What’s the Deal with Fish Oil?

by Kamal Patel
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What’s the Deal with Fish Oil?

Among the rows and rows of vitamins and supplements on store shelves these days, fish oil stands out. Experts speak highly of it, and many Americans are already popping a gel cap daily, but what exactly are you swallowing? What does “omega-3” mean? Do you need to supplement with “omega-6” as well? And, perhaps most importantly, does fish oil actually deserve its health halo?

To understand fish oil, you need to understand oils and fats

Fat comes in solid and liquid forms. Most animal fats are solid, such as butter or beef fat, and most plant fats are liquid, such as olive oil. One of the most notable exceptions is fish oil, which is liquid at room temperature.

Fish have a different fat profile than warm-blooded land animals. Unlike beef fat, fish fat is liquid because fish are cold-blooded and often swim in cold water. If their fat stores were mostly saturated, the fat would be solid at those cool temperatures, and solid fat would lead to one stiff fish—not exactly conducive to swimming.

Seafood is unique in its high omega-3 content, especially the fats known as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which are very important for human health, namely for optimal immune and nervous system function. Since the human body cannot produce them, omega-3 and omega-6 fats must come from the diet.

Omega-3 vs. omega-6

Wonder why you see lots of omega-3 supplements, but rarely come across omega-6 supplements? It’s because we tend to get way too much omega-6 in our diets. The omega-6 to omega-3 ratio of human diets was somewhere between 1:1 and 4:1 as humans evolved, meaning early humans ate almost the same amount of omega-6 fats as omega-3 fats. The ratio remained that way until a few decades ago. With the advent of inexpensive corn and soybean oil, which both happen to be rich in omega-6, Americans now consume vastly more omega-6 than omega-3 than their earlier ancestors. Today, ratios of 15:1 to 20:1 are more common.

There are several different types of omega-6 fats, and some are can actually be healthy. Omega-6 rich olive oil, for example, has very different health effects than unhealthy corn oil, which is also rich in omega-6. Corn oil has five times as much omega-6 as olive oil, and offers no nutritional benefits, while olive oil has been linked to a decrease in chronic disease.

Should you supplement with fish oil?

Fish oil supplements, in pill or liquid form, are not recommended for everyone. If you eat fatty fish, such as wild salmon, arctic char, and atlantic mackerel, on a regular basis, you’re likely getting plenty of omega-3 in your diet—in a much tastier way than those pills. Fish oil is not something that you need daily, and it’s also possible that you’re getting some omega-3 by eating grass-fed meats and free-range eggs. Plus, those who avoid vegetable oils high in the unhealthy types of omega-6, like corn and soybean oil, will have better omega-3 to omega-6 ratios and may not need fish oil supplements.

If thinking about taking a supplement, consider the following benefits: fish oil has been shown in studies to reduce heart disease predictors, including triglycerides and blood pressure. It also shows promise for helping to alleviate depression, though more research is needed to confirm this effect. Still, eating several servings of foods high in omega-3 and including healthy fats from olive oil, pastured meats, and coconut oil may make supplementation unnecessary.

While potentially beneficial, fish oil supplements may also come with a few side effects. Though there isn’t much evidence to suggest fish oil is directly harmful, it’s not a good idea to consume a lot of it daily. For example, taking more than a few teaspoons of fish oil at a time may lead to stomach upset. More importantly, large doses over time could increase the risk of hemorrhage. And those with blood disorders, including conditions that prevent blood coagulation, should talk to their doctor before supplementing fish oil. (It’s a good idea to discuss any and all supplements you take—or plan to take—with your physician.)

To supplement omega-3 effectively, stay away from combination supplements that contain omega-3 in addition to omega-6, and in some cases even omega-9—you just don’t need those extra 6s and 9s. For those trying to avoid animal-based supplements, flaxseed oil is an option—it’s a major plant source of omega-3. However, only about 10% of the omega-3 found in flaxseed is converted in the body to the EPA and DHA that we need. Marine-derived oils are usually a better choice for supplementing omega-3 due to their preformed EPA and DHA.

