title: Antioxidant micronutrients and cardiovascular risk in patients with diabetes: a systematic review.
abstract: BACKGROUND
  Inverse associations between micronutrient intake and cardiovascular outcomes have been previously shown, but did not focus on diabetic patients.
  
  
  OBJECTIVE
  To systematically review the role of micronutrients in the development/presence of cardiovascular outcomes in patients with diabetes.
  
  
  METHODS
  We searched Medline, Embase, and Scopus (January/1949-March/2012) for observational studies that evaluated micronutrients and cardiovascular outcomes in patients with diabetes, and then selected and extracted the data (two independent reviewers).
  
  
  RESULTS
  From the 15 658 studies identified, five were included, comprising three case-control and two cohorts, with a follow-up of 7-15 years. A meta-analysis was not performed due to the different antioxidant micronutrients (types and measurement methods) and outcomes evaluated. The micronutrients assessed were vitamin C intake in diet and/or supplementation, chromium and selenium in toenail samples, and α-tocopherol and zinc in serum levels. Intake of >300 mg of vitamin C through supplementation was associated with increased risk of cardiovascular disease, coronary artery disease (CAD), and stroke (RR 1.69-2.37). High levels of α-tocopherol in serum were associated with 30% lower CAD risk in another study (HR 0.71; 95%CI 0.53-0.94). Among minerals (zinc, selenium, and chromium), an inverse association between zinc and CAD was observed; levels lower than 14.1 µmol/L were associated with an increased risk for CAD (RR 1.70; 95%CI 1.21-2.38).
  
  
  CONCLUSIONS
  The information available on this issue is scarce. Further prospective studies are needed to elucidate the role of these nutrients in the cardiovascular risk of patients with diabetes.
authors.forename: Roberta Aguiar
authors.initials: RA
authors.lastname: Sarmento
authors.forename: Flávia Moraes
authors.initials: FM
authors.lastname: Silva
authors.forename: Graciele
authors.initials: G
authors.lastname: Sbruzzi
authors.forename: Beatriz D'Agord
authors.initials: BD
authors.lastname: Schaan
authors.forename: Jussara Carnevale de
authors.initials: JC
authors.lastname: Almeida
mesh_terms: D000975:Antioxidants / Q000009:adverse effects / Q000378:metabolism*; D002318:Cardiovascular Diseases / Q000139:chemically induced*; D048909:Diabetes Complications / Q000378:metabolism*; D003927:Diet, Diabetic; D006801:Humans; D018977:Micronutrients / Q000009:adverse effects / Q000378:metabolism*; D012307:Risk Factors
chemical_list: D000975:Antioxidants; D018977:Micronutrients