Categories: ChocolateFreshnessOmega-3Pregnancy

Rancid Prenatal Omega-3 Supplements Are a Problem

Bo Martinsen, MD
July 28, 2016

This month, two scientific reports came out that should have caught the attention of the media and expecting parents.

The first piece discussed how getting enough DHA omega-3 during pregnancy could save the US healthcare system a projected $6 billion dollars by reducing the number of premature births (1).

The second was more obscure. In the study, scientists gave rancid fish oil to pregnant rats and compared the effects to that of non-oxidized fish oil. The results were astonishing. The rancid (oxidized) omega-3 oil was clearly harmful, and increased the odds of newborn mortality by 13 times (2).

These studies highlight two important points to remember about omega-3 fatty acids: Getting enough omega-3 is crucial for good health — and particularly for mother and child during pregnancy. Besides the noted benefits for preventing premature births, omega-3s are also important for reducing the risk of postpartum depression (3, 4) and promoting fetal brain development (5).

But as we stress the importance of getting enough omega-3, we cannot forget that the benefits of fish oil are dependent on source and quality. This new rat study clearly illustrates why we can no longer make blanket statements about the effectiveness of omega-3 supplements in general.

How Prevalent Are Rancid Omega-3 Supplements?

The above research on pregnant rats is one of handful of studies to compare the effects of rancid and fresh fish oil. While limited studies exist so far, they powerfully substantiate a theory researchers have maintained for years: Rancid omega-3 oil is likely toxic when consumed long term (6).

But how probable is it that pregnant mothers will run across rancid omega-3 supplements? Very likely, according to researchers from Norway (7), South Africa (8), New Zealand (9) and Canada (10). Studies from these nations have consistently found that the majority of omega-3 supplements sold at retail stores have exceeded international freshness standards long before their stated expiration dates.

Sadly, as the recent Canadian study concluded, the fish oil supplements typically targeted towards children have the highest oxidation values of all (10). There is no reason to believe that prenatal supplements are any better.

How Do You Know Whether an Omega-3 Supplement Is Fresh?

Since expiration dates are unreliable, how should parents determine whether their omega-3 supplement is fresh or rancid?

For consumers, the best way to assess freshness is to taste and smell the supplement. If the oil smells or tastes fishy, it is rancid and should be thrown away. As we say here at Omega3 Innovations, liquid fish oil should taste just like fresh fish. And as seafood lovers know, truly fresh fish has no fishy taste.

On principle, be wary of using any gelatin fish oil capsules without first breaking them open and tasting and smelling the oil inside. Also, stay clear of products that use heavy flavoring, which is how the industry conceals bad-tasting, rancid oil.

Tackling the Nausea and Gagging Issue with Supplements

Swallowing large capsules or doses of oil can trigger the gag reflex, particularly for expectant mothers already suffering from nausea.

If you start with fresh oil that has no fishy taste or smell like Omega Cure®, the freshness factor will go a long way towards stemming the gag response. For women who still struggle with oily textures, however, there are other options.

One good way to avoid the oily texture is to mix your fresh fish oil into other foods, such as yogurt or juice. You can even use the oil as part of a salad dressing. You can also satisfy your chocolate cravings and get your daily omega-3 requirement with Omega Passion® or Omega Heaven®.

Consuming Omega-3 Foods During Pregnancy

The Omega Passion chocolate truffles and Omega Heaven cookies are two products we often recommend to pregnant women who are looking for a way to cover their omega-3 needs in a solid food form.

Each Omega Passion truffle delivers 300 mg of EPA/DHA (approximately one regular fish oil capsule worth of omega-3), plus soluble fiber. It is made with non-alkalized dark chocolate that’s both tasty and antioxidant-rich. The award-winning Omega Heaven cookie, which functions as a breakfast meal replacement, provides 1000 mg of EPA/DHA omega-3, in addition to gluten-free oat fiber and non-alkalized dark chocolate.

Besides delivering significant doses of fresh omega-3, these products provide additional benefits for soon-to-be mothers. They serve as nutritious meal or snack replacements. They don’t trigger the gag reflex. And they also provide healthy servings of fiber, which plays an important role in stemming the risk of preeclampsia (11), gestational diabetes (12) and constipation during pregnancy (13).

Can Pregnant Women Overdose on Omega-3 Fatty Acids?

