Trans-fats come under fire
Nutrition experts call for ban on hidden food
villain.
19 May 2004
HELEN
PEARSON
Now there is a new reason to avoid a side of fries. The latest food
culprits are called trans-fatty acids, or "trans-fats", and
a campaign is being launched today to purge these molecules from the
United States' cakes, snacks and fast foods.
Never heard of them? You undoubtedly eat them. Small quantities of
trans-fats occur naturally in meats and dairy products, but most
arrive in our stomachs through processed foods. They are manufactured
by pumping hydrogen into vegetable oils to create partially
hydrogenated oils and soild margarines.
Such fats are preferred by industry because they are versatile and
last longer. But nutrition experts say trans-fats are disastrous for
your health. Whereas saturated fats raise both 'bad' low density
lipoprotein cholesterol (LDL) and 'good' high density lipoproteins (HDL),
trans-fats boost LDL without affecting HDL, increasing the risk of
heart disease.
Nutritional guidelines have long advocated cutting back on the
saturated fatty acids found in meat and dairy products, and boosting
unsaturated fats abundant in nuts, seeds and vegetable oils.
But trans-fats have taken longer to attract attention because their
effects on health were less clear. "There wasn't a strong enough
science base to make a case," says Elaine Turner who studies
human nutrition at the University of Florida, Gainesville.
TransFreeAmerica
Evidence for the harmful effects of trans-fats has mounted, however.
In 2002, a US expert committee charged with making nutritional
recommendations concluded that there was no level of trans-fats in the
diet that could be deemed safe.
A US nutritional group called the Center for Science in the Public
Interest, based in Washington DC, now hopes that its TransFreeAmerica
campaign will raise awareness of the health concerns. It is urging
food manufacturers to eliminate trans-fats and advising consumers to
boycott foods containing them. It is also calling on the US Food and
Drug Administration to outlaw partially hydrogenated vegetable oils.
The plan is likely to meet resistance from some food industry
members reluctant to change existing supply and production processes,
predicts Turner. "It's difficult to think we would ever get
completely trans-fat free," she says.
Some countries and companies have already made moves to cut
trans-fats. In 2003, the Danish government issued regulations slashing
the amount allowed in foods.
In the United States, some food manufacturers such as Kraft Foods
and McCain are scaling back the amount of trans-fats in their products.
And from 2006, food companies will be required to list the amount of
trans-fat on nutrition labels, so that consumers can choose what to
buy.
The new campaign, "may accelerate the rate at which the
industry moves," says nutrition expert Alice Lichtenstein of
Tufts University in Boston. But it is important that trans-fats are
replaced with healthy alternatives, she points out, such as plant oils
rather than butter.
Food for thought
Fatty acids are the building blocks of fats, and the different
types are distinguished based on their chemical structure. All are
made up of strings of carbon atoms with hydrogen atoms attached to
them. In saturated fats, each carbon atom is bonded to as many
hydrogen atoms as it can hold.
Unsaturated fats contain fewer hydrogen atoms, and one or more
pairs of carbon atoms are linked by double chemical bonds. A fatty
acid with one double bond is called monounsaturated, those with more
than one are called polyunsaturated.
Manufacturers create trans-fats by adding hydrogen to unsaturated
fats. The process rearranges the hydrogen atoms around the double
bonds so they are on opposite sides of the carbon chain.
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