Stevia is a type of natural sweetener derived from the leaves of a variety of plants that primarily grow throughout North and South America. Stevia is used as a sweetener and a sugar substitute because it has about 300 times the sweetness of sugar without the calories. However, stevia's safety and potential side effects have generated controversy. According to the Mayo Clinic, the U.S. Food and Drug Administration, FDA, has approved refined stevia for use as a sugar substitute; however, whole-leaf or crude extracts of stevia are not approved. Consult your physician before using a product containing stevia.
Central Nervous System Effects
Your central nervous system is composed of your brain and spinal cord and serves as the collection point for nerve impulses. Stevia contains beta-caryophyllene and caryophyllene oxide, compounds that may depress the activity of your central nervous system. Beta-caryophyllene epoxides may depress central nervous system activity by crossing the blood-brain barrier and binding to cellular receptors that regulate neurological impulses within your brain. More research is needed to determine the long-term effects of stevia on both brain and spinal cord.
Peripheral Nervous System Effects
Long-term stevia use may have adverse effects on your peripheral nervous system, which is comprised of sensory nerves that send and receive messages to and from your spinal cord and brain. Stevia may affect the transmission of nerve impulses to and from your central nervous system and may slow down nerve conduction velocity. Overdosing with stevia may lead to tingling or numbness in your hands and feet, similar to the feeling of neuropathy, as well as a temporary loss in motor control.
Stevia use may cause mild to severe psychological side effects, accordingn to The New Encyclopedia of Vitamins, Minerals, Supplements, and Herbs. Individuals suffering from psychosis, schizophrenia and other psychotic disorders may find a worsening of their symptoms as a result of stevia use. Stevia may interfere with the actions of anti-psychotic medications because they can compete for the same cellular receptors in the brain. Individuals taking anti-psychotic medications should consult with their physicians prior to using any products containing stevia.
Effects on Mood
Stevia may affect hormone and neurotransmitter production in the brain. Neurotransmitters, such as dopamine and serotonin, are important in the natural regulation of mood and greatly influence thoughts of happiness and satisfaction. When these compounds are inhibited, you may have increased thoughts of depression and sadness. If you suffer from depression, anxiety, or nervousness, stevia may compound these symptoms because it slows the release of dopamine and serotonin.