Fat supplementation, health, and endurance performance

Dietary Supplementation with Lauric Acid Improves Aerobic Endurance in Sedentary Mice via Enhancing Fat Mobilization and Glyconeogenesis

BACKGROUND

Lauric acid (LA), a major, natural, medium-chain fatty acid, is considered an efficient energy substrate for intense exercise and in patients with long-chain fatty acid β-oxidation disorders. However, few studies have focused on the role of LA in exercise performance and related glucolipid metabolism in vivo.

OBJECTIVES

We aimed to investigate the effect of dietary supplementation with LA on exercise performance and related metabolic mechanisms.

METHODS

Male C57BL/6N mice (14 wk old) were fed a basal diet or a diet containing 1% LA, and a series of exercise tests, including a high-speed treadmill test, aerobic endurance exercises, a 4-limb hanging test, and acute aerobic exercises, were performed.

RESULTS

Dietary supplementation with 1.0% LA accelerated the recovery from fatigue after explosive exercise (P < 0.05) and improved aerobic endurance and muscle strength in sedentary mice (P = 0.039). Lauric acid intake not only changed muscle fatty acid profiles, including increases in C12:0 and n-6/n-3 PUFAs (P < 0.001) and reductions in C18:0, C20:4n-6, C22:6n-3, and n-3 PUFAs (P < 0.05) but also enhanced fat mobilization from adipose tissue and fatty acid oxidation in the liver, at least partly via the AMP-activated protein kinase-acetyl CoA carboxylase pathway (P < 0.05). Likewise, LA supplementation promoted liver glyconeogenesis and conserved muscular glycogen during acute aerobic exercise (P < 0.05), which was accompanied by an increase in the mitochondrial DNA copy number and Krebs cycle activity in skeletal muscle (P < 0.05).

CONCLUSIONS

Dietary supplemental LA serves as an efficient energy substrate for sedentary mice to improve aerobic exercise endurance and muscle strength through regulation of glucolipid metabolism. These findings imply that LA supplementation might be a promising nutritional strategy to improve aerobic exercise performance in sedentary people.

The effect of conjugated linoleic acids on inflammation, oxidative stress, body composition and physical performance: a comprehensive review of putative molecular mechanisms

Conjugated linoleic acids (CLAs) are polyunsaturated fatty acids primarily found in dairy products and ruminant animal products such as beef, lamb, and butter. Supplementation of CLAs has recently become popular among athletes due to the variety of health-promoting effects, including improvements in physical performance. Preclinical and some clinical studies have shown that CLAs can reduce inflammation and oxidative stress and favorably modulate body composition and physical performance; however, the results of previously published clinical trials are mixed. Here, we performed a comprehensive review of previously published clinical trials that assessed the role of CLAs in modulating inflammation, oxidative stress, body composition, and select indices of physical performance, emphasizing the molecular mechanisms governing these changes. The findings of our review demonstrate that the effect of supplementation with CLAs on inflammation and oxidative stress is controversial, but this supplement can decrease body fat mass and increase physical performance. Future well-designed randomized clinical trials are warranted to determine the effectiveness of (1) specific doses of CLAs; (2) different dosing durations of CLAs; (3) various CLA isomers, and the exact molecular mechanisms by which CLAs positively influence oxidative stress, inflammation, body composition, and physical performance.

Phospholipid Fatty Acid Profiles of Plasma and Erythrocyte Membranes in Dogs Fed with Commercial Granulated Food

Intake of long-chain n-3 polyunsaturated fatty acids (PUFA) benefits human and animal health. Our study aimed to analyze the long-chain n-3 PUFA content of two types of food and their effect on plasma and erythrocyte phospholipids of Belgian Shepherd dogs. A total of 10 dogs were fed commercial granulated food (Food 1), and another 10 were provided commercial Premium granulated food of high quality (Food 2). All the analyses were performed using gas-liquid chromatography. Our results showed that Food 1 contained more n-3 PUFA than Food 2, which was reflected in higher n-3 PUFA in plasma and erythrocyte phospholipids. Because long-chain n-3 PUFA in phospholipids are precursors for antioxidative molecules, further studies should investigate the effects of the analyzed commercial granulated food rich in n-3 on oxidative stress parameters in dogs.

Octanoic Acid-Enrichment Diet Improves Endurance Capacity and Reprograms Mitochondrial Biogenesis in Skeletal Muscle of Mice

Background: Medium Chain Fatty Acids (MCFAs) are a dietary supplement that exhibit interesting properties, due to their smaller molecular size. The acute consumption of MCFAs is expected to enhance exercise performance. However, the short-term effects of MCFAs on endurance performance remains poorly understood. The aim of our study is to evaluate the octanoic acid (C8)-rich diet effect on endurance capacity, and to explore their molecular and cellular effects. Methods: C57BL/6J mice were fed with a chow diet (Control group) or an octanoic acid-rich diet (C8 diet) for 6 weeks. Spontaneous activity, submaximal and maximal exercise tests were carried out to characterize the exercise capacities of the mice. Beta-oxidation and mitochondrial biogenesis pathways were explored in skeletal muscle by RT-qPCR, Western Blot (Quadriceps) and histochemical staining (Gastrocnemius). Results: Mice fed with a C8-rich diet presented a higher spontaneous activity (p < 0.05) and endurance capacities (p < 0.05) than the control, but no effect on maximal effort was observed. They also presented changes in the skeletal muscle metabolic phenotype, with a higher number of the oxidative fibers, rich in mitochondria. At the molecular level, the C8-diet induced an AMPK activation (p < 0.05), associated with a significant increase in PGC1a and CS gene expression and protein levels. Conclusion: Our study provided evidence that C8-enrichment as a food supplementation improves endurance capacities and activates mitochondrial biogenesis pathways leading to higher skeletal muscle oxidative capacities.

