Stevia, a non-nutritive sweetener derived from the leaves of the Stevia rebaudiana plant, has become a popular sugar substitute for those aiming to reduce their calorie and sugar intake. It is available in various forms, from highly purified extracts to less-refined crude versions and blends with other sweeteners. While refined stevia is generally recognized as safe (GRAS) by the U.S. Food and Drug Administration (FDA) and other global bodies, potential side effects can arise, often related to additives in commercial products or individual sensitivities. Understanding these potential issues is key to determining if stevia is the right choice for you.
Gastrointestinal Issues and Sugar Alcohols
One of the most frequently reported negative side effects of stevia is digestive discomfort. However, this is often caused by the other ingredients added to many commercial stevia products, not the stevia extract itself. Stevia blends are commonly bulked up with sugar alcohols like erythritol to make them easier to measure and use.
When consumed in large quantities, sugar alcohols can cause a range of gastrointestinal symptoms in some individuals.
- Bloating and gas: Sugar alcohols are not fully absorbed by the small intestine and travel to the large intestine, where gut bacteria ferment them, leading to gas and bloating.
- Nausea and cramping: For sensitive individuals, the fermentation process can also cause feelings of nausea, abdominal pain, and cramping.
- Diarrhea: Due to their laxative-like properties, overconsumption of sugar alcohols can lead to diarrhea.
Impact on Blood Pressure and Blood Sugar
Stevia's effects on blood pressure and blood sugar, while beneficial for some, can be a negative side effect for others, especially those on medication.
- Blood Pressure: Stevia is known to act as a vasodilator, widening blood vessels and lowering blood pressure. While this can be a positive for people with hypertension, it could be problematic for those with naturally low blood pressure or those taking antihypertensive drugs, potentially causing it to drop too low.
- Blood Sugar: Some studies indicate that stevia can lower blood sugar levels. This is great for people with diabetes managing their blood glucose. However, if you are already taking diabetes medication, combining it with stevia might cause your blood sugar to fall to dangerously low levels, a condition known as hypoglycemia. For people with diabetes, it's also important to note that some stevia products contain additives like maltodextrin and dextrose, which can raise blood sugar levels.
Potential Allergic Reactions
Although rare, some individuals may experience an allergic reaction to stevia. This is primarily linked to cross-reactivity with plants in the Asteraceae family, which includes ragweed, daisies, and chrysanthemums.
- Cross-Reactivity Risk: People with a known sensitivity to ragweed are theorized to have a higher risk of reacting to stevia due to similar protein structures.
- Product Purity Matters: The risk of a cross-reactive reaction is much lower with highly purified stevia, as many of the allergens are removed during processing. Crude extracts or whole stevia leaves carry a higher risk.
Concerns Regarding Kidneys and Liver
Early and some recent animal studies have raised concerns about the long-term effects of high stevia intake on the kidneys and liver. For instance, a 2020 study in mice showed high stevia consumption was associated with increased inflammation proteins in the liver and kidneys. However, human studies are limited and have generally shown either no harmful effects or even protective effects at moderate intake levels. Much of the historical concern centered on less refined or crude extracts, which are not approved by the FDA.
The Gut Microbiome
Research on stevia's impact on the gut microbiome has produced mixed results. Some studies suggest potential interference with beneficial gut bacteria, while others have found no significant negative impact. This is an area of ongoing research, and more data is needed to fully understand any long-term consequences.
The Importance of Product Purity: Comparison of Stevia Types
Understanding the different forms of stevia is key to managing potential side effects. The product you choose can significantly impact your experience.
| Feature | Highly Purified Stevia Extracts | Stevia Blends | Crude Stevia Extracts / Whole Leaf |
|---|---|---|---|
| Processing | Highly refined; isolates specific steviol glycosides | Processed stevia extract mixed with other ingredients | Minimal processing; contains full leaf and compounds |
| FDA Status | Generally Recognized as Safe (GRAS) | GRAS status applies to the purified extract used | Not approved for use as a sweetener in the U.S. |
| Additives | Minimal or none | Commonly includes sugar alcohols (erythritol) or dextrose/maltodextrin | Contains all natural compounds from the leaf |
| Side Effect Risk | Low; minimal gastrointestinal issues | Moderate; GI issues (bloating, gas) from additives; blood sugar spikes from dextrose | Higher; potential for allergic reactions due to less refined proteins; unknown health effects |
| Best For | General consumption, low-risk use | Baking or cooking, where additives are useful | Not recommended for consumption |
Conclusion
While highly purified stevia extract is generally a safe and effective sugar alternative, several negative side effects can arise, often stemming from additives in commercial products or interactions with medications. Gastrointestinal distress from added sugar alcohols is a common issue, and the blood pressure and blood sugar-lowering effects can pose a risk for those on specific medications. Less refined stevia can also cause allergic reactions in sensitive individuals, and further research is needed on its effects on the gut microbiome. To minimize risks, always read product labels, choose high-purity extracts, and consult a healthcare provider if you have underlying health conditions or take medication. For more details, see the article on stevia safety from Verywell Health.
