title: Isoflavone intake in persons at high risk of cardiovascular events: implications for vascular endothelial function and the carotid atherosclerotic burden.
abstract: BACKGROUND
  Epidemiologic studies have suggested that a high phytoestrogen intake is inversely associated with cardiovascular disease risk factors and the incidence of cardiovascular events. However, the relation between the intake of isoflavone, a major component of phytoestrogen, and vascular endothelial function and the atherosclerotic burden remains unclear.
  
  
  OBJECTIVE
  We aimed to investigate the effects of various dietary soy isoflavone intakes on brachial artery flow-mediated dilation and mean maximum carotid intima-media thickness.
  
  
  METHODS
  We studied 126 consecutive patients (x +/- SD age: 66.5 +/- 11.1 y; 69% male) at high risk of cardiovascular events (94% had documented coronary artery disease or stroke; 44% had diabetes). A validated food-frequency questionnaire was used to estimate their dietary intake after they achieved stable dietary patterns for 3 mo.
  
  
  RESULTS
  The median intakes of isoflavone and soy protein were 5.5 (range: 2.2-13.3) mg/d and 1.2 (range: 0.4-2.8) g/d, respectively. Persons in the 4th quartile of daily isoflavone intake had significantly (P < 0.05) greater flow-mediated dilation-but not mean maximum carotid intima-media thickness-than did those in the lower quartiles. After adjustment for potential confounders, a higher isoflavone intake in the 4th than in the 1st quartile (>13.3 mg/d), but not a higher intake of soy protein, predicted an absolute 2.71% increase in flow-mediated dilation (relative increase: 103%; P = 0.02) and a 0.17-mm decrease in mean maximum carotid intima-media thickness (relative decrease: 14.5%; P = 0.04).
  
  
  CONCLUSIONS
  In persons at high risk of cardiovascular events, a greater isoflavone intake is associated with better vascular endothelial function and lower carotid atherosclerotic burden.
authors.affiliation: Cardiology Division, Department of Medicine, The University of Hong Kong, Queen Mary Hospital, Hong Kong, China.
authors.forename: Yap-Hang
authors.initials: YH
authors.lastname: Chan
authors.forename: Kui-Kai
authors.initials: KK
authors.lastname: Lau
authors.forename: Kai-Hang
authors.initials: KH
authors.lastname: Yiu
authors.forename: Sheung-Wai
authors.initials: SW
authors.lastname: Li
authors.forename: Hiu-Ting
authors.initials: HT
authors.lastname: Chan
authors.forename: Sidney
authors.initials: S
authors.lastname: Tam
authors.forename: Xiao-Ou
authors.initials: XO
authors.lastname: Shu
authors.forename: Chu-Pak
authors.initials: CP
authors.lastname: Lau
authors.forename: Hung-Fat
authors.initials: HF
authors.lastname: Tse
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D001783:Blood Flow Velocity; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D002318:Cardiovascular Diseases / Q000453:epidemiology* / Q000378:metabolism; D002339:Carotid Arteries / Q000000981:diagnostic imaging / Q000473:pathology*; D004034:Diet Surveys; D004730:Endothelium, Vascular / Q000187:drug effects / Q000502:physiology*; D005260:Female; D006801:Humans; D015994:Incidence; D007529:Isoflavones / Q000008:administration & dosage*; D050356:Lipid Metabolism / Q000187:drug effects / Q000502:physiology; D008297:Male; D012307:Risk Factors; D030262:Soybean Proteins / Q000008:administration & dosage*; D013025:Glycine max / Q000737:chemistry; D011795:Surveys and Questionnaires; D017539:Tunica Intima / Q000000981:diagnostic imaging / Q000473:pathology; D017540:Tunica Media / Q000000981:diagnostic imaging / Q000473:pathology; D014463:Ultrasonography
chemical_list: D007529:Isoflavones; D030262:Soybean Proteins