Prenatal Nutrition Guidelines for Health Professionals – Fish and Omega-3 Fatty Acids by Health Canada

© Her Majesty the Queen in Right of Canada, represented by the Minister of Health Canada 2009


Recognizing the increasing scientific evidence for the health benefits of consuming fish containing omega-3 fatty acids during pregnancy , Health Canada has recently published Guidelines and Key messages on fish for women of childbearing age. The key points are:

  • Have at least 150 grams (5 ounces) of cooked fish weekly (two 75-gram servings/week) as a source of long-chain omega-3 fatty acids (incl. salmon, trout, herring, canned light tuna, sole, others). Since many pregnancies are unplanned, the advice presented in this document also applies to all women of childbearing age, including breastfeeding women.
  • Vary the types of fish you eat and follow advice from Health Canada

Experts around the world agree with Health Canada’s recommendation (WHO/FAO, 2003; US 2005 Dietary Advisory Committee, 2005; UK Scientific Advisory Committee on Nutrition, 2005; European Food Safety Authority, 2005). It is noted however some types of fish contain environmental contaminants like methyl mercury, as such health professionals need to inform women about the types of fish to choose most often to limit exposure to environmental contaminants.

Key considerations from the document:

Fish contributes to a healthy pregnancy

Experts agree that fish can contribute to a healthy diet during pregnancy (UK Scientific Advisory Committee on Nutrition, 2005; European Food Safety Authority, 2005; IOM, 2007; Kris-Etherton et al, 2007). The benefits of eating fish are greater than not eating fish (IOM, 2007).

Pregnant women who eat fish give their growing fetus important nutrients. Fish is generally lower in saturated fats and higher in the long chain polyunsaturated omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Fish also contains high quality protein and other essential nutrients: vitamins (such as vitamin D and choline) and minerals (such as selenium, iodine, iron, zinc and copper).

Omega-3 fatty acids in pregnancy

The document states that women need more omega-3 fatty acids in pregnancy (IOM, 2002). Omega-3 fatty acids are transferred across the placenta and play an important role in the growth and development of the infant.

According to the document, there are different types of omega-3 fatty acids in the diet. The omega-3 fat, alphalinolenic acid (ALA) is found in some vegetable oils, nuts and seeds. These include canola oil, flax oil, walnut oil, walnuts and flax seeds. Our bodies can convert ALA into other omega-3 fats including docosahexaenoic acid (DHA). DHA and another omega-3 fatty acid, eicosapentaonoic acid (EPA) are found only in animal tissue lipids. DHA is an important omega-3 fatty acid in the brain. During pregnancy, DHA is transferred from the mother across the placenta and accumulates in the growing fetal brain and other tissues. After birth, DHA is transferred through breast milk. Dietary DHA contributes to the mother’s DHA status, and pregnant and breastfeeding women with higher intakes of DHA transfer more DHA to their fetus, and supply more DHA in their breast milk (IOM, 2007).