Sodium benzoate is a sodium salt that is commonly used as a chemical preservative, but can also occur naturally in some foods. This chemical is often found in processed foods such as sodas, fruit juices, vinegar, pharmaceuticals, cosmetics, dyes or industrial settings. It is often added to items like salad dressing to extend shelf life. It may also be used to cease the fermentation process in items like wine. Understanding where and how you are exposed to sodium benzoate can help you better determine how to prevent overexposure to this chemical or inadvertently creating benzene in your diet.
Sodium benzoate can be found in a variety of substances, both naturally and as a chemical additive.
Many fruits such as berries, plums, apples or cranberries naturally contain low levels of this chemical. However, most people are exposed to this chemical because it is used as a preservative in processed foods. Around 75 percent of people can taste the bitter, salty flavor that sodium benzoate adds to food. Some even report that this tastes sweet. The most common food source of sodium benzoate is soft drinks. Though it is not considered toxic and no ill health effects are associated with normal exposure to this chemical, the FDA currently prohibits sodium benzoate additions to foods that are over .1 percent.
In addition to acting as a preservative in food sources, sodium benzoate is used to extend the shelf life of toothpaste, deodorant, mouthwash, shampoo, lotions, ointments, medicinal syrups or pills. This can be added to prevent the growth of bacteria or as a corrosion inhibitor that will keep metallic products from rusting. Metal cans that contain cleansers or liquid food items will often be coated in sodium benzoate so they will not corrode. Machinery such as vehicle engines will be coated in this chemical for similar reasons.
Both the Health Protection Branch of Canada and the Food and Drug Administration note that sodium benzoate is safe to consume in small doses, but it should not be combined with ascorbic acid, commonly known as citric acid or vitamin C, as this will develop a carcinogen know as benzene.
This carcinogen is believed to cause cell death, damage to the mitochondria in cells, DNA damage, Attention Deficit Hyperactivity Disorder (ADHD) or leukemia. Studies have also indicated that foods that contain both artificial coloring and sodium benzoate may cause children to exhibit hyperactivity. These effects are largely considered to be more of a concern for those that drink large amounts of soda as the benzene levels in these beverages is higher than most other foods.
During a 2005 study, the FDA investigated 200 soft drinks and similar beverages to determine their benzene levels. Most were found to be well within the FDA requirements and only 10 were found to be over the recommended allowance for benzene.
Because consumers are concerned about the potential side effects of these chemicals, United States soft drink manufacturers have started working toward removing artificial colors from their recipes. Similar efforts were enacted by the Foods Standard Agency Board from the United Kingdom beginning in 2009.
If you are concerned about exposing yourself to benzoate, it is important to read product labels carefully. Note any products that contain benzoic acid, benzene or benzoate, and pay particular attention to formulas that also include citric acid, ascorbic acid and vitamin C. Limiting your intake of processed fruit juice or soft drinks can also help to reduce this risk, particularly for children that may be susceptible to ADHD.
Additional information regarding the dangers of sodium benzoate can be found in the following video: