The Area of Nutrition Supplementation With Spirulina: the Effect of Antioxidants on Human - Research Paper Example

Introduction The title of the research article by Kalafati et al (2010): Ergogenic and Antioxidant Effects of Spirulina Supplementation in Humans accurately encapsulates the research problem. However, the subjects of the actual study being recreational runners who had trained for a minimum of one year, were not mentioned in the title, where humans as a broad category, have been denoted as the subject of the study. The abstract of the paper concisely summarizes the essential points of the study in a clearly structured format. The research problem is unambiguously stated, and is easy to identify with, because of the increasing popularity of spirulina as a supplementary health food. The problem statement and context of the study clearly underscore the concepts and the population under study. The problem has significance for nursing, since the outcome of the research investigations can help to optimize health care for the general public as well as for athletes and runners. The research problem has been investigated using the quantitative approach, most appropriate to accurately measure the ergogenic and antioxidant effects of spirulina supplementation as against the use of placebo. Significance of the Research Study Under Review The context of the research study by Kalafati et al (2010) under review, was that spirulina is a widely used nutritional supplement believed to have antioxidant and performance-enhancing effects for sportpeople and other users. The outcomes of the interventions with spirulina supplementation were measured on three parameters: exercise performance, substrate metabolism, and blood redox status at rest and after exercise. The importance of identifying its effects has been explained by the authors. Only one other study (Lu et al, 2006) was found that investigated the outcome of spirulina supplementation on redox status and exercise performance. However, in the latter research it was difficult to identify the spirulina effect because the blood samples after spirulina supplementation and exercise were compared with the resting blood samples. Moreover, the production of reactive oxygen and nitrogen species (RONS) contributes to muscle fatigue; this has led to several studies investigating the effects of antioxidants such as vitamin C or Nacetylcysteine on human redox status and exercise performance (Aguilo et al, 2007; Medved et al, 2004). On the other hand, relatively few researchers such as Panza et al (2008) and Skarpanska-Stejnborn et al (2008) have examined the effect of foods rich in antioxidants on oxidative stress induced by exercise. Therefore, “the extent to which foods rich in antioxidants such as spirulina modify the redox status responses induced by exercise is largely unknown” (Kalafati et al, 2010, p.142). A comprehensive number of relevant references have been used by the authors. A majority are recent sources within the last five years, and most of the remaining references are dated within the last ten years. Relevance of the Research Methodology and Research Design The type of research methodology used is the “double-blind, placebo-controlled, counter-balanced crossover study” (Kalafati et al, 2010, p.142). The methods used in the research are found to be consistent with the methodology planned by the researchers. Nine healthy, moderately trained men, recreational runners of an average age of 23.3 years, average height of 174.3 cm. and average weight of 70.7 kg. participated in the research study. The sample/ or intervention group to whom spirulina supplementation was given, was contrasted with the placebo group. Each subject participated in four exercise trials, with a two-week washout period between the second and the third exercise trials to avoid the effects of the interventions being carried over into the next trial. The best possible sampling technique was used, with eligibility for the research study determined on the basis of the volunteering subjects’ medical and supplementation history and details of physical activity obtained through a questionnaire. No subject was a smoker, took supplements or anti-inflammatory drugs (Kalafati et al, 2010). However, a power analysis to estimate sample size needs was not conducted, and the sample size of 9 runners appears to be lower; a larger number would help to increase the validity of the study. Half of the subjects were given the spirulina first, and the other half were given the placebo, and then this was reversed. In the research study by Kalafati et al (2010) under review, the most rigorous possible methodological design was used, to fulfill the purpose of the study with the highest accuracy and relevance. Each of the 9 subjects ran on a treadmill at an intensity corresponding to 70% to 75% of their V’O2max for 2 hours, and then at 95% of V’O2max until exhaustion. After