Did Granny pinch your nose and force you to swallow cod liver oil every morning? Chances are she thought it would protect you from rickets, a disease that makes children bow-legged. She was right – cod liver oil is rich in Vitamin D, which helps you absorb calcium and phosphorus from food, thereby keeping bones strong. I doubt, however, that Granny told you that cod liver oil also contains eicosapentaenic acid (EPA) and docosahexaenoic acid (DHA) – two omega-3 fatty acids that lower triglyceride levels and protect you from heart attacks and strokes. This little nugget has made fish oils one of 2020’s most talked about medical interventions, thanks to the December 2019 FDA-approval of pill named Vascepa.

Let’s take a step back. I bet you have a rough idea of your cholesterol level, but when was the last time you asked your doctor about your triglycerides? Cholesterol is a building block for cell membranes, and it’s also used to make hormones – your blood levels depend on how much your liver makes and how much cholesterol you eat. Too much can clog arteries. Triglycerides, on the other hand, are straight fat – they store calories for use as energy. Most fat we eat is already in triglyceride form – things like butter, margarine, and oil. Your liver also converts excess carbohydrates into triglycerides, which are then stored as fat. That’s why eating a low fat, high carbohydrate diet can still make you … well, fat. That’s one reason why knowing your blood triglyceride levels is important.


Blood triglyceride (TG) levels
Normal = under 150 mg/dL.

Borderline high = 151-200 mg/dL

High = 201-499 mg/dL

Very high = 500 mg/dL or higher

Here’s another reason: a year ago, a study was published in the New England Journal of Medicine which sought to answer the question of whether lowering triglyceride levels could reduce the chances of having a heart attack or stroke. It was called the REDUCE-IT trial, and it enrolled 8179 patients in 11 countries who had coronary artery disease or diabetes with other coronary risk factors (e.g., high blood pressure, smoking, sedentary lifestyle). All patients were already taking a statin, and their triglyceride levels were 135-499 mg/dL. Patients were assigned to receive either a highly purified fish oil capsule (Vascepa) or a placebo. After one year, patients receiving Vascepa had an 18% reduction in triglyceride level, whereas patients receiving placebo had a 2% increase. The startling finding, however, was that after 5 years, patients taking Vascepa had a 25% reduction in risk of heart attack, stroke, and death. 

I think Granny would be pleased to know that fish oils don’t just prevent rickets, but the right fish oil in the right dose can also save lives. Here’s the thing, though – not all fish oils are created equally. Vascepa, the formulation used in this study, is a highly purified concentrate of just eicosapentaenoic acid (EPA), and it was used in high doses – 4 grams per day. That green bottle of fish oils you buy without a prescription is a mixture of EPA and another fish oil, DHA. Unfortunately, because the over-the-counter preparations are unregulated, you don’t know how much EPA vs DHE you’re getting.

Of course, Vascepa has its own issues. In Bermuda, without insurance, it’s about $605.00 per month. Finances, aside, if you’re allergic to fish or shellfish, it may not be for you. Also, fish oils have a blood-thinning property which, although helpful for some persons with heart disease, may cause bleeding, especially if you’re already taking blood thinners. Some patients notice ankle swelling. There’s also a slightly higher chance of Vascepa-users being hospitalized for an irregular heart rhythm called atrial fibrillation.

Of course, high-dose fish oil capsules aren’t the only way to lower triglyceride levels. Exercise and weight loss help. So can limiting alcohol, sugar, and refined carbohydrates, and replacing saturated fat (e.g., found in red meat) with omega-3 fats found in salmon, mackerel, sardines, tuna, herring, and trout. Regardless, don’t forget to ask your doctor what your triglyceride levels are, and, if you have heart disease or are diabetic, ask specifically about Vascepa.


A final thought on fish oils, natural and unnatural:
The fishing, pharmaceutical, and supplement industries all share an agenda, and I don’t have to tell you what it is (ching-ching). Science follows its own program, and we like to think it’s the pursuit of truth. The most direct path to truth, at least as far as science is concerned, involves reducing complex systems (like fish) into parts (like EPA) to identify the properties of each constituent, then test specific doses in specific situations. Fair enough. Certainly, the discovery of what pure EPA can do for persons with heart disease and high triglycerides is great news.

What about the rest of us? I’ve always maintained that nutrients are best taken in their natural state. An orange trumps Vitamin C powder and sunshine beats a pharmaceutically-derived Vitamin D capsule. For the same reason, I prefer my fish oils via sardines or salmon, although I admit, in 2020, I wrestle with this because I know my oily fish comes with a side-order, however small, of mercury and microplastics. One advantage of fish oil capsules is that the mercury is filtered out and the coating is made of gelatin, not plastic. Of course, the pills arrive in plastic bottles, and although recyclable, some still find their way to the ocean where they disintegrate into microplastics and end up in my sardines. For me, it’s a sobering indication of our planet’s wellbeing when it might be healthier to eat a pill instead of the fish it came from. Until we get our oceans sorted out, let’s be thankful that earth also supplies plant-versions of omega-3’s – walnuts, soy, canola oil and flaxseed – for now, relatively low in mercury and plastics. I see my vegan friends smiling again. What else do they know that we don’t?

For more news on the latest developments in cardiology, visit www.ShaneMarshallMD.com, subscribe to the free newsletter The Annals of Cardiology, and follow Dr. Marshall on Twitter @ShaneMarshallMD