Winter 98 Newsletter INFACT Canada

Optimizing beneficial fats in breastmilk

A supportive gestureThe types of fat consumed by pregnant and lactating women can have an impact on the quality and availability of important omega three fatty acids for the growing infant.

Much of the fat present in our food system has been hydrogenated, i.e., the carbon bonds are saturated with hydrogen molecules. During the hydrogenation process the configuration of the fat molecules are changed to “trans” fatty acids. This gives the food manufacturer an advantage as products containing the altered fats have a much longer shelf life and are less likely to become rancid. Consumption of trans fatty acids has steadily increased in industrialized countries. In the US and Great Britain the consumption of total fats as trans has risen to over 6 per cent of total dietary fats. Until recently it was assumed that trans fatty acids did not cross the human placenta; however, this assumption has been proven wrong and trans fatty acids levels are found to be similar in cord and maternal plasma lipids.(1) Trans fatty acids also cross over into breastmilk.(2)

What are the potential side effects of trans fatty acids to the growing infant pre- and postnatally?

  • Impair and limit the production of essential fatty acids, DHA and arachidonic.
  • In newborn mice and rats fed hydrogenated oils, postnatal weight gain was impaired.
  • Lower birth weights in piglets when the sow was fed partially hydrogenated oils.
  • In premature infants total trans fatty acids were inversely correlated to the levels of long chain essential fatty acids and inversely correlated to birth weight.

What are the effects of reduced essential fatty acids?

  • During the last trimester of pregnancy there is a large accumulation of long chain polyunsaturated fatty acids (DHA, AA) corresponding with the rapid growth of neural, brain and retinol tissue. Reduced levels of the essential fatty acids may compromise the full development of the affected infants.
  • Failure to thrive is another potential impact of inadequate amounts of essential fatty acids.
  • Low reserves of essential fatty acids at birth will be further compromised if the infant is artificially fed (baby milks sold in Canada have no DHA and AA).

These problems can be easily solved. Pregnant and lactating women can clear their systems of trans fatty acids in about two weeks time if they:

  • Consume natural fats such as butter and vegetable oils (non-hydrogenated) as spread, and in cooking and baking. Avoid margarines.(3)
  • Avoid consumption of deep fried foods in fast food restaurants such as french fries and doughnuts.
  • Read labels of commercially prepared foods and avoid foods containing hydrogenated fats. Commercially baked goods, frozen french fries, snack foods can be very high in trans fatty acids.(4)
  • Consume foods containing essential fatty acids more frequently–eggs, fish, liver. Expensive supplements are not necessary.

What can be done to reduce the “dumbing down” of food products?

  • Informative labelling of the percentage of total fats present as trans fatty acids should be compulsory so that pregnant and breastfeeding women can make healthy food choices.
  • Better yet, in addition to full disclosure labelling, mandatory maximum permissible levels in commercially prepared food products should be set to bring down the extremely high levels that are currently present.
  • Write to the minister responsible for Health Canada:
    The Honourable Allan Rock
    House of Commons
    Ottawa, ON K1A 0A6
  • Tell him you want a safe food system that does not put the growth and full developmental potential of infants at risk.


1. Koletzko, B. Trans fatty acids may impair biosynthesis of long-chain polyunsaturateds and growth in man. Acta Pediatr 81: 302-306, 1992 BACK

2. Chen, Z.Y. et al. Trans Fatty Acid Isomers in Canadian Human Milk. Lipids 30:15-21, 1995 BACK

3. Ratnayake, W.M.N. et al. Fatty Acids in Canadian margarines. Can Inst Sci Technol J. 24:81-86, 1991 BACK

4. Ratnayake, W.M.N. et al. Fatty Acids in Some Common Food Items in Canada. J Am Coll Nutr. 12:651-660, 1993 BACK

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