#120 Should I Take Fish Oil?

August 30th, 2015 by

Should I Take Fish Oil?

“I hate fish,” Sarah shared with me at her last clinic visit.  “Can’t I just take fish oil instead to get my omega 3s?”

Sarah is not alone.  According to the New York Times, at least 10% of all Americans still take fish oil.  Even I used to gulp down these big pills that gave me “fish breath.”

Many of my patients would much rather take a pill than eat real food.  Can fish oil replace all of the benefits of eating wild fish?

In this article I answer the question, should I take fish oil?  If you would rather watch the highlights of this article, here is a two-minute interview I did on our local TV station about this article.

Eskimos, Fish Oil, and Heart DiseaseShould I Take Fish Oil?

Before I answer this fish oil question, I would like to back up and discuss how fish oil ever became considered as a possible heart disease treatment option.  In the 1970s, Danish researchers captivated the world’s attention by supposedly finding extremely low rates of heart disease among the Inuit Eskimos of Greenland.

These Danish researchers concluded that it was the large amount of omega 3s, from fish oil and other marine life, in their diet which prevented heart disease.  These findings seemed very counter intuitive at the time because the Eskimo Diet was largely devoid of fruits and vegetables.

While many popular internet sites still promote the “Eskimo Diet” to prevent heart disease, modern researchers have found that Eskimos have the same rates of heart disease as non-Eskimo populations.  Not only has the “Eskimo Diet” been debunked as a way to prevent heart disease, recent large studies have sadly reported that fish oil may not prevent cardiac disease.

What Are the Possible Cardiac Benefits of Fish Oil?

In general, I have found that most of my patients who take fish oil fall into one of two categories.  The first takes fish oil hoping to prevent heart or brain disease.  In contrast, the second group takes fish oil as part of a healthy diet that includes plenty of omega 3 fatty acids.

Despite the lack of strong data to support fish oil, what are the theoretical heart benefits of fish oil that still have so many people taking these supplements?

1. Fish Oil is a Blood Thinner

Like aspirin, fish oil thins the blood.  This blood thinning effect could help to prevent blood clots, heart attacks, and strokes.

2. Fish Oil Reduces Inflammation

Fish oil has a powerful anti-inflammatory effect.  As inflammation is at the “heart” of cardiovascular disease, the fact that fish oil reduces inflammation should theoretically prevent heart disease.

3. Fish Oil Reduces Triglycerides

Elevated triglycerides, or fat in the blood, is a major cause of heart disease.  As fish oil reduces triglycerides it is no surprise that the FDA has approved certain pharmaceutical grades of fish oil, like Lovaza and Vascepa, for this purpose.

Does Fish Oil Prevent Heart Disease?
Should I Take Fish Oil?

Despite early enthusiasm for fish oil based on studies of the Inuits living in Greenland, recently a growing number of studies are concluding that fish oil does not prevent cardiac disease.  While my cardiologist colleagues once recommended fish oil to most of their cardiac patients, it is now just a small minority of them who still recommend this treatment.

Does Fish Oil Prevent Alzheimer’s Disease?

Like with the heart, early research suggested that fish oil may prevent Alzheimer’s Disease.  Unfortunately, more recent research suggests that this is likely not the case.  Indeed, a large study published this past week confirmed the findings of other studies, namely that fish oil does not improve cognitive function or prevent memory loss.

Does Fish Oil Cause Cancer?

While the media misreported a 2013 study by proclaiming that fish oil causes cancer, if you examine this study closely it does not even report if they actually took fish oil.  As a follow up to this study, a 2015 study showed that fish oil just might be slightly protective against cancer.  Based on my interpretation of the medical literature, fish oil is likely neutral when it comes to cancer risk.

Can Fish Prevent Heart and Alzheimer’s Disease?

While the data for fish oil in the prevention of heart disease is unconvincing, stronger data do exist supporting oily fish for the prevention of heart disease.  Indeed, in a large study done by my former colleague, Dr. Dariush Mozafarrian, he showed that this risk of death from heart disease could be reduced by 36% by eating oily fish 1-2 times per week.  Another big study showed that regular fish consumption decreases the risk of dementia by 19%.

Can I Get Omega 3s From Plants?Should I Take Fish Oil?

For those who don’t like fish, wouldn’t it be nice to get all of your omega 3 fatty acids from plants?  I know I used to feel that way until I forced myself to start liking fish.

Unfortunately, most of the research showing a beneficial effect of omega 3s come from studying the fish forms of omega 3s, namely EPA and DHA.  However, I should point out that the body can convert some of the plant form of omega 3s, ALA, into EPA and DHA.

If you don’t like the marine forms of omega 3s don’t despair as I suspect future research will show that plant omega 3s also protect against heart disease and dementia.  If you are looking to increase your plant based omega 3s, some great options include walnuts, flax seeds, chia seeds, vegetables, and legumes.

How Should I Get My Omega 3s?

While your body can make most of the fats it needs for health, the same is not true for the omega 3 fatty acids.  These fatty acids are called essential because they must be obtained from food. Here is how I advise my patients to get omega 3s for their heart and brain health.

1. Skip the Fish Oil

While I once recommended this to my patients, and even took it myself for a period of time, recent studies don’t show any clear benefit.  Thus, unless your triglycerides are high, it may be best to skip fish oil.  If fish oil helps you then you can be reassured that the medical studies also do not show any clear harm from taking this supplement.

Of course, if your doctor has recommended fish oil, do not stop this medication.  Rather, please discuss the recent medical studies with your physician to see if you might be a candidate for real food sources of omega 3s.

2. Eat Wild Oily Fish Twice Weekly

The best way to get omega 3s is from wild oily fish.  My favorite is wild Alaskan salmon which we can get very cheaply at Costco.  Wild oily fish is high in EPA and DHA while also very low in mercury and other contaminants.

3. Eat Plant Omega 3s on Your Non-Fish Days

On the days you don’t eat fish, make sure you eat plant based omega 3s.  For example, just 1/4 cup of walnuts (14 halves), provides you with 113% of the daily recommended amount of omega 3s.

Since the scientific data no longer enthusiastically recommend fish oil, here is a list of how you can easily get all of the omega 3s your body needs each day from real food sources.  How do you get your daily dose of omega 3s?


Since writing this article, I have received many, many questions from my patients regarding fish oil.  The question of should you take fish oil is very difficult to answer in a blog article.

We know that fish oil reduces triglycerides.  We also know that high triglyceride levels cause plaque build up or atherosclerosis in the arteries of the heart and elsewhere throughout the body.  The missing link is that the scientific data are not yet clear as to whether or not fish oil prevents heart attacks.

Even in the cardiology community this subject is highly controversial.

The bottom line is that if you are a heart patient you need to have an open conversation with your cardiologist as to whether fish oil is right for you.  In my mind, as long as your fish oil is fresh (has not gone rancid) and is from a reputable source (pharmaceutical grade, USP certified, or GMP supplements) the downside risks seem to be minimal.  Whether or not there is an upside benefit is what is highly debated.

Hope this helps!