Ingestion of High-Oleic Peanut Improves Endurance Performance in Healthy Individuals

This study aimed at evaluating whether high-oleic peanuts (with skin), which are rich in oleic acid, could serve as an energy substrate for prolonged exercise and improve endurance performance. We evaluated changes in blood biomarker (triglycerides, free fatty acid (FFA), biological antioxidant potential (BAP), malondialdehyde-modified low-density lipoprotein (MDA-LDL), and serum total protein) levels at 2-h intervals for 6 h after the ingestion of 10 g and 30 g of peanuts. The results were used to determine the timing of peanut ingestion before the endurance performance test. As a result, there was a significant change in the 30-g peanut-ingested condition, and lipid levels increased 2 h after the ingestion of 30 g of peanuts. Accordingly, the endurance performance test was conducted 2 h after ingesting 30 g of peanuts. The endurance performance test involved 70 min of pedaling exercise. We measured pre- and postexercise levels of 8-hydroxy-2′-deoxyguanosine (8-OHdG), which is a biomarker of oxidative stress. There was a significantly improved workload in the endurance performance test in the high-oleic peanut-ingested condition than in the control condition. Furthermore, the rate of increase in 8-OHdG was significantly lower in the high-oleic peanut-ingested condition than in the control condition. This suggests that the increase in FFA levels resulting from the ingestion of high-oleic peanuts and the inherent antioxidant effects of peanuts improved the workload during endurance exercise.

Carboxymethyl chitosan coated medium-chain fatty acid nanoliposomes: structure, composition, stability and in vitro release investigation

Medium-chain fatty acids (MCFAs) have been proven as an easy energy source and active ingredient to prevent obesity and other metabolic disorders. However, the inherent hydrophobic nature of MCFAs causes poor aqueous solubility and dissolution in the gastrointestinal (GI) tract, thus limiting their applications in aqueous foods. To address these issues, a nutraceutical carrier system was developed by coating nanoliposomes with carboxymethyl chitosan (CMCS) through a series of well-designed processes, including thin-film hydration, dynamic high pressure microfluidization (DHPM) and surface modification. Electron microscopy investigation reveals an obvious morphology evolution from the uncoated nanoliposomes (UC-LPs) to the final CMCS coated nanoliposomes (CMCS-LPs). Together with the FTIR results, it confirms the successful coating of CMCS. More importantly, the resultant CMCS-LPs have a more negatively charged surface with a ζ-potential value of around -18.5 mV, which helps to increase the stability by avoiding severe particle aggregation. Owing to the above benefits, the encapsulated MCFAs can be safely retained in a long storage period of 90 days at 4 °C and the new carrier system also exhibits a more sustained release of MCFAs in the GI fluid.

Short-Term Influence of Caffeine and Medium-Chain Triglycerides on Ketogenesis: A Controlled Double-Blind Intervention Study

Background

Ketone bodies are a highly relevant topic in nutrition and medicine. The influence of medium-chain triglycerides (MCT) on ketogenesis is well known and has been successfully used in ketogenic diets for many years. Nevertheless, the effects of MCTs and coconut oil on the production of ketone bodies have only partially been investigated. Furthermore, the increased mobilisation of free fatty acids and release of catabolic hormones by caffeine suggest an influence of caffeine on ketogenesis.

Methods

In a controlled, double-blind intervention study, seven young healthy subjects received 10 mL of tricaprylin (C8), tricaprin (C10), C8/C10 (50% C8, 50% C10), or coconut oil with or without 150 mg of caffeine, in 250 mL of decaffeinated coffee, over ten interventions. At baseline and after every 40 minutes, for 4 h, ßHB and glucose in capillary blood as well as caffeine in saliva were measured. Furthermore, questionnaires were used to survey sensory properties, side effects, and awareness of hunger and satiety.

Results

The interventions with caffeine caused an increase in ßHB levels—in particular, the interventions with C8 highly impacted ketogenesis. The effect decreased with increased chain lengths. All interventions showed a continuous increase in hunger and diminishing satiety. Mild side effects (total = 12) occurred during the interventions.

Conclusions

The present study demonstrated an influence of caffeine and MCT on ketogenesis. The addition of caffeine showed an additive effect on the ketogenic potential of MCT and coconut oil. C8 showed the highest ketogenicity.

Carbohydrate supplementation: a critical review of recent innovations

PURPOSE

To critically examine the research on novel supplements and strategies designed to enhance carbohydrate delivery and/or availability.

METHODS

Narrative review.

RESULTS

Available data would suggest that there are varying levels of effectiveness based on the supplement/supplementation strategy in question and mechanism of action. Novel carbohydrate supplements including multiple transportable carbohydrate (MTC), modified carbohydrate (MC), and hydrogels (HGEL) have been generally effective at modifying gastric emptying and/or intestinal absorption. Moreover, these effects often correlate with altered fuel utilization patterns and/or glycogen storage. Nevertheless, performance effects differ widely based on supplement and study design. MTC consistently enhances performance, but the magnitude of the effect is yet to be fully elucidated. MC and HGEL seem unlikely to be beneficial when compared to supplementation strategies that align with current sport nutrition recommendations. Combining carbohydrate with other ergogenic substances may, in some cases, result in additive or synergistic effects on metabolism and/or performance; however, data are often lacking and results vary based on the quantity, timing, and inter-individual responses to different treatments. Altering dietary carbohydrate intake likely influences absorption, oxidation, and and/or storage of acutely ingested carbohydrate, but how this affects the ergogenicity of carbohydrate is still mostly unknown.

CONCLUSIONS

In conclusion, novel carbohydrate supplements and strategies alter carbohydrate delivery through various mechanisms. However, more research is needed to determine if/when interventions are ergogenic based on different contexts, populations, and applications.

