Hi all,

This is my first post here so I hope it works out.

I'd like to comment on the first posting in this thread, in particular on the question:

"Why does this discussion not carry over to the high heat exposure of other omega-3
sources such as in the roasting of grass fed meat or wild game, frying of
omega-3 eggs, baking of fish, and the drying of walnuts? "

Simple anwser: because cooking does not affect omega-3 or CLA in meat or fish.


There are numerous studies out there proving that fact, for example for meat:

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(1) Badiani et al. (2002). Lipid composition, retention and oxidation in fresh and completely trimmed beef muscles as affected by common culinary practices. MEAT SCIENCE 60 (2): 169-186

(2) Bragagnolo N, Rodriguez-Amaya DB (2003). New data on the total lipid, cholesterol and fatty acid composition of raw and grilled beef longissimus dorsi. ARCHIVOS LATINOAMERICANOS DE NUTRICION 53 (3): 312-319

(3) Maranes et al (2005). Effect of microwave cooking or broiling on selected nutrient contents, fatty acid patterns and true retention values in separable lean from lamb rib-loins, with emphasis on conjugated linoleic acid. FOOD CHEMISTRY 90 (1-2): 207-218
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Not even microwave cooking has an adverse affect. For fish there are similar studies out there though there seem to be differences between different fish species (see [3]):


[1] Title: Effects of microwave cooking on fish quality
Author(s): Sahin S, Sumnu G
Source: INTERNATIONAL JOURNAL OF FOOD PROPERTIES 4 (3): 501-512 2001
Abstract: Changes in tenderness, unit proteolytic activity, protein denaturation and fatty acid content of trout (Onchorhyncus mykiss) cooked in microwave oven for different time-power combinations were studied and the relationship between protein denaturation and textural changes was investigated. Trout was cooked in the microwave oven at 20, 40 and 60% powers for 10, 20, 30, 40 s. As a control uncooked fish was used. Proteolysis was controlled by using microwave energy. Texture degradation due to proteolytic enzymes was reduced as microwave power increased. As cooking time and/or power of the microwave oven increased, proteolytic activity decreased which was a sign of the increase in enzyme inactivation. A correlation was found between the variation of texture and proteolytic activity (r = 0.973). It was observed that proteolytic enzymes were effective especially on myosin. Most of the fatty acids were not destroyed during microwave cooking. The optimum cooking conditions !
 in microwave oven were determined as 60% power for 20 s of cooking time.
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[2] Title: Comparison of the effects of microwave cooking and conventional cooking methods on the composition of fatty acids and fat quality indicators in herring
Author(s): Regulska-IIow B, IIow R
Source: NAHRUNG-FOOD 46 (6): 383-388 DEC 2002
Abstract: The aim of this study was to examine the changes which occur under the influence of different heating methods in the compositions of fatty acids and selected fat quality indicators in fillets of herring. The results that are compared herein were obtained via conventional culinary techniques and using microwave radiation. Culinary processes like boiling, grilling and frying, whether done conventionally or with a microwave oven, did not lead to a reduction in the n-3 polyunsaturated fatty acids (PUFAs) fraction of the total fatty acids, indicating that these fatty acids have a high durability and a low susceptibility to thermal oxidative processes. The culinary processes used in this study also had an insignificant influence on the fat quality indicators - the peroxide and anisidine value. The fat quality indicators in herring, both after conventional and microwave heating, differ little, and indicate a low content of primary and secondary products of oxidation.
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[3] Title: Investigation of the effects of cooking processes on the fatty acid composition of finfish species by multivariate statistical analysis
Author(s): de la Rosa F, Barrado E, Vega M, Buceta N, Pardo R, Tesedo A, Romero H
Source: QUIMICA ANALITICA 17 (3): 139-145 1998
Abstract: Fatty acid composition of a variety of finfish species broadly used for human consumption (sole, pomfret, whiting, salmon, trout and cod) was determined by gas chromatography as fatty acid methyl esters (FAMEs) after transesterification. Cooking processes applied were boiling, frying, frying in breadcrumbs, microwave oven, grilling and roasting, and all raw and cooked samples were analysed to investigate the changes caused in fatty acid composition by the fish processing. The vegetable oil used for cooking consisted of a mixture of 50% olive oil and 50% sunflower oil.

Multivariate statistical analysis of the data showed significant differences between fish species and cooking treatments: (i) Fatty acid composition of pomfret, sole, whiting and cod samples cooked with vegetable oil evolves by increasing the contents of C18:1 and C18:2, mainly provided the oil, whilst little effect on salmon and trout samples is observed. (ii) Pomfret and cod contain the high percentages of saturated fatty acids. (iii) Salmon contains both saturated and unsaturated fatty acids. (iv) Fatty acid composition of raw trout, sole and whiting was found to he similar, with high contents of unsaturated fatty acids and the lower portions of saturated fatty acids.
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Hope this helps,
Pascal