Antioxidant and Vitamin D supplements for athletes: sense or nonsense?

The benefits of ashwagandha (Withania somnifera) supplements on brain function and sports performance

Ashwagandha or Withania somnifera is an herbal plant belonging to the Solanaceae family. Because of its wide range of phytochemicals, ashwagandha root extract has been used in numerous research studies, either alone or in conjunction with other natural plants, for various biomedical applications, which include its anti-microbial, anti-inflammatory, anti-stress, anti-tumor, cardioprotective, and neuroprotective properties. Additionally, it improves endothelial function, lowers reactive oxygen species, controls apoptosis, and improves mitochondrial function. These properties make it a useful treatment for a variety of conditions, including age-related symptoms, anxiety, neurodegenerative diseases, diabetes, stress, arthritis, fatigue, and cognitive/memory impairment. Despite the numerous benefits of ashwagandha supplementation, there have been just four meta-analyses on the herb's effectiveness in treating anxiety, neurobehavioral disorders, impotence, and infertility. Moreover, no reviews exist that examine how ashwagandha affects antioxidant response and physical sports performance. Consequently, the goal of this study was to analyze the scientific literature regarding the effects of ashwagandha consumption on antioxidant response and athletic performance.

Minerals and Sarcopenia in Older Adults: An Updated Systematic Review

OBJECTIVE

This systematic review aims to reevaluate the role of minerals on muscle mass, muscle strength, physical performance, and the prevalence of sarcopenia in community-dwelling and institutionalized older adults.

DESIGN

Systematic review.

SETTING AND PARTICIPANTS

In March 2022, a systematic search was performed in PubMed, Scopus, and Web of Sciences using predefined search terms. Original studies on dietary mineral intake or mineral serum blood concentrations on muscle mass, muscle strength, and physical performance or the prevalence of sarcopenia in older adults (average age ≥65 years) were included.

METHODS

Eligibility screening and data extraction was performed by 2 independent reviewers. Quality assessment was performed with the Effective Public Health Practice Project (EPHPP) Quality Assessment Tool for Quantitative Studies. Risk of bias was evaluated using the Risk Of Bias In Non-randomized Studies-of Exposure (ROBINS-E) tool.

RESULTS

From the 15,622 identified articles, a total of 45 studies were included in the review, mainly being cross-sectional and observational studies. Moderate quality of evidence showed that selenium (n = 8) and magnesium (n = 7) were significantly associated with muscle mass, strength, and physical performance as well as the prevalence of sarcopenia. For calcium and zinc, no association could be found. For potassium, iron, sodium, and phosphorus, the association with sarcopenic outcomes remains unclear as not enough studies could be included or were nonconclusive (low quality of evidence).

CONCLUSIONS AND IMPLICATIONS

This systematic review shows a potential role for selenium and magnesium on the prevention and treatment of sarcopenia in older adults. More randomized controlled trials are warranted to determine the impact of minerals on sarcopenia in older adults.

Performance-related physiological changes induced by one year of endurance training in young athletes

Introduction

Although maximal oxygen uptake (VO₂max) is generally recognized as the single best indicator of aerobic fitness in youth, interpretation of this parameter and the extent to which it can be improved by training remain controversial, as does the relative importance of VO₂max for performance in comparison to other factors such as power production. Here, we examined the influence of endurance training on the VO₂max, muscle power and sports-related performance of cross-country skiers attending a school specializing in sports, as well as potential relationships between any changes observed to one another and/or to perceived stress scale (Cohen) and certain blood parameters.

Methods

On two separate occasions, prior to the competition season and separated by one year of endurance training, the 12 participants (5 males, 7 females, 17 ± 1 years) carried out tests for VO₂max on a treadmill, explosive power utilizing countermovement jumps (CMJ) and ski-specific maximal double pole performance (DPP) employing roller skis on a treadmill. Blood levels of ferritin (Fer), vitamin D (VitD) and hemoglobin (Hg) were monitored, and stress assessed with a questionnaire.

Results

DPP improved by 10 ± 8% (P < 0.001), but no other significant changes were observed. There were no significant correlations between the changes in DPP and any other variable.

