Editor's Note
This up-to-date, comprehensive, systematic review evaluates and summarizes all research studies in the field in order to clarify the magnitude of Nigella sativa ( N. sativa ) effects on the management of Diabetes mellitus (DM) and its complications. It was found that dietary supplementation with  N. sativa  preparations can improve various secondary complications of diabetic patients. N. sativa preparations possess antidiabetic, hypoglycemic, anti-hyperlipidemic, antihypertensive, and anti-obesity effects. Beneficial effects of N. sativa preparations include the restoration of the antioxidant defense systems, the increase in the activity of antioxidant enzymes, the decrease of inflammatory biomarkers, the suppression of the production pro-inflammatory mediators, improvement of endothelial dysfunction, and hepatic, kidney, heart and immune system functions.
Abstract

Objective

The purpose of this up-to-date comprehensive systematic review was to evaluate and summarize all research studies in the field in order to clarify the magnitude of  Nigella sativa  ( N. sativa ) effects on the management of Diabetes mellitus (DM) and its complications.

Methods

A systematic review was conducted in a Cochrane style and in accordance PRISMA checklist using the published studies in PubMed/MEDLINE, SCOPUS, and EMBASE databases that were searched up to January 2019. Abstracts that met PICO criteria for qualitative studies underwent dual review for data extraction to evaluate study quality and details.

Results

Dietary supplementation with  N. sativa  preparations can improve various secondary complications of diabetic patients.  N. sativa  preparations possess antidiabetic, hypoglycemic, anti-hyperlipidemic, antihypertensive, and anti-obesity effects. Beneficial effects of  N. sativa  preparations include the restoration of the antioxidant defense systems, the increase in the activity of antioxidant enzymes, the decrease of inflammatory biomarkers, the suppression of the production pro-inflammatory mediators, improvement of endothelial dysfunction, and hepatic, kidney, heart and immune system functions. They have key roles in managing diabetes-induced inflammation and oxidative stress in diabetic patients.

Conclusion

N. sativa  preparations have key roles in herbal medicine as an adjuvant in the treatment and management of patients with DM and its complications. Moreover, the beneficial effects of  N. sativa  preparations were differently based on dosage forms, active ingredients, and duration of intervention. The best dosage to improve glycemic indices and lipid and lipoprotein profiles is 2 g daily powdered  N. sativa  for at least 12 weeks.

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