Fish oil versus flaxseed oil
Since we started practicing nutrition-based medicine 20 years or so ago we have been advocates of fish oil. The modern diet of today simply doesn’t provide enough of the omega-3 long-chain polyunsaturated fats (LCPUFA) that we need for optimal health. In Paleolithic days early humans probably got as much omega-3 fats as we did the more inflammatory omega-6 fats; today the standard American diet, thanks to the addition of vegetable oils, provides about 10-20 times more omega-6 than omega-3. We advise our patients to both avoid the high omega-6 fatty acid vegetable oils and take fish oil to increase omega-3 fats.
We are always asked our opinion of flaxseed oil as a source of good omega-3 fatty acids. We always respond that it is okay, but that taking fish oil is a much better way to increase the levels of eicosapentanoic acid (EPA) and docosahexanoic acid (DHA), the LCPUFA that we really need.
Flaxseed oil has high levels of alpha-linolenic acid (ALA), an omega-3 fat. When consumed ALA enters the fatty acid pipeline and is desaturated and elongated by the appropriate enzymes until it is partially converted to EPA then to DHA. So flaxseed oil does increase the levels of EPA and DHA, but, we think, not nearly as much as does fish oil, which already contains the preformed EPA and DHA we need.
Over the years we’ve taken a lot of flack (flax?) from various people and companies that sell flax oil. We’ve been inundated with testimonials from people who have been healed of–it seems–every disease known to man simply by taking flax oil. I don’t know why, but it seems that flaxseed oil lovers have an almost religious affinity for the stuff. Despite it all, we’ve hung tough and stuck with out recommendations for fish oil instead of flaxseed oil simply because a) it makes more sense biochemically, and b) our patients seemed to do better on fish oil.
A recent paper from the British cardiology journal Atherosclerosis bears us out.
Subjects who had fish oil added to their high omega-6 diet had much higher levels of EPA and DHA in their cell membranes after a few weeks of supplementation than did those who had added flaxseed oil. The study showed that in all lipid parameters evaluated the fish oil won out handily over the flaxseed oil. Those taking fish oil had lower levels of small dense LDL, lower levels of triglycerides, and higher levels of HDL. All this lipid lowering is fine and dandy, but since the whole idea that lipids are somehow involved in the development of cardiovascular disease is hypothetical at best, I don’t know how much importance I would attach to the lipid findings.
The critical factor is the increased levels of LCPUFA in the cell membrane. Elevated levels of LCPUFA do many good things, chief among them is protecting against cardiac arrhythmias. Heart disease is the number one killer of people in America and one third of all heart attacks have sudden death as their first symptom. That means just what it says. The very first symptom one third of the people who have a heart attack experience is sudden death, a symptom it’s difficult to recover from.
What happens is this: a blockage in the coronary artery (arteries) reduces blood flow to an area of the heart. If the area with the reduced or absent blood flow contains conductive fibers critical to the transmission of the electrical impulse that triggers the coordinated, rhythmic pumping of the heart, these fibers may be compromised and cut off the conduction of the impulse or they may conduct it aberrantly. If the impulse stops, so does the heart. When the heart stops for any length of time, so do you. LCPUFA stabilize the membranes so that they are not so prone to malfunction in the presence of lowered oxygen levels.
For my money, I would much rather have my membranes protected by the much higher levels of LCPUFA found in fish oil.