Supplement Showdown: Flaxseed Oil Vs Fish Oil

By Adrian Oaks / January 16, 2016

As an omega 3 supplement, which is better? Although they may appear similar, plant based oils and animal based ones are decidedly different. Let’s compare the benefits and weaknesses of these 2 oils. To get started, we will examine flaxseed oil and its omega 3 profile.

Flaxseed Oil & ALA

Linseed oil or (or flaxseed oil as the food variety is often called) is yellowish oil that comes from the flax plant. It contains omega3, 6, and 9 fatty acids. Its chief fatty acid is alpha-Linolenic acid or ALA. ALA is a fatty acid that is only found in plants, nuts, and seeds. This fatty acid is a short chain form of omega 3. ALA cannot be utilized in this form so the body needs to convert it to a long chain omega 3, like DHA and EPA. Ongoing research suggests that ALA by itself provides much of the same benefit as EPA and DHA, although to a lesser extent. It can help lower triglycerides, reduce inflammation, protect against heart disease, reduce the risk of stroke, and prevent high blood pressure. From this we can gather that flaxseed oil is a great substitute for fish oil if you are a vegan or vegetarian. Another added bonus is that plant based ALA does not have the risk of mercury buildup or toxic PCB’s like fish oils do. This may seem like a great alternative to fish oil at first glance, but there is one small problem: conversion.

Flaxseed oil weaknesses

ALA that is converted by the body turns into a large amount of EPA and only a small amount of DHA, resulting in an imbalanced ratio. This is due to the fact that ALA is difficult and time consuming for the body to break down. There is also some research that suggests a small amount of ALA doesn’t even get converted at all. This makes it difficult to measure the exact amount of DHA or EPA levels when considering how much ALA one should consume. However, flaxseed oil is not all about ALA.


Flaxseed oil contains chemical compounds called lignans. Lingnans are phytoestrogens that have antioxidant like properties. Phytoestrogens are a weaker version of the hormone estrogen. There is some evidence that these phytoestrogens can bind to the estrogen receptors in the brain, heart, liver, and bones. This would possibly aid in the treatment of hormone related cancers like breast or prostate cancer. The effect of these estrogen compounds is not yet fully understood however. There is some Limited research that suggests lignens can provide cardiovascular benefits, however this is still under heavy debate.

Fish Oil Strengths

Fish oils provide abundant and easy to measure amounts of fatty acids. Fish oils are high in useable DHA and EPA so the body doesn’t have to do any converting. They are rich in vitamins A, D, E and K. They also contain many other trace minerals. They have been shown to help treat a myriad of diseases, chief among them being diabetes, cancer, and arthritis. They are one of the most nutrient filled supplements you can take. There are many different options for fish oils, with krill oil & fermented cod liver oil being the most digestible.

Fish Oil Weakness

Fish oils carry the risk of contamination since most fish absorb mercury and other toxins from the ocean. Certain fish oils can have unbalanced vitamin amounts due to heavy processing. Also, some fish oils have synthetic vitamins added to them which can cause allergic reactions in some people.

Conclusion: Use both.. If Your Not A Vegetarian That Is

When you take certain fish oils, you know almost exactly how much DHA and EPA you are getting. But when you take flaxseed oil the body converts it mostly to EPA and only makes a small amount of DHA. This makes it difficult to gauge how much of a dose you are getting. To remedy this, the best course of action would be to supplement with a standard amount of fish oil, and use some flaxseed oil as well. Since flaxseed oil is possibly beneficial aside from its fatty acid profile it is a great addition to your normal regimen.

Bear in mind however that there are a few different types of flaxseed oils on the market(heres a review). The normal unrefined oil just contains pressed flaxseed oil and no lignans. Some flaxseed oil manufactures produce oil with added lignans, to varying degrees. If you are interested in supplementing with lignans, it is best to choose oils that are labeled as having “flaxseed particulate” in their ingredients list. Also, you may want to look for flaxseed oils that contain natural preservatives, like vitamin E. The reason for this is that flaxseed oil oxidizes quickly when exposed to light and heat. The shelf life of most unpreserved oils is less than 2 weeks. Flax oil will give off a rancid smell if it has oxidized. It is best to refrigerate any flax supplements you purchase.

Side note: Regardless of which oil you use, you may want to consider adding regular whole flax seeds to your diet. Flax seeds by themselves are a very nutritious food to consume regularly. They are high in fiber and protein, and have more trace minerals than flaxseed oils. Check out the tables below to get an idea of the nutrient value comparison.