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Wednesday, January 6, 2010

FAQ about choosing source of EFA

[an answer to a question about which source of EFA to choose]

To answer your questions regarding n-3FA and Flax vs Chia vs Fish oil.  Using ground vs unground flax and the reason n-3FA is important in diet are outlined below.  Some references are listed below.

First of all omega-3-Fatty Acids (n-3FA) are important in human diet for several reasons.  They make up the outer cellular wall of each of our cells as part of the bi-lipid layer (eating poor fats high in n-6 and n-9 with low n-3) will result in a poor cellular structure and poor hormone receptors which poke out through this lipid bi-layer.  Intake of higher doses of good lipids (n-3) will result in a better cell wall function in 28 to 30 days.  Also DHA and EPA which are constituent parts of n-3FA are "brain food" so to speak.

So what type of n-3FA should you take.  10 years ago the rage was Fish Oil.  But with issues of over fishing, toxins (Hg, PCBs, and other heavy metals making their way into our fish) non-pharmaceutical grade fish oil is falling out of favor.  There are plant sources such as Flax, Borage, Chia and Hemp.  However, there is an important enzyme that converts precursor EFAs (ALA) to EPA and this is delta-5-desaturase.  The problem may be that some folks don't have enough d-5-destaurase activity or any at all.  This EFAs get "stuck" in this precursor lipid and don't progress to what the body really needs.  When you take a vegetable source of EFA that is the chance you run.  ALA is converted to DHA at a rate of 2-5% and to EPA at a rate of 2-15% in the body
in general.  DHA conversion from plant EFA is less than that obtained from animal sources (fish, etc.)  Finally EPA through an enzymatic pathway yields DHA.

So a "fish" or oceanic source of EFA may be of more benefit and eliminate certain enzymatic steps within our body.  Krill oil steps up to the plate as a very good alternative to fish oil.  It is lower on the food chain, thus not a repository for heavy metals and toxins.  It is very plentiful and over fishing of Krill should not be a problem.  Additionally, Krill contains the anti-oxidant Astaxanthin which is only available in large quantities in this organism and not in plant oils and has the unique property of crossing the blood brain barrier (protecting the brain, CNS and eyes).

The scoop on Flax seeds is this:  ... to store it for freshness keep in whole.  To get the most out of its EFA grind it up.  Intake of whole unground Fax or Borage seeds is a great source of fiber bulk, but smaller quantities of the oils will be made available for absorption.

Bottom line... the best vegetable source for EFAs is Chia seed & extract.  The best animal source for EFA is Krill.  Better yet is to take a mix of both.  Variety always trumps picking only one source of any nutrient.  Hope this helps.


JP Saleeby, MD



Fatty acids and lignans in unground whole flaxseed and sesame seed are bioavailable but have minimal antioxidant and lipid-lowering effects in postmenopausal women
Karen D. Coulman 1, Zhen Liu 1, John Michaelides 2, Winston Quan Hum 2, Lilian U. Thompson 1 *
1Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
2Robin Hood Multifoods Inc., Toronto, ON, Canada

*Correspondence to Lilian U. Thompson, Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, 150 College Street, Toronto, ON, M5S 3E2 Canada Fax: +1-416-978-5882
Funded by:
 Natural Sciences and Engineering Research Council of Canada
 Robin Hood Multifoods Inc.

Antioxidants • Blood lipids • Flaxseed • Sesame seed • Tocopherols

Fatty acids and lignans in ground flaxseed and sesame seed are absorbed, metabolized, and exert some health benefits in vivo. However, it is unclear if they are absorbed, metabolized, and exert health benefits when consumed as ungroundg unground flaxseed, sesame seed, or their combination (12.5 g each) (flaxseed+sesame seed bar, FSB) for 4 wk each, separated by 4 wk washout periods. Total serum n-3 fatty acids increased with flaxseed (p<0.05) and FSB (p=0.064) while serum n-6 fatty acids increased with sesame seed (p<0.05). Urinary lignans increased similarly with all treatments (p<0.05). Plasma lipids and several antioxidant markers were unaffected by all treatments, except serum -tocopherol (GT), which increased with both sesame seed (p<0.0001) and FSB (p<0.01). In conclusion, fatty acids and lignans from unground seed in food bars are absorbed and metabolized; however, except for serum GT, the 25 g unground seed is inadequate to induce changes in plasma lipids and several biomarkers of oxidative stress. whole seed; therefore, it was investigated in this study. In a randomized crossover study, 16 postmenopausal women supplemented their diets with food bars containing either 25 

Received: 20 January 2009; Revised: 26 March 2009; Accepted: 4 April 2009




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