Dietary intake and blood concentrations of antioxidants and the risk of cardiovascular disease, total cancer, and all-cause mortality: a systematic review and dose-response meta-analysis of prospective studies

• Published in: The American journal of clinical nutrition Vol. 108; no. 5; pp. 1069 - 1091
• Main Authors: Aune, Dagfinn, Keum, NaNa, Giovannucci, Edward, Fadnes, Lars T, Boffetta, Paolo, Greenwood, Darren C, Tonstad, Serena, Vatten, Lars J, Riboli, Elio, Norat, Teresa
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01-11-2018; Oxford University Press; American Society for Clinical Nutrition, Inc
• Subjects: alpha-Tocopherol - administration & dosage; alpha-Tocopherol - blood; Antioxidants; Antioxidants - administration & dosage; Antioxidants - metabolism; Ascorbic acid; Ascorbic Acid - administration & dosage; beta-carotene; Biomarkers; Blood; Cancer; Cardiovascular disease; Cardiovascular diseases; Cardiovascular Diseases - blood; Cardiovascular Diseases - etiology; Cardiovascular Diseases - mortality; Cardiovascular Diseases - prevention & control; Carotene; Carotenoids; Carotenoids - administration & dosage; Carotenoids - blood; Cause of Death; Coronary artery disease; coronary heart disease; Diet; Dietary intake; Dietary supplements; Feeding Behavior; Fruits; Health risks; Heart diseases; Humans; Lycopene; Meta-analysis; Mortality; Neoplasms - blood; Neoplasms - etiology; Neoplasms - mortality; Neoplasms - prevention & control; Nutritional Status; Original Research Communications; Risk factors; Risk management; stroke; Systematic review; Tocopherol; Vegetables; Vitamin C; Vitamin E; Vitamin E - administration & dosage; Vitamin E - blood; β-Carotene; cardiovascular disease; carotenoids; vitamin C; beta-carotene; vitamin E; mortality; meta-analysis; coronary heart disease; cancer; stroke
• ISSN: 0002-9165; 1938-3207; 1938-3207
• DOI: 10.1093/ajcn/nqy097

High dietary intake or blood concentrations (as biomarkers of dietary intake) of vitamin C, carotenoids, and vitamin E have been associated with reduced risk of cardiovascular disease, cancer, and mortality, but these associations have not been systematically assessed.
We conducted a systematic review and meta-analysis of prospective studies of dietary intake and blood concentrations of vitamin C, carotenoids, and vitamin E in relation to these outcomes.
We searched PubMed and Embase up to 14 February 2018. Summary RRs and 95% CIs were calculated with the use of random-effects models.
Sixty-nine prospective studies (99 publications) were included. The summary RR per 100-mg/d increment of dietary vitamin C intake was 0.88 (95% CI: 0.79, 0.98, I2= 65%, n = 11) for coronary heart disease, 0.92 (95% CI: 0.87, 0.98, I2= 68%, n = 12) for stroke, 0.89 (95% CI: 0.85, 0.94, I2= 27%, n = 10) for cardiovascular disease, 0.93 (95% CI: 0.87, 0.99, I2= 46%, n = 8) for total cancer, and 0.89 (95% CI: 0.85, 0.94, I2= 80%, n = 14) for all-cause mortality. Corresponding RRs per 50-μmol/L increase in blood concentrations of vitamin C were 0.74 (95% CI: 0.65, 0.83, I2= 0%, n = 4), 0.70 (95% CI: 0.61, 0.81, I2= 0%, n = 4), 0.76 (95% CI: 0.65, 0.87, I2= 56%, n = 6), 0.74 (95% CI: 0.66, 0.82, I2= 0%, n = 5), and 0.72 (95% CI: 0.66, 0.79, I2= 0%, n = 8). Dietary intake and/or blood concentrations of carotenoids (total, β-carotene, α-carotene, β-cryptoxanthin, lycopene) and α-tocopherol, but not dietary vitamin E, were similarly inversely associated with coronary heart disease, stroke, cardiovascular disease, cancer, and/or all-cause mortality.
Higher dietary intake and/or blood concentrations of vitamin C, carotenoids, and α-tocopherol (as markers of fruit and vegetable intake) were associated with reduced risk of cardiovascular disease, total cancer, and all-cause mortality. These results support recommendations to increase fruit and vegetable intake, but not antioxidant supplement use, for chronic disease prevention.