Exploring the metabolic fate of medium-chain triglycerides in healthy individuals using a stable isotope tracer

BACKGROUND & AIMS

Medium chain triglyceride (MCT) supplementation is often recommended as treatment for patients with long-chain fatty acid β-oxidation (lcFAO) disorders, since they can be utilized as an energy source without the use of the defective enzyme. However, studies in mice and preterm infants suggest that not all medium-chain fatty acids (MCFA) are oxidized and may undergo elongation to long-chain fatty acids (LCFA). In this single blinded study, we explored the metabolic fates of MCT in healthy individuals using a ¹³C-labeled MCT tracer.

METHOD

Three healthy males in rest received on two test days a primed continuous infusion of glyceryl tri[1,2,3,4-¹³C₄]-octanoate with either an isocaloric supplementation of 1) exclusively MCT (MCT-only) or 2) a mixture of MCT, proteins and carbohydrates (MCT-mix). Gas chromatography - combustion - isotope ratio mass spectrometry (GC-C-IRMS) was used to determine ¹³C-enrichment of long-chain fatty acids in plasma and of ¹³CO₂ in exhaled air.

RESULTS

When provided as single energy source, an estimated 42% of administered MCT was converted to CO₂. In combination with carbohydrates and proteins in the diet, oxidation of MCT was higher (62%). In both diets <1% of ¹³C-label was incorporated in LCFA in plasma, indicating that administered MCT underwent chain-elongation to LCT.

CONCLUSIONS

Although the relative MCT oxidation rate was higher when combined with carbohydrates and protein, quantitatively more MCT was oxidized when given an isocaloric meal with solely MCT. As these results were obtained in the resting state opposed to during exercise, it is too early to give a recommendation concerning the use of MCT in lcFAO disorders. The data show that in resting healthy individuals only a very small part of the MCT is traced back as LCFA in plasma, suggesting that MCT treatment does not result in a large LCFA burden, however further research on storage of MCT in tissues is warranted.

REGISTRATION

The study was registered in the Nederlands Trialregister. Protocol ID: Trial NL7417 (NTR7650).

Perioperative Enteral Nutrition Improves Postoperative Recovery for Patients with Primary Liver Cancer: A Randomized Controlled Clinical Trial

OBJECTIVE

The role of perioperative protein-enriched enteral nutrition for patients with primary liver cancer is unclear. We investigated the efficacy of perioperative protein-enriched enteral nutrition for patients with primary liver cancer followed hepatectomy.

METHODS

Patients with primary liver cancer that underwent hepatectomy between January 2016 and 2018 were enrolled. Patients in the treatment group was given enteral nutrition (TP-MCT) in addition to the regular diet. The primary outcome measures were duration of hospital stay and length of postoperative hospital stay. Secondary outcome measures included time to first flatus and time to first defecation.

RESULTS

There was a significant reduction of time to first flatus and time to first defecation in the treatment group, when compared with the control group (time to first flatus: P = 0.001, time to first defecation: P < 0.001).

CONCLUSIONS

It is found that addition of protein-enriched enteral nutrition (TP-MCT) improved postoperative recovery for patients with primary liver cancer following hepatectomy, with a significant reduction in time to first flatus and time to first defecation.

Effects of diet interventions, dietary supplements, and performance-enhancing substances on the performance of CrossFit-trained individuals: A systematic review of clinical studies

CrossFit (CF) is characterized as a constantly varied, high-intensity, functional movement training program, performed with little or no rest between bouts, combining strength and endurance exercises, such as running, cycling, rowing, Olympic weightlifting, power weightlifting, and gymnastic-type exercises. Several nutritional strategies are used to improve sports performance of CF practitioners; however, most of them are empirical and lack scientific evidence. Thus, the aim of this review was to determine the effects of diet intervention, dietary supplements, and performance-enhancing substances on exercise-performance parameters of CF practitioners. MEDLINE/PubMed, Web of Science, LILACS, SciELO, and Scopus databases were searched using specific Medical Subject Headings and keywords for clinical studies that enrolled CF athletes in an intervention using diet, dietary supplements, or performance-enhancing substances. Athletic performance was considered as the primary outcome. No other filters were applied. Including grey literature search, 219 studies were identified; however only 14 studies met the eligibility criteria. Two studies evaluated the effects of caffeine supplementation on exercise performance; five studies evaluated high- or low-carbohydrate effects on performance and other parameters. One study verified the effects of multi-ingredient supplementation on CF-specific performance and body composition. One study compared the intake of protein supplements on performance and body composition. Two studies assessed the effect of green tea and (-)-epicatechin on performance and other parameters. One study evaluated the effects of nitrate supplementation on exercise performance. One study investigated the effect of betaine supplementation on body composition and muscle performance. Finally, one study examined the effects of sodium bicarbonate (SB) ingestion on exercise performance and aerobic capacity. Only SB supplementation improved CF performance. These outcomes may have been obtained due to methodological limitations such as small sample size, lack of control over influencing variables, short period of exercise intervention. Despite the popularity and growing evidence about CF, little is known about the relationship between performance-enhancing substances or dietary interventions and CF performance. Given the lack of scientific evidence, new studies with potential ergogenic supplements, a better methodological model, and practical application are required.

Effect of Almond Supplementation on Non-Esterified Fatty Acid Values and Exercise Performance

Several studies have investigated the effects of fat intake before exercise on subsequent substrate oxidation and exercise performance. While some studies have reported that unsaturated fatty acid supplementation slightly increases fat oxidation, the changes have not been reflected in the maximum oxygen uptake or in other performance and physiological parameters. We selected almonds as a fatty acid (FA) source for acute supplementation and investigated their effect on non-esterified fatty acid (NEFA) values and exercise performance. Five physically active male subjects (age 32.9 ± 12.7 years, height 178.5 ± 3.3 cm, and weight 81.3 ± 9.7 kg) were randomly assigned to take an almond or placebo supplement 2 h before participating in two cycling resistance training sessions separated by an interval of 7-10 days. Their performance was evaluated with a maximal incremental test until exhaustion. Blood samples collected before, during, and after testing were biochemically analysed. The results indicated a NEFA value average increase of 0.09 mg·dL-1 (95% CI: 0.05-0.14; p < 0.001) after active supplement intake and enhanced performance (5389 ± 1795 W vs. placebo 4470 ± 2053 W, p = 0.043) after almond supplementation compared to the placebo. The almond supplementation did not cause gastrointestinal disturbances. Our study suggests that acute almond supplementation 2 h before exercise can improve performance in endurance exercise in trained subjects.

