FDA's opinion of trans fats has become clearer after its preliminary determination published in the Federal Register on November 7, 2013 that partially hydrogenated oils (PHOs), the major dietary source of trans fats in the processed food supply, are no longer "Generally Recognized As Safe", or what is known in the industry as GRAS.  According to the agency, it made this preliminary determination because trans fats have significant adverse health effects.

Fatty acids are the chemical compounds that comprise fats.  Trans fatty acids, also known as trans fats, are made during partial hydrogenation of vegetable oils.  PHOs are used by food manufacturers to improve the texture, shelf life, and flavor stability of foods. About half of the trans fats that Americans consume are formed during food processing, and PHOs are the primary source of trans fat in the US food supply.  Trans fats are typically found in processed foods such as baked goods, margarine, coffee creamer, microwave popcorn products, ready-to-use frostings, and frozen pizza.

Trans fats first hit the radar screens of health-conscious Americans when the Center for Science in the Public Interest sent a petition to FDA requesting that trans fats be included in nutrition labeling.  Published human studies have shown that intake of trans fatty acids, similar to the intake of saturated fatty acids, increases low density lipoprotein-cholesterol (known commonly as "LDL" or "bad cholesterol") in the blood.  An elevated LDL increases the risk of developing coronary heart disease.  Trans fat may also have other adverse health effects, including lowering high-density lipoprotein cholesterol (HDL-C). Considering only the effects of trans fat from PHOs on levels of LDL-C the Centers for Disease Control and Prevention estimates that eliminating intake of trans fat from PHOs could prevent up to 20,000 cases of coronary heart disease (CHD) and up to 7,000 deaths annually.  Reports published by the Institute of Medicine and the federal government have recommended that Americans limit their intake of trans fats and other cholesterol-raising fats while consuming a nutritionally-adequate diet.  On July 11, 2003, in response to the petition and these studies, the agency published a final rule in the Federal Register that amended its regulations on food labeling to require that trans fatty acids be declared in the nutrition label of conventional foods and dietary supplements (68 FR 41434).  This rule went into effect on January 1, 2006.

FDA's most recent action will have a much more significant effect on trans fats than the food-labeling requirement did.  Under sections 201(s) and 409 of the Federal Food, Drug, and Cosmetic Act (FD&C Act), any substance that is intentionally added to food is a food additive that is subject to premarket review and approval by FDA, unless the substance is generally recognized, among qualified experts, as having been adequately shown to be safe under the conditions of its intended use, or unless the use of the substance is otherwise excluded from the definition of a food additive.  If this preliminary determination is finalized, then PHOs would become food additives subject to premarket approval by FDA. Foods containing unapproved food additives are considered adulterated under US law, meaning that they cannot legally be sold.  Removing PHOs from the GRAS list will therefore make it much harder, if not impossible, for food manufacturers to get their products on the shelves if those products contain PHOs. Food manufacturers would have to first obtain prior FDA approval for use of the product as a food additive. Trans fat would not be completely eliminated, however, because they occur naturally in small amounts in meat and dairy products and are also present at very low levels in other edible oils, such as fully hydrogenated oils, where it is unavoidably produced during the manufacturing process.

FDA is soliciting comments on how such an action would impact small businesses and how to ensure a smooth transition if a final determination is issued.  Essentially, if FDA makes a final determination that PHOs are not GRAS, the agency and food industry would have to figure out a way to phase out the use of PHOs over time and the Federal Register notice therefore calls for comment on how long it would take the food industry to phase out its use of PHOs.  The agency has acknowledged, however, that it may take it a while to implement these changes even if a final determination is issued.  The agency will accept comments for 60 days from November 7.  FDA's Consumer Updates page contains additional information.