Discussion

Whereas one year of endurance training improved the cross-country ski-specific performance of young athletes significantly, the increase in their maximal oxygen uptake was minimal. Since DPP was not correlated with VO₂max, jumping power or the levels of certain blood parameters, the improvement observed probably reflected better upper-body performance.

Effects of Punica granatum Fruit (a Super Food) Juice on Human Health

Background:

Pomegranate (Punica granatum L.), one of the oldest known edible fruits, is nowadays broadly consumed throughout the world. Its fruits and seed are rich in many bioactive compounds, as polyphenols, and the scientific interest in this plant has been constantly growing in recent years.

Introduction:

Pomegranate fruit and its juice have been shown to have health benefits relating to their antioxidant and anti-inflammatory properties. They are used in alternative medicine as adaptogens and ergogens protecting against many neurological, cardiovascular, gastrointestinal, liver, and skin disorders.

Methods:

Given the amount of evidence, this narrative review does not seek to supply a comprehensive summary of all study findings, but rather focuses on human clinical trials related the last five years. In this regard, we have performed a check in MEDLINE, and clinical trials presented in this time are summarized.

Result:

The use of pomegranate as table fruit or juice, rich source of polyphenols, can so be recommended in human nutrition for its benefic properties. The consumption of pomegranate fruit symbolizes a promising therapeutic approach to avert many chronic syndromes.

Conclusion:

Importantly, the findings call for the need for a larger, rigorously designed human clinical trials to allow continued investigation into the potential specific effects of pomegranate fruit, and to obtain the best dose and duration of supplementation with pomegranate juice.

Performance demands in the endurance rider

Endurance is one of the fastest growing equestrian disciplines worldwide. Races are long distance competitions (40-160 km), organised into loops, over variable terrain usually within one day. Horse and rider combinations in endurance races have to complete the course in good condition whilst also aiming to win. Horse welfare is paramount within the sport and horses are required to ‘pass’ a veterinary check prior to racing, after each loop of the course and at the end of the race. Despite the health, fitness and welfare of both athletes within the horse-rider dyad being essential to achieve success, few equivalent measures assessing the wellbeing of the endurance rider are implemented. This review considers evidence from ultra-endurance sports and rider performance in other equestrian disciplines, to consider physiological and psychological strategies the endurance rider could use to enhance their competition performance. Successful endurance riding requires an effective partnership to be established between horse and rider. Within this partnership, adequate rider health and fitness are key to optimal decision-making to manage the horse effectively during training and competition, but just as importantly riders should manage themselves as an athlete. Targeted management for superior rider performance can underpin more effective decision-making promoting ethical equitation practices and optimising competition performance. Therefore, the responsible and competitive endurance rider needs to consider how they prepare themselves adequately for participation in the sport. This should include engaging in appropriate physiological training for fitness and musculoskeletal strength and conditioning. Alongside planning nutritional strategies to support rider performance in training and within the pre-, peri- and post-competition periods to promote superior physical and cognitive performance, and prevent injury. By applying an evidence informed approach to self-management, the endurance athlete will support the horse and rider partnership to achieve to their optimal capacity, whilst maximising both parties physical and psychological wellbeing.

Dietary nutrient intake of Korean adolescent distance runners

This study examined the dietary nutrient intake of Korean adolescent distance runners and analyzed the difference between weekdays and weekends. The participants were 40 male middle- and long-distance runners aged 13 to 18 years, 36 of whom were analyzed. The 3-day diet records including 2 weekdays and 1 weekend day, were investigated according to the food record method and analyzed using the computer-aided nutritional analysis program. A paired t-test was used to compare the energy and nutrient intakes of the weekdays and weekends, and the chi-square test was used to compare the distribution of the nutrient intake below the estimated average requirement. The results showed that the energy intake per day was quite low at 2,051.0±304.3 kcal, with a body mass index percentile of 16.8±9.8. The nutrients that showed remarkably lower levels than the dietary reference intakes for Koreans were vitamin D, vitamin C, vitamin B₂, and calcium, among which calcium was the highest at 86.1% in the proportion of those who consumed less than the estimated average requirement. The intakes of vitamin C and calcium, in particular, showed a significant decrease during the weekends. Therefore, to improve the dietary nutrient intake of adolescent male runners, appropriate management of the weekend diet as well as school meals should be considered.

