Gettysburg Medical News
 The Clinical View
 by P.E. Hoffsten, MD
 16 November 2005

THE STORY OF FLAXSEED OIL

            Last week’s column dealt with the value of Omega-3 fatty acids in the diet.  It was pointed out that story really began with margarine in the 1940’s and 1950’s.  So called saturated fats such as butter were found to cause degeneration of blood vessels.  Unsaturated fats such as corn oil or fish oil were found to actually prevent degeneration of blood vessels and resulting heart attacks and strokes.

            Subsequent research demonstrated that the real benefit of unsaturated fats resided in a particular chemical configuration called Omega-3 or Omega-6.  Without belaboring the chemistry of fatty acids, Omega-3 means that every third chemical bond in the fatty acid chain is unsaturated.  Omega-6 fatty acids have six double bonds that are staggered every third bond in the chemical chain.  For practical purposes, the Omega-6 fatty acids are rich in fish oils. Omega-3 fatty acids are rich in flax seed oil.

            Like many of our modern crops, flax is a weed that mankind domesticated.  It is the oldest textile fiber and was used to make linen long before mankind discovered cotton.  Today, flax is cultivated both for its ability to make linen and for its ability to make flaxseed oil.  The plant has a pretty blue 5 petal flower that eventuates in a globular pod that contains the flaxseed.  Flaxseed oil is probably better known as linseed oil, the major component of oil based paint.

            In the 1970’s and 1980’s when Omega-3 fatty acids were being investigated, it was found that flaxseed oil was by far the richest source of Omega-3 fatty acids.  The specific fatty acid present in flaxseed oil is called alpha linolenic acid and cannot be synthesized by mammals.  Thus an external source of this type of unsaturated fat is necessary to supply the body’s needs.  In 2002, the following alpha linolenic acid content of various sources was published.

            Currently, the recommendation for Omega-3 fatty acids is 1-3 grams per day.  Thus with a simple teaspoon of flaxseed oil, the quota is met.  To get the same amount from soybean oil would require 3 tablespoons a day or from canola oil or walnut oil, 2 tablespoons per day.  Now flaxseed oil is sold in capsules that easily swallowed as opposed to drinking oil or putting it into one’s food.

            So the above gives the particulars of flaxseed oil.  But where is the “evidence based data” showing that flaxseed oil saves lives, prevents heart attacks or prevents strokes?  There is very creditable data showing that supplementing one’s diet with fish oil does prevent heart attacks and strokes.  There is very credible based data showing a diet rich in saturated fats causes arterial degeneration leading to heart attacks and strokes.  But to this time, there is no evidence based data from any major study that shows taking flaxseed oil supplements prevents heart attacks or strokes.  Certainly the theory appears valid that flaxseed oil would prevent heart attacks and strokes.  The theory has been tested with fish oil and found to be evidence based true.  But not yet for flaxseed oil.

            With any medication or dietary supplement, the question of side effects and safety always is considered.  To this time, flaxseed oil appears to be a very safe product with no side effects or safety issues.  More than 3 grams per day of alpha linolenic acid or fish oil seems to raise blood sugars in diabetics.  But the long term effect of this has not been determined in a human study population.  On the good side, Omega-3 and Omega-6 fatty acids lower the triglyceride level in very modest amounts.

            The price of flax seed oil is about 15 to 30 cents for 3 grams per day depending on which brand and which pharmacy a person uses.  Fish oil costs 12 to 50 cents for 3 grams per day depending on which brand and which pharmacy one uses.  As far as I know there is no brand preference.

            To this time, the Canadian agricultural industry has the biggest investment in flaxseed oil.  Whether they will be sponsoring population studies to demonstrate the effectiveness of flaxseed oil remains to be seen.  If a person’s purpose is to prevent heart attacks and strokes, then fish oil has demonstrated evidence based data saying that that works.  The recommended dose is 3 grams per day.  Flax seed oil has a theoretical basis to say that it probably works but to this time, there is not evidence based medicine showing that it does work.