title: trans Fatty acids in milk produced by women in the United States.
abstract: BACKGROUND
  trans Fatty acids (FAs) have been identified as negatively affecting human health. The trans FA composition of human milk fat must be examined to establish its influence on the nutritional quality of milk consumed by infants.
  
  
  OBJECTIVE
  We sought to ascertain the individual and total trans FA isomers (sum of FAs containing at least one trans double bond) in human milk and to identify relations between individual FAs and milk fat concentration (% by wt).
  
  
  METHODS
  The FA composition of milk samples (n = 81) from women living in the southwestern United States was ascertained. The individual 18:1t isomers were separated. Correlations between each FA, total trans FAs, groups of similar FAs, and milk fat concentrations were examined.
  
  
  RESULTS
  The mean total trans FA concentration was 7.0 +/- 2.3% (range: 2.5-13.8%). The concentration of total 18:1t was 5.1 +/- 2.0% (range: 1.5-11.6%), and Delta10t (range: Delta9-12t) was the most abundant isomer.
  
  
  CONCLUSIONS
  Milk fat from women living in the United States contains concentrations of trans FAs similar to those in milk from Canadian women but greater than those reported in milk from women in other countries. In decreasing order of concentration, the Delta10t, Delta11t, Delta9t, and Delta12t isomers represented 78.9% of the total 18:1t. These FAs generally originate from partially hydrogenated vegetable oils and ruminant fat in the diet. No relation was found between the concentration of total trans FAs and milk fat concentration.
authors.affiliation: Department of Animal and Veterinary Science, University of Idaho, Moscow, ID 83844-2330, USA.
authors.forename: Erin E
authors.initials: EE
authors.lastname: Mosley
authors.forename: Anne L
authors.initials: AL
authors.lastname: Wright
authors.forename: Michelle K
authors.initials: MK
authors.lastname: McGuire
authors.forename: Mark A
authors.initials: MA
authors.lastname: McGuire
mesh_terms: D000328:Adult; D004041:Dietary Fats / Q000378:metabolism; D005260:Female; D006801:Humans; D007227:Infant Nutritional Physiological Phenomena; D007231:Infant, Newborn; D007536:Isomerism; D007774:Lactation / Q000378:metabolism*; D008895:Milk, Human / Q000737:chemistry*; D010938:Plant Oils / Q000378:metabolism; D015206:Southwestern United States; D044242:Trans Fatty Acids / Q000032:analysis*
chemical_list: D004041:Dietary Fats; D010938:Plant Oils; D044242:Trans Fatty Acids