Guava isn’t just a tropical treat — it may help support healthier blood sugar control, especially for those managing or aiming to prevent diabetes. One of its main advantages is a low glycemic index (GI): depending on variety and origin, guava’s GI can range from about 12 to 31, meaning it causes a slow, gradual rise in blood sugar rather than a sharp spike. This slower absorption helps the body regulate glucose more smoothly.

Another strength is guava’s high fiber content, especially soluble fiber. Fiber delays sugar absorption in the digestive tract, helping blunt post‑meal glucose surges and promoting feelings of fullness — both helpful for blood sugar and weight control. Guava is also rich in vitamin C and potassium, and contains antioxidant compounds like flavonoids, which may enhance insulin sensitivity and reduce oxidative stress in metabolic tissues.

Beyond the fruit itself, guava leaf extracts have been studied for their effects on glucose metabolism. Animal studies show that guava leaf extracts significantly reduce blood sugar levels, boost insulin levels, and increase enzyme activity related to glucose breakdown (e.g. hexokinase) in diabetic models. Polysaccharides isolated from guava leaves also lowered fasting glucose, lipid markers, and oxidative stress in diabetic mice. In diet‑induced obese mice, guava leaf extract improved insulin resistance, reduced blood glucose, and improved vascular function. Some of the proposed mechanisms include inhibition of carbohydrate‑digesting enzymes (α‑glucosidase), improving insulin sensitivity, anti‑inflammatory effects, and protecting pancreatic β‑cells.

However, human clinical evidence remains limited. One small randomized trial in healthy people found that guava fruit (especially without peel) may modestly improve lipid profiles and lower LDL cholesterol, though effects on fasting glucose were not conclusive.

In summary: guava, especially when eaten whole (skin included if safe), offers promising nutritional and functional components that may support blood sugar control. Guava leaf teas or extracts carry more targeted glucose‑lowering potential in animal studies. Still, guava should be considered an adjunct (not a replacement) in diabetes care, and any dietary change or herbal remedy should be reviewed with a healthcare provider.