Keisuke Sawaki

Effects of Oral Supplementation with Cystine and Theanine on the Immune Function of Athletes in Endurance Exercise: Randomized, Double-Blind, Placebo-Controlled Trial

Athletes become increasingly susceptible to infection with intense training that results in immune suppression. The immune state was investigated after administering cystine/theanine (CT), which has been reported to have an immune reinforcement effect, to athletes before training involving a prolonged period of intense exercise. Fifteen long-distance runners were each allocated to the CT or placebo group, and the test food was ingested for 10 d prior to the start of training. Clinical examinations were performed before and after the training. The results indicate a significant increase in the high-sensitivity C-reactive protein (hs-CRP) and neutrophil count in the blood, as well as a decreasing tendency for lymphocytes in the placebo group, but not the CT group. These observations suggest that the ingestion of CT contributed to suppressing the change in inflammatory response, prevented a decrease in the immune function, and prevented infection and reduced symptoms when infected associated with continuous intense exercise.

Delayed-onset muscle injury and its modification by wheat gluten hydrolysate

OBJECTIVE We investigated the pattern of delayed-onset muscle injury in well-trained athletes after a competitive half-marathon and the effects of post-race intake of wheat gluten hydrolysate (WGH). METHODS Thirty well-trained college runners with a best time of 14-15 min over 5000 m raced in a half-marathon. Thereafter, they were divided into three groups based on finish times and given 0 (control), 10, or 20 g of WGH. Blood biochemical parameters were monitored at -1 d, +1 h, +1 d, and +2 d after the race. Data selected according to finish times and biochemical parameters were then analyzed. RESULTS Plasma creatine kinase activity peaked at 1 d after the race in the control group and correlated with post-race white blood cell counts. The post-race elevation of creatine kinase activity was dose-dependently suppressed by WGH. CONCLUSION Delayed-onset muscle injury peaked in well-trained distance runners at 1 d after a half-marathon and was dose-dependently suppressed by a post-race intake of WGH.

Preventive Effect of Lactoferrin Intake on Anemia in Female Long Distance Runners

This study investigated whether intake of lactoferrin (LF) would improve or prevent anemia in female long distance runners who were training during the summer season and had a high risk of iron-deficiency anemia. Sixteen female long distance runners were divided into a group taking LF and iron (the LF group) and a group that only took iron (the control group) for 8 weeks. In the control group, the ferritin, serum iron, and red blood cell count were significantly lower than before treatment. In the LF group, the hematology data showed no significant change during the 8 weeks. The red blood cell count was significantly higher in the LF group than in the control group. The blood lactate level following a 3,000-m pace run of the control group was also significantly higher than that of the LF group. These observations suggest the possibility that intake of LF increases the absorption and utilization of iron and would be useful in the prevention of iron deficiency anemia among female long distance runners.

Association between Yogurt Consumption and Intestinal Microbiota in Healthy Young Adults Differs by Host Gender

Human intestinal microbiota are influenced by various factors viz. diet, environment, age, gender, geographical, and socioeconomic situation, etc. among which diet has the most profound impact. However, studies investigating this impact have mostly included subjects from diverse geographic/socioeconomic backgrounds and hence the precise effects of dietary factors on gut microbiota composition remain largely confounded. Herein, with an aim to evaluate the association between dietary habits, specifically yogurt consumption, and the gut microbiota in healthy young adults sharing similar age, lifestyle routine, geographical setting, etc., we conducted a cross-sectional study wherein 293 collegiate freshmen answered a questionnaire about their frequency of yogurt consumption over the last 2 months and provided stool specimens for microbiota analysis. Fecal microbiota were analyzed by highly sensitive reverse-transcription-quantitative-PCR assays targeting bacterial 16S rRNA molecules. Fecal organic acids were measured by HPLC. Overall, the gut microbiota were predominated (97.1 ± 8.6%) by Clostridium coccoides group, Clostridium leptum subgroup, Bacteroides fragilis group, Bifidobacterium and Atopobium cluster. Interestingly, after adjusting the data for yogurt consumption, females were found to have higher total bacterial (P = 0.013) and Bifidobacterium (P = 0.046) count and fecal pH (P = 0.007) and lower fecal concentration of total organic acids (P = 0.030), succinic acid (P = 0.007) and formic acid (P = 0.046) as compared to males. Altogether, yogurt consumption showed positive linear association with Lactobacillus and Lactobacillus gasseri subgroup in both male and female subjects; however, several gender-specific disparities were also detected in this yogurt-microbiota association. Yogurt consumption demonstrated a negative association with L. sakei subgroup, Enterobacteriaceae and Staphylococcus in males but shared a positive association with L. casei subgroup and succinic acid in female subjects. The study manifests the association between yogurt consumption and gut microbiota in a healthy homogeneous cohort and show how this association can differ by host gender. The findings should be helpful for prospective studies investigating the diet–microbiome interaction in human health and disease.

Preliminary report: mitochondrial DNA 5178 polymorphism in male elite Japanese endurance runners

Elite athletic endurance ability involves multiple genetic and environmental factors, with little known about the specific genotypes involved. As a first step to finding genetic markers of endurance performance, we recruited 66 male endurance runners and 110 control athletes. We investigated the distribution of m.5178CA polymorphisms in male endurance runners. Although the m.5178A genotype has been reportedly associated with longevity, endurance runners in this study showed a significantly higher frequency (71.2%) of the m.5178C genotype than control subjects (52.7%). The-m.5178C genotype may be favorable for performance in elite endurance runners.

Krill Oil Improves Mild Knee Joint Pain: A Randomized Control Trial

Background Krill oil is an edible oil extracted from krill, a small red-colored crustacean found in the Antarctic Ocean. The administration of krill oil is reported to mitigate inflammation in patients with cardiac disease, rheumatoid arthritis, or osteoarthritis. However, the effect of krill oil on mild knee pain has not yet been determined. Objective To assess the effect of krill oil on mild knee pain. Design A randomized, double-blind, parallel-group, placebo-controlled trial of fifty adults (38–85 years old) with mild knee pain attending the Fukushima Orthopedic Clinic (Tochigi, Japan) between September 2014 and March 2015. Interventions Participants were randomized to receive 2 g per day of either krill oil or an identical placebo for 30 days. Outcomes The primary outcome was improvement in subjective symptoms of knee pain as assessed by the Japanese Knee Osteoarthritis Measure (JKOM) and Japanese Orthopaedic Association score (JOA). Secondary outcomes included blood and urine biochemical parameters. Results Both the placebo and krill oil groups showed significant improvements in the questions in the JKOM and JOA questionnaires after administration. After the intervention, krill oil group showed more improvements than placebo group in two questions regarding the pain and stiffness in knees in JKOM. Controlling for age, sex, weight, and smoking and drinking habits, krill oil significantly mitigated knee pain in sleeping (P < 0.001), standing (P < 0.001) and the range of motion of both right and left knees (both P = 0.011) compared to placebo. Krill oil administration raised plasma EPA (P = 0.048) and EPA/AA ratio (P = 0.003). Conclusion This study indicates that krill oil administration (2 g/day, 30 days) improved the subjective symptoms of knee pain in adults with mild knee pain. Trial registration UMIN-CTR; ID UMIN000014413