|What Are Transfats?
|Trans fatty acids—trans
fats—are made by adding hydrogen to vegetable oil to create
semi-solid fats, such as shortening and margarine, which help food
retain flavor and texture over a long shelf life. The arrangement
of hydrogen molecules in relation to carbon accounts for differences
between trans, saturated, and unsaturated fats. Trans fats appear
to raise heart disease risk by increasing LDL, or “bad” cholesterol,
and decreasing HDL, the “good” kind.
Trans fats are still found in many processed foods, including crackers, cookies,
and fried and baked goods. They cannot be eliminated from the diet completely,
since small amounts appear in the meat and milk of cows and other ruminant animals.
A healthy goal is to trim trans fat intake to less than 1 percent of total calories.
The first patent is filed with the British Patent Office for technology used
to make trans fats.
Two world wars and the Depression push thrifty U.S. consumers into using economical
products containing trans fats, such as sticks of margarine and Crisco.
Little is known about the relationship between dietary fats and health.
The first McDonald's restaurant opens in San Bernadino, Calif. The American
diet begins to include more and more high-fat processed and fast food.
The Lancet publishes controversial studies by University
of Minnesota scientist Ancel Keys hinting that a high-fat saturated
diet leads to coronary heart disease. Food manufacturers' studies
of a possible link between trans fats and cholesterol levels yield
Three groundbreaking, long-term epidemiologic studies uncover associations
between dietary and lifestyle factors and disease, with HSPH faculty members
serving as principal and co-investigators as the studies evolve. At Brigham
and Women's Hospital, Channing Laboratory investigator Frank Speizer launches
the first Nurses' Health Study in 1976, collecting health and dietary data
from 121,700 women, while the HSPH Department of Nutrition's Health Professionals
Follow-up Study begins in 1986, collecting data from 52,000 men. In 1989,
the Nurses' Health Study II begins, enrolling 116,000 young women.
Studies by HSPH's Sacks show that beef tallow is used in fried fast foods,
even fish. Media attention prods restaurant chains to switch to hydrogenated
vegetable oils laden with trans fats.
Health Aspects of Dietary Trans Fatty Acids, an overview of research prepared
for the FDA by the Federation of American Societies for Experimental Biology,
concludes that trans fats are probably akin to saturated fats in their cholesterol-raising
properties, but that more research is needed.
Netherlands nutrition researcher Martijn Katan asks European food conglomerate
Unilever to fund a study of the effect of trans fats on blood lipids.
The Nutrition Labeling and Education
Act (NLEA) is signed into law in response to lobbying by the American
Heart Association and other consumer groups. The law requires manufacturers
of saturated and unsaturated fats, cholesterol, sodium, sugar, fiber,
protein, and carbohydrates in food products sold in the U.S., and sets
for health claims and descriptors such as "lite" and "low
Reporting in the New England Journal
of Medicine, Katan and colleagues show that high levels of trans
fat--typical of the European diet--increase LDL ("bad")
cholesterol almost as much as saturated fat and, unlike saturated
fat, decrease HDL ("good") cholesterol. This finding will
be replicated elsewhere many times.
The U.S. Department of Agriculture unveils a new food pyramid extolling the
benefits of carbohydrates but ignoring the dangers of trans fats. Trans-fat
free margarines--already available in Europe--are introduced in the U.S.
Willett, Stampfer, Manson, and others involved in the Nurses' Health studies
find ties between trans fats and coronary artery disease in women. They
publish their findings in the Lancet, using data on the trans fatty acid
content of foods from Sacks' lab.
Citing HSPH's and others' findings, the Center for Science in the Public Interest
files a petition requesting the FDA to take steps to add trans-fats content
to nutrition labels. After inviting comments, the agency concludes that
research does not support this requirement.
At HSPH, Willett and Ascherio's commentary in the American Journal of Public
Health describes how trans fats are more damaging to heart health than
saturated fats and are likely responsible for at least 30,000 premature U.S.
deaths per year.
