Saffron nudges blood sugar and blood pressure, but only just

Metabolic syndrome bundles together raised blood sugar, unhealthy blood fats and high blood pressure, and it pushes up the risk of type 2 diabetes and heart disease. Saffron has a long history in traditional herbal medicine for exactly these kinds of conditions, and modern trials have put it to the test. The problem is that those trials have reached inconsistent conclusions, leaving no clear answer on whether the spice does anything measurable. Pooling them is the obvious way to find out whether a real signal sits beneath the noise.

The authors searched five major research databases, including PubMed, the Cochrane Library and Embase, for randomised controlled trials of saffron supplementation in people with metabolic syndrome and related disorders, covering studies published up to February 2024. Twenty-five trials qualified, involving 1486 participants in total, each comparing saffron against placebo. The team then pooled the results across trials, examining fasting blood glucose, HbA1c, cholesterol measures, triglycerides, blood pressure, insulin resistance, body mass index and waist circumference. Results were expressed as the average difference between the saffron and placebo groups.

Compared with placebo, saffron lowered fasting blood glucose by 6.67 mg/dL, HbA1c by 0.25%, total cholesterol by 4.77 mg/dL, systolic blood pressure by 1.15 mmHg and diastolic blood pressure by 1.61 mmHg. All of these changes were statistically significant, yet each is modest in absolute terms. Just as telling is what did not move: insulin resistance, triglycerides, LDL and HDL cholesterol, body mass index and waist circumference all showed no significant change. In short, saffron nudged several blood markers while leaving body size entirely untouched.

Individual saffron trials have pointed in different directions, and this pooling suggests the truth sits in the middle: a real but small effect on glucose, HbA1c, total cholesterol and blood pressure, and nothing detectable on weight, waist or insulin resistance. That pattern complicates the more sweeping claims sometimes made for the spice. The authors note that additional high-quality randomised trials involving more diverse ethnic populations are needed to validate the effect. How best to deliver the supplement also remains open, since the included trials varied in their approaches.

If you have been tempted by saffron for metabolic health, this is a reason to size your expectations honestly: the pooled evidence points to small improvements in blood sugar, cholesterol and blood pressure, not a transformation. It is equally a reason not to expect anything on the scales, since weight and waist circumference did not change. For anyone managing metabolic syndrome, these findings describe a possible adjunct, not an alternative to whatever else is doing the heavy lifting.