in adolescents with anorexia nervosa

OBJECTIVES

To study nutritional abnormalities in adolescent anorexia nervosa and to establish whether certain abnormalities persist after short-term refeeding.

METHOD

Sixty-one patients (10-19 years old) admitted to a reference unit for eating disorders between 1999 and 2000 with a diagnosis of anorexia nervosa were evaluated at admission and at discharge. A range of biochemical, nutritional, and hormonal parameters were determined.

RESULTS

At admission, no protein or lipid deficiencies were found, although many patients presented with hormonal abnormalities and red blood cell folate and zinc deficiencies. Hormonal abnormalities reverted significantly (p <.000) after renutrition. There were decreases in erythrocytes and in levels of hemoglobin (p <.000) and folic acid (p <.05). Red blood cell folate and zinc increased but did not reach normal levels.

CONCLUSIONS

In a large proportion of adolescent anorexic patients, supplementation of folic acid and zinc is recommended although protein or hormonal replacement does not seem to be necessary.