Introduction
Methods
Study design
Data sources and searches
Study selection
Inclusion criteria
Exclusion criteria
Quality assessment and Data extraction
Statistical analyses
Certainty assessment
Results
Study selection and Study characteristics
Study | Country | Study design | Diagnostic criteria | Sample size | Diet type | Study duration (weeks) | Outcomes | ||
---|---|---|---|---|---|---|---|---|---|
Intervention group | Control group | Intervention group | Control group | ||||||
Amini 2018 [20] | Iran | Randomized, double blinded | Rotterdam criteria | 27 | 27 | Fish oil n-3 PUFA supplements 2000 mg/d (Marine derived) | Paraffin oil (placebo) 100 mg/d | 12 | BW,BMI,hs-CRP,QUICK,FPG, FINS, HOMA-IR, TG, TC, LDL-C, HDL-C,VLDL-C |
Cussons 2009 [32] | Australia | Randomized, double blinded | Rotterdam criteria | 12 | 13 | Fish oil n-3 PUFA 4000 mg/d (Marine derived) | olive oil (placebo) 4000 mg/d | 8 | BMI,hs-CRP,FPG, FINS, HOMA-IR, TG, TC, LDL-C, HDL-C |
Ebrahimi 2017 [30] | Iran | Randomized, double blinded | Rotterdam criteria | 34 | 34 | Flaxseed oil n-3 PUFA 1000 mg/d (Plant origins) + vitamin E 400 IU/d | Placebo | 12 | BW,BMI,QUICK,FPG, FINS, HOMA-IR |
Jamilian 2018 [33] | Iran | Randomized, double blinded | Rotterdam criteria | 30 | 30 | Fish oil n-3 PUFA 2000 mg/d (Marine derived) + vitamin E 50,000 IU/2 weeks | Placebo | 12 | BMI, BW, hs-CRP |
Khani 2017 [19] | Iran | Randomized, double blinded | NIH criteria | 43 | 44 | n-3 PUFA supplements 2000 mg/d (360 mg EPA and 240 mg DHA) (Marine derived) | Olive oil (placebo) 2000 mg/d | 24 | BMI,WC,FPG, TG, TC, LDL-C, HDL-C |
Mejia-Montilla 2018 [26] | Venezuela | Randomized, double blinded | Specialists Consensus | 97 | 98 | n-3 PUFA supplements 1000 mg/d (180 mg EPA and 120 mg DHA) | Paraffin oil (placebo) 1000 mg/d | 12 | BMI,FINS, HOMA-IR, TG, TC, LDL-C, HDL-C,Adiponectin |
Mirmasoumi 2018 [21] | Iran | Randomized, double blinded | Rotterdam criteria | 30 | 30 | Flaxseed oil n-3 PUFA 2000 mg/d (Plant origins) | Paraffin oil (placebo) 500 mg/d | 12 | BW,BMI,hs-CRP,QUICK,FPG, FINS, HOMA-IR, TG, TC, LDL-C, HDL-C,VLDL-C |
Mohammadi 2012 [31] | Iran | Randomized, double blinded | Rotterdam criteria | 30 | 31 | n-3 PUFA supplements 4000 mg/d (720 mg EPA and 480 mg DHA) (Marine derived) | Paraffin oil (placebo) 500 mg/d | 8 | BW,BMI,WC,hs-CRP,FPG, FINS, HOMA-IR, TG, TC, LDL-C, HDL-C,Adiponectin |
Nadjarzadeh 2015 [34] | Iran | Randomized, double blinded | Rotterdam criteria | 39 | 39 | n-3 PUFA supplements 1000 mg/d (180 mg EPA and 120 mg DHA) | Paraffin oil (placebo) 1000 mg/d | 12 | BMI,WC,Adiponectin |
