Prospective Associations of Dietary Antioxidant Vitamin Intake and 8-Year Risk of Elevated Serum C-Reactive Protein Levels

TL;DR

This study found that higher vitamin C intake is linked to lower risk of elevated inflammation markers over 8 years, while excessive vitamin E may increase this risk.

Contribution

The study provides new prospective evidence on how antioxidant vitamin intake affects long-term inflammation risk.

Findings

Higher vitamin C intake was associated with reduced risk of elevated hsCRP levels.

Excessive vitamin E intake increased the risk of elevated hsCRP levels.

β-carotene showed a U-shaped association with hsCRP risk, with moderate intake being beneficial.

Abstract

Background/Objectives: Circulating high-sensitivity C-reactive protein (hsCRP) is a well-established biomarker of low-grade systemic inflammation; levels above 3 mg/L indicate high cardiovascular risk. Although cross-sectional studies have shown associations between antioxidant vitamin intake and hsCRP levels, prospective data remain limited. This study aims to investigate the associations of dietary intake of vitamins A, C, and E with the 8-year risk of elevated serum hsCRP levels (>3 mg/L). Participants/Methods: This prospective study included 7695 adults from population-based cohorts. Serum hsCRP was assayed at the 4- and 8-year follow-ups; levels above 3 mg/L were considered elevated. Dietary intake of vitamin A, retinol, β-carotene, and vitamins C and E was assessed at baseline and at the 4-year follow-up using a food frequency questionnaire. A multivariable Cox proportional hazards regression was conducted with adjustments for potential confounders. Results: When vitamin intake was categorized into quintiles, vitamin C intake demonstrated an inverse association, whereas β-carotene intake exhibited a U-shaped association with the risk of elevated serum hsCRP concentrations. Hazard ratios (HRs) [95% confidence intervals (CIs)] for the third and fourth quintiles of vitamin C intake were 0.72 [0.53, 0.98] and 0.70 [0.49, 0.98], respectively, compared with the first quintile. The HR [95% CI] for the third quintile of β-carotene intake was 0.69 [0.50, 0.95] compared with the first quintile. However, excessive consumption of vitamin E increased the risk of elevated hsCRP levels; HR (95% CI) was 1.62 [1.19, 2.21] for participants consuming >120% of adequate intake (AI) relative to those with 80–119% of AI. In stepwise analysis to identify a best-fit model, significant variables included the presence of diabetes or hypertension, calorie intake, age, body mass index, sex, educational level, moderate or vigorous physical activity, and vitamin C intake. Conclusion: These findings suggest that dietary intake of vitamins A and C may help prevent elevated hsCRP levels in the general adult population. Further epidemiological studies are warranted to confirm these potential causal associations.

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