Looking at the body of omega-3 literature, there are few risks associated with consuming fresh, purified omega-3 oils. At worst, consuming high doses of omega-3 fatty acids (over 5000 mg daily, according to the European Food Safety Authority) may increase a person’s risk of bruising (14). But even so, the risk of overdosing on omega-3 is small, especially when you consider that most pregnant women in the United States don’t even get the bare minimum omega-3 recommended for healthy pregnancies (15).

To be on the safe side, we suggest that a pregnant woman limits her intake to two Omega Heaven cookies or six pieces of Omega Passion a day.

Expectant mothers will agree though, it’s nice to be able to eat a chocolate or a cookie as a delicious, fresh alternative to fishy liquids or hard-to-swallow prenatal vitamins.


1. Daniells, Stephen. Kudos! DHA Supplements During pregnancy Could Save US Healthcare System $6 Billion. NutraIngredients – USA. 30 June, 2016.

2. Albert BB et al. Oxidised Fish Oil in Rat Pregnancy Causes High Newborn Mortality and Increases Maternal Insulin Resistance. American Journal of Physiology – Regulatory, Integrative and Comparative Physiology. doi: 10.1152/ajpregu.00005. Epub 6 July, 2016.

3. Markhus MW et al. Low Omega-3 Index in Pregnancy Is a Possible Biological Risk Factor for Postpartum Depression. PLOS ONE 8(7):e67617. doi: 10.1371/journal.pone.0067617. 3 July, 2013.

4. Omega-3 Backed for Postpartum Depression. NutraIngredients – USA. 26 November, 2012.

5. Coletta JM et al. Omega-3 Fatty Acids and Pregnancy. Reviews in Obstetrics and Gynecology. 2010; 3(4):163-171.

6. Albert BB, Cameron-Smith D, Hofman PL, Cutfield WS. Oxidation of Marine Omega-3 Supplements and Human Health. BioMed Research International, vol. 2013, Article ID 464921, 8 pages, 2013. doi:10.1155/2013/464921.

7. Laupsa-Borge, Johnny. Velg Ferske og Naturlige Omega-3 Produkter. Helsemagasinet Vitenskap & Fornuft. 9 December, 2012.

8. Opperman M, Benade S. Analysis of the Omega-3 Fatty Acid Content of South African Fish Oil Supplements: A Follow-Up Study. Cardiovascular Journal of Africa. 2013 Sep; 24(8):297-302. doi: 10.5830/CVJA-2013-074.

9. Albert BB et al. Fish oil Supplements in New Zealand Are Highly Oxidised and Do Not Meet Label Content of N-3 PUFA. Scientific Reports 5 (2015). Article ID 7928 (2015). doi:10.1038/srep07928. Epub 21 January, 2015.

10. Jackowski SA et al. Oxidation Levels of North American Over-the-Counter N-3 (Omega-3) Supplements and the Influence of Supplement Formulation and Delivery Form on Evaluating Oxidative Safety. Journal of Nutritional Science 4 (2015): e30.doi:1×0.1017/jns.2015.21. Epub 4 November, 2015.

11. Qui C et al. Dietary Fiber Intake in Early Pregnancy and Risk of Subsequent Preeclampsia. American Journal of Hypertension. 2008 Aug;21(8):903-9. doi: 10.1038/ajh.2008.209. Epub 17 July, 2008.

12. Hitti, Miranda. Planning a Pregnancy? Eat Your Fiber. WebMD Health News. 27 September, 2006.

13. Pregnancy and Constipation. American Pregnancy Association. July 2015.

14. EFSA Assesses Safety of Long-Chain Omega-3 Fatty Acids. European Food Safety Authority. 27 July, 2012.

15. Greenberg JA et al. Omega-3 Fatty Acid Supplementation During Pregnancy. Review in Obstetrics and Gynecology. 2008 Fall; 1(4): 162–169.

Bo Martinsen, MD

Dr. Martinsen is an omega-3 specialist, innovator, and advocate for natural foods. As co-founder and CEO of Omega3 Innovations, he has created multiple patented technologies for medical devices designed to improve consumer compliance. He is also the creator of several medical food products that combine dose-effective ingredients of omega-3 fish oil with soluble fibers and other nutrients. Before Omega3 Innovations, Dr. Martinsen practiced medicine in Norway for 20 years. During his career, he also served as a medical consultant to large international corporations, focusing on stress management and synergistic medicine.

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