Rahmani 2017 [29] | Iran | Randomized, double blinded | Rotterdam criteria | 34 | 34 | Flaxseed oil n-3 PUFA 1000 mg/d (Plant origins) + Vitamin E 400 IU/d | Placebo | 12 | BW,BMI,TG, TC, LDL-C, HDL-C,VLDL-C |
Talari 2018 [35] | Iran | Randomized, double blinded | Rotterdam criteria | 30 | 30 | Flaxseed oil n-3 PUFA 1000 mg/d (Plant origins) + Vitamin E 400 IU/d | Placebo | 12 | hs-CRP |
Risk of bias within studies
Meta analysis
Anthropometric indices
Subgrouped by | No. of trials | No. of participants | Meta-analysis | Heterogeneity | ||||
---|---|---|---|---|---|---|---|---|
MD | 95% CI | p-Value | I2 (%) | Cochrane Q-test (p-Value) | ||||
BW | Study duration | |||||||
≤ 8 weeks | 1 | 61 | -1.70 | -6.41, 3.01 | 0.48 | NA | NA | |
> 8 weeks | 5 | 310 | -1.40 | -4.56, 1.77 | 0.39 | 0 | 0.92 | |
Sources | ||||||||
Marine derived | 3 | 175 | -1.07 | -4.47, 2.34 | 0.54 | 0 | 0.90 | |
Plant origins | 3 | 196 | -2.11 | -6.24, 2.02 | 0.32 | 0 | 0.74 | |
Dosage | ||||||||
≤ 1000 mg | 2 | 136 | -3.25 | -8.29, 1.80 | 0.21 | 0 | 0.89 | |
> 1000 mg | 4 | 235 | -0.84 | -3.91, 2.24 | 0.59 | 0 | 0.96 | |
BMI | Study duration | |||||||
≤ 8 weeks | 2 | 86 | -0.21 | -1.71, 1.30 | 0.79 | 0 | 0.97 | |
> 8 weeks | 7 | 670 | -0.61 | -1.21, -0.02 | 0.04 | 0 | 0.93 | |
Sources | ||||||||
Marine derived | 7 | 460 | -0.59 | -1.18, -0.00 | 0.05 | 0 | 0.90 | |
Plant origins | 3 | 196 | -0.33 | -1.86, 1.21 | 0.68 | 0 | 0.84 | |
Dosage | ||||||||
≤ 1000 mg | 4 | 409 | -0.54 | -1.26, 0.18 | 0.14 | 0 | 1.0 | |
> 1000 mg | 6 | 347 | -0.59 | -1.45, 0.28 | 0.18 | 0 | 0.76 | |
WC | Study duration | |||||||
≤ 8 weeks | 1 | 61 | -0.40 | -3.57, 2.77 | 0.80 | NA | NA | |
> 8 weeks | 2 | 165 | -3.06 | -4.19, -1.93 | 0.00 | 0 | 0.87 | |
Sources | ||||||||
Marine derived | NA | NA | NA | NA | NA | NA | NA | |
Plant origins | NA | NA | NA | NA | NA | NA | NA | |
Dosage | ||||||||
≤ 1000 mg | 1 | 78 | -3.50 | -9.08, 2.08 | 0.22 | NA | NA | |
> 1000 mg | 2 | 148 | -2.73 | -3.81, -1.65 | 0.00 | 58 | 0.12 | |
FPG | Study duration | |||||||
≤ 8 weeks | 2 | 86 | -5.79 | -10.18, -1.40 | 0.01 | 43 | 0.19 | |
> 8 weeks | 4 | 269 | -3.54 | -5.49, -1.59 | 0.00 | 17 | 0.30 | |
Sources | ||||||||
Marine derived | 4 | 227 | -3.39 | -5.47, -1.31 | 0.00 | 8 | 0.35 | |
Plant origins | 2 | 128 | -5.37 | -8.84, -1.90 | 0.00 | 51 | 0.15 | |
Dosage | ||||||||
≤ 1000 mg | 1 | 68 | -7.10 | -11.31, -2.89 | 0.00 | NA | NA | |
> 1000 mg | 5 | 287 | -3.22 | -5.18, -1.25 | 0.00 | 0 | 0.47 | |
FINS | Study duration | |||||||
≤ 8 weeks | 2 | 86 | -1.29 | -2.77, 0.20 | 0.09 | 0 | 0.95 | |
> 8 weeks | 4 | 377 | -2.84 | -3.69, -1.98 | 0.00 | 0 | 0.85 | |
