News coverage of trans fat prompts shoppers to avoid certain products

Apr 20 2009

News coverage about the harmful effects of trans fat, combined with labeling information, may influence consumers' short-term purchases of foods high in trans fat, but is not enough to prompt shoppers to avoid these potentially artery-clogging purchases over the long term, according to a study in the May issue of the American Journal of Preventive Medicine.

"Our study found that when consumers are exposed to information about the harmful effects of trans fat on the local news, they buy fewer products high in trans fat. In the absence of broader changes in food policy and public education, news coverage may be insufficient to produce lasting reductions in trans-fat purchases and consumption," said Jeff Niederdeppe, Ph.D., who conducted the research as a Robert Wood Johnson Foundation Health & Society Scholar at the University of Wisconsin, and is the lead author of the study, "News Coverage and Sales of Products with Trans Fat: Effects Before and After Changes in Federal Labeling Policy."

In 2006, the Food and Drug Administration (FDA) mandated that the amount of trans fat per serving be listed on nutrition labels. This federal policy requires food products to list the amount of trans fat if it exceeds 0.5 grams per serving. The study examined news effects on the sale of seven brand-specific products that contained trans fat at the time of the study, including buttered popcorn, vegetable shortening, buttermilk biscuits, sandwich cookies, stick margarine, crescent rolls and hotdogs.

For up to one week after the stories appeared, consumer purchases dropped significantly for six out of seven products, with hot dog purchases being the exception. Three weeks later, consumer purchases went back up for half of these products.

Trans fat is found in partially hydrogenated (partially hardened) oils and is associated with a substantially increased risk of coronary heart disease.

Efforts to reduce trans-fat consumption include the implementation of state and local laws to force the food industry to replace trans fat with more healthy liquid vegetable oils. The federal government has also taken steps to lower trans-fat consumption by requiring that the amount of trans fat be listed on nutrition labels for all conventional foods and dietary supplements. Many food companies have voluntarily reduced the amount of trans fat in their products since the labeling policy went into effect.

"While news coverage is a potentially valuable source of information, and one that can help the public to make informed decisions about their health, this study shows that news coverage alone is not enough to sustain changes in consumer behavior," said Dominick L. Frosch, Ph.D., co-author of the study and an alumnus of the RWJF Health & Society Scholars Program. "Since the FDA labeling change, there has been no coordinated effort to educate the public about the dangers of trans fat."

Frosch is an assistant professor at the David Geffen School of Medicine, University of California, Los Angeles and an associate staff scientist at the Palo Alto Medical Foundation Research Institute.

Researchers examined news coverage about trans fat and sales data for seven products containing trans fat from a major grocery store chain in Los Angeles County, Calif., before and after the federal labeling change. A recurring theme of the news coverage included the relationship between trans fat consumption and coronary heart disease.

Los Angeles County was selected for the study's location because it is served by a single major daily newspaper (the Los Angeles Times), had substantial news coverage about trans fat due to a pending state ban and represents an economically and ethnically diverse population.