The Facts About Fish Consumption During Pregnancy

textgram_1537966278Recommendation of fish/ Omega 3 during pregnancy

In 2001, an advisory notice on fish consumption during pregnancy and breastfeeding was established by the FDA and it has been replaces in 2004 as well as 2017.

This advice relates mainly to the mercury content of fish and the aim of reducing exposure during pregnancy.

The 2001 notice resulted in a reduction of fish consumption by pregnant women across the US which allowed mercury intake across the US population to fall by 17% but Omega 3 intakes fell by 21% as an unintended consequence. [1]

For the 2004  guidance, there is evidence that due to confusing guidelines and lack of  readily available advice, many women stopped consuming fish altogether because they felt they had a lack of knowledge about which types of fish were safer to eat. They reported that they’d rather avoid fish than risk harm to their babies.[2]

It is essential for women to make informed choices based on balanced advice:

The importance of DHA:

Omega-3 is a long chain fatty acid that supports optimal visual and brain development in the growing fetus. It comes in the form of DHA and EPA. Many studies have demonstrated that the placenta has a selective preference for Omega 3 in the form of DHA (Docosahexaenoic acid)[3]

Expert panels worldwide have suggested that in order to reach the recommended levels of  Omega-3 for optimal fetal development , pregnant woman should aim to achieve an average dietary intake of 300mg of DHA per day[4][5].

Moms who took 1183 mg DHA/day (in the form of cod liver oil) every day until 3 months postpartum while breastfeeding had babies with better mental development  at age four [6].

Two recent studies from USA and Australia have also shown that daily omaga 3 supplementation (600-800)mg/d significantly reduced the risk of preterm birth in women who were at risk[7].

Fish and DHA

DHA is most abundant in fatty fish.

We also know that fish contains significantly more mercury these days and that mercury should be avoided during pregnancy since mercury has been linked to ADHD related disorders in children [8] and because of this as well as the FDA advisory notice on fish, most women opt for fish oil supplements.

However,  studies show that consumption of fish during pregnancy has been shown to be protective of these disorders despite the low dose prenatal mercury exposure.

Studies from the UK show a beneficial effect on development on the child, as well as increased birth weight, with fish consumption during pregnancy [9][10][11][12].

Some studies even show that avoidance of fish consumption during pregnancy to have detrimental effects.[13]

There are safe fish options and studies show that weekly fish consumption of 8-12 oz, despite mercury intake, are still more protective than it is harmful.

8-12 oz fish/week of low mercury wild caught fish options:

  • 4 oz (120g) cooked Atlantic salmon =(1200-2000mg DHA+EPA)
  • 4 oz (120g) cooked sardines =(1100-1600mg HDA+EPA)
  • 4 oz (120g) cooked Atlantic and pacific caught mackerel (not king!) = (1350-2100mg DHA+EPA)

[14]

Or for more info click here

Other than the fact that fish is a great source of all the essential amino acids(complete protein), the benefit of eating fatty fish instead of fish oil is that fish contain many other important nutrients, especially iodine, choline, vitamin D and selenium which fish oils do not. [8]

Commercial fish oils are also not created equal and most of them are likely oxidised or of poor quality.

If you are taking your Omega 3’s in supplement form, krill oil is more stable and seems to be better absorbed than fish oil supplements. If you are going to opt for cod liver oil, opt for fermented cod liver oil and be very specific about the source of the oil! (see cod liver oil blog post)

Omega 3 also comes in the form of ALA(walnuts, flaxseeds, canola oil, soybeans) that can be converted to DHA but less than 10%  of ALA is converted to DHA ,so keep that in mind.

Fish to avoid:

Farmed fish are fed grains that contain mycotoxins and pesticides. They are also often fed chicken litter from chickens that are treated with antibiotics. This drastically changes the omega 3 content of fish just like caged chicken eggs.

PS: fresh does not mean the same as wild. Make sure your source says wild caught.

Other fish to avoid:

King mackerel, marlin, sword fish, shark, big eye and Ahi tuna, orange roughly, tile fish(gulf of mexico) {6} Grouper, Blue fish, Tuna (Albacore, Yellowfin), Sea Bass (Chilean) , Sablefish, Perch (Ocean), Halibut (Atlantic, Pacific), Croaker (White Pacific)

The following is a table found at https://www.nrdc.org/stories/smart-seafood-buying-guide. “Note: The data for this guide to mercury in fish comes from two federal agencies: the U.S. Food and Drug Administration, which tests fish for mercury, and the U.S. Environmental Protection Agency, which determines mercury levels that it considers safe for women of childbearing age. View the equations we used to make these serving recommendations.”

