Fish Oil for Cardiovascular Health: A Systematic Evidence Review

Does fish oil supplementation improve cardiovascular risk factors and outcomes in adults?

35 studies 6,601 participants 1995–2026

Evidence supports: HDL Cholesterol, Triglycerides, Systolic Blood Pressure, Diastolic Blood Pressure +6 more

No clear effect: Atherosclerotic Plaque Burden, Atrial Fibrillation Control and Recurrence, Postoperative Atrial Fibrillation Burden +3 more

Mixed results: Low-Density Lipoprotein Cholesterol

Early data: HDL-Related Lipoprotein Profile, Total Cholesterol to HDL Cholesterol Ratio, Non-HDL Cholesterol +10 more

Abstract

Fish oil demonstrates selective cardiovascular benefits, not a general cleanup of every heart-risk marker. The most dependable effects in the current analysis are lower triglycerides and modest reductions in blood pressure. Across 17 trials and 5,506 participants, triglycerides fell by about 43.9 mg/dL on average, which is close to the 50 mg/dL change usually considered clinically meaningful, and the pooled effect was consistent enough to support a real average benefit even though results varied by population and dose.123461014181921232428313435 Blood pressure effects were smaller but more reliable: systolic pressure fell by about 4.9 mmHg and diastolic pressure by about 2.5 mmHg in high-certainty evidence, enough to matter at a population level even if any one person might experience only a modest change.5710172431

The routine cholesterol story is much less impressive. HDL may rise slightly, by about 4.3 mg/dL on average, but that falls just short of a commonly used 5 mg/dL threshold for a noticeable change and the studies were highly inconsistent, meaning some groups improved a lot and others barely moved.13462432 LDL results conflict, with some trials showing small decreases, others no change, and some signals of increase; the average shift, about 5.3 mg/dL, is far below the 15 mg/dL change usually needed to count as clinically meaningful.124614242932

Beyond standard lipids, early studies hint that fish oil may improve triglyceride-rich remnants and some apolipoprotein patterns, and perioperative trials do not support the common fear that it increases bleeding.182734 But several widely assumed benefits are not supported here: plaque burden has not clearly regressed, postoperative atrial fibrillation was unchanged in a large trial, hsCRP was largely unaffected, and rhythm outcomes overall are mostly neutral.92025273034 The bottom line is practical: fish oil looks most useful when the goal is lowering triglycerides, nudging blood pressure down, or possibly improving some vascular and perioperative outcomes, not broadly normalizing every cardiovascular marker.

In Plain Language

Fish oil looks most useful when the goal is to lower triglycerides, and it may also trim blood pressure a bit. It does not reliably improve every cholesterol number, and it does not look like a dependable way to prevent atrial fibrillation, shrink plaque, or broadly lower inflammation. If you are considering it for heart health, the strongest reason is elevated triglycerides, not a vague hope that it will improve everything.

Introduction

Fish oil has a reputation for doing a little bit of everything for the heart, but the evidence reviewed here supports a narrower and more believable story. The question is not whether omega-3 fats change lab values at all. The question is which cardiovascular outcomes move enough, consistently enough, to matter. In this dataset of 35 included studies and 6,601 participants, the strongest signals cluster around triglycerides and blood pressure, while many other hoped-for benefits are either mixed, small, or absent.145920242734

That distinction matters because cardiovascular risk is not a single thing. A supplement can lower triglycerides without meaningfully changing LDL, reduce blood pressure without preventing arrhythmias, or alter clotting biology without increasing bleeding. Fish oil appears to fit that pattern. Its benefits are selective rather than global, and several of the most dramatic positive findings come from small mechanistic trials, whereas the larger, more clinically decisive studies often show neutral or modest effects.918202730

The review therefore starts with the routine lipid panel, where expectations are highest, then moves into deeper lipoprotein biology, vascular function, cardiac rhythm and performance, clinical events, and inflammation. The central conclusion is straightforward: fish oil demonstrates real but limited cardiovascular value, strongest for triglycerides and modest blood pressure lowering, with much weaker support for broad cholesterol improvement or generalized anti-inflammatory effects.1518202434

Evidence 1 of 6

Routine lipids improve selectively

Fish oil suggests a real triglyceride benefit, and this is the clearest routine-lab effect in the current analysis. Across 17 trials and 5,506 participants, the pooled standardized effect was modest but solid, and the native-unit change was about 43.9 mg/dL, which is close to the 50 mg/dL threshold usually treated as clinically meaningful. Several individual trials match that pattern, including reductions of about 46 mg/dL over 8 weeks in adults with moderate hypertriglyceridemia, about 52 mg/dL over 8 weeks in adolescents with high triglycerides, and a median drop of 0.405 mmol/L over 14 months in adults with type 2 diabetes.14183435 Even smaller studies in diabetes, obesity, NAFLD, HIV, and older adults generally point the same way, though not all reached significance.236101921232431

Fish oil may raise HDL a little, but this is not a dependable headline result. The average increase was about 4.3 mg/dL, just under the 5 mg/dL threshold often used for a clinically meaningful HDL change, and the heterogeneity was very high, with I-squared at 92.5 percent. I-squared is a measure of how differently studies behave; here it means some populations saw striking HDL increases while others saw almost none, so the average effect does not describe everyone well.13462432 The large ESRD trial reported a dramatic divergence at 6 months, with HDL rising from 36.6 to 51.4 mg/dL in the fish-oil group while falling in controls, but smaller trials in HIV and migraine found little or no between-group advantage.4632

