Abstract

Objective: Nigella Sativa, commonly known as Blackseed, has been mentioned in the Hadith
as a cure for all diseases except death. In the past Black seed has been used as a
treatment for a number of medical conditions including infections and headaches. Recently
studies have been performed to evaluate the medicinal properties and therapeutic potential
of Blackseed. We conducted a systematic review and meta-analysis of controlled trials to 

assess the effect of Blackseed on cardiometabolic outcomes.Methods: MEDLINE, EMBASE,

and The Cochrane library were searched through September 2017. Randomized and non-
randomized controlled trials of ≥1-week duration that assessed cardiometabolic risk factors

in participants from all health backgrounds were included. Two independent reviewers
extracted relevant data and assessed risk of bias (Cochrane Risk of Bias tool). Data was
pooled using random effects inverse variance method and expressed as mean differences
(MDs) with 95% confidence intervals (CIs). Heterogeneity was assessed (Cochran Q) and
quantified (I2 statistic).Results: We included 15 trials (n=1,010, median length = 8 weeks).
The blackseed dose ranged from 150mg to 2g/day or 2.5ml to 5ml/day. Regular blackseed
intake reduced systolic blood pressure (MD= -7.59 mmHg [95% CI, -10.61, -3.45]), diastolic
blood pressure DBP (MD=-3.49 mmHg [95% CIs, -5.67, -1.30]), LDL-Cholesterol (MD=–4.40
mmol/L [95% CIs, -5.83, -2.98]) and increased triglycerides (MD=6.48 mmol/L [95% CIs,
2.65, 10.31]) but it had not effect HDL-cholesterol. Regular blackseed intake had no effect
(p>0.05) on glycemic markers (fasting blood glucose, HbA1c), liver enzymes (AST, ALT and
GGT), inflammatory and renal markers (uric acid, blood urea nitrogen), or adiposity (weight,
weight circumference, BMI).
Conclusion: Pooled analyses show a modest beneficial effect of blackseed intake on blood
pressure, and a varying effect on lipid markers. There is a need for larger, longer and higher
quality trials, as our confidence in the results is low.