Butylated hydroxyanisole (BHA) is an antioxidant

Antioxidant

An antioxidant is a molecule capable of inhibiting the oxidation of other molecules. Oxidation is a chemical reaction that transfers electrons or hydrogen from a substance to an oxidizing agent. Oxidation reactions can produce free radicals. In turn, these radicals can start chain reactions. When...

 consisting of a mixture of two isomer

Isomer

In chemistry, isomers are compounds with the same molecular formula but different structural formulas. Isomers do not necessarily share similar properties, unless they also have the same functional groups. There are many different classes of isomers, like stereoisomers, enantiomers, geometrical...

ic organic compounds, 2-tert-butyl-4-hydroxyanisole and 3-tert-butyl-4-hydroxyanisole. It is prepared from 4-methoxyphenol

Mequinol

Mequinol is a drug used in combination with the drug tretinoin in the treatment of liver spots. Mequinol used alone and in higher doses is used as a topical drug for medical depigmentation.-Chemistry:...

 and isobutylene

Isobutylene

Isobutylene is a hydrocarbon of significant industrial importance. It is a four-carbon branched alkene , one of the four isomers of butylene. At standard temperature and pressure it is a colorless flammable gas.-Uses:...

. It is a waxy solid used as a food additive

Food additive

Food additives are substances added to food to preserve flavor or enhance its taste and appearance.Some additives have been used for centuries; for example, preserving food by pickling , salting, as with bacon, preserving sweets or using sulfur dioxide as in some wines...

 with the E number

E number

E numbers are number codes for food additives that have been assessed for use within the European Union . They are commonly found on food labels throughout the European Union. Safety assessment and approval are the responsibility of the European Food Safety Authority...

 E320. The primary use for BHA is as an antioxidant and preservative in food, food packaging, animal feed, cosmetics, rubber, and petroleum products. BHA also is commonly used in medicines, such as isotretinoin

Isotretinoin

Isotretinoin, INN, is a medication used mostly for cystic acne. It was first developed for brain, pancreatic and other cancers. It is used to treat harlequin-type ichthyosis, a usually lethal skin disease, and lamellar ichthyosis. Its effects are systemic and nonselective...

, lovastatin

Lovastatin

Lovastatin is a member of the drug class of statins, used for lowering cholesterol in those with hypercholesterolemia and so preventing cardiovascular disease...

, and simvastatin

Simvastatin

Simvastatin is a hypolipidemic drug used to control elevated cholesterol, or hypercholesterolemia. Simvastatin is a member of the statin class of pharmaceuticals, is a synthetic derivate of a fermentation product of Aspergillus terreus.-Medical uses:The primary uses of simvastatin is for the...

, among others.

Antioxidant properties

Since 1947, BHA has been added to edible fats and fat-containing foods for its antioxidant properties as it prevents food from becoming rancid and developing objectionable odors. Like butylated hydroxytoluene

Butylated hydroxytoluene

Butylated hydroxytoluene , also known as butylhydroxytoluene, is a lipophilic organic compound that is primarily used as an antioxidant food additive as well as an antioxidant additive in cosmetics, pharmaceuticals, jet fuels, rubber, petroleum products, electrical transformer oil, and embalming...

 (BHT), the conjugated aromatic ring of BHA is able to stabilize free radicals, sequestering them. By acting as free radical scavenger

Scavenger (chemistry)

A scavenger in chemistry is a chemical substance added to a mixture in order to remove or inactivate impurities or unwanted reaction products. Their use is wide-ranged:...

s, further free radical reactions are prevented.

Controversy

Some controversy surrounds the use of BHA in foods. The US National Institutes of Health

National Institutes of Health

The National Institutes of Health are an agency of the United States Department of Health and Human Services and are the primary agency of the United States government responsible for biomedical and health-related research. Its science and engineering counterpart is the National Science Foundation...

 report that BHA is reasonably anticipated to be a human carcinogen based on evidence of carcinogenicity in experimental animals. In particular, when administered in high doses as part of their diet, BHA causes papilloma

Papilloma

Papilloma refers to a benign epithelial tumor growing exophytically in finger-like fronds. In this context papilla refers to the projection created by the tumor, not a tumor on an already existing papilla . When used without context, it frequently refers to infections caused by human...

s and squamous cell carcinoma

Squamous cell carcinoma

Squamous cell carcinoma , occasionally rendered as "squamous-cell carcinoma", is a histologically distinct form of cancer. It arises from the uncontrolled multiplication of malignant cells deriving from epithelium, or showing particular cytological or tissue architectural characteristics of...

s of the forestomach in rats and Syrian golden hamster

Hamster

Hamsters are rodents belonging to the subfamily Cricetinae. The subfamily contains about 25 species, classified in six or seven genera....

s. In mice, there is no carcingenic effect, and even evidence of a protective effect against the carcinogenicity of other chemicals.

When examining human population statistics, the usual low intake levels of BHA shows no significant association with an increased risk of cancer. The State of California, has, however, listed it as a carcinogen.