title: Contents of conjugated linoleic acid isomers in ruminant-derived foods and estimation of their contribution to daily intake in Portugal.
abstract: The present study provides a detailed overview of the contents of conjugated linoleic acid (CLA) isomers in the most consumed Portuguese CLA-rich foods (milk, butter, yoghurt, cheese, beef and lamb meat), by using silver ion-HPLC. In addition, the contribution of these ruminant-derived foods to the daily intake of CLA isomers was estimated based on Portuguese consumption habits. The total CLA concentration in milk and dairy products ranged from 4.00 mg/g fat in yoghurt to 7.22 mg/g fat in butter, and, regarding meats, from 4.45 mg/g fat in intensively produced beef to 11.29 mg/g fat in lamb meat. The predominant CLA isomers identified in these products were cis-9, trans-11 (59.89-79.21 %) and trans-7, cis-9 (8.04-20.20 %). The average estimated total CLA intake for the Portuguese population was 73.70 mg/d. Milk and cheese are probably the two products with the highest contribution to the final CLA intake, as a result of their high fat content and consumption values. The results also suggested that cis-9, trans-11 and trans-7, cis-9 are the isomers most represented, with, respectively, 76.10 and 12.56 % of the total CLA intake. Being the first detailed report on the contents of total and individual CLA isomers in Portuguese commercial ruminant-derived foods, we further discuss the implication of the results for diet characteristics and human health.
authors.affiliation: Faculdade de Medicina Veterinária - CIISA, Av. da Universidade Técnica, Pólo Universitário do Alto da Ajuda, 1300-477 Lisbon, Portugal. smartins@fmv.utl.pt
authors.forename: Susana V
authors.initials: SV
authors.lastname: Martins
authors.forename: Paula A
authors.initials: PA
authors.lastname: Lopes
authors.forename: Cristina M
authors.initials: CM
authors.lastname: Alfaia
authors.forename: Verónica S
authors.initials: VS
authors.lastname: Ribeiro
authors.forename: Teresa V
authors.initials: TV
authors.lastname: Guerreiro
authors.forename: Carlos M G A
authors.initials: CM
authors.lastname: Fontes
authors.forename: Matilde F
authors.initials: MF
authors.lastname: Castro
authors.forename: Graça
authors.initials: G
authors.lastname: Soveral
authors.forename: José A M
authors.initials: JA
authors.lastname: Prates
mesh_terms: D000818:Animals; D002079:Butter / Q000032:analysis; D002611:Cheese / Q000032:analysis; D003611:Dairy Products / Q000032:analysis*; D004032:Diet; D005504:Food Analysis; D006801:Humans; D007536:Isomerism; D044243:Linoleic Acids, Conjugated / Q000032:analysis*; D008460:Meat / Q000032:analysis*; D008892:Milk / Q000737:chemistry; D011174:Portugal; D012418:Ruminants; D015014:Yogurt / Q000032:analysis
chemical_list: D044243:Linoleic Acids, Conjugated; C046938:9,11-linoleic acid; D002079:Butter