Orange Juice Supplementation in Soccer Players
Condition: Healthy Athletes
Study type: Interventional

Summary: 
      This study aimed to verify if orange juice supplementation can be a nutritional strategy to
      ensure an adequate energy and micronutrients ingestion, influencing metabolic responses of
      soccer players.
    

Detailed description: 
      Thirty-four male soccer players aged 18.5 ± 0.5 years and BMI (Body Mass Index) of 21.41 ±
      1.48 kg/cm2 were randomly divided into two parallel groups: (1) orange juice (n = 17),
      composed of individuals receiving 1 liter/day of orange juice; (2) control (n = 17) composed
      of individuals receiving 1 liter/day of control drink with the same proportion of total
      sugars as the orange juice. The recruitment process began in September 2013, the intervention
      was carried out from November 2013 to January 2014, and the data analysis started in February
      2014. The sample size took into account the variances in total cholesterol, considering the
      high statistical variability of biochemical markers, which requires a sufficient number of
      samples to ensure representativeness and adequate statistical power of analysis, and that the
      reduction of total cholesterol is associated to the regular consumption of orange juice
      (Dourado et al., 2015). Based on unpublished data from a previous pilot experiment, it was
      expected that the total cholesterol of orange juice group would be 10% lower in relation to
      control group after intervention (orange juice = 123.41 ± 12.12 mg/dL, control drink = 37.80
      ± 11.17 mg/dL). Thus, with a type I error α = 0.05 and a type II error β = 0.2 (80% power)
      the minimum sample size should have 12 individuals per group (n = 24). Considering the high
      layoffs rate in the team, the initial sample size of study was constituted by 17 individuals
      per group (n = 34). During the intervention, four individuals from control drink group failed
      the study protocol, and the study was concluded with 30 participants (orange juice n = 17 and
      control drink n = 13). Primary and secondary endpoints were the improvement of food intake
      and changes in biochemical markers, respectively. Shapiro Wilk and Levene tests evaluated
      normality and homogeneity of data, respectively. T-test was conducted to identify possible
      differences between groups at baseline. A mixed factorial ANOVA was applied to determine the
      effect of treatment and time, within and between groups (Sidak post hoc test), and
      statistical significance was set at p < 0.05. Food intake, biochemical biomarkers and body
      composition were assessed before and after the 60 days of intervention.
    

Intervention name(s): Orange juice (1L/d); Control drink (1L/d)
Intervention type(s): Dietary Supplement; Dietary Supplement
Intervention description(s): The players (n=17) drank 1 liter per day of orange juice. We do not interfere on the volunteers' usual diet during the study, and they did not ingest any commercial nutritional supplements in this period. During the intervention, the volunteers were engaged in a common training routine specified by the coach's team.; The players (n=13) drank 1 liter per day of the control drink during a 60-day period. We do not interfere on the volunteers' usual diet during the study, and they did not ingest any commercial nutritional supplements in this period. During the intervention, the volunteers were engaged in a common training routine specified by the coach's team.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Triple (Participant, Investigator, Outcomes Assessor)
Primary purpose: Supportive Care
Keywords: Athletes; Food intake; Supplementation; Biochemical biomarkers; Soccer Players