Fish Oils in Pregnancy

Introduction
Omega 3 fatty acids are extremely important for having a healthy pregnancy. Omega 3s are a type of polyunsaturated fatty acid that are considered essential, and are often referred to as “essential fatty acids” or EFAs.

Types of Omega 3s
There are three main types of Omega 3 fatty acids. Your body can use all three of these Omega 3s to help perform different functions.
• Eicosapentaenoic acid (EPA): EPA is found primarily in fish and fish oil.
• Docosahexanoic Acid (DHA): DHA is especially important to your body, and is also found primarily in fish.
• Alpha-Linolenic Acid (ALA): ALA is found mostly in seeds, vegetable oils, and leafy green vegetables. It is converted into EPA and then into DHA in your body.

Benefits of Omega 3s During Pregnancy
Omega-3s are critical for your baby’s growth and development, playing a crucial role in brain and eye development, since 70% of brain cell development takes place during gestation and is passed from mother to fetus via the placenta. DHA is especially important during pregnancy and lactation because it is the major omega 3 in the central nervous system and retina (O’Brien 1964, Anderson 1975). Supplementation with fish oil during pregnancy results in improved DHA status in infants at birth, thus, your DHA status plays a role in your baby’s DHA status. Birth outcomes seem to be improved in mothers with higher DHA status, with longer gestation and reduced risk of preterm birth (Jacobson 2008, Olsen 2000), improved birth weight (Olsen 1990), and the prevention of neonatal brain injury (Suganuma 2010)

A number of studies link higher maternal DHA status or intake to more mature or favorable behaviors in infants and children, such as:
➢ Accelerated attentional functions (Colombo 1991, Colombo 2004, Willatts 2003)
➢ More mature sleep behavior in newborns (Cheruku 2002)
➢ Higher problem solving (Judge 2007a, 2007b)
➢ Higher visual acuity (Jacobson 2008, Innis 2001, Judge 2007a, Judge 2007b, Williams 2001)
➢ Better discrimination of native from foreign sounds (Innis 2001)
➢ Improved immune system (Prescott 2007, Denburg 2005)
➢ Improved cognitive function in childhood (Oken 2008, Hibbeln 2007)
➢ Better hand-eye coordination at 1 year of age (Dunstan 2008)
➢ Lower blood pressure at 6 years of age (Forsyth 2003)
➢ Improved motor function at 7 years of age (Bakker 2009)

Omega 3s are also necessary for your own health and wellbeing during pregnancy. Women with higher levels of DHA have been shown to be less likely to develop postpartum depression (Hibbeln 2002, Sontrop 2006, Freeman 2006).

Recommended Dosage of Omega 3s
The position of the American Dietetic Association and Dietitians of Canada is that adults should consume a combined intake of 500 mg per day of DHA and EPA, based on an intake of 2000 kcal per day (Kris-Etherton 2007). Specific recommendations for DHA intakes during pregnancy for North Americans are limited to those made by the International Society for the Study of Fatty Acids and Lipids working group, which recommend a minimum of 300 mg per day (Simopoulos 1999) and the Institute of Medicine, which recommends 200-300 mg per day (Nesheim 2007).

Current Consumption of Omega 3s
Pregnant women are reducing their intake of DHA in North America, largely due to the concern expressed regarding the heavy metal toxicity of fish. This is reflected in lower breast-milk DHA concentrations. For example, in US women, milk DHA concentration is 0.2% of total fatty acids, whereas in some Chinese women it is 2.8% of fatty acids (Carlson 2009). In fact, the mean DHA intake in Canadian women is 82 mg per day with 90% of women consuming less than the recommended 300 mg per day during pregnancy (Denomme 2005).

Maternal DHA Status Declines Throughout Pregnancy
Overall maternal essential fatty acid status declines steadily during pregnancy. For example, a study of 110 pregnant women found a temporary increase in DHA status until 20 weeks, but then a steady decline thereafter. This pattern was associated with a progressive DHA deficiency in maternal blood throughout pregnancy and resulted in a sub-optimal neonatal DHA status (Al 1995).

When To Take Omega 3s
Expectant mothers should begin to include essential fatty acids in their diets in early pregnancy to ensure that DHA is passed on to the baby’s tissues during the gestational period. The susceptible window during which dietary DHA may be needed to optimize brain development is a relatively long one and extends from mid-pregnancy (Helland 2003) into the first year of life (Jensen 2005). The most rapid rates of brain DHA accumulation in fetal brain occur during the third trimester and the first year of life (Carlson 2009). Because we are not sure whether postnatal supplementation can correct fully for prenatal deficiency, it also seems appropriate to assure an adequate maternal intake throughout pregnancy and lactation. Two strategies could make more DHA available for brain development: maternal diet could include more fish and, where that is not possible, a supplement could be provided.

Good Omega 3 Sources
Fish is definitely the best source of EFAs and it has the added bonus of being an excellent source of protein. However, given that fish can contain high levels of mercury, certain recommendations regarding fish consumption during pregnancy have been fairly well established, including:
1. Do not eat shark, swordfish, king mackerel, or tilefish;
2. Twelve ounces or less per week of fish and shellfish lower in mercury, such as shrimp, canned light tuna, salmon, pollock, and catfish is considered safe;
3. Limit albacore (“white”) tuna to 6 oz or less per week since this type of tuna contains more mercury than canned light tuna.

Fish oil supplements are available but you must check to make sure that your supplements are not made from fish livers (ie. cod liver oil). The liver can contain high amounts of vitamin A, which has been linked to birth defects. Omega-3 supplements not derived from fish livers but rather from the body of the fish are less likely to contain this type of vitamin A.

Food companies have also responded to all of the scientific and consumer interest in essential fatty acids by adding them into commonly consumed foods. For example:
➢ each 100 gram serving of Danino yogurt from Danone contains 40 mg of DHA and 25 mg of EPA;
➢ each Omega Pro egg provides 125 mg of DHA;
➢ each 50 mL serving of Break-Free Omega-3 liquid eggs provides 125 mg of DHA and 125 mg of EPA;
➢ each 250 mL of Nielson Dairy Oh 1%, 2%, and chocolate milks provide 10 mg of DHA and the homogenized milk provides 20 mg DHA.

The plant-derived omega 3 fatty acid (ALA) acid can be found in such foods as flax, canola oil, and walnuts. Below, I have listed the percentage of ALA by weight of some plant foods:
– Flaxseed: 22%
– Flax oil: 50.8%
– Hemp: very trivial
– Canola oil: 9.3% HOWEVER, these foods have NO EPA and DHA
– Soy oil: 7.0%
– Nuts: 0.2 – 0.4%
– Walnuts: 6.8%

Some of these foods are quite high in ALA. In fact, about 2000 mg of ALA is typically consumed daily in North America. However, DHA and EPA are NOT present in the plant sources of ALA – instead, a metabolic conversion has to occur to convert ALA into DHA and EPA. And what most people don’t realize is that humans have a very poor ability to convert these plants sources of ALA into DHA and EPA. The exact conversion rate of ALA to DHA in humans is controversial, but just to give you an idea of how inefficient this conversion is, it ranges from < 0.2% (Pawlosky 2001, 2003) to 3.8% (Emken 1994). Therefore, you have to eat a lot of flax or walnuts to get a good dosage of DHA and EPA.

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