Fish oil does not demonstrate a reliable LDL-lowering effect, and this is where the popular cholesterol narrative runs into trouble. The pooled average was not statistically convincing, the prediction interval crossed no effect, and the native-unit shift was only about 5.3 mg/dL, far below the 15 mg/dL threshold usually needed to count as a meaningful LDL change.124614242932 A prediction interval estimates where future study results are likely to fall; when it crosses no effect, the average benefit may be real in some settings but absent or reversed in others. That is exactly the pattern here: one 12-week trial in hypertensive patients with abdominal obesity found a modest LDL reduction of 0.25 mmol/L versus 0.05 mmol/L with corn oil, while other trials in diabetes, HIV, and migraine were neutral, and one adolescent crossover trial suggested a possible LDL rise of about 8 mg/dL.14242932

Fish oil has not shown convincing improvement in total cholesterol to HDL ratio or non-HDL cholesterol in the evidence reviewed here. The total to HDL ratio was essentially unchanged in the migraine trial, 3.81 versus 3.71 after 12 weeks, and the estimated effect was trivial.32 Non-HDL cholesterol appears too thinly studied in the current analysis to support any conclusion, despite one pilot diabetes study reporting numerically lower values after 24 weeks.26

What this means

If the goal is lowering triglycerides, fish oil looks worthwhile. If the goal is broadly improving a standard cholesterol panel, expectations should be modest. HDL may nudge upward, LDL may or may not move, and neither non-HDL cholesterol nor the total-to-HDL ratio currently support a strong claim.

HDL Cholesterol

Likely helps Good · 50
6 studies N=2,328 dRE=1.34 (0.47 to 2.21) p=0.002 I²=93%

Likely modest benefit

F 2017 (n=99)
0.59
R 2009 (n=87)
2.48
E 2024 (n=48)
0.29
M 2009 (n=48)
0.33
H 2003 (n=44)
0.94
P 2000 (n=30)
4.00
Pooled
1.34
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GRADE Assessment
Domain Rating Reason
Risk of bias No concern 16 papers, majority low risk
Inconsistency Serious I²=93% (> 75%)
Imprecision No concern N=2328 meets OIS=400
Publication bias Serious Egger's p=0.000, funnel asymmetry detected (k=11)
Indirectness No concern deferred to Phase 2 (#1546)
Overall certainty Low

Total Cholesterol to HDL Cholesterol Ratio

Not enough research Very early · 36
1 study N=48

Not enough research

Single study: E 2024, d=0.11 (n=24+24)

GRADE Assessment
Domain Rating Reason
Risk of bias No concern 1 papers, majority low risk
Inconsistency No concern single study, inconsistency N/A
Imprecision Very serious single small study (N=48)
Publication bias No concern k=1 usable (< 10), cannot assess per Cochrane 10.4
Indirectness No concern deferred to Phase 2 (#1546)
Overall certainty Low

Low-Density Lipoprotein Cholesterol

Mixed results Good · 51
7 studies N=2,225 dRE=0.44 (-0.11 to 0.98) p=0.115 I²=78%

Studies contradict

R 2009 (n=87)
-0.25
F 2017 (n=99)
0.03
E 2024 (n=48)
0.00
M 2009 (n=48)
0.17
P 2000 (n=30)
0.47
S 2014 (n=42)
2.86
B 2019 (n=69)
0.28
Pooled
0.44
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GRADE Assessment
Domain Rating Reason
Risk of bias No concern 18 papers, majority low risk
Inconsistency Serious I²=78% (> 75%)
Imprecision No concern N=2225 meets OIS=400
Publication bias Serious Egger's p=0.000, funnel asymmetry detected (k=13)
Indirectness No concern deferred to Phase 2 (#1546)
Overall certainty Low

Non-HDL Cholesterol

Not enough research Strong · 60
0 studies N=0

Not enough research

GRADE Assessment
Domain Rating Reason
Risk of bias No concern 1 papers, majority low risk
Inconsistency No concern single study, inconsistency N/A
Imprecision Serious sample size unknown
Publication bias No concern no d values
Indirectness No concern deferred to Phase 2 (#1546)
Overall certainty Moderate

Triglycerides

Likely helps Good · 59
17 studies N=5,506 dRE=0.59 (0.40 to 0.77) p=<.001 I²=72%

Likely modest benefit

F 2017 (n=99)
0.55
M 2017 (n=74)
0.09
M 2009 (n=48)
0.33
E 2024 (n=48)
0.33
P 2026 (n=415)
0.60
Y 2015 (n=70)
0.69
C 2015 (n=34)
0.77
S 2014 (n=42)
2.25
H 2019 (n=50)
0.18
M 2017 (n=21)
1.29
A 2012 (n=76)
0.58
D 2003 (n=24)
0.11
P 2000 (n=30)
0.47
S 2023 (n=20)
0.15
A 2015 (n=50)
0.83
F 1995 (n=59)
0.75
H 2003 (n=44)
0.67
Pooled
0.59
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GRADE Assessment
Domain Rating Reason
Risk of bias No concern 30 papers, majority low risk
Inconsistency Serious I²=72% (> 50%)
Imprecision No concern N=5506 meets OIS=400
Publication bias Serious Egger's p=0.000, funnel asymmetry detected (k=23)
Indirectness No concern deferred to Phase 2 (#1546)
Overall certainty Low

Evidence 2 of 6

Deeper lipoprotein remodeling remains exploratory

Fish oil may improve the parts of lipid biology most tied to triglyceride handling, but this evidence is still preliminary. The strongest signal comes from triglyceride-rich remnants and related particles, where one crossover trial in adults with moderate hypertriglyceridemia found clear reductions in VLDL cholesterol, about 10.2 mg/dL lower with 3.4 g/day than placebo, alongside triglyceride reductions of about 46 mg/dL.18 A newer 14-month diabetes trial also found a marked fall in remnant cholesterol, a median drop of 14.0 mg/dL versus 0.5 mg/dL with placebo, even though plaque outcomes themselves stayed neutral.34