International food conglomerate Unilever,
led by nutrition chief Onno Korver, moves to eliminate trans fats from
margarines and spreads, and reduce saturated fats. This policy requires
restructuring at every level, from farming to processing, labeling,
Annual direct costs of obesity to the American economy reach $100 billion,
according to an analysis by HSPH's Colditz et al. in Obesity Research.
The Center for Science in the Public Interest calls on restaurants and food
manufacturers to disclose trans fats levels and switch to liquid vegetable
oils, charging, for example, that trans fats in fries cause twice as much
damage to arteries as saturated fats. "They might as well be frying
in lard," charges one Center scientist.
Hu and others from HSPH and the Channing Laboratory publish the most detailed
analysis of types of fat in the New England Journal of Medicine.
Trans fat is by far the worst.
After taking public comments two more times, the FDA proposes rules requiring
that the amount of trans fats be listed on nutrition labels. The FDA advises
consumers to cut their intake as much as possible, then reverses course--and
holds up finalizing the process--in part to consider the 2001 Report of
the National Cholesterol Education Program from the Institute of Medicine/National
Academy of Sciences and 2000 Dietary Guidelines for Americans.
Katan and HSPH's Ascherio, Stampfer, Willett, and others find that trans fats'
adverse effects on the LDL/HDL cholesterol ratio extend to even lower doses
than was previously documented.
New dietary guidelines are released by the Department of Health and Human Services
and USDA. Guidelines committee member Meir Stampfer of HSPH sees little
difference between the 1995 and 2000 recommendations, despite mounting
evidence that some fats are healthier than others.
President George W. Bush appoints HSPH's Graham as head of the Office of Information
and Regulatory Affairs in the Office of Management and Budget.
HSPH's Willett unveils a new food pyramid
based on the Nurses' Health and Health Professionals Follow-Up studies
and others worldwide, and includes it in his book, Eat, Drink,
and Be Healthy: The Harvard Medical School Guide to Healthy Eating,
and at www.hsph.harvard.edu/nutritionsource/pyramids.html.
Graham directs the FDA to either make
the trans-fat labeling change or explain why not.
At the FDA's Center for Food Safety and Applied Nutrition, director Joseph
Levitt champions the push for trans fats labeling. The FDA reviews evidence
and recommendations from non-advocacy groups such as the Institute of Medicine,
which includes HSPH's Rimm, and the Advisory Committee on the 2000 Dietary
Guidelines for Americans, which includes Stampfer.
Many major food businesses, including Frito-Lay and Olivio margarine, switch
to more healthful cooking oils.
The FDA requires trans fats to be labeled beginning January 1, 2006.
Rimm of HSPH and co-authors, including Dariush Mozaffarian of Brigham and Women's
Channing Laboratory, publish two papers documenting that greater intake
of trans fat predicts higher levels of inflammatory factors in the blood,
which in turn herald risks of heart disease and type 2 diabetes.
The latest version of the US Dietary Guidelines is released, with a clear message:
Consume as little trans fat as possible, and limit added sugar. Guidelines
Committee member Carlos Camargo notes that traditional critics of the USDA
and food industry describe these guidelines as "the most health-oriented
The USDA unveils a controversial new food pyramid, (see http://mypyramid.gov/)
which champions exercise but omits clear directives on trans fats and sugar-laden
drinks. In a critique, Camargo says: "If you want to tell [people] to
avoid trans fats, you spell it out. You say avoid doughnuts, potato chips,
French fries. You say look at the label, and pick zero!"
January 1, 2006
The trans fats ruling becomes law. Observes
Willett: "Having to display the trans fats content of food was a strong
incentive to reduce or eliminate them, so many foods are now much lower in
trans fats than they were even a year ago. This is important because not everyone,
for example, many adolescents, pays attention to food labels while making decisions."
The battle against trans fats continues. Some consumer advocates aim to require
restaurants to eliminate trans fats. Willett wants to see partially hydrogenated
fats removed from the FDA Generally Regarded as Safe category (GRAS), which
would essentially eliminate their use. "Given that every major review
of trans fats has concluded that intake should be as low as possible," he
says, "it is indefensible that they be allowed as GRAS constituents