Variation of Serum Lycopene in Response to 100% Watermelon Juice: An Exploratory Analysis of Genetic Variants in a Randomized Controlled Crossover Study

Kristi M Crowe-White; Venkata S Voruganti; Valentina Talevi; Tanja Dudenbostel; Vinoth A Nagabooshanam; Julie L Locher; Amy C Ellis

doi:10.1093/cdn/nzaa102

Variation of Serum Lycopene in Response to 100% Watermelon Juice: An Exploratory Analysis of Genetic Variants in a Randomized Controlled Crossover Study

Curr Dev Nutr. 2020 Jun 17;4(7):nzaa102. doi: 10.1093/cdn/nzaa102. eCollection 2020 Jul.

Authors

Kristi M Crowe-White¹, Venkata S Voruganti², Valentina Talevi², Tanja Dudenbostel³, Vinoth A Nagabooshanam⁴, Julie L Locher⁵, Amy C Ellis¹

Affiliations

¹ Department of Human Nutrition, University of Alabama, Tuscaloosa, AL, USA.
² Department of Nutrition and Nutrition Research Institute, University of North Carolina-Chapel Hill, Kannapolis, NC, USA.
³ Cardiovascular Disease, Vascular Biology & Hypertension, University of Alabama at Birmingham, Birmingham, AL, USA.
⁴ Nutrition Obesity Research Center, University of Alabama at Birmingham, Birmingham, AL, USA.
⁵ Division of Gerontology, Geriatrics, and Palliative Care, University of Alabama at Birmingham, Birmingham, AL, USA.

Abstract

Background: 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. Secondly, the study explored genetic influences on lycopene metabolism and bioavailability.

Methods: A 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.

Results: Serum 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).

Conclusions: Watermelon 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.

Keywords: antioxidant capacity; carotenoids; cholesterol; lycopene; nutrigenomics; postmenopausal women; single nucleotide polymorphisms; watermelon.

Associated data

ClinicalTrials.gov/NCT03626168