Benefits
Fasting blood sugar in a juice trial without a placebo drink
In 46 adults with type 2 diabetes, 200 mL a day of barberry juice for 8 weeks lowered fasting blood sugar more than no treatment, though there was no placebo drink. In 85 women given 480 mL a day of juice or a placebo juice, insulin measures did not differ significantly before statistical adjustment. A pooled analysis of 7 barberry trials found lower insulin but no change in fasting glucose or HbA1c.
Blood cholesterol and triglyceride levels
In 84 adults with treated high blood pressure, 10 g a day of milled dried barberry for 8 weeks lowered triglycerides, total cholesterol and LDL cholesterol more than placebo, while HDL did not change. A juice trial also found lower total cholesterol than no treatment. A pooled analysis of 5 barberry trials found lower total cholesterol, LDL and triglycerides, with no significant HDL change.
Systolic blood pressure in adults already taking medication
In the same 84-person dried fruit trial, 24-hour systolic and mean arterial pressure fell more than on placebo in people already taking blood pressure medicines. A juice trial in adults with type 2 diabetes reported lower systolic and diastolic pressure than no treatment. A pooled analysis of 5 barberry trials found no significant effect on either reading.
Endothelial function and inflammation markers
In the 84-person dried fruit trial, flow-mediated dilation, an ultrasound test of how well the arm artery widens, improved compared with placebo, and blood levels of CRP and of the adhesion molecule ICAM-1 and the signaling protein MCP-1, were lower. IL-6 showed only a trend. All of this comes from one 8-week, single-blind trial.
Antioxidant balance markers in blood
In 106 adults with metabolic syndrome, three 200 mg capsules of dried barberry a day for 6 weeks lowered a blood measure of pro-oxidant to antioxidant balance more than placebo. A juice trial found a larger rise in the antioxidant enzyme paraoxonase-1 than no treatment. These are blood markers, not measures of health outcomes.
Mechanism of action
Fruit is rich in phenolics; berberine sits mainly in the root
In a lab comparison of the organs of the related purple-black barberry (Berberis integerrima), berberine was highest in the root, especially its bark, at about 209 times the level in the fruit, while the fruit and leaf held the most phenolic compounds. A matching measurement for Berberis vulgaris fruit was not found among the sources cited here.
Nitric oxide markers in the blood pressure trial
In the 84-person dried fruit trial, urinary nitrite and nitrate, breakdown products of nitric oxide, rose more on barberry than on placebo, while plasma levels and the activity of angiotensin-converting enzyme did not differ. This points to a nitric oxide route but does not prove it.
Fiber and nutrients in a 10 g daily serving
The dried fruit used in the 84-person trial contained, per 100 g, 23.8 g of fiber, 49.8 g of carbohydrate, 7.7 g of protein and 3.2 g of fat, so the 10 g daily amount supplied about 2.4 g of fiber. Its polyphenols were measured in an extract rather than per serving.
Clinical trials
Single-blind, randomized, placebo-controlled trial at Tehran, Iran (NCT04084847), reported in three papers: 10 g/day of milled dried seedless barberry fruit plus 1 g of sucrose, or a maltodextrin, citric acid and food color placebo, for 8 weeks. The protocol and the vessel-function paper (which cites Iranian registry number IRCT20160702028742N8 rather than the NCT number) call the fruit Berberis vulgaris; the lipid and blood pressure papers call it purple-black barberry (Berberis integerrima). Supported by the National Nutrition and Food Technology Research Institute, Shahid Beheshti University of Medical Sciences. (Emamat et al. 2022, BMC Complement Med Ther)
84 adults (mean age 54) with treated high blood pressure and other heart risk factors; 78 completed.
After adjustment for baseline values, triglycerides (p < 0.001), total cholesterol (p = 0.011), LDL cholesterol (p = 0.015) and CRP (p = 0.020) fell compared with placebo; HDL did not differ and IL-6 showed only a trend (p = 0.06). In the companion papers, 24-hour systolic and mean arterial pressure fell more than on placebo (p = 0.015 and p = 0.008), and flow-mediated dilation improved (adjusted difference 6.54%, p < .001) with lower ICAM-1 and MCP-1. Two people on barberry and one on placebo left with mild digestive complaints.
Randomized trial in Iran comparing 200 mL of barberry juice daily for 8 weeks with a control group that received no intervention, so there was no placebo drink. The abstract does not name the barberry species, the juice source or a funding source. (Lazavi et al. 2018, Complement Ther Clin Pract)
46 adults with type 2 diabetes randomized (23 per group); 42 completed.
Systolic and diastolic blood pressure, fasting blood sugar and total cholesterol fell more than in the control group (P < 0.05 for treatment effect), and paraoxonase-1 (PON1) rose compared with control (P < 0.0001). Triglycerides fell in the juice group, but the abstract does not report this as a between-group difference.
Double-blind, randomized, placebo-controlled trial at the nutrition clinic of Ghaem Hospital, Mashhad, Iran, in adults with metabolic syndrome, reported in two papers: three capsules a day, each holding 200 mg of dried barberry made from barberry juice, or placebo for 6 weeks, with dietary advice for everyone. For blood lipids and hs-CRP the abstract reports only changes within each group (cholesterol and LDL fell and HDL rose on barberry; hs-CRP rose on placebo), not between-group tests. The companion paper credits funding to the Research Council of Mashhad University of Medical Sciences. (Zilaee et al. 2014, Phytother Res)
106 adults aged 18 to 65 (79 women, 27 men) at a hospital nutrition clinic in Mashhad, Iran.
In the companion paper (Mohammadi et al. 2014, Iran Red Crescent Med J), the pro-oxidant-antioxidant balance, a blood marker of oxidative stress, fell more on barberry than on placebo (P = 0.01). Antibodies to heat shock protein 60 fell within the barberry group, antibodies to heat shock protein 27 fell in both groups, and those to heat shock proteins 65 and 70 did not change.
Triple-blind, randomized, placebo-controlled parallel trial at Nour-Nejat Hospital, Tabriz, Iran (IRCT2012110511335N2): 480 mL/day of Berberis vulgaris juice, provided by the maker Takdaneh, or a placebo juice matched for calories, vitamins, taste and color, for 8 weeks after a 7-day run-in. Outcomes were insulin, C-peptide, HOMA-IR, HOMA-B and the glucose to insulin ratio; a second paper from the same trial reported IGF-1 and gene-expression markers. Funded by the Nutrition Research Center, Tabriz University of Medical Sciences. (Asemani et al. 2018, Iran J Pharm Res)
85 premenopausal women with benign breast disease (44 juice, 41 placebo); 40 per group analyzed.
No unadjusted between-group difference reached significance: the fasting hormone reading was 19% and the resistance index 16% lower relative to placebo, without significance. Only after adjusting for baseline values and covariates did the changes in C-peptide and HOMA-B, an index of beta-cell function, become significant. No adverse effects were reported.
Randomized, placebo-controlled trial by a single author at Tabriz University of Medical Sciences, Iran: gelatin capsules of a water extract of dried Berberis vulgaris fruit, 600 mg/day, or placebo for 4 weeks, with lesion counts and a severity score at weeks 0, 2 and 4. The abstract does not state blinding or funding. (Fouladi 2012, J Diet Suppl)
49 adolescents aged 12 to 17 with moderate to severe acne (25 extract, 24 placebo).
Inflamed, non-inflamed and total lesion counts and the severity score fell by about 43 to 45% within the extract group (p < .001), while similar changes on placebo were not significant. The abstract compares each group with its own baseline rather than reporting a between-group test. No notable side effects were reported.