Fish oil may also nudge apolipoprotein patterns in a favorable direction, but the signal is too small and too underpowered to treat as established. In the same mechanistic crossover study, ApoB fell by about 7 mg/dL and ApoC-III by about 3 mg/dL over 8 weeks, while the ApoB to ApoA-I ratio improved modestly.18 Those changes fit the broader idea that fish oil works more through triglyceride-rich lipoprotein metabolism than through sweeping cholesterol lowering. A smaller obesity study also found reduced hepatic VLDL ApoB production after 6 weeks, which points in the same mechanistic direction even though the clinical ApoB change itself was not clearly significant.2

Healthy HDL profile changes are even more tentative. One small study contributed the signal for a healthier HDL-related profile, but with only about 50 participants and no replication, that finding remains hypothesis-generating rather than practice-changing.18 The same caution applies to ApoC-III and ApoB to ApoA-I ratio. These are biologically plausible markers, and the direction is encouraging, but they come from small studies that are exactly the kind of early literature that often looks stronger than later, larger trials.218

The deeper lipoprotein story therefore supports the triglyceride finding more than it expands it into a broad victory lap. Fish oil appears to shift particle biology in a way that makes sense for lowering remnant-rich burden, but the evidence base is still too narrow to say that these changes are durable, generalizable, or large enough to improve outcomes on their own.1834

What this means

The most promising advanced-lipid signal is not better LDL biology, but fewer triglyceride-rich particles and remnants. That fits with fish oil's routine-lab profile. It may be doing something important upstream in lipoprotein transport, but the evidence is still early and mostly built on small mechanistic trials.

HDL-Related Lipoprotein Profile

Early data Very early · 36
1 study N=50

Faint early signal

Single study: A 2015, d=0.32 (n=25+25)

GRADE Assessment
Domain Rating Reason
Risk of bias No concern 1 papers, majority low risk
Inconsistency No concern single study, inconsistency N/A
Imprecision Very serious single small study (N=50)
Publication bias No concern k=1 usable (< 10), cannot assess per Cochrane 10.4
Indirectness No concern deferred to Phase 2 (#1546)
Overall certainty Low

Triglyceride-Rich Lipoproteins and Remnants

Early data Limited · 42
1 study N=50

Large effect, needs confirmation

Single study: A 2015, d=0.82 (n=25+25)

GRADE Assessment
Domain Rating Reason
Risk of bias No concern 4 papers, majority low risk
Inconsistency No concern no concerns (consistency=100%)
Imprecision Very serious N=50 far below OIS=400
Publication bias No concern k=1 usable (< 10), cannot assess per Cochrane 10.4
Indirectness No concern deferred to Phase 2 (#1546)
Overall certainty Low

Apolipoprotein B

Early data Limited · 43
2 studies N=98 dRE=0.32 (-0.15 to 0.79) p=0.185

Barely detectable

M 2009 (n=48)
0.08
A 2015 (n=50)
0.56
Pooled
0.32
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GRADE Assessment
Domain Rating Reason
Risk of bias No concern 3 papers, majority low risk
Inconsistency No concern no concerns (no data)
Imprecision Very serious N=98 far below OIS=400
Publication bias No concern k=2 usable (< 10), cannot assess per Cochrane 10.4
Indirectness No concern deferred to Phase 2 (#1546)
Overall certainty Low

Apolipoprotein C-III

Early data Very early · 36
1 study N=50

Faint early signal

Single study: A 2015, d=0.33 (n=25+25)

GRADE Assessment
Domain Rating Reason
Risk of bias No concern 1 papers, majority low risk
Inconsistency No concern single study, inconsistency N/A
Imprecision Very serious single small study (N=50)
Publication bias No concern k=1 usable (< 10), cannot assess per Cochrane 10.4
Indirectness No concern deferred to Phase 2 (#1546)
Overall certainty Low

Apolipoprotein B / Apolipoprotein A-I Ratio

Early data Very early · 36
1 study N=50

Faint early signal

Single study: A 2015, d=0.30 (n=25+25)

GRADE Assessment
Domain Rating Reason
Risk of bias No concern 1 papers, majority low risk
Inconsistency No concern single study, inconsistency N/A
Imprecision Very serious single small study (N=50)
Publication bias No concern k=1 usable (< 10), cannot assess per Cochrane 10.4
Indirectness No concern deferred to Phase 2 (#1546)
Overall certainty Low

Evidence 3 of 6

Modest blood pressure gains, uncertain vascular remodeling

Fish oil demonstrates a modest blood-pressure benefit, and this is the most reliable non-lipid effect in the review. Systolic pressure fell by about 4.9 mmHg on average, which is almost exactly the 5 mmHg threshold usually treated as clinically meaningful, and diastolic pressure fell by about 2.5 mmHg, a smaller but still credible shift.5710172431 The certainty here is stronger than for most supplement outcomes because the pooled analyses showed relatively low inconsistency, with I-squared values of 34 percent for systolic and 26 percent for diastolic pressure. That means the studies did not all agree perfectly, but they pointed in a broadly similar direction.57102431

The size of the blood-pressure effect is modest but tangible. In a 5-week crossover trial in healthy adults aged 51 to 72, systolic pressure fell about 7 mmHg on fish oil versus 1 mmHg on placebo.10 In postmenopausal women doing resistance training, systolic pressure fell from 123.8 to 118.3 mmHg and diastolic pressure from 81.0 to 77.5 mmHg over 8 weeks, while placebo plus training showed little change.31 Not every trial found a significant difference, especially at lower doses or in healthier populations, but the overall pattern favors a small real reduction rather than noise.5724