The Effect of Abnormal Vitamin D Levels in Athletes

Vitamin D is a lipophilic prohormone integral to musculoskeletal, autoimmune, oncologic, cardiovascular, and mental health. Of particular importance to the orthopedic surgeon is the role of vitamin D in the regulation of bone mass, muscle strength, and physical performance. Although vitamin D-related skeletal pathologies are rare in industrialized nations, emerging research in the field has shown that most American adults have inadequate levels of vitamin D. Even among athletes, there is a high prevalence of vitamin D deficiency, which may place competitors at risk of stress fractures, illness, and delayed muscle recovery. Adequately identifying vitamin D-deficient individuals in need of supplementation is important to help optimize performance and prevent future injury. The goal of this review is to describe the epidemiology of vitamin D deficiency and its effects on athletic performance and musculoskeletal health. Future double-blinded studies of vitamin D supplementation in athletes are needed. We recommend treating athletes who have insufficient or deficient vitamin D levels.

Redox homeostasis in sport: do athletes really need antioxidant support?

Supplementation with antioxidants received interest as suitable tool for preventing or reducing exercise-related oxidative stress possibly leading to improvement of sport performance in athletes. To date, it is difficult to reach a conclusion on the relevance of antioxidants supplementation in athletes and/or well-trained people. The general picture that emerges from the available data indicates that antioxidants requirement can be covered by dosage equal or close to the recommended dietary allowance (RDA) provided by consumption of a balanced, well-diversified diet. Nevertheless, it remains open the possibility that in specific context, such as in sports characterized by high intensity and/or exhaustive regimes, supplementation with antioxidants could be appropriated to avoid or reduce the damaging effect of these type of exercise. This review will discuss the findings of a number of key studies on the advantages and/or disadvantages for athletes of using antioxidants supplementation, either individually or in combination.

IOC consensus statement: dietary supplements and the high-performance athlete

Nutrition usually makes a small but potentially valuable contribution to successful performance in elite athletes, and dietary supplements can make a minor contribution to this nutrition programme. Nonetheless, supplement use is widespread at all levels of sport. Products described as supplements target different issues, including (1) the management of micronutrient deficiencies, (2) supply of convenient forms of energy and macronutrients, and (3) provision of direct benefits to performance or (4) indirect benefits such as supporting intense training regimens. The appropriate use of some supplements can benefit the athlete, but others may harm the athlete's health, performance, and/or livelihood and reputation (if an antidoping rule violation results). A complete nutritional assessment should be undertaken before decisions regarding supplement use are made. Supplements claiming to directly or indirectly enhance performance are typically the largest group of products marketed to athletes, but only a few (including caffeine, creatine, specific buffering agents and nitrate) have good evidence of benefits. However, responses are affected by the scenario of use and may vary widely between individuals because of factors that include genetics, the microbiome and habitual diet. Supplements intended to enhance performance should be thoroughly trialled in training or simulated competition before being used in competition. Inadvertent ingestion of substances prohibited under the antidoping codes that govern elite sport is a known risk of taking some supplements. Protection of the athlete's health and awareness of the potential for harm must be paramount; expert professional opinion and assistance is strongly advised before an athlete embarks on supplement use.

IOC Consensus Statement: Dietary Supplements and the High-Performance Athlete

Nutrition usually makes a small but potentially valuable contribution to successful performance in elite athletes, and dietary supplements can make a minor contribution to this nutrition program. Nonetheless, supplement use is widespread at all levels of sport. Products described as supplements target different issues, including the management of micronutrient deficiencies, supply of convenient forms of energy and macronutrients, and provision of direct benefits to performance or indirect benefits such as supporting intense training regimens. The appropriate use of some supplements can offer benefits to the athlete, but others may be harmful to the athlete's health, performance, and/or livelihood and reputation if an anti-doping rule violation results. A complete nutritional assessment should be undertaken before decisions regarding supplement use are made. Supplements claiming to directly or indirectly enhance performance are typically the largest group of products marketed to athletes, but only a few (including caffeine, creatine, specific buffering agents and nitrate) have good evidence of benefits. However, responses are affected by the scenario of use and may vary widely between individuals because of factors that include genetics, the microbiome, and habitual diet. Supplements intended to enhance performance should be thoroughly trialed in training or simulated competition before implementation in competition. Inadvertent ingestion of substances prohibited under the anti-doping codes that govern elite sport is a known risk of taking some supplements. Protection of the athlete's health and awareness of the potential for harm must be paramount, and expert professional opinion and assistance is strongly advised before embarking on supplement use.

