Stevia is a zero-calorie, non-nutritive sweetener derived from the leaves of the Stevia rebaudiana plant. Native to South America, it has become a popular sugar alternative for millions seeking to reduce caloric intake. The growing popularity of non-nutritive sweeteners (NNS) has led to scrutiny regarding their effects on human health, including the nervous system. This raises the question: Is there scientific evidence linking Stevia consumption to anxiety or nervousness?
The Stevia Compound and Regulatory Status
The sweet taste of Stevia comes from natural compounds known as steviol glycosides. The commercial product is a highly purified extract, not the crude leaf, and must contain at least 95% total steviol glycosides. The most common compound is Rebaudioside A (Reb A).
Regulatory bodies only approve the purified extract for use as a food additive, distinguishing it from the unprocessed leaf. In the United States, the Food and Drug Administration (FDA) has given high-purity steviol glycosides the status of Generally Recognized as Safe (GRAS). This status, based on extensive scientific review, allows these purified compounds to be marketed and added to foods.
Investigating the Link Between Stevia and Anxiety
Current scientific literature does not support a direct causal link between the consumption of purified Stevia and the onset of anxiety in the general population. Research focuses on Stevia’s interaction with the central nervous system (CNS) and metabolic pathways. Studies show Stevia is a neutral sweetener, demonstrating no significant negative impact on neuropsychological or brainwave activity in human subjects.
While some artificial sweeteners like aspartame have been associated with cognitive and behavioral issues, including anxiety, Stevia does not fall into this category. Steviol glycosides are metabolized by the gut microbiome. Their metabolites are not shown to directly interfere with stress hormones like cortisol or major neurotransmitter activity at approved consumption levels.
Concerns about sweeteners and anxiety often stem from the complex connection between the gut and the brain, known as the gut-brain axis. Some non-nutritive sweeteners can alter the gut microbiome, influencing mood and behavior. However, the current scientific consensus suggests that purified Stevia, when consumed within established limits, does not negatively affect the central nervous system in a way that would trigger or increase anxiety.
Common Adverse Effects of Stevia
Although the anxiety link remains unsubstantiated, Stevia consumption is associated with other common adverse effects. The most frequently reported issues involve digestive discomfort, such as bloating, gas, and upset stomach. These gastrointestinal symptoms are often due to sugar alcohols, like erythritol, which are mixed with Stevia extracts to provide bulk and mask its slight aftertaste.
Steviol glycosides are not fully digested in the upper gastrointestinal tract, passing instead to the colon where gut bacteria break them down. This fermentation process can lead to gas production and bloating. In rare cases, individuals sensitive to plants in the daisy family (Asteraceae) may experience allergic reactions.
Safe Consumption Limits and Practical Use
Regulatory bodies, including the Joint FAO/WHO Expert Committee on Food Additives (JECFA), have established an Acceptable Daily Intake (ADI) for steviol glycosides. The ADI is set at 4 milligrams of steviol equivalents per kilogram of body weight per day. This limit represents the amount that can be consumed daily over a lifetime without posing a health risk.
To put this into perspective, a 150-pound (70 kg) person would need to consume approximately 40 packets of tabletop Stevia sweetener daily to reach this ADI. This demonstrates a substantial safety margin for typical consumption. Individuals who suspect an adverse reaction to Stevia, or who are taking medications that affect blood pressure or blood sugar, should consult a healthcare provider.