title: Associations of serum β-carotene and retinol concentrations with insulin resistance: the Toon Health Study.
abstract: OBJECTIVE
  Although green and yellow vegetables have beneficial effects against type 2 diabetes, the relationship of their nutritive content with insulin resistance is poorly understood. The aim of this study was to examine the associations of serum β-carotene and retinol concentrations with glucose and insulin concentrations.
  
  
  METHODS
  We recruited 951 Japanese men and women ages 30 to 79 y who were not undergoing treatment for diabetes and measured their serum β-carotene and retinol concentrations. A 75-g oral glucose tolerance test was performed and the homeostasis model assessment for insulin resistance (HOMA-IR) and the Matsuda Index were calculated as measures of insulin resistance. Several confounding factors were adjusted for with multivariable logistic models.
  
  
  RESULTS
  Multivariable-adjusted odds ratios of the highest quartile of serum β-carotene compared with the lowest quartile for HOMA-IR >1.6 and Matsuda Index <4.9 were 0.56 (95% confidence interval, 0.34-0.94) and 0.62 (0.37-1.02), respectively. When stratified by sex and overweight status, these associations were observed for women and non-overweight individuals. Serum retinol concentration was not associated with either index. Furthermore, according to the nutritional survey, serum β-carotene concentration was associated with green and yellow vegetable intake (P = 0.01).
  
  
  CONCLUSIONS
  Our findings suggest that higher serum β-carotene levels, associated with higher intake of green and yellow vegetables, confer beneficial effects against insulin resistance.
authors.affiliation: Department of Basic Nursing and Health Science, Ehime University Graduate School of Medicine, Toon, Japan; Department of Diabetes and Molecular Genetics, Ehime University Graduate School of Medicine, Toon, Japan.
authors.forename: Kana
authors.initials: K
authors.lastname: Higuchi
authors.affiliation: Department of Basic Nursing and Health Science, Ehime University Graduate School of Medicine, Toon, Japan. Electronic address: saitoi@m.ehime-u.ac.jp.
authors.forename: Isao
authors.initials: I
authors.lastname: Saito
authors.affiliation: Department of Basic Medical Research and Education, Ehime University Graduate School of Medicine, Toon, Japan.
authors.forename: Koutatsu
authors.initials: K
authors.lastname: Maruyama
authors.affiliation: Department of Public Health, Ehime University Graduate School of Medicine, Toon, Japan; Department of Public Health, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan.
authors.forename: Eri
authors.initials: E
authors.lastname: Eguchi
authors.affiliation: Department of Public Health, Ehime University Graduate School of Medicine, Toon, Japan.
authors.forename: Hiromi
authors.initials: H
authors.lastname: Mori
authors.affiliation: Center for Sleep Medicine, Ehime University Hospital, Toon, Japan.
authors.forename: Sakurako
authors.initials: S
authors.lastname: Tanno
authors.affiliation: Department of Clinical Laboratory Science, Faculty of Health Care, Tenri Health Care University, Tenri, Japan.
authors.forename: Susumu
authors.initials: S
authors.lastname: Sakurai
authors.affiliation: Faculty of Agriculture, Ehime University, Matsuyama, Japan.
authors.forename: Taro
authors.initials: T
authors.lastname: Kishida
authors.affiliation: Department of Diabetes and Molecular Genetics, Ehime University Graduate School of Medicine, Toon, Japan; Nishida Wataru Diabetes Clinic, Matsuyama, Japan.
authors.forename: Wataru
authors.initials: W
authors.lastname: Nishida
authors.affiliation: Department of Diabetes and Molecular Genetics, Ehime University Graduate School of Medicine, Toon, Japan.
authors.forename: Haruhiko
authors.initials: H
authors.lastname: Osawa
authors.affiliation: Department of Public Health, Juntendo University Graduate School of Medicine, Bunkyo, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Tanigawa
mesh_terms: D000328:Adult; D000368:Aged; D001786:Blood Glucose / Q000032:analysis; D005260:Female; D006706:Homeostasis / Q000502:physiology*; D006801:Humans; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D012307:Risk Factors; D014675:Vegetables / Q000737:chemistry*; D014801:Vitamin A / Q000097:blood*; D019207:beta Carotene / Q000097:blood*
chemical_list: D001786:Blood Glucose; D007328:Insulin; D019207:beta Carotene; D014801:Vitamin A
keywords: Insulin resistance; Serum retinol; Serum β-carotene