Fish oil oxidizes easily, making storage tricky. Keep your bottle in the refrigerator to slow oxidation, and avoid buying large bottles of capsules or liquids. While the price per capsule may be hard to resist, buying in bulk could put lead to accidental oxidation—smaller bottles are open for, and used up, in a shorter period of time.

Bottom line

Fish oil is not a must-take supplement. Think of it as a springboard to being aware of the fats in your diet. Whether you take fish oil or eat fatty fish or pastured meats, it’s important to get enough omega-3 fats, since your body can’t produce them by itself. Equally important is watching the types of oils you eat.

When cooking at home, opt for olive oil instead of standard vegetable oil (which are often a bulk mix of corn and soybean oils), and ask your waiter about the ingredients in your salad dressing when dining out. Paying attention to the types of fat you eat can go a long way toward preventing disease and maintaining health. Use MyFitnessPal to keep track of the types of fats you eat, and your body will thank you for the effort.

Do you take fish oil supplements? Share your thoughts in the comments below.



  • Fish oil was recommended to me by my eye doctor. I mentioned that my eyes were uncomfortably dry while wearing contact lenses and he thought the fish oil would help. I can’t say that it has.

    Maybe I’ll cut back the daily dosage to a few times a week after reading this article.

  • Nobam2012

    It’s good, it’s bad, it’s good, it’s bad. That’s what all health advice is turning into. Just eat within your calorie range and workout.

    • scott

      Don’t worry abut calories and get on board with the ketogenic diet. Read Fat For Fuel. Get your EFA’s from flax,chia,hemp. Then get lots of coconut,butter. I had 85 grams of fat/30grams of protein with some low carb veggies and greens for breakfast. Now it’s time for my bulletproof coffee

  • Merle

    How about fermented cod liver oil?

  • InLimine

    Fish oil alleviated the tendinitis in my big toe down to almost nothing. I don’t believe in miracle cures but a $10 bottle of fish oil did what a $1000 set of custom orthotics, religious stretching, and staying off of my feet didn’t.

  • Dan

    Whenever I take fish oil, I feel a bit confused and it becomes slightly hard for me to think clearly. I figured that I don’t really need this supplement.

    • scott

      The essential fatty acids are ALA and LA. get those from flax,chia,hemp,walnuts. Then add the DHA/EPA with bone broth and greens.Blend all together. Get on board with the ketogenic diet. Say goodbye to all grains and sugar. You will surprisingly have more enrgy. For mental clarity you need phospholipids from sunflower lecithin/RAW eggs and choline+inositol supplement. You can even try piraracetam

  • mrcreigs

    Thinking fish oil would be good for trigliserides and healthy lifestyle I bought a 6 month supply 3000 mg a day. But have been reading articles that are making me second guess. So I’ve stopped taking them after my 6 month trial.

    • Alexa

      Is there any positive result after taking the supplement for 6 months? or was it a negative results that is why you stopped taking em after 6 mos?

  • koom2014

    Was on statins for cholesterol reduction so started taking krill oil as a supplement for heart health. Since then came off the statins so not sure if the krill helped reduce it, I’ve also found joint health seems better although this could be in my head too!

  • Bobbie

    Way too much mercury….Dr. Oz was told by his Doctors to STOP eating so much fish…high in mercury….all of them….And do we really know what is in the capsule???

    • alan

      yes -some like Life Extention foundation fish oil has the mercury and heavy metals taken out.

  • Ben Bonarigo

    Check with American College of Cardiology. Fish oil is passe.
    LDLs are the 90% target. No nutritionist has ever truly been responsible for the health of an individual, though they are tangentially involved.

    • Brian T

      Ben I would disagree with you. I’ve been a nutritionist for over 17 years. Spent several years in academia as well. Many times I’ve been responsible for an individuals health after a patient has had zero success addressing their cardiovascular issues with allopathic medicine. This is not to say that drugs are never the answer, butost often, blood pressure, lipids and other risk factors are easily addressed with nutrition and exercise.

  • MsMermaid

    Lifetime fitness staff are all pushing the fish oil supplements big time. 6-8 per day. Never made it past a couple, so glad to hear that may be a bit overboard.

