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Informations about fatty acids
and olive oil

The following text is drawn from an article by the American Heart Association found at the UK web site
http://www6.mccs.uky.edu/disease/cardiac/transfat.htm  
and kindly sent to me by  Kayenoble@aol.com through OliveOil@onelist.com :
[TOP] [more about fatty acids] [trans fats] [olive oil]

Review of types of dietary fats ...

Fats and oils are mixtures of  fatty acids, which are:

saturated
monounsaturated
polyunsaturated

Saturated fats are solid at room temperature, and are more stable than the
others. They do not readily combine with oxygen, or oxidize. Saturated fatty
acids raise blood cholesterol, which is a major risk for heart disease.

Unsaturated fatty acids include two common types:

Monounsaturated oils are liquid at room temperature but start to solidify at
refrigerator temperatures. They seem to lower blood cholesterol when
substituted for saturated fatty acids.

Polyunsaturated fatty acids are liquid at room temperature and in the
refrigerator. They easily combine with oxygen in the air to become rancid.
Polyunsaturated fatty acids help to lower total blood cholesterol.

Dietary cholesterol found in animal fats also has a blood cholesterol-raising
effect. A food rich in either saturated fat or cholesterol can cause problems
for people trying to lower blood cholesterol.

In the last few years, studies published on the potential cholesterol-raising
effects of trans fatty acids have caused confusion over which types of
dietary fats are beneficial and which types add to the risk of heart disease.
Stick margarines, for example, are known to contribute more trans fatty acids
than non-hydrogenated oils or other fats. This raised public concern about
the use of margarine and whether other options, including butter, might be a
better choice.

What are trans fats?
To make foods that will stay fresh on the shelf or to get a solid fat
product, such as margarine, food manufacturers hydrogenate polyunsaturated
oils. Hydrogenate means to add hydrogen, or, in the case of fatty acids, to
saturate.

The body of a fatty acid molecule consists of a chain of carbon atoms with
hydrogen atoms attached. In their natural state, most unsaturated fatty acids
are cis fatty acids, which means on the same side. That is, the hydrogen
atoms are on the same side of the carbons.

Trans means across. When unsaturated fatty acids are hydrogenated, some of
the hydrogen atoms are added on opposite sides of the molecule.
Hydrogenation, therefore, not only makes the fatty acid more saturated, it
also changes the structure of the fatty acid molecules in another way.

These newly created fatty acids -- trans fatty acids -- tend to raise blood
cholesterol levels, but not as much as saturated fatty acids.

AHA Recommendation
Butter is rich in both saturated fat and cholesterol, and is a food that
contributes to atherosclerosis.

Most margarine is made from vegetable fat and contributes no dietary
cholesterol. The more liquid the margarine (tub or liquid forms), the less
hydrogenated it is and the less trans fatty acid it contains.

Therefore, margarine is still a preferable substitute for butter, and soft
margarines are better than hard ones.

The American Heart Association recommends that consumers use soft or liquid
margarine for spreading (my comment: olive oil is even better!).
For baking, select a stick margarine with liquid vegetable oil as the first ingredient listed on the label.

Trans fatty acids from all sources probably provide about 5 to 8 percent of
energy in a typical Western diet, which has about 12 percent of calories from
saturated fat and 34 percent of calories from total dietary fat. The AHA's
Nutrition Committee strongly advises that healthy Americans over the age of
two limit their total fat intake to less than 30 percent of total calories.
By limiting the total daily intake of fats and oils to 5-8 teaspoons, you are
not likely to get an excess of trans fatty acids.

Source: American Heart Association (AHA)

Another valuable information about fatty acids has been sent from
Adrian.Shaw@aber.ac.uk
Sefydliad Y Gwyddorau Biolegol, Prifysgol Cymru,
Aberystwyth, Ceredigion, Cymru
http://pcjagg.dbs.aber.ac.uk/mynegai.html
on Tuesday, 23 Nov 1999 through OliveOil@onelist.com

[TOP] [AHA review] [trans fats] [olive oil]

Saturated fats: The carbon chain contains only single C-C bonds (no double or
triple bonds)

Unsaturated fats: The carbon chain contains one C=C double bond
(monounsaturated, e.g. oleic acid, most common in olive oil) or more than one
(polyunsaturated). The double bonds create a natural kink, or twist in the
chain, which is nearly always of the cis form. Rarely in nature, the kink
will go the other way; this is the trans form. (Fatty acids with
triple-bonded carbon chains are also referred to as unsaturated.)

Hydrogenated fats: These are formed by bombarding unsaturated fatty
acids with hydrogen (someone please correct me if I have this wrong! this is
all from memory). Many cis bonds become trans bonds during this process.
Trans molecules have a different shape to cis molecules, and bind together
more easily, creating a harder fat. Chemically speaking, they are still
unsaturated, although UK labelling law does not allow them to be classed
under any of polyunsaturated, monounsaturated or saturated on food labels
(they are usually listed separately).

