Fabulous Fish Oil Findings: Part 3

We’ve covered a lot of information about omega-3 fatty acids over the past two weeks. Today we’ll wrap up the three-part series by looking at fish-oil supplements, as well as the potential side effects and safety issues that surround them.


Why would someone want to take fish-oil supplements? Well, if you’re like me, I happen to dislike seafood, with the exception of a tuna sandwich and the occasional piece of swordfish. Or maybe you love fish but live in an area where it’s hard to get fresh, high-quality seafood. Or it may be that you take fish-oil supplements for “health insurance” purposes. Remember, too, that if you have heart disease or have high triglycerides, the amount of omega-3s that you need can be difficult to get from eating fish alone. Whatever the reason, more and more people are turning to supplements (of all kinds).

How do you go about choosing a fish-oil supplement? First off, stay clear of taking cod-liver oil. This oil, which some of you may remember having to choke down during your childhoods, is a highly concentrated source of both vitamins A and D. Too much of either of these fat-soluble vitamins can be dangerous. Also, cod-liver oil is obviously made from the cod’s liver. The liver is the body’s filter and can harbor toxins, such as polychlorinated biphenyls (PCBs), organic pollutants that are frequently found in the fatty tissue of animals and fish.

Second, make sure you choose a supplement that contains both EPA and DHA, the two types of omega-3 fatty acids found in fish oil. Menhaden, sardines, anchovies, halibut, salmon, and mackerel are commonly used to make supplements. Most fish-oil supplements come in gelatin capsule form and are usually odorless, tasteless, and easy to swallow. (However, avoid taking any supplement that smells rancid or fishy.) If you have trouble swallowing capsules, look for a pudding-like supplement, such as Coromega, or try a liquid version. Most supplements are considered to be safe and toxin-free; choose brands that say they’ve been distilled or deodorized, which means that any contaminants have been removed.

Some “fish oil” supplements are actually not made from fish. Algae are used to make supplements, although if you take an algae-based supplement, it may not contain EPA. Also, some supplements are made from krill oil. Krill are tiny crustaceans that happen to contain a good amount of omega-3 fatty acids. Krill oil also contains antioxidants.

Third, make sure you read the label on whichever supplement you choose to determine how much you need to take. For example, if you’re aiming for 1000 milligrams (or 1 gram) of both EPA and DHA each day, you may have to take anywhere from one to four “softgels” each day, depending on the brand. Prices can vary, too, from brand to brand, which is another good reasons to figure out the dosing before you buy a particular supplement. (Check out www.consumerlab.com for a list of popular brands.) Higher-quality supplements tend to be more concentrated in omega-3s than the local grocery store brands. Always keep your fish-oil supplements in a cool, dry, dark place. Refrigerating them is not a bad idea.

Fish-oil supplements can cause side effects in some people, such as belching (along with a fishy flavor) and heartburn. If this happens, spread your dose throughout the day or switch to another brand. Take your supplements with food for better absorption. Because fish oil has blood-thinning properties, be very careful about taking it if you also take aspirin or prescription anticoagulants such as warfarin (brand name Coumadin), or if you’ve had a hemorrhagic stroke, or will be having surgery. Talk to your physician first. Fish oil may be beneficial for kidney function in people taking cyclosporine, a medicine used to prevent organ transplant rejection, but discuss your situation with your physician before using it.

Your physician may prescribe Omacor, a prescription version of omega-3 fatty acids, if you have very high triglyceride levels. This “drug” contains a highly concentrated blend of EPA and DHA. The dose of this medicine is 4 grams per day (don’t take this much of a nonprescription supplement unless you’ve checked with your physician first).

Finally, if you prefer to get your omega-3s from vegetarian sources, try taking flaxseed oil or flaxseed oil capsules. One tablespoon of flax seed oil or 3–6 flaxseed oil capsules is the typical dose. Pregnant women should not take flaxseed oil, by the way.

I hope you feel more comfortable and confident about these important omega-3 fatty acids. Aim to fit more fish into your diet and consider taking a supplement if you’re not a fan of fish.

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  • Kerr Mitchell

    Thank you for reviewing Omega 3 fatty acids. My doctor is a big proponant of fish oil. We like fish but we are too far from coast. My doc has me taking a minimum of 2,000 mg per day but I take 2,400. It has done amazing things for me and my cholosterol. HDL’s up LDL’s down. It works.

  • Lu Halverson

    I thought that recently, Diabetes Self Management published information that Diabetics should not take fish oil supplements. When I mentioned it to my doctor, she did some research and agreed. Now you are telling diabetics that it is OK to take fish oil?