  • Janet

    I take Krill oil supplements because I’ve had my gall bladder removed and, therefore, do not digest and absorb fat – healthy Omega-3 and 6 included – as readily anymore. My doctor has suggested that I supplement my diet with Krill oil to make sure that I give my body a little extra to try and absorb so that I’m getting the amount my body needs.

  • knotfreak

    Nobam2012, that’s the way science works. Knowledge builds as research progresses. That’s why science literacy is important, to help know the difference between the types of studies and their relative importance. Early studies often don’t stand up to larger, better work, so recommendations have to change. Your bottom line is correct and has stood the test of time 🙂

  • Flash

    High cholesterol and taking meds to reduce numbers. Lowered but still slightly on the high side with meds for several years. Added two fish oil pills a day and cholesterol is now in the normal range and has stayed there. It worked for me.

    • Sylvia Solution

      Switch from butter, animal fat, cheeses, to olive oil, avocado, nuts, seeds and omega fish oil, d-tocopherol E and evening primrose oil to keep the wrinkles away and your insides from drying out as you age. Also follow the Mediterranean diet for a statistically proven healthy way of eating !

  • Katanlin

    I have had high triglycerides most of my life. When I started taking 2 fish oil capsules a day, my numbers came down 1000 points in about 6 months. I continue to use fish oil capsules and changed to olive oil and watch what I buy/eat. Using low fat/fat free products, fish oil capsules, and olive oil I have lowered my numbers a few hundred more points. I am just about in a more normal range now. In my experience, it has worked for me and I can tell the difference when I don’t use fish oil in my triglyceride numbers,

  • Keith

    Responding to research reported in The Economist, I began taking a daily capsule of fish oil to treat my arthritic knee, a source of constant pain. While the pain has not gone entirely, it has been much reduced.

  • DanT

    I’ve been taking omega 3 capsules for over ten years to treat genetic hypertryglceridemea and they do work to lower triglycerides, the capsules are heavy metal free and this is something to check for when taking them over long periods.
    I’ve also found that using the capsules as well as a small amount of Apple cider vinegar everyday really helps to lower triglycerides as well, the vinegar needs to have the mother in it and will therefore probably be organic, also eating healthy and avoiding saturated fats will make a difference too.

  • RYAN

    Why does someone with a degree in public health writing like they have a degree in physiology or nutrition… A lot of what is wrote here is crap; he has no knowledge of physiology. MyFitnessPal, please use qualified writers next time.

    • Sylvia Solutions

      Doctors have a degree, but surprisingly have rarely in my experience mentioned vitamins or food cures..they usually write a prescription for a medicine. Hippocrates said “Let food be your medicine, and your medicine be your food”. He was from the Mediterranean and self taught. ! !

  • V

    Fish oil makes me dizzy. So I switched to flaxseed oil.

  • Behealthy

    I am a very active, very healthy 55 year old. I exercise 1-2 hours, 4-5 times weekly, eat right, weigh 123 lbs, Take my vitamins, calcium daily. I was taking 1200 mg of fish oil supplements daily and earlier this year, I had a brain hemorrhage. Doctors can not figure out what caused the hemorrhage. Now after reading this article, I’m wondering if it could have been from taking too much fish oil supplements. I’ve stopped taking the supplements.

  • Mikael Vitally Vyachesl

    polyunsaturated oils are toxic ..any oil extracted by high steam temperatures and then are put in a capsule and shipped to a warehouse and to the stores ?are rancid and toxic ..its a billion dollars business for the vitamin industry ,..do people in Okinawa Japan pop fish oil pills and vitamins shit pills all day ? Why Americans are mostly obese and they blow money in toxic pills ?,,,they should be slim and healthy ?

  • scott

    Start with flax,chia,hemp,coconut and lecithin or 3 raw eggs then add your cod liver/fish oil. Throw in some bone broth and whey. Then add some greens. Put that in your vitamix and your off to the races. Go ketogenic diet. That was 85 grams fat 30 grams protein and very little carbs. Then have your bullet proof coffee

  • Rhona Hall

    I suffer with depression and since I’ve started supplementing with fish oil, my mood is noticibly better. I will stay on it.