Make sure these fish are still either organically farmed or wild caught!

LEAST MERCURY MODERATE MERCURY HIGH MERCURY HIGHEST MERCURY
Enjoy these fish Eat six servings or less per month Eat three servings or less per month Avoid eating
Anchovies Bass (Saltwater, Striped, Black) Croaker (White Pacific) Bluefish
Butterfish Buffalofish Halibut (Atlantic, Pacific) Grouper
Catfish Carp Mackerel (Spanish, Gulf) Mackerel (King)
Clam Cod (Alaskan) Perch (Ocean) Marlin
Crab (Domestic) Lobster Sablefish Orange Roughy
Crawfish/Crayfish Mahi Mahi Sea Bass (Chilean) Shark
Croaker (Atlantic) Monkfish Tuna (Albacore, Yellowfin) Swordfish
Flounder Perch (Freshwater) Tuna
(Bigeye, Ahi)
Haddock (Atlantic) Sheepshead
Hake Skate
Herring Snapper
Jacksmelt (Silverside) Tilefish (Atlantic)
Mackerel
(N. Atlantic, Chub)
Tuna (Canned chunk light, Skipjack)
Mullet
Oyster
Plaice
Pollock
Salmon (Canned)
Salmon (Fresh)
Sardine
Scallop
Shrimp
Sole (Pacific)
Squid (Calamari)
Tilapia
Trout (Freshwater)
Whitefish
Whiting

References:

[1]  Shimshack JP, Ward MB. Mercury advisories and household health trade-offs. J Health Econ. 2010;29:674–685. [PubMed]
[2] A review of guidance on fish consumption in pregnancy: Is it fit for purpose?
Caroline M Taylor, Pauline M Emmett, […], and Jean Golding
[3] Larque E, Pagan A, Prieto MT et al. (2014) Placental fatty acid transfer: a key factor in fetal growth. Ann Nutr Metab 64, 247-253.
[4] EFSA (European Food Safety Authority) Panel on Dietetic Products NaA, , (2010) Scientific opinion on dietary reference values for water. EFSA Journal 8, 1459-1507.
[5] Koletzko B, Cetin I & Brenna JT (2007) Dietary fat intakes for pregnant and lactating women. Br J Nutr 98, 873-877.
[6]Maternal supplementation with very-long-chain n-3 fatty acids during pregnancy and lactation augments children’s IQ at 4 years of age. Pediatrics. 2003 Jan;111(1):e39-44.Helland IB1Smith LSaarem KSaugstad ODDrevon CA.
[7]  L.N. Yelland et al. Predicting the effect of maternal docosahexaenoic acid (DHA) supplements to reduce early preterm birth in Australia and the United States using results of within country randomized controlled trials. Prostaglandins, Leukotrienes and Essential Fatty Acids (PLEFA). 2016
[8] (https://www.ncbi.nlm.nih.gov/pubmed/27637340)
[9] A review of guidance on fish consumption in pregnancy: Is it fit for purpose?
Caroline M Taylor, Pauline M Emmett, […], and Jean Golding
[10] Golding J, Gregory S, Emond A, et al. Prenatal mercury exposure and offspring behaviour in childhood and adolescence. Neurotoxicology. 2016;57:87–94. [PubMed]
[11] Golding J, Gregory S, Iles-Caven Y, et al. Associations between prenatal mercury exposure and early child development in the ALSPAC study. Neurotoxicology. 2016;53:215–222. [PubMed]
[12] Taylor CM, Golding J, Emond AM. Blood mercury levels and fish consumption in pregnancy: Risks and benefits for birth outcomes in a prospective observational birth cohort. International journal of hygiene and environmental health. 2016;219:513–520. [PubMed]
[13] Golding J, Gregory S, Iles-Caven Y, et al. Associations between prenatal mercury exposure and early child development in the ALSPAC study. Neurotoxicology. 2016;53:215–222. [PubMed]
[14] FDA (2014) Fisch: What Pregnant Women and Parents Should Know.  

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