Sumac and metabolic syndrome markers in a cross-over trial
What it found
In 47 adults with metabolic syndrome, taking 1000 mg of sumac daily for 6 weeks lowered systolic blood pressure compared with placebo.
It did not change waist size, weight, blood sugar or cholesterol measures.
What they found
Studies in people
Systolic blood pressure
Sumac lowered systolic blood pressure by about 5 mmHg over 6 weeks. The placebo group showed almost no change, and the difference between groups was significant.
Diastolic blood pressure
Sumac did not change diastolic blood pressure compared with placebo.
Waist and weight
Sumac did not change waist circumference, weight or BMI. The placebo group had a small drop in waist circumference.
Blood sugar
Sumac did not change fasting blood sugar or other glycemic measures compared with placebo.
Blood fats
Sumac did not significantly change triglycerides, total cholesterol, LDL or HDL compared with placebo. In the per-protocol analysis, sumac appeared to prevent a small rise in triglycerides seen in the placebo group.
Side effects
Participants reported no clinical adverse effects, and no one dropped out because of a side effect from the supplement.
What the authors conclude
“This cross-over randomized controlled trial revealed that sumac supplementation could decrease systolic blood pressure and might prevent a rise in triglyceride concentration in men and women with metabolic syndrome.”
Also in their conclusions
- They conclude that sumac supplementation could reduce systolic blood pressure in men and women with metabolic syndrome.
- They state that daily intake of 1000 mg sumac, as an adjuvant therapy, may be beneficial in management of metabolic syndrome in adults.
- They suggest that adjuvant therapy with sumac could be used for metabolic syndrome treatment and decreasing its subsequent comorbidities.
How it was done
The authors wanted to test sumac in people with metabolic syndrome because previous studies looked at blood sugar, blood fats and belly fat in other groups, but not in this condition.
They ran a triple-blinded randomized placebo-controlled cross-over trial in 47 adults with metabolic syndrome, aged 20 to 70. Each person took 500 mg sumac or placebo capsules twice a day for 6 weeks, then switched after a 2-week break.
What it can’t tell you
- The trial lasted only 6 weeks per phase, so it cannot show what happens over longer periods.
- The study had a small number of participants, so it could not check for differences between men and women.
- The authors note there was no biomarker to check whether participants actually took the sumac capsules.
Who paid
- Conflicts
- None of the authors had any personal or financial conflicts of interest.
- Authors work at
- Isfahan University of Medical Sciences, Iran
The paper
- Title
- Effects of sumac supplementation on metabolic markers in adults with metabolic syndrome: a triple-blinded randomized placebo-controlled cross-over clinical trial
- Type
- Randomised controlled trial
- Evidence
- Studies in people
- Summarised from
- Full text
- Licence
- CC BY. Words in quotation marks are the authors’; the rest is our summary.
- Cite
- Mirenayat FS, Hajhashemy Z, Siavash M, Saneei P (2023). Effects of sumac supplementation on metabolic markers in adults with metabolic syndrome: a triple-blinded randomized placebo-controlled cross-over clinical trial. Nutrition journal. doi:10.1186/s12937-023-00854-9Free full textPubMed 37189189DOI
Summary written 30 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error