Nutritional needs in the professional practice of swimming: a review

[Purpose]

Swimming requires developing a high aerobic and anaerobic capacity for strength and technical efficiency. The purpose of this study was to establish the nutritional requirements and dietary strategies that can optimize swimming performance.

[Methods]

Several related studies retrieved from the databases, Dialnet, Elsevier, Medline, Pubmed, and Web of Science, through keyword search strategies were reviewed.

[Results]

The recommended carbohydrate intake ranges between 6-10-12 g/kg/d, protein 2 g/kg/d, and fat should surpass 20-25% of the daily intake.

[Conclusion]

Performance can be optimized with a hydration plan, as well as adequate periodization of supplements, such as caffeine, creatine, sodium bicarbonate, B-alanine, beetroot juice, Vitamin D, bovine colostrum, and HMB.

Nutrition and Supplementation in Soccer

Contemporary elite soccer features increased physical demands during match-play, as well as a larger number of matches per season. Now more than ever, aspects related to performance optimization are highly regarded by both players and soccer coaches. Here, nutrition takes a special role as most elite teams try to provide an adequate diet to guarantee maximum performance while ensuring a faster recovery from matches and training exertions. It is currently known that manipulation and periodization of macronutrients, as well as sound hydration practices, have the potential to interfere with training adaptation and recovery. A careful monitoring of micronutrient status is also relevant to prevent undue fatigue and immune impairment secondary to a deficiency status. Furthermore, the sensible use of evidence-based dietary supplements may also play a role in soccer performance optimization. In this sense, several nutritional recommendations have been issued. This detailed and comprehensive review addresses the most relevant and up-to-date nutritional recommendations for elite soccer players, covering from macro and micronutrients to hydration and selected supplements in different contexts (daily requirements, pre, peri and post training/match and competition).

[Nutritional supplements in sports - sense, nonsense or hazard?]

The excessive sale of dietary supplements (DSs) has become a global multi-billion market as more and more people turn to DSs for a healthy lifestyle or for aesthetic reasons. DSs are also increasingly popular among athletes; 50-85% of recreational and 35-100% of competitive athletes report taking DSs, the latter more regularly. Unless pathological deficiencies are detected, the intake of DSs for recreational athletes is not recommended. While it may be advisable for competitive athletes to supplement their diet with certain macronutrients (proteins and carbohydrates), many micronutrients (vitamins, minerals) as well as allegedly performance enhancing DSs may only show minimal impact under specific conditions and for certain sports. However, most products lack proof of their effectiveness. In some cases, DSs may even have negative effects and reduce performance. Furthermore, competitive athletes should be aware of the fact that DSs may lead to positive doping tests, as they bear the risk of being contaminated with banned substances, or components may be banned substances themselves. Every single case of taking DSs should therefore be critically assessed and discussed with experts prior to use. DSs cannot replace a balanced diet and hard practice.

Bone Health in Athletes

CONTEXT

The health of the skeletal system is important for athletes young and old. From the early benefits of exercise on bones to the importance of osteoporosis prevention and treatment, bone health affects the ability to be active throughout life.

EVIDENCE ACQUISITION

PubMed articles dating from 1986 to 2016 were used for the review. Relevant terms such as keywords and section titles of the article were searched and articles identified were reviewed for relevance to this article.

STUDY DESIGN

Clinical review.

LEVEL OF EVIDENCE

Levels 1 through 4 evidence included.

