Letter to the editor: Fish vs flax controversy continuesLetter to the editor: Fish vs flax controversy continues
April 1, 2007
I am writing regarding the editorial content in your February issue. We were very happy to see the amount of coverage given to omega-3. However, we were also very surprised to see your lack of understanding regarding the health benefits of ALA omega-3.
Regarding your comment on page seven, "…ALA omega-3 has few health benefits other than its dietary-fibre content" — I believe you meant to say that flaxseed has few health benefits other than its fibre content, since ALA certainly does not contain dietary fibre. That aside, research clearly shows that ALA omega-3 from flaxseed is beneficial in a number of areas, one being cardiovascular health.
A majority of large-scale population studies show that people who consume ALA-rich diets have a lower risk of CVD. A cardio-protective effect of ALA was seen in these studies despite differences in study populations, length of follow-up, outcomes and method of analyzing the study data statistically. As such, a consensus is emerging that ALA has beneficial effects in the prevention of CVD.1
Based upon these and a multitude of other studies equally supportive of the benefits of ALA in controlling the risks of heart disease, several large multinational cereal-based companies feel it is appropriate and justifiable to advertise the benefits of ALA omega-3 from flaxseed in supporting cardiovascular health on product packaging by using such structure-function claims such as "ALA omega-3 supports a healthy heart."
Your article titled 'Fishing for other sources of EFAs,' contains many gross misrepresentations regarding the health benefits of ALA and flaxseed in general, amongst them you state that: "Indeed the reason the FDA granted a qualified health claim for EPA and DHA from fish sources and explicitly not for flax is because of the fairly large evidence base for EPA and DHA compared to ALA."
In reality, the reason ALA omega-3 from flaxseed has not been granted a qualified health claim is because no such petition for a claim has ever been submitted — not because there is insufficient evidence available to support it.
You also state that "flaxseed oil has an inefficient conversion rate of linolenic acid to EPA and DHA — levels ranging from about 5-15 per cent for EPA."
While it may be argued that the conversion of ALA to EPA and DHA can be between 5 per cent and 15 per cent, "conversion rates of 10 per cent still provide 100-200 mg of long-chain omega-3 based on an ALA intake of 1-2g per day," and "ALA consumption is an important source of omega-3 in our daily diet," according to D Bibus, University of Minnesota.2
Pizzey's Milling USA
The Editor replies:
Further to your concerns about our two stories on omega-3 fatty acids, I would make the following points:
First, it should be noted that the story is specifically referring to fish oils and not flax. You say that research clearly shows flaxseed is beneficial in a number of areas due to ALA omega-3 content, lignans and fibre. Nobody is arguing about the benefits of flaxseed in this story and we go on to discuss those benefits in the Food Science feature. However, I agree that the writer should have made it clear that he meant flaxseed contains fibre content rather than ALA.
Food Science: 'Fishing for other sources of EFAs'
Regarding the statement "Indeed the reason the FDA granted a qualified health claim for EPA and DHA from fish sources and explicitly not for flax is because of the fairly large evidence base for EPA and DHA compared to ALA" — this statement was peer reviewed by a leading researcher in the field of oils, but you say the reason is that the fish industry submitted the petition for the claim. It is true the fish industry submitted the petition but the researcher clearly believes there is more evidence to support fish rather than flax, and we stand by that statement. Indeed, in a recent symposium on omega-3 fatty acids, leading researchers in this area did echo our expert's opinion, but did advocate plant-derived omega-3's, including flax and its derivatives, for those who are opposed to using marine sources for whatever reason.3
Clearly, there has been a lot of debate and controversy about the merits of EPA/DHA and ALA, but the contention that ALA has an inefficient conversion rate to EPA/DHA is supported by no less than six references in our story and we stand by that statement. Moreover, because the article was positioned as an "overview of ingredients" and not of varying diets, one must rely upon the evidence base to discern long-term health benefits. From this position, the body of evidence from clinical trials of EPA/DHA supplementation outweighs that of ALA supplementation.
We then devoted a paragraph explaining the benefits of flax supported by two references, and I don't believe we disagree on those benefits.
1. Renaud SC, Lanzmann-Petithory D. The beneficial effect of a-linolenic acid in coronary artery disease is not questionable. Am J Clin Nutr 2002; 76: 903-904.
2. Bibus,D, University of Minnesota, Minneapolis, MN, Cereal Foods World, September-October 2006, Vol 51, No5, pg261-263.
3. Gebauer SK, et al. N—3 fatty acid dietary recommendations and food sources to achieve essentiality and cardiovascular benefits. Am J Clin Nutr 2006;83:S1526-S1535.
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