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Evidence-Based Supplement Research
Evidence-Based Supplement Research

The effect of L-carnitine supplementation on insulin resistance, sex hormone-binding globulin and lipid profile in overweight/obese women with polycystic ovary syndrome: a randomized clinical trial.

  • 2021-11-02
  • European journal of nutrition 61(3)
    • Abbas Ali Sangouni
    • Fatemeh Pakravanfar
    • Akram Ghadiri-Anari
    • Azadeh Nadjarzadeh
    • Hossein Fallahzadeh
    • Mahdieh Hosseinzadeh

Study Design

Type
Randomized Controlled Trial (RCT)
Population
62 overweight/obese women with PCOS
Methods
randomized, double-blind, controlled clinical trial, 1000 mg/day L-carnitine or placebo (1000 mg starch) for 12 weeks
Blinding
Double-blind
Duration
12 weeks
Funding
Unclear
  • Rigorous Journal

Purpose

Polycystic ovary syndrome (PCOS) is a common endocrine disorder among reproductive-age women. Insulin resistance and dyslipidemia are linked to PCOS. L-Carnitine supplementation as a management strategy for women with PCOS has been proposed. The effect of L-carnitine supplementation on insulin resistance, sex hormone-binding globulin (SHBG) and lipid profile in overweight/obese women with PCOS was investigated.

Methods

This randomized, double-blind, controlled clinical trial, was conducted on 62overweight/obese women with PCOS. Participants were randomly assigned into two groups to receive 1000 mg/day L-carnitine or placebo (1000 mg starch) for 12 weeks.

Results

L-Carnitine supplementation compared to the placebo showed a significant improvement in insulin [- 0.7 (- 7.3 to 4.0) vs. 0.7 (- 3.0 to 5.2); P = 0.001], homeostatic model assessment for insulin resistance [- 0.4 (- 1.7 to 1.1) vs. 0.0 (- 0.7 to 1.3); P = 0.002], quantitative insulin sensitivity check index (+ 0.01 ± 0.02 vs. - 0.01 ± 0.01; P = 0.02) and a non-significant change toward improvement in SHBG (+ 11.5 ± 40.2 vs. - 3.2 ± 40.2; P = 0.2). However, there was no significant differences between the two groups in serum levels of fasting plasma glucose, total cholesterol, triglyceride, low density lipoprotein-cholesterol and high density lipoprotein cholesterol (P > 0.05).

Conclusion

12-week L-carnitine supplementation in overweight or obese women with PCOS ameliorate insulin resistance, but has no effect on SHBG and lipid profile. Studies with higher dosages and duration of L-carnitine intake are required. The trial was registered on 30 December 2019 at Iranian Registry of Clinical Trials IRCT20191016045131N1.

Trial registration

Registered on 30th December 2019 at Iranian Registry of Clinical Trials (IRCT20191016045131N1).

Research Insights

  • there was no significant differences between the two groups in serum levels of fasting plasma glucose (P > 0.05)

    Effect
    Neutral
    Effect size
    Small
    Dose
    1000 mg/day
  • L-Carnitine supplementation compared to the placebo showed a significant improvement in insulin [- 0.7 (- 7.3 to 4.0) vs. 0.7 (- 3.0 to 5.2); P = 0.001], homeostatic model assessment for insulin resistance [- 0.4 (- 1.7 to 1.1) vs. 0.0 (- 0.7 to 1.3); P = 0.002], quantitative insulin sensitivity check index (+ 0.01 ± 0.02 vs. - 0.01 ± 0.01; P = 0.02)

    Effect
    Beneficial
    Effect size
    Small
    Dose
    1000 mg/day
  • a non-significant change toward improvement in SHBG (+ 11.5 ± 40.2 vs. - 3.2 ± 40.2; P = 0.2)

    Effect
    Neutral
    Effect size
    Small
    Dose
    1000 mg/day
  • there was no significant differences between the two groups in serum levels of high density lipoprotein cholesterol (P > 0.05)

    Effect
    Neutral
    Effect size
    Small
    Dose
    1000 mg/day
  • there was no significant differences between the two groups in serum levels of total cholesterol (P > 0.05)

    Effect
    Neutral
    Effect size
    Small
    Dose
    1000 mg/day
  • there was no significant differences between the two groups in serum levels of low density lipoprotein-cholesterol (P > 0.05)

    Effect
    Neutral
    Effect size
    Small
    Dose
    1000 mg/day
  • there was no significant differences between the two groups in serum levels of triglyceride (P > 0.05)

    Effect
    Neutral
    Effect size
    Small
    Dose
    1000 mg/day
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