Conversion of ALA into EPA and DHA
Flaxseeds are the richest commercial source of plant-based Omega 3 fatty acids. The prominent Omega 3 in flaxseed oil is alpha linolenic acid (ALA). ALA is the parent compound of Omega 3 and can be converted by enzymes into the longer chain Omega 3 fatty acids EPA (eicosapentaenoic acid) and DHA (docosaheaxaenoic acid).
There is controversy around the issue of how much ALA is converted into EPA and DHA. Humans have enzymes which can facilitate the conversion but unfortunately Western eating habits interfere with the conversion. There are a number of factors which hinder this conversion:
- High intake of Omega 6 relative to Omega 3.
- A deficiency of the nutritional co-factors vitamins B3, B6, C, the minerals zinc and magnesium support conversion enzymes.
- Trans-fatty acids destroy the conversion enzymes and tissues have to manufacture new ones to replace those damaged by trans-fats.
- Alcohol abuse poisons these enzymes.
- Excess insulin in the bloodstream diminishes enzyme function.
The question is how much dietary ALA do our tissues convert into EPA and DHA? These rates vary by gender, age and genetic factors. Women are more efficient at converting ALA into EPA and DHA because estrogens support the conversion enzymes.
Human conversion of ALA into EPA ranges from 8% to 20%. Conversion of ALA to DHA ranges from 1% to 9%. One tablespoon of flaxseed oil per 100 pounds of bodyweight is the recommended daily dose. To maintain general cardiovascular health we need 1000 mg daily combined EPA/DHA.
ALA content of one tablespoon of flaxseed oil is 6000 mg, conservatively speaking. Therefore each tablespoon of flaxseed oil provides:
- 20% conversion of 6000 mg of ALA = 1200 mg EPA
- 4% conversion of 6000 mg of ALA = 240 mg DHA
- Combined, converted EPA/DHA per tablespoon flaxseed oil = 1440 mg
Women may be more efficient in the conversion of ALA but most men would be using 1 ½ to 2 tablespoons of flax oil daily since men generally weigh more than women. Improving dietary and lifestyle factors will definitely improve the conversion of ALA into EPA and DHA.