Should You Be Worried About the Sodium Benzoate in Certain Foods and Drinks?

If you read food labels, you've undoubtedly spotted "sodium benzoate" on the ingredient lists of at least a handful of products in the grocery store.

Sodium benzoate is added to foods to extend their shelf lives, and it also has uses that go beyond the supermarket.

Sodium benzoate is a type of salt-based preservative added to food, beverage and condiments to extend the items' shelf life, according to the National Institutes of Health (NIH).

While it is generally recognized as safe (GRAS) by the FDA in small doses, sodium benzoate may cause harmful health effects under certain conditions.

The substance is an odorless, crystalline powder made by combining benzoic acid and sodium hydroxide, per a December 2015 article in ​Biotechnology and Health Sciences​. Beyond food products, sodium benzoate is sometimes added to cosmetic and personal care products

Sodium benzoate is a strong antimicrobial, according to the NIH. It is commonly used to preserve acidic foods such as pickles, salad dressing, sodas and fruit juices, per the Center for Science in the Public Interest (CSPI).

Sodium benzoate is heavily used by the soft drink industry due to the demand for high-fructose corn syrup in carbonated drinks, according to the International Program on Chemical Safety. Sodium benzoate increases the acidity of soft drinks, which also increases the intensity of flavor from the high-fructose corn syrup. On the back of a soda can, you can find sodium benzoate in the ingredients list as E211, which is the number assigned to it as a food additive.

Sodium benzoate's antimicrobial properties have also made it a common ingredient in many personal products like lotions, shampoos and makeup. It is also used in detergents and other cleaning products, as well as in certain medications, according to the NCBI.

Sodium benzoate does not occur naturally, according to the Electronic Code of Federal Regulations. It's formed when sodium hydroxide combines with benzoic acid, which is found in many plants and animal tissues, according to a May 2017 article in ​Critical Reviews in Food Science and Nutrition.​

Sodium benzoate may hamper the growth of bacteria and mold in foods, which can prevent spoilage, per an older October 2004 study in the ​British Journal of Dermatology​.

Similarly, sodium benzoate can act as a preservative in certain medications (like cough syrup), extending the shelf life of OTC aids. It can also help smooth medical tablets in the manufacturing process, making them easier to swallow, per the article in ​Biotechnology and Health Sciences.​

it can be a lubricant in pill manufacturing and makes tablets transparent and smooth, helping them break down rapidly after you swallow them

Sodium benzoate inhibits the growth of potentially harmful bacteria, mold and other microbes in food, thus deterring spoilage. It's particularly effective in acidic foods.

While some people are wary of any human-made additive included in food, sodium benzoate is listed as GRAS by the FDA. The current safe level of sodium benzoate in food is 0.1 percent, which is a very small amount.

Still, sodium benzoate may become a health concern when it is combined with ascorbic acid, aka vitamin C.

When combined, sodium benzoate and ascorbic acid — both common ingredients in sodas — can form a chemical called benzene. Benzene has been linked to an increased risk of cancer, according to the FDA. The standard permissible amount of benzene in a beverage is 5 parts per billion (ppb).

The FDA cites a study conducted by the Center for Food Safety and Applied Nutrition (CFSAN) from 2005 to 2007 on the amount of benzene in sodas and other beverages. CFSAN found that "a small number of products sampled contained more than 5 ppb of benzene." When these products were reformulated as a result of this study, however, they contained less than 1.5 ppb of benzene. That's good news, but there hasn't been an update since 2007.

What's more, diet beverages are more prone to benzene formation, Bonnie Taub-Dix, RDN and author of ​Read It Before You Eat It: Taking You from Label to Table,​ tells LIVESTRONG.com. "The conversion [of sodium benzoate to benzene] may also be affected by a drink's exposure to light and heat during storage," Taub-Dix says.

Some small studies have shown that sodium benzoate may lead to some unexpected health side effects.

Case in point: People who drank beverages with high levels of sodium benzoate (like soda) reported an increase in attention-deficit/hyperactivity disorder (ADHD) symptoms, according to an April 2014 study published in the ​Journal of Attention Disorders.​

And taking in preservatives such as sodium benzoate could lead to low-grade inflammation in the body, a study published in March 2012 in the ​British Journal of Nutrition​ found. This kind of low-grade inflammation can be chronic in people with obesity. Note, however, that this study was only done in a laboratory setting rather than in humans.

More research is needed to determine if sodium benzoate food additives exacerbate obesity-related health consequences.