RESULTS

There is strong evidence that exercise benefits bone health at every age and is a critical factor in osteoporosis prevention and treatment. Vitamin D, calcium, and hormones play vital roles in ensuring optimal bone health. When there is an imbalance between exercise and nutrition, as seen in the female athlete triad, bone health is compromised and can lead to bone stress injuries and early osteoporosis. Both of these can lead to morbidity and lost time from training and competition. Thus, early recognition and appropriate treatment of the female athlete triad and other stress fracture risk factors are vital to preventing long-term bone health problems.

CONCLUSION

To optimize bone health, adequate nutrition, appropriate weightbearing exercise, strength training, and adequate calcium and vitamin D are necessary throughout life.

Nutritional supplements use in high-performance athletes is related with lower nutritional inadequacy from food

BACKGROUND

The use of nutritional supplements (NS) among athletes is widespread. However, little is known about the relationship between nutritional adequacy and NS usage. The aims of this study were to evaluate the NS usage and to compare the nutritional intake from food and prevalence of micronutrient inadequacy (PMI) between NS users and non-users.

METHODS

Portuguese athletes from 13 sports completed an NS usage questionnaire and a semi-quantitative food-frequency questionnaire assessing information over the previous 12 months. The estimated average requirement cut-point method was used to calculate PMI. General linear models were used to compare nutritional intake and NS usage. Chi-squared tests and logistic regression were performed to study, respectively, relationships and associations between PMI and NS usage.

RESULTS

From the 244 athletes (66% males, 13-37 years), 64% reported NS usage. After adjustment, NS users showed a higher intake from food (p < 0.05), for at least 1 gender, for energy, and for 7 of the 17 studied nutrients. The highest PMI were seen for vitamins D and E, calcium, folate, and magnesium. After adjustment, NS users, irrespective of gender, reported lower PMI for calcium (OR = 0.28, 95%CI: 0.12-0.65), and female users for magnesium (OR = 0.06, 95%CI: 0.00-0.98).

CONCLUSION

Athletes using NS reported a higher nutritional intake from food, and a lower PMI for several nutrients. Perhaps, those who were taking NS were probably the ones who would least benefit from it.

Plasma vitamin D metabolites and C-reactive protein in stage-stop racing endurance sled dogs

Background

Dogs are a unique model for examining the effects of exercise on vitamin D status because of their lack of vitamin D synthesis by UV exposure. In addition, the inflammatory response may be associated with hypovitaminosis D.

Objectives

To investigate the effects of several days of endurance exercise on plasma vitamin D (25‐(OH)D₃, 24,25‐(OH)D₃ and 1,25(OH)D₃) and serum C‐reactive protein (CRP) concentrations in stage‐stop racing sled dogs.

Animals

12 racing sled dogs and 8 control dogs.

Methods

Blood was collected before the race and immediately after racing on days 2 and 8. Plasma vitamin D metabolites and serum CRP concentrations were measured.

Results

Racing dogs showed a significant increase in 25(OH)D₃ on day 2 (P = .027) and day 8 of the race (P < .001), whereas no increases were observed in control dogs. The plasma concentration of 24,25(OH)D₃ showed a significant increase by day 8 (P < .001). There were no significant changes in 1,25(OH) D₃ concentrations across all time points and groups. Racing dogs had significantly increased CRP concentrations by day 2 (39.3 ± 30.1 μg/mL; P < .001).

Conclusions and Clinical Importance

Increases in vitamin D metabolites as well as increases in CRP concentrations were observed in racing sled dogs. This finding was contrary to the hypothesis that decreases in vitamin D status in athletes may be related to the acute phase inflammatory response during exercise. In addition, the increased 24,25(OH)D₃ concentrations compared to what is observed in other species suggests metabolic variations in dogs that lead to enhanced disposal of vitamin D.

Effects of vitamin D and quercetin, alone and in combination, on cardiorespiratory fitness and muscle function in physically active male adults

Introduction

Vitamin D and the antioxidant quercetin, are promising agents for improving physical performance because of their possible beneficial effects on muscular strength and cardiorespiratory fitness.

Purpose

The purpose of this study was to determine the effects of increased intakes of vitamin D, quercetin, and their combination on antioxidant status, the steroid hormone regulators of muscle function, and measures of physical performance in apparently healthy male adults engaged in moderate-to-vigorous-intensity exercise training.

