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More
Bad News about Trans Fats
July 2008
More Bad News about Trans Fats
Several decades ago scientists discovered
saturated fats in our diets, including butter and lard, tend to increase
the risk of heart disease by increasing the amount of LDL cholesterol (the
bad cholesterol) in our blood. As a result, food chemists went to work to
develop a fat that would have some of the same desirable properties as
saturated fats, but not be saturated. They turned their attention to
unsaturated fats which generally decrease LDL cholesterol. The
scientists altered the molecular make up of these fats through a process
called partial hydrogenation, resulting in the creation of trans
fats. So satisfactory were these fat and oil substitutes that they were
readily accepted as ingredients in many of our favorite foods such as bakery
products, margarine and dressings— providing many benefits such as extended
shelf life and desirable texture.
Problem solved? Unfortunately, several years
later studies began finding that trans fats were not decreasing our risk of
heart disease, but rather increasing it even more than saturated fat
did! What happened? It turned out that trans fats were not only increasing
LDL cholesterol, but also decreasing HDL cholesterol (the good cholesterol).
Trans fats were also found to cause inflammation of blood vessels,
increasing the risk of clot formation which can trigger a cardiovascular
event such as heart attack or stroke.
If that isn’t bad enough, recent studies have
shown an association between trans fats and increased risk of invasive
breast cancer. A seven-year study conducted by the French component of the
European Prospective Investigation into Cancer and Nutrition followed
almost 20,000 women who completed diet histories and provided blood samples.
In analyzing the results, scientists calculated that trans fats were
associated with a 75% increase in invasive breast cancer risk.
In another study, Harvard researchers followed
15,000 men over 13 years. Findings suggested that an increased intake of
trans fats may raise the risk of non-aggressive prostate tumors by
nearly 100%. However, trans fats do not appear to be linked to risk of
aggressive prostate tumor development.
Although it has not been proven in human
infants, a Brazilian study found that rats fed diets which included
partially hydrogenated oil (trans fats) had insulin insensitivity when they
matured. This suggests that exposure to trans fats causes blood glucose to
remain at a higher level than normal as rats mature, and thereby heightens
the risk of type 2 diabetes. These preliminary findings suggest further
examination of the impact on trans fats in humans is in order.
What can we do now to protect ourselves? The
FDA has mandated that trans fats be listed on all nutrition fact labels.
That’s good, but it is not a panacea. If trans fats are in a product at less
than .5g/ serving, identification is not required. An individual who
consumes several servings of processed foods could easily be ingesting much
more than the American Heart Association’s recommendation of no more than 1%
of calories/day from trans fats (approximately 2g/day in a 2000 calorie
diet).
The bad press on trans fats has not been lost
on the food industry. It has redoubled its efforts to eliminate trans fats
in our processed foods through chemical manipulation (esterification) of a
variety of oils. In the meantime, we can be empowered consumers by carefully
scrutinizing the nutrition facts label and the list of ingredients on
a food product, looking for words like "trans" and "partially hydrogenated."
We can ask restaurants we frequent if they use partially hydrogenated oils,
we can select "trans fat free" liquid or soft margarine, and we can
modify our recipes to use a variety of natural, unhydrogenated oils such as
olive and canola.
- Sources:
- American Journal of Epidemiology. Association between serum
trans-monounsaturated fatty acids and breast cancer risk in the E3N-DPIC
Study. June 2008.
- Cancer Epidemiology Biomarkers & Prevention (Vol. 17). A
prospective study of trans-fatty acid levels in blood and risk of
prostate cancer. Jan. 2008.
- Nutrition. Trans fatty acids in maternal milk lead to cardiac
insulin resistance in adult offspring. July-August 2008.
For more information about healthy eating, contact your
local extension office. The
Food Assistance Program can help people of all ages with low income buy
nutritious foods for a better diet. To find out more, call toll-free
1-888-369-4777.
Contents of this publication may be freely reproduced for
educational purposes. All other rights reserved. In each case, credit Karen
Hudson, MEd, RD, LD, Family Nutrition Program Coordinator, Department of
Human Nutrition; Kansas State
University; More Bad News about Trans Fats;
July 2008.
K-State Research and Extension is a short name for the
Kansas State University Agricultural Experiment Station and Cooperative
Extension Service, a program designed to generate and distribute useful
knowledge for the well-being of Kansans. Supported by county, state, federal
and private funds, the program has county Extension offices, experiment
fields, area Extension offices and regional research centers statewide. Its
headquarters is on the K-State campus, Manhattan. Brand names appearing in this publication are for product
identification purposes only. No endorsement is intended, nor is criticism implied of
similar products not mentioned.
Kansas State University Agricultural
Experiment Station and Cooperative Extension Service,
Manhattan, Kansas.
Kansas
State University is an equal opportunity provider and employer. Kansas State
University, County Extension Councils, Extension Districts, and the U.S.
Department of Agriculture cooperating.
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