Life after Trans Fat?

Linda Kronheim, PA NEN

Trans fat, originally touted as an inexpensive and useful ingredient in food manufacturing, has become a dietary villain over the past several years. This transition occurred due to evidence that the hydrogenation process commonly used to produce this type of manufacturing-friendly fat is also detrimental to health, particularly heart health. Once the evidence of harmful health effects accumulated, legislative attempts to protect the public from consuming excessive amounts of trans fat began. Changes to the 2006 Food Label regulations required companies to declare the amount of trans fat in their products on labels. Continuing the trend, New York City then adopted the controversial ban of trans fats in its restaurants.

This pressure has pushed companies to reformulate products by either removing trans fat or by at least reducing the amounts enough to claim the trans fat–free label. (A product can be labeled trans fat–free if it contains less than ½ gram of trans fat per serving.) Food manufactures have been struggling to find a replacement that delivers a tasty product still acceptable to consumers. Trans fat became prevalent because of its taste, low cost, long shelf life and culinary properties. Manufacturers cite both the cost to find a replacement fat and the need to reformulate product with a new fat as major barriers to conforming to new dietary standards. What are the options for manufacturers and some of the dietary implications for consumers?

One option is to use alternative fats such as butter or tropical oils (including palm, palm kernel or coconut oil) that provide some desirable cooking characteristics. The dietary disadvantage is that these products are high in saturated fat, which is linked to heart disease risk. Decreasing saturated fats in the diet was an original impetus for using partially hydrogenated oils as a substitute; replacing trans fat with saturated fats seems like a step backward from a health perspective. A second option is to replace trans fats with oils high in mono or polyunsaturated fats. Conventional plant breeding and genetic engineering advances have allowed the production of oils with modified fatty acid composition. For example, high–oleic acid oils have a longer shelf life and are more stable when used for deep-frying. Widespread use of these genetically engineered oils may pose a problem for consumers who wish to avoid foods produced by this technology.

The third option is the use of interesterified fats. This process rearranges the fatty acids on a triglyceride in order to “custom build” a fat with the desired culinary characteristic. For example, this process can produce a liquid fat that acts more like a solid fat, which is useful in snack foods and bakery products. The health effects of interesterified fats are under debate. Stearic acid, a fatty acid found in both saturated fats and interesterified fats, is thought to have a relatively neutral impact on cholesterol at normal consumption levels. However, research recently published in Nutrition & Metabolism showed that a diet high in stearic acid–rich interesterified fat had detrimental effects on both cholesterol (decreasing HDL) and more surprisingly, glucose metabolism (increasing fasting and post-meal blood glucose and decreasing fasting insulin levels). Due to the significant metabolic changes in a short time period, the authors recommend additional research before widely recommending interesterified fats as a replacement for trans fat. This research is somewhat controversial; other researchers critique the study design and point out that the types of fats compared in the study are not equal substitutions for each other from a culinary perspective.

So what is the bottom line for nutrition educators? Regardless of the debate over the merits of legislating removal of trans fat from the food system, it seems clear that replacement fats are inevitable. We do know that saturated fat can contribute to heart disease and should still be limited in the diet. We also know that food labels can be somewhat deceiving; due to the “loophole” in labeling regulations, consumers can still consume a relatively high amount of trans fat even when eating products labeled trans fat–free. It appears that the scientific jury is still out on the health impacts of possible replacements for trans fat. Pennsylvania has initiated a task force to explore the best way to educate the public about the health risks and sources of trans fat. At this point, the best advice seems to focus on obtaining fat from mono or polyunsaturated fat sources, to avoid saturated and trans fats and to stay tuned for more information.

To read more, please see:

Food Products and Trans Fat-Staying on Top of Recent Changes http://www.eatright.org/cps/rde/xchg/ada/hs.xsl/nutrition_9899_ENU_HTML.htm

Stearic acid–rich interesterified fat and trans-rich fat raise the LDL/HDL ratio and plasma glucose relative to palm olein in humans
http://www.nutritionandmetabolism.com/content/4/1/3