Antioxidants in cardiovascular disease: randomized trials

Area of Science:

• Nutritional Science
• Cardiovascular Research
• Preventive Medicine

Background:

• Observational studies link high fruit and vegetable intake to lower cardiovascular disease (CVD) and cancer rates.
• Antioxidants in fruits and vegetables are hypothesized to explain these protective effects.
• Basic research suggests a plausible mechanism for antioxidants reducing atherosclerosis risk.

Purpose of the Study:

• To evaluate the role of antioxidant vitamins (C, E, beta-carotene) in the primary prevention of cardiovascular disease.
• To synthesize findings from observational studies and randomized controlled trials (RCTs) on antioxidant supplements and CVD risk.

Main Methods:

• Review of basic research, epidemiologic studies (descriptive, case-control, cohort), and large-scale randomized trials of antioxidant supplements.
• Analysis of data on the association between antioxidant vitamin consumption and CVD risk.

Main Results:

• Epidemiologic data suggest an association between antioxidant vitamin consumption and reduced CVD risk.
• Results from major RCTs on antioxidant supplements are inconsistent, neither proving nor disproving their benefit.
• Some RCTs suggest potential overestimation of benefits from observational studies and possible adverse effects.

Conclusions:

• Current RCT data are insufficient to definitively assess the risk-benefit ratio of antioxidant supplements for CVD prevention.
• Further research is required to clarify the role of antioxidants in preventing atherosclerotic disease and cancer.
• Antioxidant supplements' role in primary and secondary CVD prevention remains uncertain pending more robust data.