Transforming the American Diet

Presented by Jean Zancanella MS RD

Division of Nutrition, University of Utah

June 12, 2007

The Newest Food Fear!

What are trans fats?

Trans fats are formed during the process of partial hydrogenation

They are used to harden and stabilize liquid vegetable oil

Review of fats

Saturated (no double bonds between carbons) Unsaturated (one or more double bonds between carbons)

Mono-unsaturatedPolyunsaturatedOmega 3 fatty acids

Fatty acid configurations

Fatty acid composition of oils

What are trans fats

Trans fat is the common name for a type of unsaturated fat with trans isomer fatty acid(s). They may be monounsaturated or polyunsaturated.

A particular class of trans fats occurs, in very small quantities, in meat and dairy products from ruminants

Most trans fats consumed today, however, are industrially created as a side effect of hydrogenation of plant oils

Hydrogenation

Hydrogenation results in the conversion of liquid vegetable oils to solid or semi-solid fats, such as those present in margarine.

Hydrogenation converts unsaturated fatty acids to saturated ones. In practice the process is not usually carried to completion.

The result is usually described as partially hydrogenated vegetable oil.

Cis Fatty acid

Trans fatty acids (kinky fat)

Major trans fat found in vegetable oil (elaidic acid)

Oleic acid (a cis unsaturated fatty acid that makes up 55-80% of olive oil

Why do food processors use them?

They improve shelf life

Changes the melting point

Produces a more desirable texture in baking

Produces a desirable mouth feel

For years we thought they were better than the alternative saturated fats (prior to 1988)

The health concerns

Trans fat consumption has been strongly linked to risk for coronary heart disease

Trans fats have adverse effects on serum lipids and lipoprotein patterns

Trans fats increase LDL cholesterol and decrease HDL cholesterol

Saturated fats increase LDL cholesterol but have no effect on HDL levels

Lipoprotein review

HDL: high density lipoprotein, aka good cholesterol

LDL: low density lipoprotein; aka bad cholesterol

Cholesterol: a sterol found only in animal products. In humans it is strongly correlated with cardiovascular disease

The Nurses Health Study

A Harvard study in which 120,000 nurses have been followed since 1976.

Analyzed 14 years of data and 900 coronary events.

For each 2% increase in energy from trans fats, a nurses CHD risk doubled

Trans fats and disease risk

There may be other risks for disease as wellCancer

Diabetes

Obesity

Liver Disfunction

Infertility• At this time results are inconclusive

The regulatory environment

FDA regulations

On July 11, 2003, the FDA issued a regulation requiring manufacturers to list trans fat on the Nutrition Facts panel of foods and some dietary supplements.

The regulation allows trans fat levels of less than 0.5 grams per serving to be labeled as 0 grams per serving. The FDA did not approve nutrient content claims such as "trans fat free" or "low trans fat,"

Declaration of Trans Fat in the Nutrition Facts Panel

Trans fat is included in the U.S. Nutrition Facts table on a separate line immediately under the line for saturated fat. No DV is listed for trans fat. Declared as "0" if < 0.5 g per serving; if "0" may omit declaration and state "not a significant source of trans fat"

Nutrition Facts Panel

The Food Industry

Trans fat free Crisco!

Main approaches used by industry to decrease trans fat in food

Customization of crop varieties (genetic engineering of crops)

Modification of fatty acid composition by processing

Use of fully saturated fats (animal fats, tropical oils, etc)

Food reformulation (change the “recipe”)

University Dining Services at Princeton

Can the restaurant industry step up?

Applebees

Denny’s

Starbucks

McDonalds

Kentucky Fried Chicken

Friday’s

The Walt Disney Co.

Red Lobster

Olive Garden

Wendy’s

How much are we eating and how much should we be eating?

Average trans fat intake vs recommended intake

About 5.8 grams (2.6% of calories)

American Heart Association recommends <1% of daily calories as trans fatFDA guidelines: 2 grams or less

How much trans fat are we eating?

Large Order of Fries 8 grams

Fast food fried apple pie

4.5 grams

Four shortbread cookies

1.5 grams

Large order popcorn chicken

7 grams

Chicken pot pie 14 grams

Mozaffarian D et al. N Engl J Med 2006;354:1601-1613

Typical Trans Fatty Acid Content of Foods Produced or Prepared with Partially Hydrogenated Vegetable Oils in the United States

Reducing intake of trans fats“Optimal Levels: Adverse effects are seen even at low levels of intake: 1 to 3 percent of total energy intake, or approximately 20 to 60 calories (2 to 7 g) for a person consuming 2000 calories per day.”

“Thus, complete or near-complete avoidance of industrially produced trans fats — consumption of less than 0.5 percent of the total energy intake — may be necessary to avoid adverse effects and would be prudent to minimize health risks. “

NEJM, April 2006

What not to eat Avoid foods with "partially hydrogenated" or "shortening" in the ingredients list. Even if the label says zero trans fats, don't believe it. If the words "partially hydrogenated" or "shortening" are in the ingredients list, it DOES contain trans fat.Assume that all unlabeled baked and fried goods contain partially hydrogenated oil, unless you know otherwise. Keep saturated fat intake low too. Remember that polyunsaturated fat and monounsaturated fats are good fats.

Questions????

Bibliographyhydrogenation." Wikipedia. Wikipedia, 2007. June. 2007.

Canadian Task Force on Trans Fats:TRANSforming the Food Supply, co-chaired by Health Canada and the Heart and Stroke Foundation of Canada, June 2006

FDA: Revealing Trans Fats, FDA Consumer September 2003

Trans Fats: Wikipedia 2007, June 2007

The American Heart Association

Bantransfats.com: the campaign to ban partially hydrogenated oils

Mayo Clinic.com: Trans Fats; a Cholesterol Double Whammy, December 2006

New England Journal of Medicine, April 2006

What are trans fats?Chemically, trans fats are made of the same building blocks as non-trans fats, but have a different arrangement. In trans fatty acid molecules, the hydrogen atoms bonded to pair(s) of doubly bonded carbon atoms (characteristic of all unsaturated fats) are in the trans rather than the cis arrangement. This results in a straight, rather than kinked, shape for the carbon chain. The shapes of these trans molecules are similar to saturated fats, which are always straight chains.