Fish oil may improve vascular function slightly, but that signal is weaker than the blood-pressure story. Endothelial function, which reflects how well blood vessels dilate and respond to stress, showed a favorable summary signal in the current analysis, but it is based on limited evidence and the estimated effect is too small to expect someone to feel directly.34 Pulse wave velocity and arterial compliance, which are measures of arterial stiffness, are also only early signals. In overweight and obese adults, DHA-rich fish oil increased large artery compliance over 12 weeks in a dose-related fashion, strongest at 6 g/day, but small artery compliance and blood pressure did not change within that same trial.5

Fish oil does not appear to shrink established plaque burden in any convincing way. In the 14-month diabetes plaque trial, high-dose fish oil did not significantly reduce overall carotid plaque prevalence, did not clearly lower new-plaque incidence, and did not meaningfully increase plaque regression, although maximum intima-media thickness trended slightly lower, by a median 0.010 mm versus no change in controls.34 Older angiographic evidence points the same way: about 28 months of fish oil did not produce major regression of coronary atherosclerosis despite lowering triglycerides.35

What this means

Blood pressure is the vascular outcome where fish oil has the best case. The average drop is not dramatic, but it is large enough to matter. By contrast, claims about reversing arterial disease or remodeling plaques run ahead of the evidence.

Systolic Blood Pressure

Proven benefit Strong · 93
6 studies N=1,026 dRE=0.37 (0.16 to 0.59) p=<.001 I²=34%

Proven modest benefit

P 2012 (n=94)
0.46
F 2017 (n=99)
0.16
N 2010 (n=34)
0.46
A 2012 (n=76)
0.46
S 2023 (n=20)
0.85
C 2015 (n=24)
0.19
Pooled
0.37
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GRADE Assessment
Domain Rating Reason
Risk of bias No concern 8 papers, majority low risk
Inconsistency No concern no concerns (I²=34%, consistency=100%, PI crosses null)
Imprecision No concern N=1026 meets OIS=400
Publication bias No concern k=7 usable (< 10), cannot assess per Cochrane 10.4
Indirectness No concern deferred to Phase 2 (#1546)
Overall certainty High

Diastolic Blood Pressure

Proven benefit Strong · 92
5 studies N=757 dRE=0.28 (0.04 to 0.53) p=0.023 I²=26%

Proven modest benefit

P 2012 (n=94)
0.25
F 2017 (n=99)
0.16
N 2010 (n=34)
0.50
A 2012 (n=76)
0.14
S 2023 (n=20)
1.19
Pooled
0.28
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GRADE Assessment
Domain Rating Reason
Risk of bias No concern 7 papers, majority low risk
Inconsistency No concern no concerns (I²=26%, PI crosses null)
Imprecision No concern N=757 meets OIS=400
Publication bias No concern k=6 usable (< 10), cannot assess per Cochrane 10.4
Indirectness No concern deferred to Phase 2 (#1546)
Overall certainty High

Pulse Wave Velocity

Early data Very early · 35
1 study N=34

Promising early signal

Single study: N 2010, d=0.31 (n=17+17)

GRADE Assessment
Domain Rating Reason
Risk of bias No concern 1 papers, majority low risk
Inconsistency No concern single study, inconsistency N/A
Imprecision Very serious single small study (N=34)
Publication bias No concern k=1 usable (< 10), cannot assess per Cochrane 10.4
Indirectness No concern deferred to Phase 2 (#1546)
Overall certainty Low

Endothelial Function

Likely helps Strong · 71
0 studies N=1,385

Likely real but unnoticeable

GRADE Assessment
Domain Rating Reason
Risk of bias No concern 1 papers, majority low risk
Inconsistency No concern single study, inconsistency N/A
Imprecision Serious single study (N=1385), unreplicated
Publication bias No concern k=1 usable (< 10), cannot assess per Cochrane 10.4
Indirectness No concern deferred to Phase 2 (#1546)
Overall certainty Moderate

Atherosclerotic Plaque Burden

Likely no effect Strong · 68
1 study N=415

Probably doesn't help

Single study: P 2026, d=0.33 (n=207+208)

GRADE Assessment
Domain Rating Reason
Risk of bias No concern 1 papers, majority low risk
Inconsistency No concern single study, inconsistency N/A
Imprecision Serious single study (N=415), unreplicated
Publication bias No concern k=1 usable (< 10), cannot assess per Cochrane 10.4
Indirectness No concern deferred to Phase 2 (#1546)
Overall certainty Moderate

Evidence 4 of 6

Heart function may benefit more than rhythm control

Fish oil may help heart performance more than heart rhythm, and the rhythm data are mostly negative. The most promising cardiac-performance signal in the current analysis is left ventricular ejection fraction, a measure of how much blood the heart pumps out with each beat, where summary evidence suggests a large improvement. But this rests on limited trial representation in the material reviewed here, so the direction is encouraging while the exact size remains uncertain.34

Fish oil does not appear to meaningfully slow resting heart rate in a way most people would notice. The average change was only about 1.6 beats per minute, well below the 5 bpm threshold typically considered clinically meaningful, and the pooled result was statistically unconvincing despite high overall certainty that any effect is trivial.57 That is a useful negative finding because it means fish oil is not acting like a broad autonomic reset in ordinary use.