Sources | ||||||||
Marine derived | 4 | 335 | -2.40 | -3.20, -1.61 | 0.00 | 22 | 0.28 | |
Plant origins | 2 | 128 | -2.75 | -4.73, -0.77 | 0.00 | 0 | 0.96 | |
Dosage | ||||||||
≤ 1000 mg | 2 | 263 | -3.05 | -4.06, -2.03 | 0.00 | 0 | 0.79 | |
> 1000 mg | 4 | 200 | -1.77 | -2.86, -0.68 | 0.00 | 0 | 0.79 | |
HOMA-IR | Study duration | |||||||
≤ 8 weeks | 2 | 86 | 0.82 | -2.19, 3.83 | 0.59 | 91 | 0.00 | |
> 8 weeks | 4 | 377 | -0.47 | -0.66, -0.29 | 0.00 | 0 | 0.63 | |
Sources | ||||||||
Marine derived | 4 | 335 | -0.30 | -0.78, 0.17 | 0.21 | 74 | 0.00 | |
Plant origins | 2 | 128 | -0.75 | -1.23, -0.27 | 0.00 | 0 | 0.84 | |
Dosage | ||||||||
≤ 1000 mg | 2 | 263 | -0.43 | -0.65, -0.22 | 0.00 | 0 | 0.41 | |
> 1000 mg | 4 | 200 | -0.29 | -0.96, 0.37 | 0.39 | 76 | 0.00 | |
QUICKI | Study duration | |||||||
≤ 8 weeks | NA | NA | NA | NA | NA | NA | NA | |
> 8 weeks | NA | NA | NA | NA | NA | NA | NA | |
Sources | ||||||||
Marine derived | 1 | 54 | 0.01 | 0.00, 0.02 | 0.02 | NA | NA | |
Plant origins | 2 | 128 | 0.01 | 0.01, 0.02 | 0.00 | 50 | 0.16 | |
Dosage | ||||||||
≤ 1000 mg | 1 | 68 | 0.01 | 0.00, 0.02 | 0.04 | NA | NA | |
> 1000 mg | 2 | 114 | 0.01 | 0.01, 0.02 | 0.00 | 55 | 0.14 | |
Adiponectin | Study duration | |||||||
≤ 8 weeks | 1 | 61 | 1.50 | 0.11, 2.89 | 0.03 | NA | NA | |
> 8 weeks | 2 | 273 | 1.46 | 1.11, 1.81 | 0.00 | 0 | 0.44 | |
Sources | ||||||||
Marine derived | NA | NA | NA | NA | NA | NA | NA | |
Plant origins | NA | NA | NA | NA | NA | NA | NA | |
Dosage | ||||||||
≤ 1000 mg | 2 | 273 | 1.46 | 1.11, 1.81 | 0.00 | 0 | 0.44 | |
> 1000 mg | 1 | 61 | 1.50 | 0.11, 2.89 | 0.03 | NA | NA | |
TG | Study duration | |||||||
≤ 8 weeks | 2 | 86 | -5.55 | -16.85, 5.74 | 0.33 | 21 | 0.26 | |
> 8 weeks | 5 | 464 | -9.37 | -10.61, -8.14 | 0.00 | 55 | 0.06 | |
Sources | ||||||||
Marine derived | 5 | 422 | -9.28 | -10.51, -8.05 | 0.00 | 55 | 0.07 | |
Plant origins | 2 | 128 | -24.94 | -48.00, -1.87 | 0.03 | 0 | 0.78 | |
Dosage | ||||||||
≤ 1000 mg | 2 | 263 | -16.71 | -22.50, -10.93 | 0.00 | 0 | 0.47 | |
> 1000 mg | 5 | 287 | -8.98 | -10.24, -7.72 | 0.00 | 0 | 0.47 | |
TC | Study duration | |||||||
≤ 8 weeks | 2 | 86 | -13.42 | -26.67, -0.17 | 0.05 | 0 | 0.36 | |
> 8 weeks | 5 | 464 | -12.20 | -20.18, -4.22 | 0.00 | 79 | 0.00 | |
Sources | ||||||||
Marine derived | 5 | 422 | -12.18 | -20.45, -3.92 | 0.00 | 79 | 0.00 | |
Plant origins | 2 | 128 | -12.91 | -24.77, -1.05 | 0.03 | 0 | 0.33 | |
Dosage | ||||||||
≤ 1000 mg | 2 | 263 | -20.97 | -26.04, -15.90 | 0.00 | 0 | 0.58 | |
> 1000 mg | 5 | 287 | -9.08 | -11.55, -6.60 | 0.00 | 0 | 0.65 | |
