Abstract
ABSTRACTBackgroundWatermelon, a rich source of lycopene, has garnered attention for cardioprotective effects including cholesterol reduction and promotion of redox balance. It is unknown whether 100% watermelon juice may represent a food-first approach to confer cardioprotective benefits of lycopene.ObjectivesThis study examined influences of 100% watermelon juice on serum lycopene, lipids, and antioxidant capacity. Secondly, the study explored genetic influences on lycopene metabolism and bioavailability.MethodsA placebo-controlled, randomized, double-blind, crossover trial with postmenopausal women (n = 16, mean ± SD age: 60 ± 4.1 y) assessed effects of 100% watermelon juice on mechanistic and clinical outcomes influencing vascular function. Participants maintained low-lycopene diets for a 1-wk run-in period and throughout the study. Morning and evening consumption of 100% watermelon juice provided a daily dose of 14.4 ± 0.34 mg lycopene. Study arms of 4 wk were separated by a 2-wk washout period. Saliva was collected for genetic analysis of single nucleotide polymorphisms, and fasting blood samples were taken pre– and post–study arms. Statistical analyses included mixed models, linear regression, and nonparametric tests.ResultsSerum lycopene exhibited a significant treatment effect (P = 0.002) along with notable interindividual responses; however, significant improvements in serum lipids or antioxidant capacity were not observed. Genetic variant rs6564851 in the β-carotene 15,15’-oxygenase-1 (BCO1) gene was associated with changes in lycopene such that TT homozygotes exhibited a significantly greater increase (β ± SE: 13.4 ± 1.6, P = 1.4 × 10−06).ConclusionsWatermelon juice supplementation did not result in improvements in serum lipids or antioxidant capacity; however, results support findings in which watermelon juice significantly, yet differentially, increased circulating lycopene. Genetics appears to explain some of the variability. Given that dose has been shown to overcome individual responsiveness to lycopene interventions, future investigations with varying doses of lycopene-rich foods would be strengthened by genotyping so as to establish personalized nutrition recommendations.This trial was registered at clinicaltrials.gov as NCT03626168.
Highlights
Lycopene is among the most abundant carotenoids in human serum, and research suggests that it has superior singlet oxygen quenching potential compared with other carotenoids [1,2,3,4]
Albeit understudied, studies suggest several genetic variants involved in carotenoid metabolism may influence lycopene bioavailability (Table 1) [12, 15,16,17,18,19,20,21]
Results from the mixed models revealed that, as opposed to the group randomly assigned to the placebo, those randomly assigned to watermelon juice had significantly higher circulating serum lycopene (β coefficient: 0.5475; 95% CI: 0.204, 0.891; P = 0.0028)
Summary
Lycopene is among the most abundant carotenoids in human serum, and research suggests that it has superior singlet oxygen quenching potential compared with other carotenoids [1,2,3,4]. Mechanisms underpinning the effect of lycopene on vascular health may be attenuated by numerous factors known to influence lycopene bioavailability. Additional factors influencing the bioavailability and efficacy of lycopene include the form of consumption: food compared with supplement. Watermelon, a rich source of lycopene, has garnered attention for cardioprotective effects including cholesterol reduction and promotion of redox balance. It is unknown whether 100% watermelon juice may represent a food-first approach to confer cardioprotective benefits of lycopene. Objectives: This study examined influences of 100% watermelon juice on serum lycopene, lipids, and antioxidant capacity.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