The impact of lactic acid and medium chain triglyceride on blood glucose, lactate and diurnal motor activity: A re-examination of a treatment of major depression using lactic acid

While investigating the effect of alternative energy substrates on extracellular brain glucose or lactate, Béland-Millar (2017) noted a reduction of physical activity after intraperitoneal administration of lactate and ketone bodies. These observations were similar to an older study that examined the impact of drinking a sodium lactate/lactic acid solution before sleep in hospitalized patients with major depression. Patients and control participants self-reported drowsiness, early sleep onset and better overall sleep after consumption. Some patients showed improved mood after several days of treatment. We re-evaluated the effects of the solution used (0.59 g/kg) as well as several smaller doses (0.47, 0.35, 0.24 and 0.12 g/kg) on blood lactate and glucose in CD-1 mice and on sleep onset associated activity reduction. Because of adverse effects with the lactate/lactic acid solution, we also examined the effects of a medium chain triglyceride (MCT) solution (10, 5, 2.5, and 1 ml/kg) on blood lactate and glucose. Oral gavage administration of lactic acid/lactate produced adverse effects particularly for the largest doses. However consumption of 10 and 5 ml/kg volumes of MCT oils significantly increased blood lactate concentration to levels comparable to Lowenbach's solution without piloerection indicative of adverse effects. To evaluate pre-sleep activity reduction produced by lactate, mice were intraperitoneally administered diluted sodium lactate (2.0 g/kg, 1.0 g/kg, 0.5 g/kg, 0.25 g/kg, or saline) for 6 days, 120 min before their sleep period and their running activity was measured. Larger lactate doses reduced pre-sleep running each day up to 60 min post injection. Smaller doses reduced running after a single treatment only. These results suggest that the modulation of blood lactate levels may be useful in treating sleep onset problems associated with depression.

Neuropsychiatric and Behavioral Involvement in AAS Abusers. A Literature Review

Background and Objectives: Anabolic androgenic steroids (AASs) are a complex group of molecules that include both steroidal androgens and synthetic compounds, derived from testosterone. AASs are commonly used to support pharmacological therapy in cases of primary or secondary hypogonadism, major burns, and neoplastic cachexia. Their prolonged and supra-physiological consumption can provoke several adverse effects on various organs and systems. Among these, the physiopathological mechanisms that induce neuropsychiatric disorders related to AAS abuse are poorly known. For this reason, the proposed review aims to retrace the pathway of action of testosterone to focus on the effects on the central nervous system and specifically highlight the effects of AASs on neuropsychiatric and behavioral functions, as well as on lifestyle. Materials and Methods: This review was conducted using PubMed and Google Scholar databases. On these database websites, we searched for articles from 1 January 1980 to March 2019 using the key terms: "AAS," "Anabolic Androgenic Steroids," "brain," and "neurology." Results: The use of AASs through self-administration yields circulating androgens levels, inducing neuron apoptosis, which is linked to thinner cortex and, in general, less cortical volume. The same alterations affect the putamen. These differences were more evident when correlated with longer use. From a functional point of view, prolonged AAS consumption seemed to be related to lower connectivity between amygdala and frontal, striatal, limbic, hippocampal and visual cortical areas. On the other hand, AAS use seems to negatively condition the positive effects of the sport exercise, reducing its important anti-apoptotic and pro-proliferative functions on the hippocampus, implicated in anxiolytic control. Conclusion: This review clarifies the major aspects of the side effects related to AAS use/abuse highlighting the complex mechanisms on neuropsychiatric and cognitive pathological alterations and also the emotional and behavioral dysfunctions.

Acute Caffeine and Coconut Oil Intake, Isolated or Combined, Does Not Improve Running Times of Recreational Runners: A Randomized, Placebo-Controlled and Crossover Study

The aim was to evaluate the effect of caffeine (CAF) and extra virgin coconut oil (CO), isolated or combined, on running performance in runners. Methods: A randomized, placebo-controlled, and crossover study was conducted with thirteen recreational runners aged 18-40. All volunteers performed a 1600 m time trial at a 400 m track, each ingesting four different substances: (1) placebo (water), (2) decaffeinated coffee plus isolated CAF (DECAF + CAF), (3) decaffeinated coffee plus isolated CAF plus soy oil (DECAF + CAF + SO), and (4) decaffeinated coffee plus isolated CAF plus extra virgin coconut oil (DECAF + CAF + CO). The substances were ingested 60 min before the trials, the order of the situations was randomized, and there were one-week intervals between them. At the end of the trials, the Borg scale was applied to evaluate the rating of perceived exertion (RPE) and the time was measured. Results: Our data did not show differences in running time among the trials (placebo: 7.64 ± 0.80, DECAF + CAF: 7.61 ± 1.02, DECAF + CAF + SO: 7.66 ± 0.89, and DECAF + CAF + CO: 7.58 ± 0.74 min; p = 0.93), nor RPE (placebo: 6.15 ± 2.03, DECAF + CAF: 6.00 ± 2.27, DECAF + CAF + SO: 6.54 ± 2.73, and DECAF + CAF + CO: 6.00 ± 2.45 score; p = 0.99). Lactate concentrations (placebo: 6.23 ± 2.72, DECAF + CAF: 4.43 ± 3.77, DECAF + CAF + SO: 5.29 ± 3.77, and DECAF + CAF + CO: 6.17 ± 4.18 mmol/L; p = 0.55) also was not modified. Conclusion: Our study shows that ingestion of decaffeinated coffee with the addition of isolated CAF and extra virgin CO, either isolated or combined, does not improve 1600 m running times, nor influence RPE and lactate concentrations in recreational runners. Thus, combination of coffee with CO as a pre-workout supplement seems to be unsubstantiated for a short-distance race.

