In November of 2006, the New York City Department of Health
issued a citywide ban on the use of trans fats in restaurants. Another
directive has been to post calorie counts on menus as well, but we're not
dealing with this subject today.
It's the fats issue that has me preoccupied.
First, let's get our facts straight. Trans fats cannot be
seen, nor bought at the market. They are technically known as trans
fatty acids, and are part of some other fat or oil that can in fact be
bought.
Fats are made of chains containing mostly carbon and
hydrogen (there may be as many as 24 carbons in a chain). Each carbon has
four bonds, and each hydrogen has one, so a single carbon atom can hook up
with four hydrogen atoms. In a saturated fat chain, each carbon atom hooks
up with two hydrogens and one other carbon (except the first and the last
ones); in other words, saturated fats have only single bonds between
carbons.
h h h h h h h h h h
-c-c-c-c-c-c-c-c-c-c-c- ……
h h h h h h h h h h
A mono-unsaturated fat has one double bond between two
carbons only, and therefore is missing two hydrogen atoms.
h h h h h h h
-c-c-c=c-c-c-c-c-c-c-c- ……
h h h h h h h h h h
Polyunsaturated fats have two or more double bonds between
three or more carbons, and they are missing even more hydrogen atoms, which
makes them liquid at room temperature.
h h h h h
-c-c-c=c=c=c-c-c-c- ……
h h h h h h h
Hydrogenation or partial hydrogenation is an industrial
process that forces hydrogen back onto the carbon chain, thereby
artificially saturating it again. It is that process that causes the
appearance of the trans fats.
In natural poly-unsaturated fats, the carbon chain shows a
kink at the double bond point, called a cis configuration. When
polyunsaturated fats are industrially processed and partially hydrogenated
(to make them more solid at room temperature, or more saturated), the carbon
chain will be straight, rather than kinked, at the double bond point. That
is called a trans configuration. Because of this, trans fatty
acids are firmer and have a higher melting point than the equivalent cis
fatty acids.
The partial hydrogenation of plant oils was developed early in the 20th
Century, and first commercialized as shortening in 1911, and later on as
margarine. Partially hydrogenated fats have culinary properties similar to
butter or lard, but are much cheaper to produce. After World War II in
Europe, margarine became very popular, although the dairy industry was
violently opposed to it. The growing notion that saturated fats such as
butter produce heart disease is what fueled the demand for butter
substitutes. Industrially, it turned out that partially hydrogenated fats
performed excellently well in baked goods, and were cheaper to boot, so they
were quickly propelled into the market place. Eventually, a propaganda war
by the oil industry eliminated all naturally saturated fats (such as coconut
and palm oils), from all industrially produced cookies, crackers, and other
baked goods – even though there was scant evidence that those traditional
fats had anything at all to do with heart disease…. What replaced those
natural fats were, of course, hydrogenated and partially hydrogenated plant
fats, just like the oil industry wanted.
Although trans fats appear naturally in small amounts in meat and milk, the
problem really lies with the partially hydrogenated oils. A number of
studies, including data from the Nurses Study at Harvard, have clearly shown
that eating foods containing trans fat increases the risk of coronary heart
disease, and has been linked to chronic health conditions. Many restaurants
are voluntarily removing trans fats from their foods, and companies
are creating trans-fat-free products.
So far so good, but not good enough. Here are a few
problems I see. The ostensible bad guys are the "trans fats" – not the
partially hydrogenated fats, which I think are the real culprits. It may be
possible to create an industrially manipulated fat that is technically
similar to butter or shortening but without the trans fats. This would make
the NYC Dept of Health very happy – but it would still be an artificial fat,
in my eyes, and just as much of a problem. It will just take another 40
years to figure out what the problem is.
In the world of food and cooking, fats have a distinct and
important role to play. They carry flavor, contribute to satiety, and impart
textures that are essential to a variety of culinary creations. Saturated
fats are essential to classical European-style baking – cakes, cookies,
icings, pie crusts. Traditionally, these fats have been butter and lard;
coconut and palm oils became popular in processed foods in the middle of the
20th Century. They were replaced by the hydrogenated and
partially hydrogenated fats as I mentioned above. What now? It would make
perfect sense, now that the latter fats high in trans fatty acids have been
shown to be so detrimental, to go back to the traditional baking fats.
However, that is not likely to happen, as people are stuck in their
automatic notions that saturated fats are still undesirable.
The curious thing is that natural saturated fats, either
from plants or from healthy animals, are slowly being recognized as
healthful foods. Mary Enig, Ph.D., a specialist in the properties and uses
of fats and oils, has demonstrated conclusively that coconut oil is an
excellent ingredient in cooking, particularly because of its antibacterial
properties. A 2004 study published in the American Journal of Clinical
Nutrition found that in post menopausal women, a higher intake of
saturated fats was associated with a lower rate of progression of
atherosclerosis, whereas a high intake of carbohydrates as well as
polyunsaturated oils was associated with an increased rate of
atherosclerotic progression.
So yes, let’s eliminate trans fats from our foods.
More importantly, let’s eliminate hydrogenated and partly hydrogenated fats
from our foods, and go back to the natural fats that humans have consumed
for thousands of years: extra virgin olive oil, unrefined sesame oil,
butter, coconut oil, palm kernel oil, and other natural, local, and
traditional fats from healthy plants and animals.
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REFERENCES:
1. Enig MG. Know Your Fats: The Complete Primer for
Understanding the Nutrition of Fats, Oils, and Cholesterol. Silver Spring,
MD: Bethesda Press; 2000.
2. Mozaffarian D, Rimm EB, Herrington DM. Dietary fats, carbohydrate, and
progression of coronary atherosclerosis in postmenopausal women. Am J Clin
Nutr. Nov 2004;80(5):1175-1184.