Heart rate variability, often promoted as a sign of better autonomic balance, remains too uncertain to trust. A few small studies reported promising changes, including a roughly 2.6 ms increase in RMSSD and a 20.6 percent increase in total HRV power after 3.4 g/day for 8 weeks in adults with moderate hypertriglyceridemia, and a dose-response drop in LF to HF ratio in a subgroup of overweight adults.511 But the pooled evidence was very low certainty, the sample size across studies was only 98, and heterogeneity was high, with I-squared near 76 percent. In plain terms, the studies were too small and too different to know whether the apparent benefit is real or just fragile.51117

Fish oil does not appear to prevent atrial fibrillation in the settings studied here. The clearest evidence comes from the large OPERA trial in 1,516 cardiac-surgery patients, where postoperative atrial fibrillation occurred in 30.0 percent of fish-oil patients versus 30.7 percent on placebo, with no difference in time to first event, symptomatic or treated episodes, or days spent in hospital with atrial fibrillation.9 That is a properly powered null result, meaning the trial was large enough that the lack of benefit is informative rather than inconclusive.

The broader rhythm story stays negative beyond postoperative AF. In the current analysis, atrial fibrillation control and recurrence, sudden cardiac death risk, and implantable defibrillator shock outcomes all leaned neutral rather than helpful.9 Taken together, fish oil does not look like a reliable anti-arrhythmic strategy, even if it may help some upstream risk factors such as triglycerides and blood pressure.

What this means

If fish oil helps the heart directly, the better target seems to be pumping function, not rhythm stabilization. The evidence reviewed here does not support using fish oil with the expectation that it will prevent atrial fibrillation or other rhythm events.

Resting Heart Rate

Proven benefit Strong · 92
2 studies N=1,806 dRE=0.14 (-0.21 to 0.49) p=0.434 I²=0%

Proven but unnoticeable

P 2012 (n=94)
0.19
N 2010 (n=34)
0.00
Pooled
0.14
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GRADE Assessment
Domain Rating Reason
Risk of bias No concern 3 papers, majority low risk
Inconsistency No concern no concerns (I²=0%, consistency=100%, PI crosses null)
Imprecision No concern N=1806 meets OIS=400
Publication bias No concern k=3 usable (< 10), cannot assess per Cochrane 10.4
Indirectness No concern deferred to Phase 2 (#1546)
Overall certainty High

Heart Rate Variability

Early data Very early · 15
3 studies N=98 dRE=0.70 (-0.24 to 1.65) p=0.146 I²=76%

Faint early signal

K 2013 (n=50)
0.22
N 2010 (n=24)
0.20
C 2015 (n=24)
1.85
Pooled
0.70
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GRADE Assessment
Domain Rating Reason
Risk of bias No concern 3 papers, majority low risk
Inconsistency Serious I²=76% (> 75%)
Imprecision Very serious N=98 far below OIS=400
Publication bias No concern k=3 usable (< 10), cannot assess per Cochrane 10.4
Indirectness No concern deferred to Phase 2 (#1546)
Overall certainty Very low

Left Ventricular Ejection Fraction

Likely helps Strong · 72
0 studies N=9,075

Likely strong benefit

GRADE Assessment
Domain Rating Reason
Risk of bias No concern 1 papers, majority low risk
Inconsistency No concern single study, inconsistency N/A
Imprecision Serious single study (N=9075), unreplicated
Publication bias No concern k=1 usable (< 10), cannot assess per Cochrane 10.4
Indirectness No concern deferred to Phase 2 (#1546)
Overall certainty Moderate

Atrial Fibrillation Control and Recurrence

Likely no effect Strong · 72
0 studies N=1,990

Probably doesn't help

GRADE Assessment
Domain Rating Reason
Risk of bias No concern 1 papers, majority low risk
Inconsistency No concern single study, inconsistency N/A
Imprecision Serious single study (N=1990), unreplicated
Publication bias No concern k=1 usable (< 10), cannot assess per Cochrane 10.4
Indirectness No concern deferred to Phase 2 (#1546)
Overall certainty Moderate

Postoperative Atrial Fibrillation Burden

No clear effect Strong · 75
1 study N=4,203

Doesn't appear to help

Single study: D 2012, d=0.02 (n=758+758)

GRADE Assessment
Domain Rating Reason
Risk of bias No concern 2 papers, majority low risk
Inconsistency Serious I²=53% (> 50%)
Imprecision No concern N=4203 meets OIS=400
Publication bias No concern k=2 usable (< 10), cannot assess per Cochrane 10.4
Indirectness No concern deferred to Phase 2 (#1546)
Overall certainty Moderate

Sudden Cardiac Death Risk

Likely no effect Strong · 72
0 studies N=31,111

Probably doesn't help

GRADE Assessment
Domain Rating Reason
Risk of bias No concern 1 papers, majority low risk
Inconsistency No concern single study, inconsistency N/A
Imprecision Serious single study (N=31111), unreplicated
Publication bias No concern k=1 usable (< 10), cannot assess per Cochrane 10.4
Indirectness No concern deferred to Phase 2 (#1546)
Overall certainty Moderate

Implantable Cardioverter Defibrillator Discharge

Likely no effect Strong · 73
0 studies N=1,148

Probably doesn't help

GRADE Assessment
Domain Rating Reason
Risk of bias No concern 2 papers, majority low risk
Inconsistency Serious I²=71% (> 50%)
Imprecision No concern N=1148 meets OIS=400
Publication bias No concern k=1 usable (< 10), cannot assess per Cochrane 10.4
Indirectness No concern deferred to Phase 2 (#1546)
Overall certainty Moderate

Evidence 5 of 6

Clinical events and clotting balance

Fish oil does not appear to increase clinically important perioperative bleeding, and this directly challenges one of the most persistent safety fears around omega-3 supplements. In the large cardiac-surgery trial, patients randomized to fish oil actually required fewer transfused blood units overall, 1.61 versus 1.92 on average, with similar reductions during surgery and after surgery.27 That does not prove fish oil protects against bleeding in every setting, but it does show that routine perioperative use did not create the excess bleeding signal many clinicians worry about.

