Stevia, a natural sweetener derived from the leaves of the stevia rebaudiana plant (also known as Candyleaf), offers a calorie-free alternative to sugar. Its popularity is driven by a growing awareness of the potential health risks associated with excessive sugar consumption, such as the increased risk of obesity and Type 2 diabetes. (1)
As health-conscious consumers seek sugar alternatives, a key question arises: Does stevia’s positive impact stop at reducing calorie intake, or could it also improve gut health?
On Apr. 11, 2024, Dr. Layne Norton (Ph.D. in Nutritional Sciences) published a video on his YouTube channel, breaking down a 2024 randomized controlled trial published in the Journal of Nutrition that evaluated the effects of stevia and sucrose-sweetened beverages on the human gut microbiome (HGM). Norton also discussed artificial sweeteners impact on gut health. Check out the complete video below: (2)
The randomized controlled trial comprised two groups: controlled and stevia. Participants in the stevia group consumed 10 drops of stevia, equivalent to two servings, twice a day for 12 weeks. Researchers analyzed the gut microbiome of both groups to see if stevia consumption affected certain gut bacteria.
The results showed that daily consumption of a beverage sweetened with 25 percent of the acceptable daily intake of stevia for four weeks had no significant effects on the HGM, fecal short-chain fatty acid (SCFA), or fasting cardiometabolic measures compared with daily consumption of a beverage sweetened with 30 grams of sucrose.
Norton highlights two limitations of the study. First, the study did not use a placebo (a substance that looks and tastes identical to the test substance). Including a placebo group in a study helps control the placebo effect, a phenomenon where people’s perception of what they are taking can influence the results.
However, Norton recognized the challenge of using a sucrose-based placebo, which could alter the study’s findings. “There is evidence that sucrose (table sugar) and other artificial sweeteners or non-nutritive sweeteners can change the gut microbiome,” Norton said. “While this is a limitation, I don’t know what [the researchers] could have done differently.”
Second, the study only lasted for 12 weeks. Norton pointed out that while this period might be short, there is evidence that even one to two weeks of dietary change can influence the gut microbiome.
Norton broadened the discussion to artificial sweeteners, noting some studies have shown artificial sweeteners like aspartame and sucralose do not affect the gut microbiome. In contrast, other studies, including a randomized controlled trial published in Cell, showed sucralose and saccharin can induce gut dysbiosis, a condition where the balance of good and bad bacteria in the gut is disrupted. (3)
Notably, the controlled trial on sucralose and saccharin focused on individuals without exposure to artificial sweeteners. Norton added that since this is a very specific group of people, the study’s results may not apply to people who already consume artificial sweeteners regularly.
“The most important thing to consider is the effect of artificial sweeteners on the gut microbiome and overall health outcomes,” said Norton. “Are these changes a net positive, negative, or neutral for our health?”
Multiple studies suggest that artificial sweeteners have neutral or positive effects on health outcomes, such as body weight, body fat, and insulin sensitivity.
The positive effects are not anything inherent to the non-nutritive sweeteners.
The benefits are likely because people consume fewer calories when using artificial sweeteners instead of sugar.
Norton concluded by acknowledging that while there is no strong evidence that stevia negatively affects the gut microbiome, more research is needed to draw a definitive conclusion on the impact of artificial sweeteners on gut health.
References
- Hu, F. B., & Malik, V. S. (2010). Sugar-sweetened beverages and risk of obesity and type 2 diabetes: epidemiologic evidence. Physiology & behavior, 100(1), 47–54.
- Kwok, D., Scott, C., Strom, N., Au-Yeung, F., Lam, C., Chakrabarti, A., Hutton, T., & Wolever, T. M. (2024). Comparison of a Daily Steviol Glycoside Beverage compared with a Sucrose Beverage for Four Weeks on Gut Microbiome in Healthy Adults. The Journal of Nutrition, 154(4), 1298–1308.
- Suez, J., Cohen, Y., Valdés-Mas, R., Mor, U., Dori-Bachash, M., Federici, S., Zmora, N., Leshem, A., Heinemann, M., Linevsky, R., Zur, M., Ben-Zeev Brik, R., Bukimer, A., Eliyahu-Miller, S., Metz, A., Fischbein, R., Sharov, O., Malitsky, S., Itkin, M., Stettner, N., … Elinav, E. (2022). Personalized microbiome-driven effects of non-nutritive sweeteners on human glucose tolerance. Cell, 185(18), 3307–3328.e19.
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