Priority use of medium-chain fatty acids during high-intensity exercise in cross-country skiers

Background

One of the topics discussed in sports science is the use of medium-chain saturated fat as an energy-saving nutrient additive when approaching high-intensity exercise. The purpose of this study was to compare the blood concentrations of medium-chain and long-chain fatty acids (FAs) across different intensity loads.

Methods

Fifteen male highly trained athletes from the Russian cross-country skiing team participated in the study. Blood samples were drawn at rest, at the peak of veloergometric test with a growing exercise load till exhaustion (97–100% VO2max), and after competitions. The plasma FA profile was determined using gas-liquid chromatography.

Results

We observed a substantial increase in the concentrations of capric acid (С10:0) (+ 164.1%), lauric acid (С12:0) (+ 223.9%), and myristic acid (С14:0) (+ 130.2%) in skiers after a sprint distance (1.3 km). A less intense increase in the concentrations of these acids (p < 0.05) was observed after a middle length distance or cycle exercise «until exhaustion». No significant differences in long-chain saturated FA content relative to baselines during exercise tests or competitions were revealed.

Conclusions

In conclusion, the obtained results demonstrate activation of the lipolysis and the oxidation of medium-chain FA involved in the energy supply for highly trained athletes at maximum exercise loads.

Understanding the factors that effect maximal fat oxidation

Lipids as a fuel source for energy supply during submaximal exercise originate from subcutaneous adipose tissue derived fatty acids (FA), intramuscular triacylglycerides (IMTG), cholesterol and dietary fat. These sources of fat contribute to fatty acid oxidation (FAox) in various ways. The regulation and utilization of FAs in a maximal capacity occur primarily at exercise intensities between 45 and 65% VO_2max, is known as maximal fat oxidation (MFO), and is measured in g/min. Fatty acid oxidation occurs during submaximal exercise intensities, but is also complimentary to carbohydrate oxidation (CHOox). Due to limitations within FA transport across the cell and mitochondrial membranes, FAox is limited at higher exercise intensities. The point at which FAox reaches maximum and begins to decline is referred to as the crossover point. Exercise intensities that exceed the crossover point (~65% VO_2max) utilize CHO as the predominant fuel source for energy supply. Training status, exercise intensity, exercise duration, sex differences, and nutrition have all been shown to affect cellular expression responsible for FAox rate. Each stimulus affects the process of FAox differently, resulting in specific adaptions that influence endurance exercise performance. Endurance training, specifically long duration (>2 h) facilitate adaptations that alter both the origin of FAs and FAox rate. Additionally, the influence of sex and nutrition on FAox are discussed. Finally, the role of FAox in the improvement of performance during endurance training is discussed.

[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.

Conjugated linoleic acid supplementation does not maximize motor performance and abdominal and trunk fat loss induced by aerobic training in overweight women

ABSTRACT Objective: To analyze the effect of eight weeks of conjugated linoleic acid supplementation on physical performance, and trunk and abdominal fat in overweight women submitted to an aerobic training program. Methods: Twenty-eight overweight women (body mass index ³25 kg/m2) were divided randomly and double-blindly to receive conjugated linoleic acid or placebo, both associated with an aerobic exercise program (frequency = three times a week, duration=30 min/session, intensity=80% of maximum heart rate). Conjugated linoleic acid (3.2 g) and placebo (4.0 g) supplements were consumed daily (four capsules) for eight weeks. Maximum speed and time to exhaustion were determined in incremental treadmill test. Trunk fat was estimated by dual-energy X-Ray absorptiometry. Waist circumference was used as indicator of abdominal fat. Results: Main effect of time (p<0.05) showed increased maximum speed (conjugated linoleic acid=+6.3% vs. placebo=+7.5%) and time to exhaustion (conjugated linoleic acid=+7.1% vs. placebo=+8.6%) in the incremental treadmill test, with no differences between the groups (p>0.05). Similarly, significant reductions (p<0.05) in trunk fat (conjugated linoleic acid=-1.7% vs. placebo=-1.5%) and abdominal fat (conjugated linoleic acid=-4.7% vs. placebo=-4.0%) were found after eight weeks of intervention, with no differences between the groups (p>0.05). Conclusion: The results of this study suggest that conjugated linoleic acid supplementation does not maximize motor performance, and loss of body and abdominal fat induced by aerobic training in overweight women.

Effects of Conjugated Linoleic Acid Associated With Endurance Exercise on Muscle Fibres and Peroxisome Proliferator-Activated Receptor γ Coactivator 1 α Isoforms

