title: Vitamin B-12 deficiency and malabsorption are highly prevalent in rural Mexican communities.
abstract: Vitamin B-12 status of rural Mexicans was evaluated in two studies, 6 y apart. In the first, a single blood sample was collected from children and adults, including pregnant and lactating women. Prevalence of deficient plasma vitamin B-12 values ranged from 19% to 41% among groups, but plasma folate status was normal in all individuals. Breast milk vitamin B-12 concentration was low in 62% of samples. The second study was conducted in 219 children aged 18-36 mo in five communities, whose prevalence of deficient and low plasma vitamin B-12 concentrations, respectively, was 8% and 33% on entry, 3% and 22% 6 mo later, and 7% and 29% 12 mo later. Prevalence of low holotranscobalamin II concentrations, indicating malabsorption of the vitamin, averaged 18-40% across the three same periods. Both vitamin B-12 status indicators differed significantly between communities. The widespread vitamin B-12 deficiency was probably caused by malabsorption, perhaps exacerbated by low dietary intake and, for young children, maternal depletion of the vitamin.
authors.affiliation: Department of Nutrition, University of California, Davis 95616-8669, USA.
authors.forename: L H
authors.initials: LH
authors.lastname: Allen
authors.forename: J L
authors.initials: JL
authors.lastname: Rosado
authors.forename: J E
authors.initials: JE
authors.lastname: Casterline
authors.forename: H
authors.initials: H
authors.lastname: Martinez
authors.forename: P
authors.initials: P
authors.lastname: Lopez
authors.forename: E
authors.initials: E
authors.lastname: Muñoz
authors.forename: A K
authors.initials: AK
authors.lastname: Black
mesh_terms: D000328:Adult; D002648:Child; D002675:Child, Preschool; D002149:Energy Intake; D005260:Female; D006801:Humans; D007223:Infant; D007958:Leukocyte Count; D008286:Malabsorption Syndromes / Q000097:blood / Q000453:epidemiology*; D008297:Male; D008800:Mexico / Q000453:epidemiology; D008895:Milk, Human / Q000737:chemistry; D011247:Pregnancy; D011248:Pregnancy Complications / Q000097:blood / Q000453:epidemiology; D015995:Prevalence; D012424:Rural Population; D014805:Vitamin B 12 / Q000032:analysis / Q000097:blood; D014806:Vitamin B 12 Deficiency / Q000097:blood / Q000453:epidemiology*
chemical_list: D014805:Vitamin B 12