Fish oil may even improve the balance between bleeding and clot risk in surgical settings. In the OPERA trial, arterial thromboembolism within 30 days occurred in 0.7 percent with fish oil versus 1.7 percent with placebo, and the composite of arterial thromboembolism or death occurred in 1.7 percent versus 3.6 percent.9 These were small event counts, so they should not be treated as final, but the direction is notable precisely because it runs opposite to the fear that fish oil makes surgery more hazardous.927

Cardiovascular mortality also shows a small favorable summary signal in the current analysis, but the supporting evidence is not detailed enough in the reviewed trial-level material to pin down where that benefit is most likely to occur.27 The effect appears small rather than transformative, and it should be read alongside the much more mixed story for surrogate markers such as LDL, plaque burden, and rhythm outcomes.

The mechanistic coagulation data are much less decisive than the perioperative clinical outcomes. Platelet aggregation was unchanged after 3 months of 2 g/day EPA plus DHA in patients with diabetes and atherosclerotic disease, with ADP-induced aggregation at 58.2 percent versus 60.6 percent on placebo and no clear change with arachidonic acid stimulation either.25 Thrombin generation and fibrinolysis showed only patchy early signals: one biomarker of thrombin generation, prothrombin fragment 1.2, was lower with fish oil, while clot lysis time only trended toward a difference, and a small adolescent crossover trial found lower PAI-1, which suggests improved fibrinolytic balance.1425 These are interesting clues, not settled mechanisms.

The contrast between biomarker uncertainty and perioperative outcome reassurance is important. Fish oil may be altering clot biology in subtle ways that standard platelet assays do not fully capture, but the clinically meaningful takeaway from the current analysis is simpler: the evidence reviewed here does not support the idea that fish oil broadly worsens bleeding risk, and it leaves room for modest protection against perioperative arterial clot events.92527

What this means

The best-supported coagulation message is a safety one: fish oil did not increase surgical bleeding in a large randomized trial. There may also be a small protective effect against perioperative arterial clots, but the biomarker literature is still too patchy to explain that confidently.

Cardiovascular Mortality

Likely helps Strong · 72
0 studies N=32,519

Likely benefit

GRADE Assessment
Domain Rating Reason
Risk of bias No concern 1 papers, majority low risk
Inconsistency No concern single study, inconsistency N/A
Imprecision Serious single study (N=32519), unreplicated
Publication bias No concern k=1 usable (< 10), cannot assess per Cochrane 10.4
Indirectness No concern deferred to Phase 2 (#1546)
Overall certainty Moderate

Platelet Aggregation

Not enough research Very early · 38
1 study N=74

Not enough research

Single study: M 2017, d=0.10 (n=36+38)

GRADE Assessment
Domain Rating Reason
Risk of bias No concern 1 papers, majority low risk
Inconsistency No concern single study, inconsistency N/A
Imprecision Very serious single small study (N=74)
Publication bias No concern k=1 usable (< 10), cannot assess per Cochrane 10.4
Indirectness No concern deferred to Phase 2 (#1546)
Overall certainty Low

Thrombin Generation

Early data Very early · 38
1 study N=74

Faint early signal

Single study: M 2017, d=0.28 (n=36+38)

GRADE Assessment
Domain Rating Reason
Risk of bias No concern 1 papers, majority low risk
Inconsistency No concern single study, inconsistency N/A
Imprecision Very serious single small study (N=74)
Publication bias No concern k=1 usable (< 10), cannot assess per Cochrane 10.4
Indirectness No concern deferred to Phase 2 (#1546)
Overall certainty Low

Fibrinolytic Activity

Early data Limited · 42
2 studies N=116 dRE=1.57 (-0.70 to 3.85) p=0.175

Faint early signal

M 2017 (n=74)
0.44
S 2014 (n=42)
2.76
Pooled
1.57
Favours control MCID Favours supplement
GRADE Assessment
Domain Rating Reason
Risk of bias No concern 2 papers, majority low risk
Inconsistency No concern no concerns (no data)
Imprecision Very serious N=116 far below OIS=400
Publication bias No concern k=2 usable (< 10), cannot assess per Cochrane 10.4
Indirectness No concern deferred to Phase 2 (#1546)
Overall certainty Low

Perioperative Bleeding / Transfusion Requirement

Likely helps Strong · 71
1 study N=1,516

Likely benefit

Single study: E 2018, d=0.09 (n=758+758)

GRADE Assessment
Domain Rating Reason
Risk of bias No concern 1 papers, majority low risk
Inconsistency No concern single study, inconsistency N/A
Imprecision Serious single study (N=1516), unreplicated
Publication bias No concern k=1 usable (< 10), cannot assess per Cochrane 10.4
Indirectness No concern deferred to Phase 2 (#1546)
Overall certainty Moderate

Perioperative Arterial Thromboembolism

Likely helps Strong · 71
1 study N=1,516

Likely strong benefit

Single study: D 2012, d=0.51 (n=758+758)

GRADE Assessment
Domain Rating Reason
Risk of bias No concern 1 papers, majority low risk
Inconsistency No concern single study, inconsistency N/A
Imprecision Serious single study (N=1516), unreplicated
Publication bias No concern k=1 usable (< 10), cannot assess per Cochrane 10.4
Indirectness No concern deferred to Phase 2 (#1546)
Overall certainty Moderate

Evidence 6 of 6

Inflammation is not the main story

The anti-inflammatory case for fish oil is weaker than its reputation suggests. High-sensitivity C-reactive protein, or hsCRP, which is a common blood marker of systemic inflammation, was largely unchanged across 5 trials and 879 participants. The average reduction was about 0.9 mg/L, close to the 1.0 mg/L threshold often used for clinical relevance, but the pooled result was not statistically convincing and the prediction interval crossed no effect, meaning some future studies would be expected to show no meaningful change at all.61315202530

The larger and more informative trials are especially unsupportive. In 261 healthy adults, 1.4 g/day for about 18 weeks did not reduce CRP, with a between-group difference of only 0.05 mg/L.20 In the VITAL ancillary cohort of 1,054 older adults followed for 2 and 4 years, marine omega-3 at 1 g/day also did not significantly change hsCRP or IL-6 at either time point.30 Those long-duration null findings carry more practical weight than a few smaller positive-looking studies.