Conjugated linoleic acid (CLA) has been reported to improve muscle hypertrophy, steroidogenesis, physical activity, and endurance capacity in mice, although the molecular mechanisms of its actions are not completely understood. The aim of the present study was to identify whether CLA alters the expression of any of the peroxisome proliferator-activated receptor γ coactivator 1α (PGC1α) isoforms, and to evaluate the possible existence of fibre-type-specific hypertrophy in the gastrocnemius and plantaris muscles. Mice were randomly assigned to one of four groups: placebo sedentary, CLA sedentary, placebo trained, or CLA trained. The CLA groups were gavaged with 35 μl per day of Tonalin® FFA 80 food supplement containing CLA throughout the 6-week experimental period, whereas the placebo groups were gavaged with 35 μl sunflower oil each day. Each administered dose of CLA corresponded to approximately 0.7 g/kg or 0.5%, of the dietary daily intake. Trained groups ran 5 days per week on a Rota-Rod for 6 weeks at increasing speeds and durations. Mice were sacrificed by cervical dislocation and hind limb posterior muscle groups were dissected and used for histological and molecular analyses. Endurance training stimulated mitochondrial biogenesis by PGC1α isoforms (tot, α1, α2, and α3) but CLA supplementation did not stimulate PGC1α isoforms or mitochondrial biogenesis in trained or sedentary mice. In the plantaris muscle, CLA supplementation induced a fibre-type-specific hypertrophy of type IIx muscle fibres, which was associated with increased capillary density and was different from the fibre-type-specific hypertrophy induced by endurance exercise (of types I and IIb muscle fibres). J. Cell. Physiol. 232: 1086-1094, 2017. © 2016 Wiley Periodicals, Inc.

Effects of medium-chain fatty acids on performance, carcass characteristics, blood biochemical parameters and immune response in Japanese quail

This study had the aim of evaluating the effects of medium-chain fatty acids (MCFA) on performance, carcass characteristics, some blood parameters and antibody titre against sheep red blood cells (SRBC) in quail. A total of 240 quail chicks were allotted to 4 treatments consisting of respectively 0, 1, 2 and 4 g/kg dietary MCFA. There were no significant differences in body weight, feed intake and feed conversion ratio among treatments at different stages of the experiment. MCFAs had no significant effect on breast, thigh, liver, spleen and bursa of Fabricius weight ratios. However, the relative weight of abdominal fat significantly decreased in quail receiving 0.2 and 0.4 MCFA as compared to other treatments. Concentrations of low-density lipoprotein-cholesterol (LDL), triglycerides and total cholesterol were decreased and high-density lipoprotein (HDL)-cholesterol was increased in quail chicks receiving MCFA compared with control quail chicks. The concentrations of SRBC antibody were not statistically different among treatments. It is concluded that MCFA significantly decreased LDL, triglycerides, cholesterol and abdominal fat and increased HDL in quail chicks.

A 9-wk docosahexaenoic acid-enriched supplementation improves endurance exercise capacity and skeletal muscle mitochondrial function in adult rats

Decline in skeletal muscle mass and function starts during adulthood. Among the causes, modifications of the mitochondrial function could be of major importance. Polyunsaturated fatty (ω-3) acids have been shown to play a role in intracellular functions. We hypothesize that docosahexaenoic acid (DHA) supplementation could improve muscle mitochondrial function that could contribute to limit the early consequences of aging on adult muscle. Twelve-month-old male Wistar rats were fed a low-polyunsaturated fat diet and were given DHA (DHA group) or placebo (control group) for 9 wk. Rats from the DHA group showed a higher endurance capacity (+56%, P < 0.05) compared with control animals. Permeabilized myofibers from soleus muscle showed higher O2 consumptions (P < 0.05) in the DHA group compared with the control group, with glutamate-malate as substrates, both in basal conditions (i.e., state 2) and under maximal conditions (i.e., state 3, using ADP), along with a higher apparent Km for ADP (P < 0.05). Calcium retention capacity of isolated mitochondria was lower in DHA group compared with the control group (P < 0.05). Phospho-AMPK/AMPK ratio and PPARδ mRNA content were higher in the DHA group compared with the control group (P < 0.05). Results showed that DHA enhanced endurance capacity in adult animals, a beneficial effect potentially resulting from improvement in mitochondrial function, as suggested by our results on permeabilized fibers. DHA supplementation could be of potential interest for the muscle function in adults and for fighting the decline in exercise tolerance with age that could imply energy-sensing pathway, as suggested by changes in phospho-AMPK/AMPK ratio.

Nutritional Considerations for Performance in Young Athletes

Nutrition is an integral component to any athletes training and performance program. In adults the balance between energy intake and energy demands is crucial in training, recovery, and performance. In young athletes the demands for training and performance remain but should be a secondary focus behind the demands associated with maintaining the proper growth and maturation. Research interventions imposing significant physiological loads and diet manipulation are limited in youth due to the ethical considerations related to potential negative impacts on the growth and maturation processes associated with younger individuals. This necessary limitation results in practitioners providing nutritional guidance to young athletes to rely on exercise nutrition recommendations intended for adults. While many of the recommendations can appropriately be repurposed for the younger athlete attention needs to be taken towards the differences in metabolic needs and physiological differences.

Nutrition for working and service dogs

Conformation, genetics, and behavioral drive are the major determinants of success in canine athletes, although controllable variables, such as training and nutrition, play an important role. The scope and breadth of canine athletic events has expanded dramatically in the past 30 years, but with limited research on performance nutrition. There are considerable data examining nutritional physiology in endurance dogs and in sprinting dogs; however, nutritional studies for agility, field trial, and detection are rare. This article highlights basic nutritional physiology and interventions for exercise, and reviews newer investigations regarding aging working and service dogs, and canine detection activities.

Endurance exercise and conjugated linoleic acid (CLA) supplementation up-regulate CYP17A1 and stimulate testosterone biosynthesis

A new role for fat supplements, in particular conjugated linoleic acid (CLA), has been delineated in steroidogenesis, although the underlying molecular mechanisms have not yet been elucidated. The aims of the present study were to identify the pathway stimulated by CLA supplementation using a cell culture model and to determine whether this same pathway is also stimulated in vivo by CLA supplementation associated with exercise. In vitro, Leydig tumour rat cells (R2C) supplemented with different concentrations of CLA exhibited increasing testosterone biosynthesis accompanied by increasing levels of CYP17A1 mRNA and protein. In vivo, trained mice showed an increase in free plasma testosterone and an up-regulation of CYP17A1 mRNA and protein. The effect of training on CYP17A1 expression and testosterone biosynthesis was significantly higher in the trained mice supplemented with CLA compared to the placebo. The results of the present study demonstrated that CLA stimulates testosterone biosynthesis via CYP17A1, and endurance training led to the synthesis of testosterone in vivo by inducing the overexpression of CYP17A1 mRNA and protein in the Leydig cells of the testis. This effect was enhanced by CLA supplementation. Therefore, CLA-associated physical activity may be used for its steroidogenic property in different fields, such as alimentary industry, human reproductive medicine, sport science, and anti-muscle wasting.

