What are Steviol Glycosides?
Steviol glycosides are the naturally occurring, intensely sweet compounds found in the leaves of the Stevia rebaudiana (Bertoni) plant. Native to South America, the stevia plant has been used for centuries by indigenous populations to sweeten food and drink. The sweetening power of these compounds is significant, with some being up to 400 times sweeter than table sugar (sucrose). After a processing and purification phase, these compounds become the zero-calorie sweetener known as stevia extract that is sold commercially.
The Purification Process
It is crucial to differentiate between raw stevia leaves and the highly purified steviol glycoside extracts found in approved food products. Regulatory bodies like the U.S. Food and Drug Administration (FDA) and the European Food Safety Authority (EFSA) only recognize the high-purity extracts (typically 95% or higher steviol glycosides) as Generally Recognized As Safe (GRAS). Raw stevia leaf and crude extracts are not approved for use in foods due to insufficient safety data.
Potential Health Benefits of Steviol Glycosides
For many, the main appeal of steviol glycosides is their zero-calorie nature, making them a useful tool for weight management and sugar reduction. However, research also points to other potential health benefits:
- Blood Sugar Management: Numerous studies suggest that replacing sugar with steviol glycosides can help manage blood sugar levels in individuals with diabetes. Since the body does not metabolize them for energy, they do not cause a spike in blood glucose or insulin levels. A 2018 study even found a decrease in blood glucose levels in participants with chronic kidney disease who consumed stevia supplements.
- Weight Control: By providing a sweet taste without the calories of sugar, steviol glycosides can help reduce overall calorie intake. This can be a beneficial strategy for people looking to lose or maintain weight. Randomized controlled trials have shown that sweeteners like stevia can assist with weight loss goals.
- Dental Health: Unlike sugar, steviol glycosides are not fermented by oral bacteria, meaning they do not contribute to tooth decay or cavities. This makes them a great option for promoting better dental hygiene.
- Blood Pressure: Some research indicates that steviol glycosides may have a positive effect on blood pressure by acting as a vasodilator, widening blood vessels. However, this is not a universally confirmed effect, and individuals with low blood pressure should be cautious.
- Antioxidant and Anti-inflammatory Properties: The Stevia rebaudiana plant contains antioxidants like kaempferol and quercetin. While the purification process may reduce these, some evidence suggests steviol glycosides still offer antioxidant and anti-inflammatory benefits.
Potential Risks and Side Effects
Despite the benefits, there are important considerations and potential drawbacks associated with steviol glycoside consumption:
- Digestive Issues: Some stevia products are blended with sugar alcohols, such as erythritol, to improve taste and bulk. These can cause gastrointestinal distress, including bloating, gas, and nausea in sensitive individuals.
- Altered Gut Microbiome: While inconclusive, some studies suggest that zero-calorie sweeteners like steviol glycosides could potentially interfere with the balance of beneficial gut bacteria. The long-term effects of this are not yet fully understood.
- Medication Interactions: Steviol glycosides can lower both blood sugar and blood pressure, potentially causing interactions with medications prescribed for diabetes and hypertension. It is important to consult a healthcare provider if you take these medications.
- Hidden Additives: Many commercial stevia products are not 100% pure steviol glycosides. Always check the label for added sugars (like maltodextrin and dextrose) or other sweeteners, which can add calories or affect blood sugar levels.
- Aftertaste: Some people find that stevia has a distinct, sometimes bitter, licorice-like aftertaste, especially in less refined products. This can be a deterrent for some consumers.
Comparison: Steviol Glycosides vs. Table Sugar (Sucrose)
| Feature | Steviol Glycosides | Table Sugar (Sucrose) |
|---|---|---|
| Source | Natural plant extract (Stevia rebaudiana) | Naturally occurring in plants (sugar cane, beets) |
| Calories | Zero | Approximately 16 calories per teaspoon |
| Glycemic Impact | No effect on blood sugar or insulin levels | Rapidly raises blood sugar and insulin levels |
| Sweetness | 200-400 times sweeter than sucrose | Standard unit of comparison for sweetness |
| Dental Effects | Non-cariogenic; does not cause tooth decay | Major contributor to cavities and tooth decay |
| Weight Management | Can aid in weight control by reducing calorie intake | Excessive consumption linked to weight gain and obesity |
| Common Forms | Highly purified extracts (Reb-A, Reb-M) | Refined crystals |
| Potential Issues | Aftertaste, potential gut microbiome effects | Weight gain, diabetes, dental problems |
Conclusion
In conclusion, the question of whether steviol glycosides are 'good' or 'bad' for you largely depends on context and product form. High-purity steviol glycoside extracts are approved by regulatory bodies worldwide, including the FDA, and are generally considered a safe, zero-calorie alternative to sugar. They can be a beneficial tool for managing blood sugar, controlling weight, and protecting dental health. However, the key is moderation and careful product selection. Blended stevia products containing other additives, such as sugar alcohols or sugars, can negate some of the health benefits and may cause side effects. Furthermore, individuals on certain medications for blood pressure or diabetes should consult a doctor due to potential interactions. While raw stevia leaves are not approved for food use and lack safety data, purified steviol glycosides offer a sweet taste without the caloric burden of sugar, representing a smart choice for many seeking to reduce their sugar intake. National Institutes of Health (NIH) on Steviol Glycosides
