Overview
- The Tufts review and meta‑analysis, published Tuesday, pooled 21 randomized trials and found that non‑nutritive sweeteners raised fasting insulin and HbA1c and showed a trend toward worse insulin sensitivity compared with noncaloric controls.
- Several trials in the review reported changes in gut microbial composition and function after sweetener exposure, and one study used human‑to‑mouse microbiome transfer to show those changes can affect metabolism.
- Large observational studies generally associate sweetener use with higher cardiometabolic risk, but researchers warn these studies may be biased because people at risk are more likely to choose sugar substitutes.
- Adelaide University has launched the 'Sweet n Sour' head‑to‑head study recruiting participants to test aspartame, stevia, sucralose, saccharin and acesulfame potassium across organs and the gut microbiome with results expected by year‑end.
- Researchers and public‑health groups say policy and research gaps limit clarity: U.S. labels list sweetener ingredients but not amounts, long‑term randomized trials are scarce, and consumers may need clearer guidance if different sweeteners have different metabolic effects.