Abstract
BACKGROUND: Obesity is associated with systemic inflammation, increasing chronic disease risk. Carotenoids possess anti-inflammatory properties, yet the short-term impact of carotenoid-rich juice intake on inflammation in individuals with obesity remains unclear. Therefore, the purpose of this paper was to examine: (1) participant adherence to a 3-week lycopene-rich juice intervention; (2) variance and effect sizes of responses to the dietary intervention; (3) changes in skin and plasma carotenoids, and inflammatory markers among adults with obesity. METHODS: Twenty-five participants with body mass index (BMI) > 30 kg/m(2) were recruited and completed the study. Participants drank 4 ounces (118.3 mL) of study-provided tomato juice, providing 8400 µg lycopene daily, for 3 weeks. Participants were asked to keep their diets isocaloric and to continue with the habitual diet. Skin and plasma carotenoids were measured at baseline and at 3-weeks, using reflection spectroscopy and high-performance liquid chromatography, respectively. Thirteen inflammatory markers and C-reactive protein were quantified, and 3-week changes were analyzed using Wilcoxon signed-rank tests. RESULTS: Mean age was 38.6 (10.7) years and mean BMI was 35.9 (4.1) kg/m(2). Ten participants drank 83–99% and 15 participants drank 100% of the juice assigned. Effect sizes for inflammatory markers ranged from Cohen’s d = 0.07 to d = 0.57. There was a significant 3-week increase in plasma lycopene concentrations (9.72 (-1.04, 14.1) µg/dL, p = 0.029), but not in concentrations of other plasma carotenoids (p > 0.273). There was no change in skin carotenoid scores (p = 0.592); however, there was a reduction in IL-1β, TNF-⍺, IL-6, IL-17 A, IL-12p70, IL-23, IL-33 out of 13 inflammatory markers tested (p < 0.037). CONCLUSIONS: A 3-week lycopene rich juice intervention was associated with an increase in plasma lycopene and a reduction in inflammatory markers. There was not an increase in skin carotenoid scores. More research is needed to further understand the mechanisms by which carotenoid intake can influence inflammation among adults with obesity. TRIAL REGISTRATION: This trial was retrospectively registered at ClinicalTrials.gov Identifier NCT07120035 on August 12, 2025. The trial protocol and statistical analysis plan can be accessed by contacting the corresponding author.