Trans fats do not occur in significant quantities in any natural food; they
are an unnatural product in our diet. Their safety is currently the subject
of much debate.

More about trans fats

Failure to provide complete and accurate labeling of groups of fatty acids, including the trans fatty acids and the medium-chain fatty acids such as lauric acid, has led to confusion and misinformation for the clinician and researcher, as well as for the public at large, about the fats and oils in the foods. The 1990 labeling law did not improve the situation, and the continued removal from our foods of the more stable fats and oils such as the antimicrobial, antiviral lauric fats, and their replacement with even more of the partially hydrogenated oils, led to further increases in trans fatty acids in the U.S. foods. In January 1999, the U.S. Food and Drug Administration announced that regulations to require the labeling of the trans fatty acids has been put on the "A list" (highest priority) for 1999. According to the Institute of Shortening and Edible Oils spokesperson, the regulation information will be forthcoming in August 1999.
Mary G. Enig, Ph.D.

Lichtenstein et al (NEJM June 24, 1999) has confirmed the finding of others that there is lowering of Lp(a), the lipoprotein associated with increased risk of development of cardiovascular disease, by saturated fat and the raising of Lp(a) by trans fatty acids. This study was conducted using a number of soybean oil sources including soybean oil shortening containing 9.9 grams of trans fatty acids per 100 grams of fat, whereas most of the soybean oil shortenings used in cakes, cookies, crackers, and donuts, as well as in deep fat frying, in the US contain between 35 and 50 grams of trans fatty acids per 100 grams of fat. The stick margarine used for the study contained 20.1 grams of trans fatty acids per 100 grams of fat, whereas some of the popular stick margarines contains more than 30 grams of trans fatty acids per 100 grams of fat. All of the soybean oil diets lowered HDL cholesterol levels. Thus the findings of adverse effects from consumption of the trans fatty acids were seen in diets potentially lower in trans than it is possible for some people to be consuming. Ascherio et al (NEJM June 24, 1999) has reviewed the trans fatty acid and coronary heart disease research and conclude with several points including the fact that "...studies indicate an adverse effect of trans fatty acids on the risk of coronary heart disease...[and that]...on a per-gram basis, the adverse effect of trans fatty acids appears to be stronger than that of saturated fatty acids." These researchers conclude that "[t]hese data highlight the need for labeling requirements that include fast foods."
Mary G. Enig, Ph.D.

Why it's better to use
Extravergine Olive Oil
in your food
[TOP] [fatty acids][more about fatty acids]

Extra vergin olive oil is significantly better digestible than other vegetal oils. A publication of the Region of Umbria, Italy (*) says that if olive oil is given a figure of 100% other oils are digestible as follows:

sunflower  83%
peanut      81%
linseed      79%
sesame     57%
corn         36%

(*)The figures come from a booklet on olive oil in Umbria. It is available from: Regione Umbria, Centro Direzionale Fontivegge, 06100 Perugia, Italy. (This information has been given by Brian Chatterton)

Extravergine olive oil is composed mainly of unsaturated fat acids which lower blood colesterol, with a high part of monounsaturated fat acids, which are more stable than the polyunsaturated fat acids. It also contains very important antioxidants like polyphenolic components and tocoferols (vitamin E). It does not contain hydrogenated or trans fatty acids.

The following results are drawn from a research in several editions (see references below) of "Uliveto Italia", the magazine of the italian association "Mastri Oleari" and have been published in OliveOil@onelist.com on September,2nd 1999.

According to various studies, the ratio of oleic/linoleic oil varies between different countries (nr.34 march 1996, see also nr.32 1995): (medium values, table of Wolff)

As the monoinsatured fatty acids are more "valid" for health than the polyunsaturated fatty acids, and within the first category the oleic acid is the most favourable for our diet, the ratio between these two categories is ONE criteria (not the only one!) for the quality of the olive oil.
According to this list the Spanish oil has the highest ratio, followed by the italian oils. Of course there are big differences within each nation, so the south italian oil is said to have a lower ratio than the northern one.
But as I already stated this alone does not mean very much,  because even within the regions there can be big differences, according to the altitude, the cultivar and other factors as the type of extraction process.
From another research made on olives from the central-south of Italy result ratios of oleic/linoleic varying from 5.9 to 17.0 (nr.29 1994). The lowest value in this research is an oil from Frantoio olives in the province of Grosseto (south-west Tuscany), the highest is from Leccino olives of Benevento (more or less the area of Naples). But this is not necessarily a general characteristic, so from Grosseto there are other oils with a ratio as high as 12.6 or 14.1 !

Very important is also the content of antioxidants like polyphenolic components and tocoferols (mainly alpha-tocopherol or vitamin E, see nr.17 1992), and the ratio of saturated to unsaturated fatty acids which should as low as possible. Medium values in Italy are around 0.13 to 0.20 saturated/unsaturated.