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BHA and BHT

Dateline: 04/10/00

By Alan Bruzel

What Are BHA and BHT?

Most consumers recognize the abbreviated names of these compounds from their appearance on the list of added ingredients in fat-containing foods, dry foods and everything in between. For the record, BHA is butylated hydroxyanisole (or 2-t-butyl-4-methoxyphenol), and BHT is butylated hydroxytoluene (or 2,6-di-t-butyl-4-methylphenol).

BHA	BHT

These phenol derivatives inhibit free radical-initiated oxidation reactions that can lead to changes in the food's color and taste. Free radical reactions are chain reactions; their domino effect, if not stopped, will eventually result in a product unfit for consumption. Most food components, after their conversion to free radicals, will, in turn, begin their own free radical attacks on other food components. In contrast, when BHA and BHT are converted to free radicals, their ability to maintain a stable resonance structure makes them more likely to terminate, rather than to propagate, the free radical chain reaction.

Are BHA and BHT Healthy?

If these compounds inhibit free radical reactions – and these reactions are believed to be important causes of aging and of cancer – then are BHA or BHT preventatives of these conditions? As it turns out, these antioxidants have exhibited contradictory actions depending on the study and on the experimental animal studied. For example, mice show increased longevity and fruit flies decreased longevity when given these food additives. Cancer growth has been shown to be inhibited in some studies, and increased in other studies. Conclusive evidence is still in short supply.

What the Web Has to Say about:
BHA and BHT

A Fresh Look at Food Preservatives
Article by Judith E. Foulke (with an update from Maribeth LaVecchia) describing agents commonly used to prevent food spoilage. From the U.S. Food and Drug Administration.

Common Food Additives
Reasons for their use and reported side effects. From CNN.com.

Food and Product Additives
Many more additives than just BHA and BHT are on this list. From About.com's Allergies Guide.

Lipids/Fats: Rancidity
Various forms of rancidity and their remedies. From ZoeAnn Holmes, Oregon State University at Corvallis.

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