supplementation with spirulina to the sample group, and administering of placebo to the other group, the exercise performance and respiratory quotient of both groups were measured. Blood samples were drawn for both the groups: before, immediately after, and at 1, 24, and 48 hours after exercise. Reduced glutathione (GSH), oxidized glutathione (GSSG), GSH/ GSSG, thiobarbituric acid-reactive substances (TBARS), protein carbonyls, catalase activity, and total antioxidant capacity were determined. The time to reach fatigue and termination of exercise was recorded as a measure of aerobic performance. Expired gas samples were obtained every ten minutes to ensure the prescribed exercise intensity, and to calculate the oxidation rates of the fat and carbohydrate (Kalafati et al, 2010). V’O2max is the maximum volume of oxygen that can be utilized in one minute while undertaking maximal or exhaustive exercise. It is represented as milliliters of oxygen used in one minute per kilogram of body weight. Maximal oxygen uptake or V’O2max identifies an athlete’s capacity to perform sustained exercise. It is a measure of aerobic fitness, and is the best indicator of cardiorespiratory endurance (Wilmore et al, 2008). The theoretical basis of indirect calorimetry appears to be less problematic during low to moderate intensity exercise than at rest. “During high intensity exercise of over 75% V’O2max, the validity of using gas exchange measurements to calculate substrate oxidation must be questioned”, state Jeukendrup & Wallis (2005, S36). Studies that investigated fat oxidation over a wide range of intensities and determined the exercise intensity at which fat oxidation is maximal, have provided vital evidence regarding the differences in fat oxidation between individuals, and about the factors that affect fat oxidation. The variation of fat oxidation between individuals is very wide, but its measurements are reproducible within the same person to a great extent. Some of the variation can be accounted for by “diet, lean body mass, estimated physical activity level, V’O2max, gender and fat mass” (Jeukendrup & Wallis, 2005, S37) Taking into consideration the purpose of the study by Kalafati et al (2010), the research methodology and administration of interventions were appropriately designed, conducted, clearly explained by the authors, and can be repeated independently by other researchers. The sample group and the placebo group both underwent the same procedures, except for the study intervention. Validity of the Research Study All threats to internal and external validity of the present research study were controlled by the study design and methodology used, as discussed above. The recording of baseline measurements one or two weeks before the start of the research study was essential for determining the extent of the effects of the spirulina and placebo interventions. After the 4-week supplementation period, subjects returned to the laboratory to perform the second exercise bout with conditions identical to the first exercise trial. A 2-week washout interval between the second and third exercise trials was to avoid any possible carry-over effects (Kalafati et al, 2010). Taking into consideration the short supplementation period of 4 weeks, the 2-week washout period was considered adequate to eliminate any effects of spirulina or placebo. The washout period was followed by the third and fourth exercise trials in which the exercise conditions of the first and second trials were followed. “The first and third exercise trials were performed to ensure that the two-week washout period was adequate to have similar physiological and biochemical values before the two periods of supplementation” (Kalafati et al, 2010, p.144). Further, similar to the present study, one earlier research study (Baicus & Baicus, 2007) had used a 2-week washout period, and a crossover design, to investigate the effects of spirulina supplementation on humans. No specific method of randomization of the intervention and control groups has been mentioned. It is stated by the authors that half the total number of 9 runners selected for the study were administered spirulina supplementation in the first and second trials, and placebo in the third and fourth trials; while the reverse was undertaken for the remaining half of the group. Since the volunteers were an odd number of 9, it is not certain exactly how many volunteers were in the spirulina intervention group and in the placebo group, at the beginning of the research. The randomization list was not concealed from the subjects, or others involved in the research. To increase the validity of the results of the study, the patients in both groups were similar at the start of the study, with respect to physical ability to undertake the test. Moreover, participants had “similar levels of macronutrient and antioxidant intake during the period of data collection” (Kalafati et al, 