National Athletic Trainers' Association position statement: evaluation of dietary supplements for performance nutrition

OBJECTIVES

To help athletic trainers promote a "food-first" philosophy to support health and performance, understand federal and sport governing body rules and regulations regarding dietary supplements and banned substances, and become familiar with reliable resources for evaluating the safety, purity, and efficacy of dietary supplements.

BACKGROUND

The dietary supplement industry is poorly regulated and takes in billions of dollars per year. Uneducated athletes need to gain a better understanding of the safety, eligibility, and efficacy concerns associated with choosing to take dietary supplements. The athletic trainer is a valuable athletic team member who can help in the educational process. In many cases, athletic trainers are asked to help evaluate the legality, safety, and efficacy of dietary supplements. For this position statement, our mission is to provide the athletic trainer with the necessary resources for these tasks.

RECOMMENDATIONS

Proper nutrition and changes in the athlete's habitual diet should be considered first when improved performance is the goal. Athletes need to understand the level of regulation (or lack thereof) governing the dietary supplement industry at the international, federal, state, and individual sport-participation levels. Athletes should not assume a product is safe simply because it is marketed over the counter. All products athletes are considering using should be evaluated for purity (ie, truth in labeling), safety, and efficacy.

Do fat supplements increase physical performance?

Fish oil and conjugated linoleic acid (CLA) belong to a popular class of food supplements known as "fat supplements", which are claimed to reduce muscle glycogen breakdown, reduce body mass, as well as reduce muscle damage and inflammatory responses. Sport athletes consume fish oil and CLA mainly to increase lean body mass and reduce body fat. Recent evidence indicates that this kind of supplementation may have other side-effects and a new role has been identified in steroidogenensis. Preliminary findings demonstrate that fish oil and CLA may induce a physiological increase in testosterone synthesis. The aim of this review is to describe the effects of fish oil and CLA on physical performance (endurance and resistance exercise), and highlight the new results on the effects on testosterone biosynthesis. In view of these new data, we can hypothesize that fat supplements may improve the anabolic effect of exercise.

Molecular cloning and characterisation of an acyl carrier protein thioesterase gene (CocoFatB1) expressed in the endosperm of coconut (Cocos nucifera) and its heterologous expression in Nicotiana tabacum to engineer the accumulation of different fatty acids

Coconut (Cocos nucifera L.) contains large amounts of medium chain fatty acids, which mostly recognise acyl-acyl carrier protein (ACP) thioesterases that hydrolyse acyl-ACP into free fatty acids to terminate acyl chain elongation during fatty acid biosynthesis. A full-length cDNA of an acyl-ACP thioesterase, designated CocoFatB1, was isolated from cDNA libraries prepared from coconut endosperm during fruit development. The gene contained an open reading frame of 1254 bp, encoding a 417-amino acid protein. The amino acid sequence of the CocoFatB1 protein showed 100% and 95% sequence similarity to CnFatB1 and oil palm (Elaeis guineensis Jacq.) acyl-ACP thioesterases, respectively. Real-time fluorescent quantitative PCR analysis indicated that the CocoFatB1 transcript was most abundant in the endosperm from 8-month-old coconuts; the leaves and endosperm from 15-month-old coconuts had ~80% and ~10% of this level. The CocoFatB1 coding region was overexpressed in tobacco (Nicotiana tabacum L.) under the control of the seed-specific napin promoter following Agrobacterium tumefaciens-mediated transformation. CocoFatB1 transcript expression varied 20-fold between different transgenic plants, with 21 plants exhibiting detectable levels of CocoFatB1 expression. Analysis of the fatty acid composition of transgenic tobacco seeds showed that the levels of myristic acid (14 : 0), palmitic acid (16 : 0) and stearic acid (18 : 0) were increased by 25%, 34% and 17%, respectively, compared with untransformed plants. These results indicated that CocoFatB1 acts specifically on 14 : 0-ACP, 16 : 0-ACP and 18 : 0-ACP, and can increase medium chain saturated fatty acids. The gene may valuable for engineering fatty acid metabolism in crop improvement programmes.

Effect of conjugated linoleic acid on testosterone levels in vitro and in vivo after an acute bout of resistance exercise

The purposes of the present study were to investigate the effect of conjugated linoleic acid (CLA) supplementation on testosterone levels in vitro on a cell line derived from Leydig cells (R2C) and in vivo in the blood of physically active subjects before and after a resistance exercise bout. In vitro R2C cells were treated with different CLA concentrations (0-30 μM) for 24 and 48 hours. After treatment, supernatant media were tested to determine testosterone secretion. The CLA increased the testosterone secretion only after 48 hours. In vivo, 10 resistance-trained male subjects, in a double-blind placebo-controlled and crossover study design were randomized for 3 weeks of either 6 g·d⁻¹ CLA or placebo. Blood was drawn pre and post each resistance exercise bout to determine the total testosterone and sex hormone-binding globulin (SHBG) levels. No significant differences were observed for total testosterone or SHBG pre and post each resistance exercise bout; although after the resistance exercise bouts, total testosterone increased moderately (effect size = moderate), whereas after CLA supplementation, there was a large increase in total testosterone (effect size = large). CLA supplementation induced an increase in testosterone levels in Leydig cells in vitro after 48 hours but not in vivo before and after a resistance exercise bout. These findings suggest that CLA supplementation may promote testosterone synthesis through a molecular pathway that should be investigated in the future, although this effect did not have an anabolic relevance in our in vivo model.

