Stronger Proof That Trans
Fats Are Bad
April 10, 2004
Scientists have warned us that
eating lots of trans fats, a common component in a variety of fatty foods,
can lead to heart problems. A recent study has strengthened the caution, as
researchers have investigated these fats in the bodies of first-heart-attack
patients.
From 1995 to 1997, scientists from the Commonwealth Scientific and
Industrial Research Organization (CSIRO) in Adelaide, South Australia,
acquired dietary information as well as fat biopsy samples from 79 people.
Each had just had a first heart attack. The researchers obtained similar
information and biopsy samples from 167 residents of Adelaide without heart
problems. The researchers inquired specifically about the participants' type
and amount of fat intake. The heart patients and healthy individuals were
also matched for age, gender, and socioeconomic background.
Analysis revealed that trans fats from both animal and vegetable sources
were significantly more abundant in the fat tissues of heart attack patients
than in the healthy volunteers. The finding supports the idea that trans
fats increase the risk of heart disease. "It doesn't necessarily absolutely
confirm cause and effect, but it's certainly very damning evidence," says
study coauthor Manny Noakes.
Moreover, trans fats are "possibly worse" for the heart than saturated fats
are, Noakes adds, as the relationship of abundant trans fats with heart risk
remained even after the scientists statistically accounted for the effect of
saturated fats in the participants' diets. The findings appear in the April
Journal of Nutrition.
Noakes says that the significance of her team's findings stems from their
measurement of trans fats in body fat, which correlates with a relatively
long-term record of trans fat intake. Earlier studies based on blood-fat
data and other observations about people with heart disease linked
cardiovascular disease with trans fat consumption. The older data and the
stronger CSIRO study together are "sufficiently strong to make a
recommendation to reduce the level of trans fat in the food supply," says
Noakes.
Disappearing act
Indeed, trans fats' adverse effects on people's health have prompted a few
countries to urge consumers away from trans fat-rich foods. Last year,
Denmark became the first country to announce that it would ban hydrogenated
fats, says Noakes. The United States has since requested food manufacturers
to label quantities of hydrogenated trans fat in most foods (http://www.sciencenews.org/articles/20030719/food.asp).
Australia also plans trans fat labeling of foods so people at risk of heart
disease, type 2 diabetes, and other conditions can avoid excessive
consumption of trans fats.
During the CSIRO study, major margarine producers in Australia voluntarily
and coincidentally replaced trans fats in their products with small amounts
of saturated fats. Margarine had been the primary vegetable source of trans
fats and had accounted for between 36 and 64 percent of the country's total
trans fat intake.
The removal of trans fats from the product during the study gave Noakes'
team an opportunity to assess how quickly trans fats clear from body fat.
The data show that the body clears such fats "unexpectedly" rapidly in
people with and without heart disease, Noakes says. The concentration of
trans fats in the body fat of people who continued to eat margarine dropped
by some 20 percent within a few months.
What happened to the trans fats? "As we change our diet, the nature of our
[body] fat changes too," because it's constantly being used for energy,
Noakes explains.
The quick disappearance of trans fats from fat tissue is "not surprising,
but still is nice to see," says Willett. Overall, he says, the findings from
the CSIRO study strengthen the argument that "trans fats should be removed
from the food supply as rapidly as possible." Indeed, he finds it troubling
that some of the U.S. food industry hasn't followed the lead of European
food producers, who have nearly eliminated trans fats from their products.
He describes hydrogenated fat as a "metabolic poison with zero nutritional
value." He asks, "At what point does . . . feeding it to people without
their consent become criminal?"