<div>
(soflsun @ May 22 2008,8:45)</div><div id="QUOTEHEAD">QUOTE</div><div id="QUOTE">Do you consider all fats to be equal? Is there a preferred source...saturated, hydrogenated, monounsaturated, polyunsaturated? It would seem that the health of a high fat diet could vary greatly based on the type of fats consumed.</div>
If you want to know more, and want to know the truth, read
The Colesterol Myths, by Uffe Ravnskov, MD, PhD. His book is the most well researched book I've ever read.
FYI, here are some snippets on polyunsaturated fatty acids: <div></div><div id="QUOTEHEAD">QUOTE</div><div id="QUOTE">The main part of a fatty acid is composed of a core of carbon atoms to which hydrogen atoms are attached. When the number of hydrogen atoms is optimal, their electrons form stable pairs with those of the carbon atoms. Examples of stable molecules are the saturated fatty acids, those said to be dangerous to the heart and the vessels. They are called saturated because they are saturated with hydrogen. Unsaturated fatty acids are missing hydrogen atoms. Monounsaturated fatty acids are missing two atoms, polyunsaturated fatty acids are missing four or more. This means that instead of sharing one pair of electrons with each other, some of the carbon atoms are sharing two pairs of electrons with their neighbor carbon instead of one pair, forming the so-called double bond. A double bond is less stable than a single bond. A hydrogen atom sitting close to a double bond is easily snatched by a free radical. Free radicals snatch hydrogen atoms because one or more of their electrons lack their partner; they are unpaired.
...
Inside the cells of our body oxidation is vital to cell function and life as long as this process is controlled by hormones and enzymes. Step by step, sugar and other fuel molecules are oxidized to water and carbon dioxide, a process that releases energy for the cell machinery. So far so good. But if oxidation occurs without control, as it may do if we are exposed to free radicals, molecules other than sugar may be oxidized. Among these others are the unstable polyunsaturated fatty acids. Loss of hydrogen atoms is disastrous to a polyunsaturated fatty acid (as to other molecules as well), because its stability is ruined and it is oxidized or split into lesser molecules with nasty qualities. Usually the human body is protected against oxidation thanks to many various antioxidats, kind molecules that donate hydrogen atoms to free radicals, thus protecting us against uncontrolled oxidation. Vitamin E, for example, is a well-known and important antioxidant that protects the polyunsaturated fatty acids in our cell membranes. There are many others. But if too many polyunsaturated fatty acids are present, or if too many free radicals are available, or if the amount of antioxidants are insufficient, then the antioxidants may fail to protect the body.
...
When too much polyunsaturated oil is given to laboratory animals, their white blood cells become damaged so that the animals die more easily from infectious diseases and cancer. We do not know for sure whether the same is valid for human beings, but we know that our immune system is sensitive to a surplus of polyunsaturated fatty acids. If preparation of such oils are added to the diet of patients who have received a kidney graft, the function of their white blood cells is hampered, resulting in better acceptance of foreighn material, including the transplanted kidney.
But other foreign and less useful material, such as bacteria and viruses, may also be accepted.
...
Today most deep-frying is done in vegetable oils. Very few know that if polyunsaturated fatty acids are kept hot over many hours, their tendency to produce cancer in laboratory animals increases.
...
The fact that polyunsaturated oils may increase aging was demonstrated by Dr. Edward Pickney. ... he asked a large number of patients how much polyunsaturated oils they usually consumed.
Fifty-four percent of the patients said that they had increased their intake considerably. Of those patients, 78 percent showed marked clinical signs of premature aging, and 60 percent had required the removal of one ore more skin lesions because of suspected malignany. Of the patients who had made no special efforts to consume polyunsaturated oils, thier figures were 18 and 8 percent respectively.
...
In the worldwide epidemiological study of atherosclerosis, the investigators found a connection between the degree of atherosclerosis and the total intake of fat. As there was no association between the intake of saturated fat and atherosclerosis, the association obviously concerned unsaturated fats.
...
The fact that polyunsaturated fats such as corn, soybean and sunflower oils are liquid, even at cold temperatures, has been a problem for oil manufacturers in countries where butter and lard, and not vegetable oil, were traditionally used in the diet. Vegetable oil cannot be spread on bread, give unsatisfactory results in baking and produce burnt and rancid smells when used for frying.
However, ... food technologists invented a method for converting liquid vegetable oil into solid fat. This method ... changes the chemical structure of the polysaturated fatty acids and creates something called trans fatty acids. ...
The final product, which is a mixture of various polyunsaturated, saturated and trans fatty acids, is called partially hydrogenated oil and is used as an ingredient in many food products including margarine, crackers, cookies, doughnuts, french fries, potatoe chips, pastries and sweets.
...
... there is experimental evidence that trans fatty acids may inhibit growth. ... After two years the body weight of the mice fed with trans fatty acids was 20-25 percent lower than the weight of the control mice. Thus, although the mice had received exactly the same amount of calories, those who got trans fatty acids instead of other naturally occuring fatty acids did not grow as they should have.
... The consumption of trans fat has increased substantially in most Western countries during the last century.
... very often fat that is called polyunsaturated on the food labels may actually be trans fat, and foods labeled "low-fat" may in fact contain large amounts of fat, particularly trans fat.
</div>
Still wanna pour those vegetable oils onto your foods? Still wanna use margarine in baking?
But, polys are not entirely evil - used in moderation:
<div></div><div id="QUOTEHEAD">QUOTE</div><div id="QUOTE">What we know for certain is that polyunsaturated fatty acids may produce a great many unfortunate effects, none of them pleasant for human beings. We need polyunsaturated fats in small amounts to keep us healthy; some of them are even essential to life.</div>From wikipedia on omega-3 and omega-6 fatty acids:
<div></div><div id="QUOTEHEAD">QUOTE</div><div id="QUOTE">n-3 fatty acids (popularly referred to as [omega]-3 fatty acids or omega-3 fatty acids) are a family of
[poly]unsaturated fatty acids which have in common a carbon–carbon double bond in the n-3 position; that is, the third bond from the end of the fatty acid. Important nutritionally essential n-3 fatty acids are: [alpha]-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA).
...
n-6 fatty acids (popularly referred to as [omega]-6 fatty acids or omega-6 fatty acids) are a family of
[poly]unsaturated fatty acids which have in common a carbon–carbon double bond in the n-6 position; that is, the sixth bond from the end of the fatty acid. Linoleic acid (18:2, n-6), the shortest-chained n-6 fatty acid, is an essential fatty acid. Arachidonic acid (20:4) is a physiologically significant n-6 fatty acid and is the precursor for prostaglandins and other physiologically active molecules.</div>
