In a research study published in Europe PubMed Central, Dr. Ali Noorafshan found that rats subject to constant doses of sodium benzoate develop anxiety and demonstrate motor impairment. Why should we care? Sodium benzoate is commonly found in processed foods such as sodas and jams. Food manufactures have been synthesizing this substance in labs and adding it to the things we eat in order to increase shelf life. Also known to cause cancer when synthesized with vitamin C, sodium benzoate is now proving to have more immediate, negative effects.

Anxious Behavior And Poor Motor Skills

Twenty rats were used in this experiment. Of the twenty, 10 were given 200mg/kg of sodium benzoate daily for four weeks. Afterwards, an elevated plus maze (EPM) and rotarod test were used to measure anxiety and motor ability.

An EPM measured the anxiety of the rats. The EPM itself is like a 3D plus sign. One arm is open, so that means that if you walk on that arm, there are no walls or railings to prevent you from falling off. The other arm is closed, and has walls that keep you safe. We expect those with less anxiety to spend more time on the open arms of the EPM, while those with anxiety to retreat to the closed arms.

A rotarod test measured balance and coordination. Picture a lumberjack balancing on a log in a river. This is essentially a rotarod test. The length of time the rat can stay on the rod shows the rat's ability to think and act quickly. That said, the rats that can stay on the rod longer have better motor abilities.

How Preservatives Affect The Body

According to the EPM test, control rats spent 26% of the time in the open arms, whereas sodium benzoate rats only spent 9.5%. Because sodium benzoate rats were more inclined to find safety in the closed arms, they had a higher indication of anxiety levels. In the rotarod test, sodium benzoate rats were unable to stay on the rod for as long as the control rats: a result of impaired mobile ability. These outcomes show that sodium benzoate plays a big role in mental health and motor abilities. From this, Dr. Noorafshan concluded that sodium benzoate induces anxiety and impairs movement and coordination.

Although sodium benzoate can be found naturally in foods, sodium benzoate becomes harmful when excessive amounts. Here's a breakdown of how chemical imbalances from sodium benzoate affect the mind and body:

  • Glycine: The liver uses glycine to metabolize sodium benzoate. Dr. Arcady Markel showed that low glycine levels lead to anxiety.
  • Zinc: Sodium benzoate reduces zinc levels in the brain. Evidence has been found that zinc deficiency impairs motor abilities.

Processed Junk Food Is Everywhere

Although increasing the shelf life of food economically benefits companies and adds a little stretch to your dollar, its cost may outweigh its advantages. Dr. Noorafshan acknowledged the fact that “with the increase in production of processed, convenience, and fast foods, food additives have become increasingly important in modern food." As the backlash against unhealthy foods grows stronger, we see allegations of sodium benzoate in big name companies. Making the choice not to eat foods high in preservatives is easy, however finding food without sodium benzoate may be harder than we think.

Recommended For You

Katherine J. Gold, M.D., M.S.W., M.S.
Liz Matheis, Ph.D.
Sigal Sharf
Sigal Sharf


Date of original publication:

Updated: January 16, 2017