Dietary carotenoids and breast cancer risk: evidence from a large population-based incident case-control study

BACKGROUND: Although mechanistic studies suggest protective roles for carotenoids against breast cancer (BC), human studies yield inconsistent findings. Few have comprehensively evaluated dietary intake of individual and grouped carotenoids in relation to BC risk.

METHODS: This population-based case-control study recruited 600 patients with newly diagnosed BC and 600 healthy controls. Dietary carotenoid intake was assessed using a validated 168-item food frequency questionnaire. The intake levels of α-carotene, β-carotene, β-cryptoxanthin, lutein/zeaxanthin, lycopene, astaxanthin, phytoene, phytofluene, neoxanthin, violaxanthin, and total carotenoids were categorized into quartiles. Logistic regression models were employed to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for BC risk, controlling for potential confounders.

RESULTS: Higher intake of lycopene, phytoene, phytofluene, total non-provitamin A and provitamin A, β-carotene, lutein/zeaxanthin, as well as total carotenoids was significantly associated with reduced BC risk Lycopene showed the strongest inverse association (Q4 vs. Q1: OR = 0.23; 95% CI: 0.14-0.37). Total provitamin A (Q4 OR = 0.46; 95% CI: 0.29-0.75) and total non-provitamin A carotenoids (Q4 OR = 0.25; 95% CI: 0.15-0.41) also showed strong protective associations. Total carotenoid (Q4 OR = 0.34, 95% CI: 0.20-0.56, p < 0.001) intake also showed inverse associations across all quartiles. Conversely, α-carotene, β-cryptoxanthin, astaxanthin, neoxanthin, and violaxanthin displayed weaker or inconsistent associations.

CONCLUSION: These findings support an inverse association between dietary intake of specific carotenoids, particularly lycopene, lutein/zeaxanthin, and colorless carotenoids (phytoene and phytofluene) and BC risk. Promoting a carotenoid-rich diet may represent a feasible strategy for BC prevention.