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A crossover randomized controlled trial examining the effects of black seed (Nigella sativa) supplementation on IL-1β, IL-6 and leptin, and insulin parameters in overweight and obese women.

  • 2024-01-05
  • BMC complementary medicine and therapies 24(1)
    • Elham Razmpoosh
    • Sara Safi
    • Mahta Mazaheri
    • Saman Khalesi
    • Majid Nazari
    • Parvin Mirmiran
    • Azadeh Nadjarzadeh

Study Design

Type
Randomized Controlled Trial (RCT)
Population
overweight/obese women
Methods
crossover design, participants randomized to receive either NS supplements (2000 mg/day) or placebo for 2 durations (8 weeks); repeated-measure ANOVA
Duration
8 weeks

Background

Nigella sativa (NS) oil has been found to have advantageous benefits in the management of inflammation and obesity. This study investigated the effect of NS supplementation on blood mRNA expressions and serum levels of IL-1β, IL-6, leptin, and insulin concentrations in overweight/obese women.

Methods

In a crossover design, participants were randomized to receive either NS supplements(2000 mg/day) or placebo for 2 durations(8 weeks). With between-subject and within-subject components and interactions, a repeated-measure ANOVA model was used considering the treatment, time, and the carryover effects. Cohen's d(d) was used to measure the magnitude of the effects.

Results

Forty-six eligible participants were included. NS supplementation significantly reduced the mRNA expressions(d=-0.68, P = 0.03) and serum levels of IL-1β with medium-high effect sizes(d=-1.6, P < 0.001). Significant reductions with large effect sizes were observed in the gene expression and serum levels of IL-6(d=-1.8, d=-0.78, respectively; P < 0.01) and Leptin(d=-1.9, d=-0.89, respectively; P < 0.01, serum leptin P carryover < 0.001). Despite the meaningful carryover effect for serum leptin, results remained significant following the first intervention period analysis(P < 0.001). A significant but low effect size decrease in serum insulin was observed(d=-0.3, P = 0.02).

Conclusions

The clinical significance of present findings regarding improvements in obesity-related pro-inflammatory markers must be interpreted with caution due to some observed medium-low effect sizes.

Trial registration

IRCT20180430039475N1 (Date:25/6/2018).

Research Insights

  • Black Cumin→Improved Insulin Levels

    A significant but low effect size decrease in serum insulin was observed(d=-0.3, P = 0.02).

    Effect
    Beneficial
    Effect size
    Small
    Dose
    2000 mg/day
  • Black Cumin→Reduced Interleukin-1β Levels

    and serum levels of IL-1β with medium-high effect sizes(d=-1.6, P < 0.001).

    Effect
    Beneficial
    Effect size
    Large
    Dose
    2000 mg/day
  • Black Cumin→Reduced Interleukin-1β mRNA Expression

    NS supplementation significantly reduced the mRNA expressions(d=-0.68, P = 0.03)

    Effect
    Beneficial
    Effect size
    Moderate
    Dose
    2000 mg/day
  • Black Cumin→Reduced Interleukin-6 Levels

    Significant reductions with large effect sizes were observed in the gene expression and serum levels of IL-6(d=-1.8, d=-0.78, respectively; P < 0.01)

    Effect
    Beneficial
    Effect size
    Moderate
    Dose
    2000 mg/day
  • Black Cumin→Reduced Interleukin-6 mRNA Expression

    Significant reductions with large effect sizes were observed in the gene expression and serum levels of IL-6(d=-1.8, d=-0.78, respectively; P < 0.01)

    Effect
    Beneficial
    Effect size
    Large
    Dose
    2000 mg/day
  • Black Cumin→Reduced Leptin Levels

    and Leptin(d=-1.9, d=-0.89, respectively; P < 0.01, serum leptin P carryover < 0.001). Despite the meaningful carryover effect for serum leptin, results remained significant following the first intervention period analysis(P < 0.001).

    Effect
    Beneficial
    Effect size
    Moderate
    Dose
    2000 mg/day
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