IL-6 is the one inflammatory pathway that still shows an exploratory signal, but it is not yet a convincing explanation for fish oil's cardiovascular effects. The pooled estimate suggested benefit, yet heterogeneity was very high at nearly 79 percent and the prediction interval crossed no effect widely. That means studies disagreed sharply about both whether IL-6 changes and how much.1215202225303133 Small exercise-related studies reported substantial short-term reductions, such as lower IL-6 after eccentric exercise and a roughly 10.9 percent decrease in postmenopausal women training with fish oil, while several metabolic and endotoxemia studies found no significant change.1222253133

This pattern suggests that inflammation is probably context-dependent rather than a general mechanism. Fish oil may dampen specific inflammatory responses under physiologic stress, exercise injury, or certain metabolic conditions, but it does not consistently lower baseline systemic inflammation in ordinary ambulatory adults.122022253031 That makes it a poor primary rationale for supplementation when the better-supported effects are elsewhere.

What this means

Fish oil should not be sold as a reliable general anti-inflammatory supplement on the basis of this cardiovascular evidence. If it helps, it is more likely through triglyceride biology and modest vascular effects than through a broad, repeatable lowering of hsCRP or IL-6.

High-Sensitivity C-Reactive Protein

Likely no effect Strong · 73
5 studies N=879 dRE=0.39 (-0.06 to 0.84) p=0.086 I²=72%

Probably doesn't help

M 2016 (n=261)
0.03
M 2017 (n=74)
0.10
M 2014 (n=46)
0.30
M 2009 (n=48)
0.24
S 2014 (n=42)
1.60
Pooled
0.39
Favours control MCID Favours supplement
GRADE Assessment
Domain Rating Reason
Risk of bias No concern 12 papers, majority low risk
Inconsistency Serious I²=72% (> 50%)
Imprecision No concern N=879 meets OIS=400
Publication bias No concern k=8 usable (< 10), cannot assess per Cochrane 10.4
Indirectness No concern deferred to Phase 2 (#1546)
Overall certainty Moderate

Interleukin-6 Signaling

Early data Limited · 45
5 studies N=206 dRE=0.86 (0.21 to 1.52) p=0.010 I²=79%

Faint early signal

M 2017 (n=74)
0.16
M 2014 (n=46)
0.26
Y 2016 (n=24)
1.13
S 2014 (n=42)
1.80
S 2023 (n=20)
1.21
Pooled
0.86
Favours control MCID Favours supplement
GRADE Assessment
Domain Rating Reason
Risk of bias No concern 9 papers, majority low risk
Inconsistency Serious I²=79% (> 75%)
Imprecision Serious N=206 below OIS=400
Publication bias No concern k=5 usable (< 10), cannot assess per Cochrane 10.4
Indirectness No concern deferred to Phase 2 (#1546)
Overall certainty Low

Across the Evidence

The clearest pattern across outcomes is selective benefit rather than global cardiovascular improvement. Fish oil most consistently improves triglycerides and, to a lesser degree, blood pressure, while LDL-centered lipids, plaque burden, arrhythmia outcomes, and hsCRP remain mixed or neutral.5918202434 That pattern is biologically coherent. Omega-3 fatty acids are well positioned to alter hepatic triglyceride synthesis, VLDL export, and remnant handling, so it makes sense that triglycerides, VLDL cholesterol, remnant cholesterol, and some apolipoprotein markers move more readily than LDL cholesterol or established plaque.21834

The heterogeneity across several pooled outcomes also tells a useful story. HDL, LDL, triglycerides, hsCRP, IL-6, and HRV all showed substantial inconsistency, often with I-squared above 70 percent.134611152024 Heterogeneity means the average effect exists, but not everyone gets the same result. In this dataset, that likely reflects differences in baseline triglyceride burden, diabetes status, obesity, dialysis, surgical stress, dose, EPA to DHA ratio, and intervention length. Studies in metabolically stressed groups often showed larger benefits than studies in healthy adults with little room to improve.2419202434

The dose pattern fits that explanation. Several stronger signals appeared at around 3 to 4 g/day, including triglycerides, ApoB-related markers, remnant cholesterol, and some HRV outcomes, whereas 1 g/day often looked neutral, especially in healthier populations.1118202430 That does not prove high dose is always necessary, but it weakens the idea that low-dose fish oil produces broad cardiometabolic effects regardless of context.

Another cross-cutting pattern is that small mechanistic trials often look more dramatic than large clinical trials. The most eye-catching HDL, IL-6, HRV, and vascular-function results commonly came from small studies with dozens of participants, while larger studies were likelier to show either modest average effects or clear null findings.45112030 That is a familiar pattern in supplement research and usually means the direction of effect may be real, but the early literature exaggerates its size.

