title: Trends in dietary intake of folate, vitamins B6, and B12 among Japanese adults in two rural communities from 1974 through 2001.
abstract: BACKGROUND
  The 5th edition of the Japanese food composition table enables us to evaluate intakes of folate and vitamins B6 and B12, which are associated with risk of chronic diseases.
  
  
  METHODS
  We investigated long-term trends in dietary intake of those nutrients in two rural communities; Ikawa from1974 through 2000, and Kyowa from 1982 through 2001. The 24-hour recall method was adopted. Intake of green tea interviewed from 1994 was used to examine food sources for these nutrients in the latest period, but not to evaluate long-term trends. Reduced intakes of nutrients due to cooking were not taken into account.
  
  
  RESULTS
  Age-adjusted mean folate intake increased by 30% in Ikawa between the 1970's and 1980's, and then leveled off to the latest survey, while that in Kyowa did not change throughout the survey periods. The increased folate intake was primarily due to green/yellow vegetables. Mean vitamin B6 intake did not change except that it increased for Ikawa women in the 1980's and decreased for Kyowa men in the latest period. No secular trend was found for mean vitamin B12 intake. The largest source for folate intake was total vegetables (38-58% of total intake) and the second largest source was alcohol/beverages including green tea (11-24%). Fish/shellfish was the largest source for vitamins B6 (16-23%) and B12 (77-84%).
  
  
  CONCLUSIONS
  Dietary intakes of folate, vitamins B6 and B12 showed no notable long-term trend, except for an increased folate intake between the 1970's and 1980's due to an increased intake of green/yellow vegetables.
authors.affiliation: Department of Public Health Medicine, Doctoral Program in Social and Environmental Medicine, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Ibaraki 305-8575, Japan.
authors.forename: Kaori
authors.initials: K
authors.lastname: Yoshino
authors.forename: Mieko
authors.initials: M
authors.lastname: Inagawa
authors.forename: Miyuki
authors.initials: M
authors.lastname: Oshima
authors.forename: Kimiko
authors.initials: K
authors.lastname: Yokota
authors.forename: Mitsumasa
authors.initials: M
authors.lastname: Umesawa
authors.forename: Ma
authors.initials: M
authors.lastname: Enbo
authors.forename: Kazumasa
authors.initials: K
authors.lastname: Yamagishi
authors.forename: Takeshi
authors.initials: T
authors.lastname: Tanigawa
authors.forename: Shinichi
authors.initials: S
authors.lastname: Sato
authors.forename: Takashi
authors.initials: T
authors.lastname: Shimamoto
authors.forename: Hiroyasu
authors.initials: H
authors.lastname: Iso
mesh_terms: D000328:Adult; D000368:Aged; D004032:Diet / Q000639:trends*; D015930:Diet Records; D005260:Female; D005492:Folic Acid / Q000008:administration & dosage*; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D012424:Rural Population; D014805:Vitamin B 12 / Q000008:administration & dosage*; D025101:Vitamin B 6 / Q000008:administration & dosage*
chemical_list: D025101:Vitamin B 6; D005492:Folic Acid; D014805:Vitamin B 12