Ravi, there is a big difference! Plant-based omega-3s (alpha-linolenic acid) are shorter-chained. Fish-based omega-3s (docosahexanoic acid and eicosapentanoic acid) are long-chained. The plant-based omega-3s must be converted to long-chained in the body, but the conversion in humans is limited in its efficiency. The majority of the studies showing cardiovascular benefit are from those using fish oil omega-3s.
Hello Ravi
For in-depth information, a long list of clinical studies, and nutritional details, especially of plant oils, see
www.udoerasmus.com
he has been studying essential fatty acids for more than 25 years -
though he sells his own blend of a nutritional plant/algae oil, too, his articles and compilations of studies are very un-biased -
in short - nutritionally, fish oils (omega3-DHA & EPA) do not supply the overall daily requirements and quantity of essential fatty acids (omega 3 and omega 6); they also are - some more some less - processed oils. Though, even with plant oils one ought be careful to choose properly pressed versions, as regular pressing methods especially of small and hard seeds will involve high pressure and friction, thus creating heat up to 150 degrees Celsius; technically, such an oil can still be labelled 'cold-pressed' (even delicately in-stable flax oil may be pressed in this manner and sold as cold-pressed ! It is more efficient that way for commercial interests - so ask some questions before buying to find one that is pressed with health in mind ! )
There are numerous studies in the context of vascular health showing benefit from plant omega 3, too, but there seems less profit to be made from plant oils, compared to the fish oil industry.
To be sure, I fully agree that there is a therapeutic place for fish oil benefits; in actual daily practice, however, many people will begin taking fish oils exclusively (with the majority of the marketing messages being related to fish oils), ignoring the requirements of the body for daily supplies of omega 3 ALA and omega 6 LA.
As for conversions of ALA (plant omega 3) to EPA and DHA - at the average rates of
2 to 9 % DHA from ALA (women naturally convert more in their bodies than men, as women can get pregnant and pass on most of their DHA to the infant - pregnancy and nursing ), even at minimum conversion rates of 2%, with 2 - 3 tablespoons (minimum daily average for average size adult) of plant omega3 (flax, chia, or a Omega 3-6-9 Blend), one still converts up to between 200 - 300mg of DHA from those 2 - 3 tablespoons of plant omega 3 -
Personally, I take on average between 5 - 8 tablespoons of the 3-6-9 blend daily and would have plenty more than what the average daily DHA/Fish oil supplement would provide - even if I would have minimum/limited conversion -
The few true medical conditions in which conversion is indeed compromised can certainly be *supplemented* with a direct DHA supplement (even then, it may be worthwhile to consider algae oil based DHA, instead of fish oil based DHA).
Important, after all this, is to keep in mind that before supplementing with specific DHA product, one may wish to make sure the nutritional foundation is taken care of first - providing ample amounts of daily ALA and LA as the actual *essential* fatty acids for overall healthy physiological function, then *adding* the therapeutically indicated specific nutrient/s case by case -
Please see www.udoerasmus.com
for all sources, bibliography, and references
good wishes
peter
The original study on ALA conversion to DHA was reported from the U.S. Department of Agriculture in 1994 wherein the conversion efficiency of ALA to DHA in young adult male subjects was reported to be at the level of a 4% efficiency, which would predict that 25 parts of dietary ALA would be needed to provide the equivalent rise in circulating levels of DHA which could be delivered by the direct consumption of one part of DHA. The overall conversion efficiency from ALA to EPA plus DHA combined was estimated to be 12%. It is noteworthy that the very limited conversion of ALA to DHA was also highly variable between the individual subjects thereby indicating difficulty in predicting those in the population who may have extremely compromised capacities for the conversion of ALA to DHA. Subsequent studies by Pawlosky et al. (2001) using similar technology and that more recently by Hussein et al. (2005) showed estimated conversions from ALA to DHA of less than 0.1% and a conversion to EPA plus DHA combined of less than 0.4% efficiency overall. The latter study was conducted over a fairly lengthy time period of 12-weeks in duration. Burgee et al. from the U.K. has compared the apparent conversion efficiency of ALA to DHA in young adult men and women. Interestingly, no detectable formation of DHA was found in the men whereas an approximate conversion efficiency from ALA to DHA of 9% was found in women. This difference was regarded to be due to the influence of oestrogen on the conversion rate and men seem to hive higher oxidation levels of ALA.
These studies, however point to the fact that even in healthy subjects it is near impossible to predict an individual's capability for conversion. Genetic factors seem to have some influence but to what effect is not yet clear. This is why some researchers have now raised the question whether DHA should be considered as essential after all.
Unfortunately many metabolic states also affect the conversion rate as do some medications (statins and beta-blockers for example). So, if you suspect a lack of EPA or DHA, animal/fish origin omega oil which contains EPA and DHA would be the better choice.
Zinc and selenium are also needed for delta-5 and delta-6 desaturase function.
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