Fish Oil

The Foundation for IgA Nephropathy

Fish Oil

IMPORTANT

Do not confuse with cod liver oil

Fish oil is short for "fish body oil". It is not the same thing as "cod liver oil". Cod liver oil contains high concentrations of vitamin A. Taking cod liver oil in the same amounts that are recommended for fish oil can be toxic, and even more so in people who have chronic renal failure (because vitamin A can build up to toxic levels). See also the contraindications paragraph later in this article.

Introduction

Fish oil first came to the attention of the general public in the 1980's, when it was reported that the omega-3 fatty acids in fish oil might help to prevent heart attacks and high blood pressure. In the mid-1990's, a very few media first reported that fish oil might slow down the progression of a disease most people had never heard about until then: IgA nephropathy. Of course, these reports were mostly noticed by only a few IgAN patients. As with many other things, it took the popularization of the Internet to spread the word about fish oil among the IgAN community.

Those news items circa 1995 were reporting on a study that had been conducted by the Mayo Clinic in the U.S. Recommendations regarding fish oil are still mainly based on that study and later studies conducted by the Mayo Clinic. So far, clinical trial and observational trial reports were published in 1994 and 1999. While the Mayo Clinic trials reported moderately-positive results, an equal number of trials conducted elsewhere did not show positive results. As a result, there is still at least a mild level of ongoing controversy about the usefulness of fish oil for the treatment of IgAN. Those who aren't convinced about fish oil will cite a possible flaw in the Mayo Clinic trials, while those who are convinced will question the validity of the other trials that did not show positive results. As with tonsillectomy, this website will not take a position on either side of such a controversy. We will simply provide you with some basic information that you should know about.

As you communicate with other IgAN patients, you will undoubtedly find that some are on fish oil, and others aren't. This is because some nephrologists recommend it to some of their patients, while others aren't convinced of its usefulness. A third group will recommend it, but not too convincingly (on the basis that it can't hurt). In some cases, there can also be specific reasons not to recommend fish oil. Because of the high doses involved (for IgAN, the dosages are higher than what you will see on the label when you buy fish oil) and the possibility of contraindications, we strongly recommend that you not take fish oil on your own initiative, but rather consult with your nephrologist.

That having been said, a simple recommendation by your nephrologist to take a certain number of fish oil capsules per day is no longer sufficient, in our opinion. This is because as time has gone by, different concentrations of fish oil have entered the market, and so, there are differences not only in the actual amounts of fish oil contained in a given capsule, but also in the concentration of the omega-3 fatty acids EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid). Some may contain twice as much as others. Since these are the fatty acids that are thought to provide the benefits of fish oil, it's important to know how much is in one capsule. To complicate matters further, labeling on some fish oil brands can be misleading. For example, one brand may appear to contain twice as much EPA and DHA as another, but if you read the dosage instructions closely, you may find that the stated higher dose actually refers to two capsules instead of just one capsule. Therefore, given that fish oil is not a prescription item, you should ask your nephrologist for examples of specific brands that may be available in your area, or a specific daily dosage of EPA and DHA.

Dosages

The optimum dosage for fish oil still remains to be determined (even according to the principal figure behind the Mayo Clinic trials). The best information we have at the present time is this:

In the 1994 Mayo Clinic trial report, the total daily dosage was 1.9 g of eicosapentanoic acid (EPA) and 1.4 g of docosahexanoic acid (DHA), given as 12 capsules (multicenter, placebo-controlled, randomized, 2-yr clinical trial).

In the study report published in 1999 (observational extension of study -- open label), the daily dosage was as follows:

MaxEPA (Seven Seas Health Care, Hull, United Kingdom), given in a dosage of six 1 gram soft gelatin capsules twice daily providing 1.9 g of EPA and 1.4 g of DHA, or

Ethyl esters (obtained from the Fish Oil Test Materials Program, sponsored by National Institutes of Health and the National Oceanic and Atmospheric Administration based at the Southeast Fisheries Science Center, National Marine Fisheries Service, Charleston, SC), given in a daily dosage of five 1 gram soft gelatin capsules providing 1.8 g of EPA and 1.4 g of DHA, or

OmacorTM (Pronova Biocare, Lysaker, Norway), a highly concentrated form of omega-3 fatty acids, given in a daily dosage of four or eight 1-g soft gelatin capsules providing 1.9 to 3.8 g of EPA and 1.4 to 2.8 g of DHA.

So, whatever the amount in each capsule you happen to be taking, if you want to take what was given to patients in the study, it should add up to the total daily amounts quoted above. If you are not familiar with the metric system of measurement, 1 gram is the same as 1000 mg. Most fish oil capsules are of the 1 gram size.

Some nephrologists are using smaller doses, especially with children. One common dosage is 5 x 1 gm/d soft gelatin caps of MaxEPA.

Where do you get fish oil?

Fish oil is available at most health food stores, most pharmacies, and even at big box discount supermarkets. Pay attention to the "best before" or the expiry date when you buy it, as fish oil can become rancid. Also, be aware that most fish oil comes from fish that are harvested in fish farms. Some products on the market claim to be from "wild fish". Whichever you buy, you should not buy any product that does not specifically list the amount of EPA and DHA it contains.

What will it do for you?

