arkie6

From that link posted, how did you come to title of this topic "No amount of trans fatty acid safe"? I didn't get that from that link. Did I miss something? The title of that very long report (33 page pdf file) is "Letter Report on Dietary Reference Intakes for Trans Fatty Acids" by the Institutes of Medicine. I may have overlooked it, but nowhere in that report did I find anything to support the title of this topic. In the summary of that report they state:

"There is a positive linear trend between trans fatty acid intake and total and LDL cholesterol concentration, and therefore increased risk fo CHD, thus suggesting a Tolerable Upper Intake Level UL of zero. Because trans fatty acids are unavoidable in ordinary diets, achieving such a UL would require extraordinary changes in patterns of dietary intake. Such extraordinary adjustments may introduce other undesirable effects, e.g. elimination of foods such as dairy products and meats, that contain trans fatty acids may result in inadequate intakes of protein and certain macronutrients, and uknown unquatifiable health risks may be introduced by any extreme adjustments in dietary pattern. For these reasons, no UL is proposed. Nevertheles, it is recommended that trans fatty acid consumption be as low as possible while consuming nutrionally adequate diet."

It should also be noted (it was mentioned in the report but with little emphasis) that the trans fatty acids found in meat and dairy are the naturally occurring result of the bacterial fermentation of polyunsaturated fats that ruminants (cows, sheep, goats, deer, etc) consume in grasses and grains. These runinant trans fatty acids are primarily vaccenic acid. On the other hand, the trans fatty acids created during the partial hydrodgenation of vegetable oils is primarily elaidic acid, a relative rarity in the human diet prior to industrialization.

Studies that have shown adverse health effects from trans fatty acids have primarily focused on the trans fats from partial hydrogenation. In addition, the contribution in the average diet today from naturally occurring vaccenic acid from things like meat and dairy is approximately 10% or less of that contribution from elaidic acid, which is found in things like margarine, shortening, and the majority of processed foods.

Your above quote even states that human milk is approximately 1-5% trans fats, which is approximately the same percentage as that found in dairy and meat products, compared to 20%-50% trans found in stick margarine and shortening. So is the NIH suggesting that new mothers should not nurse their babies?

Oh yeah, another thing, that link and several others that I have read recently indicates that the naturally occurring trans vaccenic acid converts in tissues to the isomer conjugated linoleic acid (CLA) which has been shown in several studies to have anti-carciogenic properties. That sounds like a beneficial property to me, contrary to what that report might indicate.

Alan

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The tragedy of science is the slaying of a beautiful hypothesis by an ugly fact. T H Huxley