Methods

A total of 40 adult male participants were randomized to either 4,000 IU vitamin D/d, 1,000 mg/d quercetin, vitamin D plus quercetin, or placebo for 8 weeks. Measures of cardiorespiratory fitness and muscle function, blood markers for antioxidant and vitamin D status, and hormones 1,25-dihydroxyvitamin D₃ (1,25(OH)₂D₃) and testosterone were measured pre- and postsupplementation.

Results

At enrollment, 88.6% of participants were vitamin D sufficient (serum 25-hydroxyvitamin D >50 nmol/L) and had normal serum testosterone levels. Supplementation with vitamin D significantly increased serum 25(OH)D concentration (by 87.3% in the vitamin D group, P<0.001) and was associated with an increasing trend of testosterone concentration. There were no changes in concentration of 1,25(OH)₂D₃ and markers of antioxidant status associated with vitamin D or quercetin supplementation. No improvements in physical performance measures associated with vitamin D and quercetin supplementation were found.

Conclusion

The findings obtained demonstrate that long-term vitamin D and quercetin supplementation, alone or in combination, does not improve physical performance in male adults with adequate vitamin D, testosterone, and antioxidant status.

Exercise training combined with antioxidant supplementation prevents the antiproliferative activity of their single treatment in prostate cancer through inhibition of redox adaptation

In preclinical models, exercise training (ET) or pomegranate juice (PJ) prevents prostate cancer progression. Here, we hypothesized that physical exercise combined with antioxidants could induce synergistic effects through oxidative stress modulation. Forty male Copenhagen rats with prostate tumors were divided into four groups: control, PJ, ET, and PJ+ET. Rats from the PJ group consumed 750 µl of PJ daily, rats from the ET group ran on a treadmill 5 days per week, and PJ+ET rats received the combined treatment. Each week, tumor growth was evaluated. After 4 weeks of treatment, the rats were euthanized and blood, muscles, and tumors were collected. Tumor Ki67, extracellular signal-regulated kinase (ERK) activation, Bcl-2 expression, and enzymatic and nonenzymatic antioxidant defenses, as well as oxidative stress markers (oxidized base, lipid peroxidation, protein carbonylation), were measured. PJ or ET significantly decreased prostate tumor proliferation (Ki67 staining, p<0.05) through the modulation of ERK phosphorylation, whereas the combination of treatments did not limit cancer progression. PJ significantly reduced Bcl-2 expression in tumors (p<0.05) and the combination of PJ and ET prevented this effect. PJ or ET increased enzymatic antioxidant defenses in muscle, PJ increased nonenzymatic antioxidant defenses in plasma and whole blood. In addition, PJ reduced TBARS and 8-oxodGuo levels in tumors as well as ET (p<0.05), whereas protein carbonyl levels were not affected by these two strategies. Paradoxically, association of PJ+ET did not increase antioxidant defenses and no reduction in oxidative stress markers was induced. Loading cancer cells with antioxidants blunts the positive effects of ET and interferes with important reactive oxygen species-mediated physiological processes such as antioxidant adaptations.

Prevalence of Abnormal Vitamin D Levels Among Division I NCAA Athletes

Background:

Up to 1 billion people have insufficient or deficient vitamin D levels. Despite the well-documented, widespread prevalence of low vitamin D levels and the importance of vitamin D for athletes, there is a paucity of research investigating the prevalence of vitamin D deficiency in athletes.

Hypothesis:

We investigated the prevalence of abnormal vitamin D levels in National Collegiate Athletic Association (NCAA) Division I college athletes at a single institution. We hypothesized that vitamin D insufficiency is prevalent among our cohort.

Study Design:

Cohort study.

Level of Evidence:

Level 1.

Methods:

We measured serum 25-hydroxyvitamin D (25(OH)D) levels of 223 NCAA Division I athletes between June 2012 and August 2012. The prevalence of normal (≥32 ng/mL), insufficient (20 to <32 ng/mL), and deficient (<20 ng/mL) vitamin D levels was determined. Logistic regression was utilized to analyze risk factors for abnormal vitamin D levels.