Medium-chain fatty acid nanoliposomes suppress body fat accumulation in mice

Medium-chain fatty acids (MCFA) are widely used in diets for patients with obesity. To develop a delivery system for suppressing dietary fat accumulation into adipose tissue, MCFA were encapsulated in nanoliposomes (NL), which can overcome the drawbacks of MCFA and keep their properties unchanged. In the present study, crude liposomes were first produced by the thin-layer dispersion method, and then dynamic high-pressure microfluidisation (DHPM) and DHPM combined with freeze-thawing methods were used to prepare MCFA NL (NL-1 and NL-2, respectively). NL-1 exhibited smaller average size (77.6 (SD 4.3) nm), higher zeta potential (- 40.8 (SD 1.7) mV) and entrapment efficiency (73.3 (SD 16.1) %) and better stability, while NL-2 showed narrower distribution (polydispersion index 0.193 (SD 0.016)). The body fat reduction property of NL-1 and NL-2 were evaluated by short-term (2 weeks) and long-term (6 weeks) experiments of mice. In contrast to the MCFA group, the NL groups had overcome the poor palatability of MCFA because the normal diet of mice was maintained. The body fat and total cholesterol (TCH) of NL-1 (1.54 (SD 0.30) g, P = 0.039 and 2.33 (SD 0.44) mmol/l, P = 0.021, respectively) and NL-2 (1.58 (SD 0.69) g, P = 0.041 and 2.29 (SD 0.38) mmol/l, P = 0.015, respectively) significantly decreased when compared with the control group (2.11 (SD 0.82) g and 2.99 (SD 0.48) mmol/l, respectively). The TAG concentration of the NL-1 group (0.55 (SD 0.14) mmol/l) was remarkably lower (P = 0.045) than the control group (0.94 (SD 0.37) mmol/l). No significant difference in weight and fat gain, TCH and TAG was detected between the MCFA NL and MCFA groups. Therefore, MCFA NL could be potential nutritional candidates for obesity to suppress body fat accumulation.

The limits of human performance

Human performance, defined by mechanical resistance and distance per time, includes human, task and environmental factors, all interrelated. It requires metabolic energy provided by anaerobic and aerobic metabolic energy sources. These sources have specific limitations in the capacity and rate to provide re-phosphorylation energy, which determines individual ratios of aerobic and anaerobic metabolic power and their sustainability. In healthy athletes, limits to provide and utilize metabolic energy are multifactorial, carefully matched and include a safety margin imposed in order to protect the integrity of the human organism under maximal effort. Perception of afferent input associated with effort leads to conscious or unconscious decisions to modulate or terminate performance; however, the underlying mechanisms of cerebral control are not fully understood. The idea to move borders of performance with the help of biochemicals is two millennia old. Biochemical findings resulted in highly effective substances widely used to increase performance in daily life, during preparation for sport events and during competition, but many of them must be considered as doping and therefore illegal. Supplements and food have ergogenic potential; however, numerous concepts are controversially discussed with respect to legality and particularly evidence in terms of usefulness and risks. The effect of evidence-based nutritional strategies on adaptations in terms of gene and protein expression that occur in skeletal muscle during and after exercise training sessions is widely unknown. Biochemical research is essential for better understanding of the basic mechanisms causing fatigue and the regulation of the dynamic adaptation to physical and mental training.

The effect of nutritional manipulation on ultra-endurance performance: a case study

The Atlantic Rowing Race requires teams of two to cover 3,000 nautical miles over 40-90 days. During this ultra-endurance event, competitors require substantial energy intake to meet metabolic requirements; therefore, sufficient physiological and nutritional support is paramount. Two highly trained males (aged 46) engaged in two 14d dietary interventions, with a 14d recovery period in between, to investigate the effect of such interventions on physiological (cardiovascular, cardiorespiratory, and blood-based measures) and performance-based (distance and split time) parameters during an ultra-endurance (2h on 2h off, for 24h) laboratory-based rowing protocol at 60% VO2max. Diet 1: high fat (HF) [60% fat, 30% carbohydrate and 10% protein] and Diet 2: high carbohydrate (HC) [20%, 70% and 10% respectively]. A greater distance was rowed by both subjects (155, 329 m and 134, 797 m vs 130, 089 m and 122, 112 m) with a concomitant reduced heart rate, volume of oxygen uptake, and respiratory exchange ratio, following the HF as opposed to HC dietary intervention. In summary, ultra-endurance performance was enhanced following a 14d HF diet, without apparent implications on liver function and overall lipid profile.

Optimizing fat oxidation through exercise and diet

Interventions aimed at increasing fat metabolism could potentially reduce the symptoms of metabolic diseases such as obesity and type 2 diabetes and may have tremendous clinical relevance. Hence, an understanding of the factors that increase or decrease fat oxidation is important. Exercise intensity and duration are important determinants of fat oxidation. Fat oxidation rates increase from low to moderate intensities and then decrease when the intensity becomes high. Maximal rates of fat oxidation have been shown to be reached at intensities between 59% and 64% of maximum oxygen consumption in trained individuals and between 47% and 52% of maximum oxygen consumption in a large sample of the general population. The mode of exercise can also affect fat oxidation, with fat oxidation being higher during running than cycling. Endurance training induces a multitude of adaptations that result in increased fat oxidation. The duration and intensity of exercise training required to induce changes in fat oxidation is currently unknown. Ingestion of carbohydrate in the hours before or on commencement of exercise reduces the rate of fat oxidation significantly compared with fasted conditions, whereas fasting longer than 6 h optimizes fat oxidation. Fat oxidation rates have been shown to decrease after ingestion of high-fat diets, partly as a result of decreased glycogen stores and partly because of adaptations at the muscle level.