2010). Monitoring diet consumption was through a written set of guidelines and a record sheet for recording food intake. They were asked to record their diet for 3 days prior to their first visit to the laboratory, and to repeat the same diet before their next 3 visits to the laboratory. Diet records were analyzed with the help of nutritional analysis system ScienceFit Diet 200A. In this double-blind research study, the participants as well as those directly involved with them such as those who recorded the data were kept in the dark till the end of the study about which was the spirulina intervention group, and which was the control group administered with the placebo. Thus, by using the method of blinding, the researchers greatly increased the validity of the study, which could otherwise have been influenced by psychological factors arising from knowing which group the runners belonged to. All the 9 patients who participated in the study were accounted for in the end. Data Analysis The data collection procedures are explained in detail by the researchers. Ethical considerations, however, are not explicitly discussed by the authors. Kalafati et al (2010, p.144) state that “the procedures were in accordance with the Helsinki Declaration of 1975 and approved by the institutional review board”. No issues of ethical concern have been noted in the research study. The data analysis methods were appropriate for the type of data collected. “The distribution of all dependent variables was examined by the Shapiro-Wilk test and was found to not differ significantly from normal” (Kalafati et al, 2010, p.147). With repeated measures on time, the two-way trial x time ANOVA and the two-way group x time ANOVA were used respectively, to analyse the first and third trials (to ensure that the 2-week washout period was sufficient), and the second and fourth trials (to assess the effects of supplementation and exercise). Pairwise comparisons were done on significant interactions, through simple main effect analysis. One-way ANOVA was used for examining differences in diet among groups. Aerobic performance at the second and fourth exercise trials, as well as carbohydrate and lipid oxidation rates during the 2-hour run at the second and fourth exercise trials were examined by paired t-test. P < 0.05 was considered as statistically significant. All analyses were performed with the SPSS version 15.0. All data are presented as mean plus/ minus Standard Error of Measurement (SEM). The tables and figures are presented accurately. Results of the Research Study Irrespective of statistical significance, the results from the present research are also clinically significant. The results indicate that spirulina supplementation promoted a significant increase in the time of exercise performance, fat oxidation rate, and concentration of reduced glutathione (GSH), as compared with the placebo trials. These findings support the conclusions drawn by the authors. According to Kalafati et al (2010), the supplement significantly reduced carbohydrate oxidation rate and terminated the increase in lipid production caused by exercise. In the placebo group, the levels of thiobarbituric acid reactive substance (TBARS) increased after exercise, when administered the placebo, but this increase did not occur after supplementation with spirulina. In both groups, protein carbonyls, catalase, and total antioxidant capacity (TAC) increased immediately after and 1 hour after exercise in both groups. The findings and conclusions address the research question on determining the ergogenic and antioxidant effects of spirulina supplementation in humans. Limitations, Outcomes and Applicability of the Research Study The authors have not discussed the limitations of their study. The main limitation that is required to be considered is the small group of only 9 participants, in the research study. Further, the authors have not explained the method of randomization used, in delegating the initial sample group and control group. However, the two groups were counter-balanced and crossed over, by changing the administering of spirulina to placebo/ and vice versa for the third and fourth trials. Despite the small number of subjects, the validity level of the results and conclusions are high because the study was double-blind, randomized, and counter-balanced through crossover. Kalafati et al (2010) present suggestions for future studies. They state that the actual reasons behind the increase in performance and fat oxidation after spirulina supplementation are not clearly understood. Therefore, more research is required to identify the causes, particularly further investigation is required on the outcomes of spirulina intervention on mitochondrial function and (beta) oxidation together with inflammation and oxidative stress. The article reports all the relevant outcomes of the study, including side effects. The main outcomes recorded were based on data