Omega-3 fatty acids and fish during pregnancy

When you are pregnant, you need more omega-3 fatty acids in your diet. Omega-3 fatty acids travel through your placenta to your baby, and support the growth of your baby's brain and tissues.

Fish is an important source of omega-3 fatty acids and other nutrients like vitamin D, zinc and iron. Studies suggest that regular consumption of fish helps the development of your growing baby's nervous system. All fish are also a significant source of nutrients like selenium, iodine, magnesium, iron and copper.

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Dietary sources of omega-3 fatty acids

There are three types of omega-3 fatty acids in food:

  • alpha-linolenic acid (ALA)
  • docosahexaenoic acid (DHA), and
  • eicosapentaenoic acid (EPA)

ALA is found in some vegetable oils (for example, canola oil, soybean oil, flax oil and walnut oil), walnuts and flax seeds.

The other omega-3 fatty acids, DHA and EPA, are only found naturally in fish and other seafood. The best source of EPA and DHA is fatty fish such assalmon, herring or trout.

Fish is unique because it is high in EPA and DHA omega-3 fatty acids. If you eat fish during your pregnancy, you give your growing infant important nutrients.

Health Canada recommends you eat at least 5 ounces (150 grams) of cooked fish every week. You can also get EPA and DHA omega-3 fatty acids from eggs, fish oil supplements and EPA and DHA-enriched foods. Following a healthy diet that contains omega-3 fatty acids derived from non-fish sources is also safe for pregnancy.

Do you eat less fish than Canada's Food Guide recommends because you are worried about mercury? If so, follow the advice from Health Canada about choosing safer fish options. This will help you select a variety of fish to eat, and limit exposure to toxins like mercury.

If you eat locally caught fish, speak to your health care provider about contamination risks. Check with your local, provincial or territorial government for any information about the safety of the fish in your area. There may already be existing fish consumption advisories.

Examples of fish with low levels of mercury:

  • salmon
  • trout
  • herring
  • pollock (Boston bluefish)
  • sole
  • flounder
  • anchovy
  • char
  • hake
  • mullet
  • smelt
  • Atlantic mackerel
  • lake white fish

See Health Canada's prenatal nutrition guidelines for a list of food sources of DHA and EPA.

How to include fish in your diet

When you eat fish during pregnancy, you can get a lot of omega-3 fats and other important nutrients like protein, vitamin D, zinc and iron.

If you do not really like fish, you can try adding different flavours to change the taste. For example, you can cook fish with lemon juice, herbs (such as dill) or spices (such as curry). You can also eat canned fish cold in a salad or sandwich because it has a mild flavour. The healthiest way to cook fish includes grilling, poaching, broiling or baking.

Make sure to cook fish and seafood completely, including refrigerated smoked products. If you eat raw or partially cooked fish and seafood, you risk getting a food-borne illness like listeriosis.

If you do not eat fish, there are other sources of omega-3 fatty acid. For example, chicken eggs enriched with EPA and DHA can be a source of some omega-3 fatty acid.

Using fish oil supplements

If you take fish oil supplements, make sure they have a Natural Product Number (NPN) on the package. These products are safe for pregnant women. Canada has specific standards for all natural health products, including fish oil supplements. A NPN number means the product was tested for heavy metals, pesticides and toxins.

Make sure your daily dose of fish oil supplement contains no more than three grams of EPA plus DHA. This amount has been studied and is safe for pregnant women.

Do not take cod liver oil along with a multivitamin supplement. There is a risk you could have unsafe levels of vitamin A. The daily maximum of vitamin A is 3,000 micrograms retinol activity equivalent (RAE) or 10,000 international units (IU).

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