HDL-C | Study duration | |||||||
≤ 8 weeks | 2 | 86 | 0.64 | -2.06, 3.35 | 0.64 | 0 | 0.78 | |
> 8 weeks | 5 | 464 | 2.60 | 0.07, 5.14 | 0.04 | 81 | 0.00 | |
Sources | ||||||||
Marine derived | 5 | 422 | 3.09 | 0.65, 5.52 | 0.01 | 81 | 0.00 | |
Plant origins | 2 | 128 | -0.65 | -4.08, 2.78 | 0.71 | 0 | 0.76 | |
Dosage | ||||||||
≤ 1000 mg | 2 | 263 | 2.27 | -3.57, 8.10 | 0.45 | 83 | 0.01 | |
> 1000 mg | 5 | 287 | 1.52 | -2.30, 5.35 | 0.43 | 83 | 0.00 | |
LDL-C | Study duration | |||||||
≤ 8 weeks | 2 | 86 | -9.98 | -25.36, 5.40 | 0.20 | 22 | 0.26 | |
> 8 weeks | 5 | 464 | -10.86 | -21.05, -0.68 | 0.04 | 94 | 0.00 | |
Sources | ||||||||
Marine derived | 5 | 422 | -11.87 | -22.46, -1.28 | 0.03 | 94 | 0.00 | |
Plant origins | 2 | 128 | -6.97 | -17.79, 3.86 | 0.21 | 0 | 0.39 | |
Dosage | ||||||||
≤ 1000 mg | 2 | 263 | -19.45 | -34.19, -4.71 | 0.01 | 79 | 0.03 | |
> 1000 mg | 5 | 287 | -9.50 | -10.74, -8.27 | 0.00 | 1 | 0.40 | |
VLDL-C | Study duration | |||||||
≤ 8 weeks | NA | NA | NA | NA | NA | NA | NA | |
> 8 weeks | NA | NA | NA | NA | NA | NA | NA | |
Sources | ||||||||
Marine derived | 1 | 54 | 1.70 | -3.92, 7.32 | 0.55 | NA | NA | |
Plant origins | 2 | 128 | -5.05 | -9.66, -0.44 | 0.03 | 0 | 0.78 | |
Dosage | ||||||||
≤ 1000 mg | 1 | 68 | -5.60 | -11.68, 0.48 | 0.07 | NA | NA | |
> 1000 mg | 2 | 114 | -0.62 | -5.02, 3.78 | 0.78 | 41 | 0.19 | |
hs-CRP | Study duration | |||||||
≤ 8 weeks | 2 | 86 | 0.03 | -0.37, 0.43 | 0.89 | 0 | 0.92 | |
> 8 weeks | 4 | 234 | -0.83 | -1.69, 0.04 | 0.06 | 71 | 0.02 | |
Sources | ||||||||
Marine derived | 4 | 422 | -11.87 | -22.46, -1.28 | 0.03 | 94 | 0.00 | |
Plant origins | 2 | 128 | -6.97 | -17.79, 3.86 | 0.21 | 0 | 0.39 | |
Dosage | ||||||||
≤ 1000 mg | 1 | 60 | 0.20 | -0.47, 0.87 | 0.56 | NA | NA | |
> 1000 mg | 5 | 260 | -0.82 | -1.62, -0.02 | 0.04 | 68 | 0.01 |
The metabolic status in IR
The metabolic status in lipid profiles
Sensitivity analysis and publication bias
Certainty assessment
Certainty assessment | № of patients | Effect | Certainty | Importance | |||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
№ of studies | Study design | Risk of bias | Inconsistency | Indirectness | Imprecision | Other considerations | n-3 PUFA | control | Relative (95% CI) | Absolute (95% CI) | |||
BW | |||||||||||||
6 | randomised trials | not serious | not serious | not serious | very seriousa,b | none | 185 | 186 | - | MD 1.49 lower (4.12 lower to 1.14 higher) | ⨁⨁◯◯ Low | NOT IMPORTANT | |
BMI | |||||||||||||
10 | randomised trials | not serious | not serious | not serious | not serious | none | 376 | 380 | - | MD 0.56 lower (1.11 lower to 0.01 lower) | ⨁⨁⨁⨁ High | NOT IMPORTANT | |