Results:

The mean serum 25(OH)D level for the 223 members of this study was 40.1 ± 14.9 ng/mL. Overall, 148 (66.4%) participants had sufficient 25(OH)D levels, and 75 (33.6%) had abnormal levels. Univariate analysis revealed the following significant predictors of abnormal vitamin D levels: male sex (odds ratio [OR] = 2.83; P = 0.0006), Hispanic race (OR = 6.07; P = 0.0063), black race (OR = 19.1; P < 0.0001), and dark skin tone (OR = 15.2; P < 0.0001). Only dark skin tone remained a significant predictor of abnormal vitamin D levels after multivariate analysis (adjusted OR = 15.2; P < 0.0001).

Conclusion:

In a large cohort of NCAA athletes, more than one third had abnormal vitamin D levels. Races with dark skin tones are at much higher risk than white athletes. Male athletes are more likely than female athletes to be vitamin D deficient. Our study demonstrates a high prevalence of vitamin D deficiency among healthy NCAA athletes.

Clinical Relevance:

Many studies indicate a significant prevalence of vitamin-D insufficiency across various populations. Recent studies have demonstrated a direct relationship between serum 25(OH)D levels and muscle power, force, velocity, and optimal bone mass. In fact, studies examining muscle biopsies from patients with low vitamin D levels have demonstrated atrophic changes in type II muscle fibers, which are crucial to most athletes. Furthermore, insufficient 25(OH)D levels can result in secondary hyperparathyroidism, increased bone turnover, bone loss, and increased risk of low trauma fractures and muscle injuries. Despite this well-documented relationship between vitamin D and athletic performance, the prevalence of vitamin D deficiency in NCAA athletes has not been well studied.

Effects of dietary extra-virgin olive oil on oxidative stress resulting from exhaustive exercise in rat skeletal muscle: a morphological study

Physical exercise induces oxidative stress through production of reactive oxygen species and can cause damage to muscle tissue. Oxidative stress, resulting from exhaustive exercise is high and improvement of antioxidant defenses of the body may ameliorate damage caused by free radicals. Extra-virgin olive oil is widely considered to possess anti-oxidative properties. The aim of this study was to determine if extra-virgin olive oil improved the adaptive responses in conditions of oxidative stress. Twenty-four 12-week-old male Sprague-Dawley rats were divided in three groups: (1) rats fed with standard chow and not subjected to physical exercise; (2) rats fed with standard chow and subjected to exhaustive exercise; (3) rats fed with a diet rich in oleic acid, the major component of extra-virgin olive oil, and subjected to exhaustive exercise. Exhaustive exercise consisted of forced running in a five-lane 10° inclined treadmill at a speed of 30 m/min for 70-75 min. We studied some biomarkers of oxidative stress and of antioxidant defenses, histology and ultrastructure of the Quadriceps femoris muscle (Rectus femoris). We observed that, in rats of group 3, parameters indicating oxidative stress such as hydroperoxides and thiobarbituric acid-reactive substances decreased, parameters indicating antioxidant defenses of the body such as non-enzymatic antioxidant capacity and Hsp70 expression increased, and R. femoris muscle did not show histological and ultrastructural alterations. Results of this study support the view that extra-virgin olive oil can improve the adaptive response of the body in conditions of oxidative stress.

Dietary strategies to recover from exercise-induced muscle damage

Exhaustive or unaccustomed intense exercise can cause exercise-induced muscle damage (EIMD) and its undesirable consequences may decrease the ability to exercise and to adhere to a training programme. This review briefly summarises the muscle damage process, focusing predominantly on oxidative stress and inflammation as contributing factors, and describes how nutrition may be positively used to recover from EIMD. The combined intake of carbohydrates and proteins and the use of antioxidants and/or anti-inflammatory nutrients within physiological ranges are interventions that may assist the recovery process. Although the works studying food instead of nutritional supplements are very scarce, their results seem to indicate that food might be a favourable option as a recovery strategy. To date, the only tested foods were milk, cherries, blueberries and pomegranate with promising results. Other potential solutions are foods rich in protein, carbohydrates, antioxidants and/or anti-inflammatory nutrients.

