BHA and BHT: Two preservatives to avoid?
Pick up a bag of chips, a bottle of vegetable oil, a package of sausage, or a box of cereal or cookies and chances are you'll find BHA and/or BHT in the ingredients list. BHA (butylated hydroxyanisole) and BHT (butylated hydroxytoluene) are widely used by the food industry as preservatives, mainly to prevent oils in foods from oxidizing and becoming rancid.
Oxidation affects the flavor, color and odor of foods and reduces some nutrients. BHA and BHT may have some antimicrobial properties, too. BHT is even sold in supplements, as an antioxidant.
There's ongoing controversy, however, about the safety of BHA and BHT. Most research has been in animals and test tubesnot in people. The FDA categorizes these food additives as GRAS (generally recognized as safe), which means they are widely considered safe for their intended use in specified amounts, but did not have to undergo pre-market review. A subsequent review by an independent committee supported their general safety, but concluded that "uncertainties exist, requiring that additional studies be conducted."
Other health organizations have raised concerns. Based on animal studies, the National Toxicology Program has concluded that BHA "is reasonably anticipated to be a human carcinogen," while BHT has been linked to an increased—or sometimes decreased—risk of cancer in animals. The consumer group the Center for Science in the Public Interest thus cites BHA as an additive to "avoid" and puts BHT in its "caution" column.
BHA and BHT are broken down and absorbed by the body. As such, they have biological effects, some of which may be harmful, but some of which may be beneficial, too. Some lab and animal studies have found that BHA and BHT—at high levels as well as at lower levels found in foods—may have anti-cancer properties, possibly through the scavenging of damaging free radicals or by stimulating production of enzymes that detoxify carcinogens. Other research suggests that low doses of BHA are toxic to cells, while high doses are protective—or the reverse, that low doses are okay, but high doses are harmful. In other words, no one really knows how BHA and BHT act in the human body.
Words to the wise: You don't have to go out of your way to avoid BHA or BHT. The nutritional benefits of, say, a whole-grain cereal with the additives outweigh any risk. But because their health effects are still unclear, limit how much you consume, especially from snacks and sweets, which are not healthful foods anyway. Eat more fresh and minimally processed foods, which contain few or no additives and are usually more nutritious overall. You can also look for packaged foods that use other preservatives, such as vitamin E, or have no preservatives at all.
Source: Originally published in The University of California, Berkeley Wellness Letter (February 2011)