The purpose of this study was to test the hypothesis that acute intake of inorganic nitrate (NO₃⁻) via supplementation would attenuate the venoconstriction and pressor response to exercise. Sixteen healthy young adults were assigned in a randomized crossover design to receive beetroot juice (BRJ) or an NO₃⁻-depleted control beverage (prune juice: CON). Two hours after consuming the allocated beverage, participants rested in the supine position. Following the baseline period of 4 min, static handgrip exercise of the left hand was performed at 30% of the maximal voluntary contraction for 2 min. Mean arterial pressure (MAP) and heart rate (HR) were measured. Changes in venous volume in the right forearm and right calf were also measured using venous occlusion plethysmography while cuffs on the upper arm and thigh were inflated constantly to 30–40 mmHg. The plasma NO₃⁻ concentration was elevated with BRJ intake (p < 0.05). Exercise increased MAP and HR and decreased venous volume in the forearm and calf, but there were no differences between CON and BRJ. Thus, these findings suggest that acute BRJ intake does not alter the sympathetic venoconstriction in the non-exercising limbs and MAP response to exercise in healthy young adults, despite the enhanced activity of nitric oxide.

Background: Acute exercise is one factor that increases blood homocysteine levels, and elevated homocysteine levels cause oxidative stress. Albumin, which is abundant in blood, is an antioxidant, and the redox state of albumin is used as an index of oxidative stress in blood. This study aimed to assess the effect of acute exercise on plasma homocysteine levels and the blood non-mercaptoalbumin/mercaptoalbumin ratio as an oxidative stress marker. Methods: This study used a crossover design with exercise and control conditions. Under exercise conditions, a bicycle ergometer was used to perform 40 min of transient constant-load exercise at 65% heart rate reserve. Under control conditions, participants rested for 40 min. Blood was collected before, 30 min after, and 90 min after exercise, and at the same time points under control conditions. Samples were analyzed for the homocysteine concentration and non-mercaptoalbumin/mercaptoalbumin ratio. Results: The results revealed that a 65% heart rate reserve and 40 min of acute exercise increased plasma homocysteine concentration and non-mercaptoalbumin ratio. In the intra-condition comparison, the plasma Hcy concentration was significantly increased at Post 30 min (+ 0.83 ± 0.70 µmol/L, P = 0.003) compared with that at Pre in the exercise condition. Furthermore, 90 min after exercise, the blood non-mercaptoalbumin ratio was significantly increased (+ 0.35 ± 0.71%, P = 0.030) compared to Pre. Conclusion: These results indicate that the plasma Hcy concentration first increased, and then the non-mercaptoalbumin/mercaptoalbumin ratio increased as the elevated state was maintained. This study revealed that 65% heart rate reserve, 40 min of acute exercise increased plasma Hcy concentration and non-mercaptoalbumin ratio.

Background: Supplements are popular among athletes. To prevent anti-doping rule violations, athletes, registered dietitians, and support professionals must assess the safety, efficacy, and necessity of supplements. However, the relationship between experience with receiving nutritional support and supplement intake has not yet been examined. Objective: In this study, we aimed to investigated differences in supplement use according to nutritional support experience using the Australian Institute of Sport classification system. Methods: A self-administered questionnaire was completed by 800 athletes representing Japan at the Paris 2024 Olympic Games (including candidates). The survey assessed supplement intake over the past year, nutritional support experience, and knowledge and practices regarding supplements and hydration. Results: Overall, 92.3% of athletes used supplements, with a higher percentage among those who had nutritional support experience ( p < 0.01). Among athletes who consumed group A sports foods (evidence-based supplements), the intake rates were higher among those with nutritional support experience than among those without nutritional support experience ( p < 0.01). Even after adjusting for age and sex, nutritional support experience was associated with total supplements and sports foods intake. Conclusion: Nutritional support experience appears to be associated with the intake of supplements, particularly sports foods. Although limited to associations, these findings highlight the need for dietitians to collaborate with multidisciplinary staff when providing athletes with comprehensive, evidence-based education on supplement efficacy and safety.

Background Acute exercise is one factor that increases blood homocysteine levels, and elevated homocysteine levels cause oxidative stress. Albumin, which is abundant in blood, is an antioxidant, and the redox state of albumin is used as an index of oxidative stress in blood. This study aimed to assess the effect of acute exercise on plasma homocysteine levels and the blood non-mercaptoalbumin/mercaptoalbumin ratio as an oxidative stress marker. Methods This study used a crossover design with exercise and control conditions. Under exercise conditions, a bicycle ergometer was used to perform 40 min of transient constant-load exercise at 65% heart rate reserve. Under control conditions, participants rested for 40 min. Blood was collected before, 30 min after, and 90 min after exercise, and at the same time points under control conditions. Samples were analyzed for the homocysteine concentration and non-mercaptoalbumin/mercaptoalbumin ratio. Results The results revealed that a 65% heart rate reserve and 40 min of acute exercise increased plasma homocysteine concentration and non-mercaptoalbumin ratio. In the intra-condition comparison, the plasma Hcy concentration was significantly increased at Post 30 min (་0.83 ± 0.70 µmol/L, P = 0.003) compared with that at Pre in the exercise condition. Furthermore, 90 min after exercise, the blood non-mercaptoalbumin ratio was significantly increased (་0.35 ± 0.71%, P = 0.030) compared to Pre. Conclusion These results indicate that the plasma Hcy concentration first increased, and then the non-mercaptoalbumin/mercaptoalbumin ratio increased as the elevated state was maintained. This study revealed that 65% HRR, 40 min of acute exercise increased plasma Hcy concentraion and non-mercaptoalbumin ratio.

Female athletes who endure physical strain on the same bone area are prone to stress fractures. Preventing these improves their quality of life. Blood vitamin B2 (V.B2) and E (V.E) levels influence blood homocysteine (Hcy) levels, which, when elevated, increase the risk of stress fractures. We aimed to determine the effects of V.B2 and V.E supplementation on plasma Hcy concentrations in these athletes carrying the C677T polymorphism in methylenetetrahydrofolate reductase (MTHFR). This study is a before–after study in 16 female athletes. It was divided into three intervention periods of V.B2 (28 mg/day), V.E (60 mg/day), and V.B2 + V.E intake, and each period was 14 days. Blood samples were collected before and after each period, and plasma Hcy concentration and each blood vitamin concentration were measured. Plasma Hcy concentration significantly decreased in all periods, but the maximum lowering effect was obtained when V.B2 and V.E were used in combination. The administration of V.B2 might have lowered the plasma Hcy level by maximizing the catalytic activity of MTHFR; V.E might have suppressed cell oxidation, increasing the efficiency of folate in lowering the plasma Hcy level. We propose the combined intake of V.B2 and V.E as effective nutrients to reduce plasma Hcy concentrations in female athletes with MTHFR polymorphisms.