title: Signs of impaired cognitive function in adolescents with marginal cobalamin status.
abstract: BACKGROUND
  Lack of cobalamin may lead to neurologic disorders, which have been reported in strict vegetarians.
  
  
  OBJECTIVE
  The objective of this study was to investigate whether cognitive functioning is affected in adolescents (aged 10-16 y) with marginal cobalamin status as a result of being fed a macrobiotic diet up to an average age of 6 y.
  
  
  METHODS
  Data on dietary intake, psychological test performance, and biochemical variables of cobalamin status were collected from 48 adolescents who consumed macrobiotic (vegan type) diets up to the age of 6 y, subsequently followed by lactovegetarian or omnivorous diets, and from 24 subjects (aged 10-18 y) who were fed omnivorous diets from birth onward. Thirty-one subjects from the previously macrobiotic group were cobalamin deficient according to their plasma methylmalonic acid concentrations. Seventeen previously macrobiotic subjects and all control subjects had normal cobalamin status.
  
  
  RESULTS
  The control subjects performed better on most psychological tests than did macrobiotic subjects with low or normal cobalamin status. A significant relation between test score and cobalamin deficiency (P: = 0.01) was observed for a test measuring fluid intelligence (correlation coefficient: -0.28; 95% CI: -0.48, -0.08). This effect became more pronounced (P: = 0.003) within the subgroup of macrobiotic subjects (correlation coefficient: -0.38; 95% CI: -0.62, - 0.14).
  
  
  CONCLUSIONS
  Our data suggest that cobalamin deficiency, in the absence of hematologic signs, may lead to impaired cognitive performance in adolescents.
authors.affiliation: Division of Human Nutrition and Epidemiology, Wageningen Agricultural University, Netherlands.
authors.forename: M W
authors.initials: MW
authors.lastname: Louwman
authors.forename: M
authors.initials: M
authors.lastname: van Dusseldorp
authors.forename: F J
authors.initials: FJ
authors.lastname: van de Vijver
authors.forename: C M
authors.initials: CM
authors.lastname: Thomas
authors.forename: J
authors.initials: J
authors.lastname: Schneede
authors.forename: P M
authors.initials: PM
authors.lastname: Ueland
authors.forename: H
authors.initials: H
authors.lastname: Refsum
authors.forename: W A
authors.initials: WA
authors.lastname: van Staveren
mesh_terms: D000293:Adolescent; D002648:Child; D003071:Cognition; D003072:Cognition Disorders / Q000209:etiology; D015331:Cohort Studies; D015623:Diet, Macrobiotic; D005260:Female; D006801:Humans; D007360:Intelligence; D008297:Male; D011581:Psychological Tests; D011597:Psychomotor Performance; D012016:Reference Values; D014805:Vitamin B 12 / Q000097:blood*; D014806:Vitamin B 12 Deficiency / Q000150:complications / Q000523:psychology
chemical_list: D014805:Vitamin B 12