related to dietary analysis and exercise performance. These include exercise performance and increased fat oxidation rate, increased GSH concentration, effect of spirulina on redox status at rest, and effect of spirulina supplementation on redox status after exercise. Other outcomes recorded were fat and carbohydrate oxidation, plasma volume, creatine kinase, GSH status, catalase and total antioxidant capacity (TAC). Significant differences were found in the outcomes of the treatments with spirulina and placebo, with P < 0.05. Applicability of the evidence from this research study is high in various sports, medical, nursing as well as daily-use environments, towards optimal health outcomes. Conclusion The results of the present study indicate that spirulina supplementation for 4 weeks promoted a significantly marked increase in exercise performance, enhanced fat oxidation, and higher levels of glutathione (GSH) concentration; it also reduced and finally terminated the increases in lipid peroxidation produced by exercise. Thus, increased levels of fat oxidation and GSH give rise to enhanced exercise performance. The results are interpreted in terms of the study hypothesis and conceptual framework. Most research studies undertaken earlier on the effect of spirulina are related to individual nutrients that spirulina contains such as different antioxidants, and very few direct research studies been conducted using spirulina. Hence, this article is a significant pioneer in research in the area of nutrition supplementation with spirulina for enhanced health, physical performance and activity levels. The evidence can be useful for individuals’ personal optimization of health outcomes, for health care settings particularly in nursing administration and patient care, for utilization by sportspersons for enhancing physical performance levels, and by commercial organizations for producing new dietary supplements. Taking into consideration the evidence from related research (Dartsch, 2008; McCarty, 2007; Sandhu et al, 2010), this study has added to the body of knowledge and confirmed earlier findings on the benefits of spirulina supplementation. The above critique of the research paper by Kalafati et al (2010), has appraised the merits of the report. The main strengths of the study were its double-blind, randomized, and counter-balance through crossover techniques. Thus, the validity levels were high, with all threats to internal and external validity controlled by the study design and methodology used. Though the authors have not discussed any limitations in conducting the study, the main weakness was found to be its small group of subjects, only 9 participants in total for the study. This may be due to the rigorous nature and lengthy duration of several weeks of the research study, involving various restrictions and requirements in dietary intake. Further, the study involved regular and routine use of supplementation in a disciplined fashion. Moreover, the prospect of lengthy and physically taxing exercise trials of up to 2 hours at high intensity, may have appealed to only the limited number of volunteers who complied with the rules for the research. References Aguilo, A., Tauler, P., Sureda, A., Cases, N., Tur, J. & Pons, A. (2007). Antioxidant diet supplementation enhances aerobic performance in amateur sportsmen. Journal of Sports Science, 25(11): pp.1203-1210. Baicus, C. & Baicus, A. (2007). Spirulina did not ameliorate idiopathic chronic fatigue in four N-of-1 randomized controlled trials. Phytotherapy Research, 21(6): pp.570-573. Dartsch, P.C. (2008). Antioxidant potential of selected Spirulina platensis preparations. Physiotherapy Research, 22: pp.627-633. Jeukendrup, A.E. & Wallis, G.A. (2005). Measurement of substrate oxidation during exercise by means of gas exchange measurements. International Journal of Sports Medicine, 26(Supplement 1): S28-S37. Kalafati, M., Jamurtas, A.Z., Nikolaidis, M.G., Paschalis, V., Theodorou, A.A., Sakellariou, G.K., … Koutedakis, Y. (2010). Ergogenic and antioxidant effects of spirulina supplementation in humans. Medicine & Science in Sports & Exercise, 42 (1): pp.142-151. Lu, H.-K., Hsieh, C.-C., Hsu, J.-J., Yang, Y.-K. & Chou, H.-N. (2006). Preventive effects of Spirulina platensis on skeletal muscle damage under exercise-induced oxidative stress. Euopean Journal of Applied Physiology, 98: pp.220-226. McCarty, M.F. (2007). Clinical potential of spirulina as a source of phycocyanobilin. Journal of Medicinal Food, 10(4): pp.566-570. Medved, I., Brown, M.J., Bjorksten, A.R., Murphy, K.T., Peterson, A.C., Sostaric, S. .. ..Gong, X. (2004). N-Acetylcysteine enhances muscle cysteine and glutathion availability and attenuates fatigue during prolonged exercise in endurance-trained individuals. 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Physiology of sport and exercise. Edition 4. The United Kingdom: Human Kinetics Publications. Read More