Is Fish Oil Good For You?

Real Food Recipes Supplements

I started popping fish oil pills in high school.

*Nerd alert*

This is back when I religiously followed the silly nutrition dogma that I now give the stink eye (fat is your enemy, soy is your BFF, and so on).

Now don’t get me wrong, fish oil is very healthy (more on this below) — but most of the commonly found fish oil supplements like the one I was taking back then contain rancid fish oil and may be doing more harm than good.

Why is fish oil such a popular supplement?

Fish oil has been shown to decrease the risk and/or symptoms of heart disease, ADHD, anxiety, depression, inflammatory bowel disease, arthritis, Alzheimer’s disease, eczema, diabetes, cancer, depressed immunity, autoimmune disease, and macular degeneration. It can also aid weight loss and fertility, and contributes to a healthy skin and energy levels.

These benefits are largely due to fish oil’s high anti-inflammatory omega-3 essential fatty acid content. You may recall from our previous discussion about which fats are healthy that there are two types of essential fatty acids — omega-3 and omega-6 — and that these are considered “essential” because the body cannot naturally produce them. That means that we must get them through our diet (i.e. eat them). But here’s the thing: there’s a severe essential fatty acid imbalance in the Standard American Diet. The average American eats WAY too many omega-6s and very few omega-3s… about ten times more omega-6s. Ideally, we should consume the same amount of both, and an imbalance has been attributed to a host of health issues.

It’s no wonder why most Americans eat so many omega-6s: they largely come from processed foods, and the Standard American Diet is all about cheap and easy. Many Americans use highly-refined “vegetable” oils like soy and canola for cooking, and eat a lot of packaged/prepared foods that contain these oils. Soybean oil alone is now so common in processed foods that it accounts for 20% of all calories in the Standard American Diet! This is not good… not good at all.

And while there are a number of excellent plant-based sources of omega-3 fatty acids (like flax seed oil), the types of omega-3 fatty acids that are believed to be the most beneficial — the long-chain (and long-name) omega-3s eicosapentanaenoic acid (EPA) and docosahexaenoic acid (DHA) — are found exclusively in fish and marine algae.

Unfortunately, most fish oil supplements are rancid.

Fats can either be saturated, monounsaturated, or polyunsaturated. Saturated fats are the most stable, monounsaturated fats less so, and polyunsaturated fats are the least stable. So polyunsaturated fats go rancid easily and must be handled with care: kept refrigerated, stored in a dark glass bottle, never heated, and consumed relatively quickly. Essential fatty acids = polyunsaturated fats = very unstable. So fish oil = very unstable.

Researchers at New Zealand’s Crop and Food Research Institute tested a number of different brands of fish oil from around the world and found that the majority had begun to oxidize and turn rancid. These rancid fish oils will not only not benefit those who take them, but they may actually cause harm. Rancid fish oil may increase the risk of atherosclerosis (hardening of the arteries and the #1 cause of heart disease) and thrombosis (increased blood clotting). Yes, these are the exact opposite results than what people who take omega-3s are looking for! “It’s like 10,000 spoons when all you need is a knife…”

Fish oil supplements go rancid because of poor processing and storage. Much like refined vegetable oils, mass-produced fish oils that line drugstore shelves are often produced mechanically with heat and possibly the help of chemical solvents. And remember: heat is polyunsaturated fat’s enemy. Then consider the fact that these oils sit on shelves for quite some time before making their way into your home. And are there instructions for you to refrigerate the fish oil to help preserve it? Of course not (though it would really be a hopeless cause at that point).

is fish oil healthy

So what’s the solution? You have a couple options:

1) Invest in a high-quality fish oil supplement.

My current favorite is Rosita’s extra virgin cod liver oil from Norway. This extra-virgin cod liver oil is bottled within 48 hours of the fish being caught in remote (i.e. very clean) waters of Norway. Rosita does their own fishing, which ensures their quality standards from the beginning (it’s like knowing your farmer), and does not use any heat, chemicals, or mechanical processing methods. Plus it’s one of a kind: “Rosita is the only company that has been granted permission to advertise their cod liver oil as genuine ‘Extra-Virgin’ by The Norwegian Institute of Food, Fisheries and Aquaculture Research. In addition, they are the only company using a very ancient and rare method to produce their cod liver oils.”

2) Eat more fish!

While all fish contain omega-3 fatty acids, cold-water fatty fish have the highest amounts:

  • Wild salmon
  • Anchovies
  • Sardines
  • White fish
  • Bluefin tuna
  • Atlantic herring
  • Pacific and Jack mackerel

BUT be sure to do your homework. Many fish are “factory-farmed” in large pools where they’re fed GMO corn (yuck) and antibiotics (double yuck). In addition to producing unhealthy fish, these fish farms pollute the environment (much like CAFOs that pump out cow and chicken meat). So again, the burden is on us to be educated consumers. For more information, check out NRDC’s Sustainable Seafood Guide and Monteray Bay Aquarium Seafood Watch’s Consumer Guides. And don’t be scared! See Chris Kresser’s article on why eating fish is a lot safer than not eating fish.

Sources and further reading:


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  1. Yes, a high-quality fish oil really should be refrigerated to protect the delicate oils.

  2. I was wondering what your thoughts might be on DHA supplements for babies, which are derived from fish oil. I’ve unfortunately had to move on to formula with my little one and found the Honest Co’s Baby DHA supplement and I’m wondering if there are the same concerns for this type of supplement?

  3. Well it’s so wonderful you know that you have a sensitivity!! And thanks for asking – I really should have looked into a non-cod option. I think this post would be helpful to you: Do you know Chris Kresser? His site is such a wonderful resource and I admire him so much. He gives some non-cod options as well as a marine algae option I’d personally really like to try!!

    As an aside… I just clicked over to your blog and fell down a rabbit-hole reading your posts about paying off your student debt! What a great series. My fiancee and I are also 4 years out of school and on that path. It’s always great to read someone else’s experiences.

  4. Thanks for that link, Katherine! I didn’t see that one yet. And YES, SO confusing!!

    Thanks – I’ll have to fix that (and perhaps change the language there).

    P.S. You have such a beautiful site! Looks like you’re up to great things. I’m so happy to connect with you!!

  5. Thanks for the recommendation, Maeghan! And that’s great to know for my future MIL who was just recently diagnosed with macular degeneration.

  6. I personally love Renew Life critical omega capsules! My eyesight has actually improved since I’ve started taking them.