The Safe vs. Unsafe Forms of Stevia
It is crucial to differentiate between the forms of stevia when discussing its safety. The potential risks are largely associated with a lack of moderation and with products containing additional ingredients.
- Purified Steviol Glycosides: This is the highly refined extract, such as Reb-A, that is approved by the FDA as GRAS (Generally Recognized As Safe) for use in foods and beverages. Most studies pointing to stevia's safety refer to this form.
- Crude Stevia Extracts & Whole Leaves: The FDA has not approved these less-processed forms due to a lack of safety research. In some cases, crude extracts have been linked to health concerns related to the kidneys, cardiovascular system, and reproductive health.
Gastrointestinal Upset: The Most Common Complaint
The most frequent side effect of consuming too much stevia, especially products blended with other ingredients, is digestive discomfort. Many commercial stevia products are bulked up with sugar alcohols like erythritol to improve their texture and sweetness profile.
These sugar alcohols are not fully absorbed by the body. Instead, they travel to the large intestine where they are fermented by gut bacteria, which can lead to unpleasant symptoms.
Digestive Issues from Stevia with Fillers
- Bloating and Gas: The fermentation process by gut bacteria releases gas, causing a feeling of fullness and bloating.
- Diarrhea and Loose Stools: Large doses of sugar alcohols can have a laxative effect, resulting in diarrhea.
- Nausea and Cramping: The digestive system's struggle to process these compounds can lead to stomach upset and cramping.
Potential Impact on the Gut Microbiome
Beyond immediate digestive distress, there is evolving research on how non-nutritive sweeteners like stevia could alter the balance of the gut microbiome. The gut's bacterial community plays a vital role in health, and disruptions can have widespread effects.
Some studies, including a 2019 report, have suggested a link between certain non-nutritive sweeteners and alterations to beneficial intestinal flora. While human studies are still limited and sometimes conflicting, some animal studies show that high stevia intake could lead to a microbial imbalance in the gut.
Cardiovascular and Blood Pressure Concerns
Stevia is known to have a mild blood pressure-lowering effect, acting as a vasodilator that widens blood vessels. While this may be beneficial for some, overconsumption could be problematic for others.
For individuals with naturally low blood pressure or those taking blood pressure-lowering medications, too much stevia could cause blood pressure to drop dangerously low. Symptoms might include dizziness, lightheadedness, and fatigue. It is crucial for these individuals to monitor their intake and consult a doctor.
Interaction with Medications
Stevia can interact with certain medications, primarily those related to blood sugar and blood pressure management.
- Diabetes Medications: Stevia's ability to lower blood sugar means that when taken with diabetes medications, it could potentially cause hypoglycemia, or dangerously low blood sugar levels.
- Blood Pressure Medications: Similarly, its blood pressure-lowering properties could amplify the effects of antihypertensive drugs, leading to blood pressure that is too low.
- Lithium: Stevia acts as a diuretic, potentially affecting how the body eliminates lithium. This can lead to increased lithium levels and severe side effects.
The Taste Factor: The Body's Signal
In addition to physiological effects, consuming too much stevia can also result in a bitter, licorice-like aftertaste. This is a clear signal from your body that you have used an excessive amount of the sweetener. While not a direct health risk, it can ruin the taste of food and beverages, preventing further overconsumption.
Stevia vs. Table Sugar: A Quick Comparison
When considering your options, it's helpful to compare stevia and table sugar on various factors. This table highlights some key differences in their effects when consumed in excess.
| Feature | Excessive Stevia (Pure Extract) | Excessive Table Sugar (Sucrose) |
|---|---|---|
| Calories | Virtually none | High; contributes to weight gain |
| Glycemic Impact | Low to none | High; causes rapid blood sugar spikes |
| Digestive System | Digestive issues often due to sugar alcohol fillers | Can promote inflammation and obesity-related gut problems |
| Blood Pressure | Can lower blood pressure, risky for hypotensive individuals | Contributes to high blood pressure |
| Weight Management | Can aid weight loss by reducing calorie intake; potential for cravings | Directly contributes to obesity and metabolic syndrome |
| Dental Health | Non-cariogenic; doesn't cause cavities | A major cause of dental caries |
| Known Long-Term Effects | Research ongoing; limited long-term human studies | Strong link to Type 2 diabetes, heart disease, and other chronic illnesses |
Setting the Limit: Acceptable Daily Intake (ADI)
To avoid the potential downsides of overconsumption, it is important to adhere to the acceptable daily intake (ADI). The World Health Organization (WHO) and other regulatory bodies recommend an ADI of 4 mg of steviol equivalents per kilogram of body weight per day. For a 150-pound (approx. 68 kg) person, this equals about 272 mg of stevia extract per day, which is far more than most people would use.
It is important to remember that this ADI applies to high-purity stevia extracts. The amount is much lower for whole leaf or crude extracts.
Conclusion: Moderation is Key
In conclusion, while purified stevia is a generally safe and helpful sugar alternative for most people, moderation is essential. Consuming too much, particularly products containing sugar alcohol fillers, can lead to unpleasant digestive side effects like bloating, gas, and nausea. For individuals with certain pre-existing conditions or those on specific medications, overconsumption could pose risks related to blood sugar and blood pressure.
As research continues, it is wise to stick to the recommended acceptable daily intake and pay attention to how your body responds. If you experience any negative side effects, reducing your intake or choosing a different sweetener is the best course of action. Consulting with a healthcare professional is always recommended for personalized advice, especially if you are managing a chronic health condition. Using stevia as part of a balanced diet, rather than a total replacement for all sources of sweetness, is the healthiest approach.
Authoritative Link
For more information on the Acceptable Daily Intake of steviol glycosides, you can consult the official document from the World Health Organization (WHO).
Note: This article is for informational purposes only and does not constitute medical advice. Consult a healthcare professional before making significant dietary changes, especially if you have pre-existing health conditions.