The effects of vitamin D deficiency in athletes

Vitamin D acts to maintain calcium and phosphate homeostasis within the body. It is now estimated that 1 billion people worldwide are vitamin D deficient. This problem is particularly important to athletes of all ages, as vitamin D plays a significant role in bone health, immune function, and physical performance. In the deficient state, the athlete may be at an increased risk for potential problems such as stress fractures, respiratory infections, and muscle injuries. The purpose of this article is to examine vitamin D deficiency and review its relationship to the athlete.

Vitamin D in exercise: physiologic and analytical concerns

Despite a wide number of studies performed on the general population, little is known about the Vitamin D status of athletes. A particular influence of many factors, including skin pigmentation, early- or late-day training, indoor training, geographic location and extensive sunscreen use, has been observed in this specific population. The need of supplementation with Vitamin D in athletes is not defined or, when supplementation is needed, even the optimal amount of Vitamin D to be used is not specified. The periodic measurement of Vitamin D is the only procedure capable to define athletes' status. Although various methods for the measurement of Vitamin D are routinely used, they often give discordant and poorly reproducible results; thus, it is necessary to standardize the various methods, in order to have comparable results. In conclusion, current available data indicate both that little is known about the Vitamin D status of athletes and that is still unclear if supplementation could be desirable. Finally, it must be pointed out that all the papers about Vitamin D status should indicate in detail the method used for really allowing a correct interpretation of data.

Impact of oral ubiquinol on blood oxidative stress and exercise performance

Coenzyme Q10 (CoQ10) plays an important role in bioenergetic processes and has antioxidant activity. Fifteen exercise-trained individuals (10 men and 5 women; 30–65 years) received reduced CoQ10 (Kaneka QH ubiquinol; 300 mg per day) or a placebo for four weeks in a random order, double blind, cross-over design (3 week washout). After each four-week period, a graded exercise treadmill test and a repeated cycle sprint test were performed (separated by 48 hours). Blood samples were collected before and immediately following both exercise tests and analyzed for lactate, malondialdehyde, and hydrogen peroxide. Resting blood samples were analyzed for CoQ10 (ubiquinone and ubiquinol) profile before and after each treatment period. Treatment with CoQ10 resulted in a significant increase in total blood CoQ10 (138%; P = 0.02) and reduced blood CoQ10 (168%; P = 0.02), but did not improve exercise performance (with the exception of selected individuals) or impact oxidative stress. The relationship between the percentage change in total blood CoQ10 and the cycle sprint total work (R² = 0.6009) was noted to be moderate to strong. We conclude that treatment with CoQ10 in healthy, exercise-trained subjects increases total and reduced blood CoQ10, but this increase does not translate into improved exercise performance or decreased oxidative stress.

Redox biology of exercise: an integrative and comparative consideration of some overlooked issues

The central aim of this review is to address the highly multidisciplinary topic of redox biology as related to exercise using an integrative and comparative approach rather than focusing on blood, skeletal muscle or humans. An attempt is also made to re-define ‘oxidative stress’ as well as to introduce the term ‘alterations in redox homeostasis’ to describe changes in redox homeostasis indicating oxidative stress, reductive stress or both. The literature analysis shows that the effects of non-muscle-damaging exercise and muscle-damaging exercise on redox homeostasis are completely different. Non-muscle-damaging exercise induces alterations in redox homeostasis that last a few hours post exercise, whereas muscle-damaging exercise causes alterations in redox homeostasis that may persist for and/or appear several days post exercise. Both exhaustive maximal exercise lasting only 30 s and isometric exercise lasting 1–3 min (the latter activating in addition a small muscle mass) induce systemic oxidative stress. With the necessary modifications, exercise is capable of inducing redox homeostasis alterations in all fluids, cells, tissues and organs studied so far, irrespective of strains and species. More importantly, ‘exercise-induced oxidative stress’ is not an ‘oddity’ associated with a particular type of exercise, tissue or species. Rather, oxidative stress constitutes a ubiquitous fundamental biological response to the alteration of redox homeostasis imposed by exercise. The hormesis concept could provide an interpretative framework to reconcile differences that emerge among studies in the field of exercise redox biology. Integrative and comparative approaches can help determine the interactions of key redox responses at multiple levels of biological organization.