WC | |||||||||||||
3 | randomised trials | not serious | not serious | not serious | seriousa | none | 112 | 114 | - | MD 2.76 lower (3.82 lower to 1.69 lower) | ⨁⨁⨁◯ Moderate | NOT IMPORTANT | |
FPG | |||||||||||||
6 | randomised trials | not serious | not serious | not serious | seriousa | none | 176 | 179 | - | MD 3.91 lower (5.69 lower to 2.13 lower) | ⨁⨁⨁◯ Moderate | IMPORTANT | |
FINS | |||||||||||||
6 | randomised trials | not serious | not serious | not serious | not serious | none | 230 | 233 | - | MD 2.45 lower (3.19 lower to 1.71 lower) | ⨁⨁⨁⨁ High | IMPORTANT | |
HOMA-IR | |||||||||||||
6 | randomised trials | seriousc | not serious | not serious | not serious | publication bias strongly suspectedc | 230 | 233 | - | MD 0.45 lower (0.8 lower to 0.11 lower) | ⨁⨁◯◯ Low | IMPORTANT | |
QUICKI | |||||||||||||
3 | randomised trials | seriousc | not serious | not serious | seriousa | publication bias strongly suspectedc | 91 | 91 | - | MD 0.01 higher (0.01 higher to 0.02 higher) | ⨁◯◯◯ Very low | IMPORTANT | |
Adiponectin | |||||||||||||
3 | randomised trials | seriousc | not serious | not serious | seriousa | publication bias strongly suspectedc | 166 | 168 | - | MD 1.46 higher (1.12 higher to 1.8 higher) | ⨁◯◯◯ Very low | IMPORTANT | |
TG | |||||||||||||
7 | randomised trials | not serious | not serious | not serious | not serious | none | 273 | 277 | - | MD 9.33 lower (10.56 lower to 8.1 lower) | ⨁⨁⨁⨁ High | IMPORTANT | |
TC | |||||||||||||
7 | randomised trials | seriousc | not serious | not serious | not serious | publication bias strongly suspectedc | 273 | 277 | - | MD 12.32 lower (19.15 lower to 5.5 lower) | ⨁⨁◯◯ Low | IMPORTANT | |
HDL-C | |||||||||||||
7 | randomised trials | seriousc | seriousd | not serious | seriousb | publication bias strongly suspectedc | 273 | 277 | - | MD 2.1 higher (0.29 lower to 4.5 higher) | ⨁◯◯◯ Very low | IMPORTANT | |
LDL-C | |||||||||||||
7 | randomised trials | seriousc | not serious | not serious | not serious | publication bias strongly suspectedc | 273 | 277 | - | MD 10.53 lower (19.31 lower to 1.75 lower) | ⨁⨁◯◯ Low | IMPORTANT | |
VLDL-C | |||||||||||||
3 | randomised trials | not serious | not serious | not serious | very seriousa,b | none | 91 | 91 | - | MD 2.33 lower (5.9 lower to 1.23 higher) | ⨁⨁◯◯ Low | IMPORTANT | |
hs-CRP | |||||||||||||
6 | randomised trials | seriousc | not serious | not serious | very seriousa,b | publication bias strongly suspectedc | 159 | 161 | - | MD 0.56 lower (1.19 lower to 0.07 higher) | ⨁◯◯◯ Very low | IMPORTANT |