Information on Omega-3 Essential Fatty Acids

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This site is intended for continuing nursing education, and it appears to

be free from commercial bias.

http://www.powerpak.com/CE/omega3/nursing/lesson.cfm

The topic can be confusing, and I found this report to be of great value in

sorting out what I wanted to do. (I changed from flaxseed to fish oil -

but that's my choice, your milage may very :-))>

A summary: not all omega-3 fatty acids are identical.

At least three are signification:

LNA alpha-linolenic acid (18:3w3) LA linoleic acid (18:2w6)

EPA eicosapentaeonic acid (20:5w3)

DPA docosapentaenoic acid (22:5w3)

DHA docosahexaenoic acid (22:6w3)

The first number refers to the total number of carbons in the fatty acid

chain, the second refers to the number of carbon-carbon double bonds, and

the last (or omega 'w' number) refers to the position of the first

carbon-carbon double bond that occurs from the methyl terminus of the

molecule. As all modification of unsaturaetion and/or chain length in

humans occurs at the carboxyl terminus or within nine carbons of the

terminus, the " omega " nomenclature classifies fatty acids into families

whose terminal structure never changes. In addition, mammals (unlike

plants) cannot change an omega 3 fatty acid into an omega 6 fatty acid or

visa versa.

Essential Fatty Acid Supplements

Several different types of EFA (essential fatty acids) exist in the

marketplace today. The vast majority are related to omega-3 fatty acids.

Predominant sources of supplemental omega-3 fatty acids include flaxseed,

fish oil, and single cell oils derived from algae. Flaxseed is rich in the

short-chain omega 3, alpha linolenic acid (18 " 3w3) whereas fish oils are

rich in long-chain omega 3 fatty acids EPA and DHA. Fish oil or fish body

oils are a rich source of long-chain omega 3, with typical concentrations

of omega 3 in fish being around 30% or about 30 mg of EPA and DHA 180 mg

EPA /120 mg DHA) per 1 gram capsule.

Flaxseed and flaxseed oil products also comprise a n abundance of the

supplemental fatty acid market. Flaxseed and its derived oil provide a

rich source of alpha-linolenic acid, the parent omega 3 essential fatty

acid. By weight, flaxseed contains 40% to 45% oil, which on average

contains about 55% LNA. Thus the overall weight percentage of LNA is about

22% of the total flaxseed weight.

It should be noted that flaxseed or flaxseed oils do not contain EPA. Thus

flaxseed and fish oil are not interchangeable sources of omega-3 fatty

acids per se. Before making a recommendation to consume " omega 3 " fatty

acids, diligent care should b taken to discern the actual omega 3

constituents of a product, and a survey of the literature conducted to

define the actual components (LNA, EPA, or DHA) used in clinical trials.

Misinformation

Consumer and patient confusion regarding fatty acids abounds, often a

direct result of " ambiguous " marketing practices. Contributing to this

confusion is the trading off of studies by using the general purpose term

omega-3 without specifying LNA, EPA, or DHA content or application. For

example a sales ad or product literature for flaxseed or flaxseed oil

product may cite a study confirming treatment efficacy with " omega-3 " when

in fact the study referenced was conducted with a high dose of fish oil

containing EPA and DHA. Whenever a product makes a claim regarding

composition and function scientific principles should be applied to discern

fact from fiction.

Dosage

Therapeutic does of 15 g fish oil per day (~5g EPA and DHA) or greater

should be administered under the supervision of a healthcare professional.

In addition, the type (short chain or long chain) and concentration (mg

omega-3/supplemental unit) should be considered to accurately determine

daily dosages.