Fish oil has been shown in some studies to improve your chances of delaying progression towards end-stage renal failure over a long period of time. While some patients may coincidentally notice a reduction in proteinuria, any such reduction due to fish oil will be very mild at best. Fish oil is not prescribed as a means of reducing proteinuria, and it has not been shown to do so at this point. ACE inhibitors and angiotensin II receptor blockers (high blood pressure medications) are more effective at reducing mild proteinuria, and of course, for heavy proteinuria, nothing is in the same league as prednisone. Fish oil may also lower your blood triglycerides (possibly a desirable effect). At present, the most recent thinking is that while fish oil may slow progression of the disease at first, it may not do anything in the longer term. This is something that remains to be determined, and prospective studies are continuing. It's also important for patients with IgAN to know that fish oil may not necessarily do anything for them specifically, and that other independent studies have not shown any benefit to taking fish oil supplements.

Adverse effects

Not everyone can take or tolerate fish oil. Allergic reactions have been reported, and it's not known if this is due to the fish oil itself, or the gelatin capsules they come in. More serious contraindications may be excessive bleeding in people who may be taking blood thinners (or who simply have a tendency to bleed), and fish oil may not be advisable if severe high blood pressure is not under control (due to possibly increased risk of a hemorrhagic stroke). If in doubt, consult your nephrologist.

Interaction with NSAIDs. There is one specific drug interaction that needs to be considered. Fish oil may enhance anti-platelet action of Aspirin and other NSAID's ( COX-1 type, Ibuprofen, others). Therefore, use of fish oil together with aspirin (especially daily low dose as used to prevent strokes and heart attacks) may be harmful. As with everything else you may read on this website, the decision to use fish oil or not in combination with these drugs must be taken by patient and nephrologist together, weighing potential risk and potential benefits. There cannot be a blanket recommendation that applies to everyone.

Immune system suppression. It has been reported in some sources that large doses of fish oil may suppress the immune system to some extent, and consequently, it might not be advisable for people with a suppressed immune system to take larger doses of it, if any. A large dose in this case is considered to be 3 grams per day or more. The dose usually taken by IgAN patients is definitely more than 3 grams per day. No significant adverse effects were noted in the IgAN fish oil trials, but then, with trials, it depends what they are looking or testing for. As you are probably aware, many people with IgAN may have a suppressed immune system due to taking some medications. As with any medicine or dietary advice, this website only provides information. We don't want people to make their own treatment decisions based on what they read here. This is something you should discuss with your nephrologist.

Pregnancy. No adverse effects on pregnancy have been shown in humans. However, some studies in animals have reported an increase in the rates of prolonged and difficult labors and an increase in blood loss during labor.

Other side effects

Some people have reported allergic reactions - rashes mostly. The main side effect is likely to be indigestion, especially if you have a problem digesting fats. Others have commonly reported fishy burps, and with prolonged use, a fishy odour on their skin. Most people do not experience any intolerable side effects beyond the fishy burps and mild indigestion, however, other possibilities are diarrhea and hypoglycemia. There were concerns about cholesterol content in early preparations of fish oil on the market, and there is some concern about toxic substances in fish such as mercury. These concerns have been addressed by the industry, and good quality fish oil should not cause these problems. Elevations in blood sugar and cholesterol levels may occur in some individuals who take fish oil. Again, it is not advisable to take fish oil without your nephrologist's advice.

Other sources of omega-3 fatty acids

Fish oil is not the only product that contains omega-3 fatty acids. Other readily-available sources are flax and hemp oil. However, with fish oil, the fish has already converted the fatty acids into EPA and DHA. Other products such as flax oil provide your body with the basic building blocks, but your own body must metabolise them in order to produce EPA and DHA. In order to achieve the intake of EPA and DHA contained in, say, 6 to 12 capsules of fish oil, you would have to consume impossibly large quantities of flax or hemp oil daily.

A final word

You may wonder if you should or should not take fish oil. We must defer to your nephrologist's advice, since he or she knows your medical history best. However, it should be noted that many, many people have had IgAN for decades without ever taking any fish oil, and did not progress to end-stage renal failure, or did so only very slowly after many years (20 or more). On the other hand, we have seen many people diagnosed with IgAN more recently who took fish oil, and who ended up on dialysis or with a kidney transplant anyway within a relatively short time (not that we are suggesting this is because of taking fish oil). So, it's hard to say what the real benefits are. Since IgAN generally progresses very slowly, it will take another decade or two to know if the taking of fish oil has any significant benefits in the long term. Even the best current studies are prospective, in the sense that they are trying to find out if there is a long term benefit, and consencus seems to be building that while fish oil may be beneficial in the short term (like the first few years), it may not make any difference to the progression of the disease over the long term. It's a question that simply cannot be answered with any certainty at this time. As a patient, it seems like you are just as likely to encounter a nephrologist who is against the use of fish oil as one who is for it. Despite the possible adverse effects listed above, most people seem to tolerate fish oil fairly well, and no significant adverse effects have been reported in the fish oil studies.

The still-in-progress North American IgA Nephropathy Study should help provide some answers with regard to fish oil. It is a randomized, placebo-controlled, multi-center trial with the Administrative Coordinating Center located at Columbia Hospital at Medical Center in Dallas, Texas. The purpose of this study is to test the hypothesis that alternate-day prednisone or daily fish oil supplements will retard or prevent the decline in renal function in children, adolescents, and young adults with moderate to severe IgAN.

Interesting link:

Long term outcome of patients with IgA nephropathy treated with fish oil (Dr. Donadio's 1999 article)

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