Influence of organic diet on the amount of conjugated linoleic acids in breast milk of lactating women in the Netherlands

Lukas Rista1 , André Muellera2, Christiane Barthela2, Bianca Snijdersa3, Margje Jansena4, A. Paula Simões-Wüsta1, Machteld Hubera5, Ischa Kummelinga3, Ursula von Mandacha6, Hans Steinharta2 and Carel Thijsa3

a1 Research Department, Paracelsus Hospital Richterswil, Bergstrasse 16, CH-8805 Richterswil, Switzerland

a2 Institute of Biochemistry and Food Chemistry, Department of Food Chemistry, University of Hamburg, Grindelallee 117, D-20146 Hamburg, Germany

a3 Department of Epidemiology, Nutrition and Toxicology Research Institute Maastricht (Nutrim) and Care and Public Health Research Institute (Caphri), Maastricht University, P.O. Box 616, NL-6200 MD Maastricht, The Netherlands

a4 TNO Nutrition and Food Research, P.O. Box 360, NL-3700 AJ Zeist, The Netherlands

a5 Louis Bolk Institute, Hoofdstraat 24, NL-3972 LA Driebergen, The Netherlands

a6 Department of Obstetrics, Zurich University Hospital, Frauenklinikstrasse 10, CH-8091 Zurich, Switzerland


The aim of the present study was to find out whether the incorporation of organic dairy and meat products in the maternal diet affects the contents of the conjugated linoleic acid isomers (CLA) and trans-vaccenic acid (TVA) in human breast milk. To this purpose, milk samples from 312 breastfeeding mothers participating in the KOALA Birth Cohort Study have been analysed. The participants had documented varying lifestyles in relation to the use of conventional or organic products. Breast milk samples were collected 1 month postpartum and analysed for fatty acid composition. The content of rumenic acid (the main CLA) increased in a statistically significant way while going from a conventional diet (no organic dairy/meat products, 0·25 weight % (wt%), n 186) to a moderately organic diet (50–90 % organic dairy/meat, 0·29 wt%, n 33, P = 0·02) and to a strict organic diet (>90 % organic dairy/meat, 0·34 wt%, n 37, P ≤ 0·001). The levels of TVA were augmented among the participants with a moderately organic diet (0·54 wt%) and those with a strict organic diet (0·59 wt%, P ≤ 0·001), in comparison with the conventional group (0·48 wt%). After adjusting for covariables (recruitment group, maternal age, maternal education, use of supplements and season), statistical significance was retained in the group of the strict organic dairy users (P < 0·001 for rumenic acid). Hence, the levels of CLA and TVA in human milk can be modulated if breastfeeding mothers replace conventional dairy and/or meat products by organic ones. A potential contribution of CLA and TVA to health improvement is briefly discussed.

(Received June 29 2006)

(Revised October 30 2006)

(Accepted November 06 2006)

Key Words:

  • Conjugated linoleic acid;
  • trans-Vaccenic acid;
  • Human milk;
  • Organic nutrition


c1 Corresponding author: Dr Lukas Rist, fax +41 (0)44 787 29 40, email


  Abbreviations: CLA, conjugated linoleic acid; FID, free induction decay; TVA, trans-vaccenic acid; wt%, weight percentage