Orange Juice Supplementation in Soccer Players

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 Based on unpublished data from a previous pilot experiment, it was expected that the total cholesterol of orange juice group would be 10% lower in relation to control group after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.

• Orange juice (1L/d) (Dietary supplement): 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.
• Control drink (1L/d) (Dietary supplement): 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.

Primary outcomes

• Food intake [60 days]: Food intake was assessed by 24-hour recall

Secondary outcomes

• Glucose [60 days]: Blood dosing using commercial kits
• Glycated hemoglobin [60 days]: Blood dosing using commercial kits
• Total cholesterol [60 days]: Blood dosing using commercial kits
• Low Density Lipoprotein Cholesterol (LDL-C) [60 days]: Calculated with an equation described by Friedewald et al. (1972)
• High Density Lipoprotein Cholesterol (HDL-C) [60 days]: Blood dosing using commercial kits
• Triglycerides [60 days]: Blood dosing using commercial kits
• Creatinine [60 days]: Blood dosing using commercial kits

Other outcomes

• Body Mass Index (BMI kg/cm2) [60 days]: Weight and height will be combined to report BMI (kg/cm2) by the following equation: BMI (kg/cm2) = Weight (kg) / (Height (m))2
• % Lean body mass [60 days]: Assessed by deuterium oxide method
• % Fat body mass [60 days]: Assessed by deuterium oxide method
• % body water [60 days]: Assessed by deuterium oxide method

Sex: Male, ages: 18 Years to 19 Years, accepts healthy volunteers

Inclusion Criteria:

* Three consecutive years of soccer training prior to the start of the study.

Exclusion Criteria:

* Historic of chronic disease, use of hormones, drugs, vitamins supplements and/or other dietary supplements during the study.

• Friedewald WT, Levy RI, Fredrickson DS. Estimation of the concentration of low-density lipoprotein cholesterol in plasma, without use of the preparative ultracentrifuge. Clin Chem. 1972 Jun;18(6):499-502. No abstract available. PMID 4337382
• Results publication: Dourado GK, Cesar TB. Investigation of cytokines, oxidative stress, metabolic, and inflammatory biomarkers after orange juice consumption by normal and overweight subjects. Food Nutr Res. 2015 Oct 20;59:28147. doi: 10.3402/fnr.v59.28147. eCollection 2015. PMID 26490535

• Ellen C De Freitas, Ph.D., Principal investigator, University of São Paulo, School of Physical Education and Sports of Ribeirão Preto
• Sara M Terrazas, Msc, Study chair, Sao Paulo State University "Julio de Mesquita Filho", Faculty of Pharmaceutical Sciences