  • acampbell

    Hi Lu,

    It’s great that you checked with your doctor about taking fish oil supplements. I believe the Diabetes Self-Management article you’re referring to is on the website and was just updated this past September. Most of the research on fish oil and diabetes indicates that fish oil is beneficial for people with type 2 diabetes. Fish oil can lower triglyceride and blood pressure levels, as well as reduce the chances of sudden death from a heart attack. And since people with diabetes have twice the risk of heart disease as people without diabetes, it’s probably a good idea to either include a lot of healthy fish dishes in your eating plan, or else take a supplement. The downside is that fish oil may slightly raise LDL (bad)cholesterol levels in some people. However, LDL cholesterol can be closely monitored by your doctor, and if it’s high, lifestyle changes and medication can help. Have another talk with your physician and together, weigh the pros and cons of taking a supplement.

  • Willow


    I also have been told that fish oil is bad for Diabetics and that in fact all supplemts should be avoided for that of a healthy diet instead and balanced properly. The reason I wan’t to take fish oils..is I want to lower my LDL cholesterol and that is my problem. My LDL isn’t very high but too high for a Diabetic. I am also having a lot of body ches and joint aches after exercise. More than when I was younger (now I’m 57). I believe that fish oils may help. I don’t like fish much and although I can eat it, I cannot stomach it often. It’s a) too expensive and b) many kinds that are cheaper are too rich. Like Salmon. Fresh Tuna is my favourite but very very expensive now. I do *not* take statins and I have refused them. In my case it’s more a precautionary measure as they seem to give you Statins as par for the course if you are Diabetic nowadays. That is not for me. I was taking Salmon capsules. I decided just one 2 or 3 times a week would do. better than nothing I guess. Can you please advise or even suggest?


  • acampbell

    Hi Willow,

    While there are always exceptions, much of the research done with omega-3 fatty acids (fish oils) seem to show that the potential benefits outweigh any risks. And while most health agencies will recommend choosing food over supplements, the reality is that, in the case of fish oils, not everybody likes to eat or can eat fish. For that reason, taking a fish oil supplement may be a good idea. In general the recommendation is to aim for 500 milligrams of DHA/EPA per day; the American Heart Association suggests that people who have heart disease aim for 1000 milligrams per day. Also, fish oils are more beneficial for lowering triglycerides (blood fats) than for lowering LDL (“bad”) cholesterol (which is why statins are often prescribed). I’d suggest talking with your doctor about the best course of action for you. And consider meeting with a dietitian to discuss lifestyle steps for lowering your LDL.

  • Linda

    When I increased by Fish Oil tablets from two to four my blood sugar levels went up. I have been off of them for two days and did not change my diet and my blood sugar levels have dropped considerably i.e. (10-20). Could this be due to the gylcerin in them and if so are there any tablets made without gylcerin?

  • acampbell

    Hi Linda,

    There are reports of fish oils causing slight increases in blood glucose levels. Interestingly, though, hemoglobin A1C levels don’t seem to increase as a result. Most brands of fish oil contain glycerin; however, it’s probably not the glycerin in them that is causing the blood glucose increase, since the amount of glycerin is pretty small. An increase of 10–20 points in glucose is not that much, depending on your usual glucose range. In other words, if your glucose levels are around 120 and they increase to 130 or 140, that’s not all that high. You might try cutting back your dose to two tablets per day, rather than stopping them altogether, and see if that makes a difference.

  • Ron

    My glucose was 87 and my A1C was 5.7 but I had high cholesterol and so I started taking fish oil capsules. I took 2 1200mg. capsules with breakfast and another 2 1200mg. capsules with dinner (this was probably at least double what I should have been doing) — my cholesterol went down about 30 pts BUT my glucose shot up to 148 and A1C up to 6.8. I know it was due to the fish oil because my glucose had been between 84 – 89 and my A1C was in the mid-5’s for the last 10 yrs.

    Since going off the fish oil I’ve only been able to get the glucose down to 118 and my A1C is now at 5.8 but I am on 500 mg. Metformin. I am hoping my doctor will allow me to go off the Metformin next month when I see him and see if without the small amount of Metformin I can keep the A1C under 6.0 so he will take away the classificatiion of myself as a Type 2 diabetic because it is impairing my ability to get health insurance at standard rates.

  • Hilary Denny

    My husband has just been diagnosed with cancer and he is due to start cemo very soon. A recent article i came across by chance – said fish oil is a benefit to cemo patients. Trouble is he has heart problems and diabetes.Im going to ask his consultant
    on our next visit – heres hoping! Ill keep you posted.

  • acampbell

    Hi Hilary,

    I too read the article regarding fish oil’s benefits for cancer patients. Hopefully this is something that will be helpful. And definitely check with his health-care provider first. Best wishes to your husband!