Sodium benzoate is a sodium salt that occurring naturally in some foods, but is also widely used as a chemical preservative. It is used mainly as a food preservative, but is also found in cosmetics, dyes, pharmaceuticals, industrial settings. Sodium benzoate is a common ingredient in highly processed foods such as carbonated sodas, vinegar, fruit juices; in mixed ingredients like salad dressings; and to stop the fermentation process in wines. The U.S. Food and Drug Administration (FDA) and the Health Protection Branch in Canada (HPB) report that in low doses it is safe for consumption, although when combined with ascorbic acid it forms the chemical benzene, a suspected carcinogen.
Sodium benzoate naturally occurs in low levels in fruits such as apples, plums, berries and cranberries, and in a few sweet spices, including cloves and cinnamon. When added to foods as a chemical preservative, about 75% of people can taste it. Since it is a sodium salt, it tastes salty, bitter, or sour for most people; but to others it may taste sweet. The FDA currently permits a maximum of 0.1% benzoate in foods. Soft drinks are the number one source of sodium benzoate in the diet. On its own, it is not considered toxic, and studies show no adverse health effects in humans under normal conditions.
Besides its use as a preservative in food, sodium benzoate is used in cosmetic products like mouthwash, toothpaste, deodorant, lotion, and shampoo. This is usually done to keep bacteria from growing in the products. It's also used in medicinal syrups, ointments, and pills. Industrially, sodium benzoate acts as a corrosion inhibitor, and is used to keep many different types of metals from rusting. It's commonly used in metal cans containing liquid foods or household cleaners, manufacturing machinery that is exposed to moisture, and in vehicle engines.
When combined with ascorbic acid — also known as vitamin C or citric acid — the preservative converts to benzene, a carcinogen reported to cause leukemia, DNA damage, damage to mitochondria in cells, cell death and Attention Deficit Hyperactivity Disorder (ADHD). Additional studies show that sodium benzoate mixed with certain artificial food coloring causes hyperactivity in children. Since many people consume soft drinks on a regular basis and the preservative is usually unnoticed in most diets, benzene levels may be very high for heavy soda drinkers.
Tests on Food and Resulting Actions
In 2005, the FDA tested nearly 200 soft drinks and related beverages for benzene and found only ten that scored higher than the recommended allowance. More than half tested negative for benzene or contained levels that were below the allowance. Still, in response to consumer concerns, soft drink manufacturers in the US have also begun eliminating artificial colors from their drinks to lower benzene levels. The Foods Standard Agency Board (FSAB) of the United Kingdom began removing artificial food coloring from foods in 2009.
Those who wish to reduce exposure to benzoates should carefully read labels on products and avoid those with benzene, benzoate, or benzoic acid; especially when combined with ascorbic acid, citric acid, and vitamin C ingredients. It may also be a good idea to limit soft drinks and processed fruit juices, especially for children.