The perioperative data provide one of the more clinically reassuring contrasts in the whole review. Fish oil changed neither postoperative atrial fibrillation nor bleeding risk in the feared direction, and it may have improved transfusion needs and arterial thromboembolism outcomes.927 That combination suggests fish oil's effects on hemostasis are subtler than the simple folk belief that it is a bleeding risk. The clinical outcomes matter more than isolated biomarker shifts when the two do not line up cleanly.92527

Discussion

The evidence reviewed here supports a practical, moderately confident conclusion: fish oil has real cardiovascular effects, but they are narrow enough that it should not be treated as a universal heart-health fix. The most credible benefits are modest triglyceride lowering and small blood-pressure reductions.510182434 Those are meaningful outcomes, especially in people starting with elevated triglycerides or cardiometabolic risk, and they are more convincing than the broader claims often made for cholesterol normalization, anti-inflammatory action, or rhythm protection.

What is supported is more specific than the marketing. Fish oil shows a plausible extension from triglycerides into triglyceride-rich lipoproteins and remnants, and it may improve endothelial function slightly, left ventricular ejection fraction, perioperative transfusion burden, and perioperative arterial clot risk.182734 What is not well supported in the current analysis is broad LDL lowering, plaque regression, atrial fibrillation prevention, meaningful resting heart-rate change, sudden death reduction, ICD shock prevention, or consistent lowering of hsCRP.92025303435

The main reason not to overstate the benefits is not that the evidence is poor across the board. It is that the positive signals are uneven. Several important outcomes rely on one study or two-study pools, and many pooled analyses showed wide variation between studies.511182034 In supplement research, that usually means the benefit depends heavily on who is taking it, at what dose, and for how long. The current analysis includes healthy adults, people with diabetes, obesity, dialysis dependence, surgical patients, and people with hypertriglyceridemia, so a single one-size-fits-all answer would be misleading.14919202434

What would change confidence most is replication of the promising mechanistic and event-level findings in larger targeted trials. The remnant-cholesterol signal, ApoB-related changes, endothelial findings, and perioperative arterial clot reduction would all become more persuasive if they reappeared across multiple independent studies with harmonized dosing and better population matching.182734 On the other hand, if future large trials in high-triglyceride or high-risk patients fail to reproduce the triglyceride and blood-pressure effects, that would substantially weaken the current bottom line.

For now, the evidence reviewed here supports fish oil best as a selective tool. It is reasonable when triglycerides are the main target and defensible when modest blood-pressure support is welcome. It is much less convincing as a way to broadly improve every cholesterol marker, reverse plaque, quiet inflammation, or prevent rhythm disturbances.

Methodology

We searched PubMed for studies on fish oil and cardiovascular health, then filtered to the study types shown in the PRISMA summary, primarily randomized controlled trials in adults. We read each included study, recorded what it measured, how large it was, how long it lasted, and what it found. We assessed evidence quality with the GRADE framework and judged clinical importance against published thresholds for meaningful change, such as mg/dL for lipids and mmHg for blood pressure. Every study cited here is publicly indexed on PubMed.

One caution is important. GRADE was built mainly for pharmaceutical interventions and tends to rate nutrition and supplement evidence conservatively. It automatically downgrades observational research and usually only upgrades for very large effects, often above what is realistic for nutrition. Our continuous trust score adds a more nuanced view by combining study quality, consistency, and whether the effect approaches a meaningful real-world threshold. So a finding can reasonably read as clinically useful here even when GRADE still labels it low certainty. Known limitations include heterogeneous populations, variable EPA to DHA formulations and doses, many short trials, and several outcomes supported by only one or two studies.

Study Selection

175 Papers in fishoil corpus
11 wrong study type, 7 wrong comparator
53 With matching outcomes
35 After study type & comparator filters
35 Included in review

Characteristics of Included Studies

Study Design N Population Dose Duration RoB
F 1995 FT rct 80 clinical 12 capsules/day (6 g n-3 fatty acids daily) average 28 months Some
P 2000 FT rct 60 clinical Fish oil 1.5 g daily for 2 months 2 months Some
D 2003 FT rct 24 clinical 4 g/day fish oil for 6 weeks (vs corn-oil placebo) 6 wk treatment period (3-wk run-in diet-stabilizing period before randomization) Low
H 2003 FT rct 44 clinical Fish oil (4 g oil/day) for 8 weeks 8-week intervention (preceded by 4-week corn-oil run-in) Some
R 2009 FT rct 87 clinical Fish oil 6 g/day for 6 months 6 months Some
M 2009 FT rct 51 clinical ~3.6 g/day n-3 PUFA (Omacor) for 12 weeks 12 weeks Some
N 2010 FT rct 67 clinical 6 g fish oil daily (≈1.56 g DHA) for 12 weeks 12 weeks Some
P 2012 FT rct 140 healthy 1 g fish oil daily (EPA-rich) for 12 weeks 12 weeks Some
S 2012 FT rct 40 clinical Fish oil 6 capsules/day for 12 weeks 12 weeks Some
D 2012 FT rct 1516 clinical Loading: 8–10 g pre-op; then 2 g/day until discharge (up to 10 days) Until hospital discharge or postoperative day 10, whichever occurred first Some
A 2012 FT rct 44 healthy 3 g n-3 PUFA daily for 5 weeks 5 weeks per intervention period with a 5-week washout (cognitive tests and bloodwork after each period). Some
K 2013 FT rct 26 clinical 3.4 g/day for 8 weeks 8 weeks treatment per period with 6-week washout (three-period crossover) Some
M 2013 FT rct 125 healthy 300–1800 mg/day for ~5 months (1.8 g/day produced ~9.5%) ≈5 months Low
J 2014 FT rct 60 healthy 3600 mg/day for ~6–8 weeks 8 weeks Some
S 2014 FT rct 42 clinical 4 g/day for 8 weeks Two 8-week treatment periods separated by a 4-week washout (crossover); visits up to week 28 Some
M 2014 FT rct 125 healthy 1800 mg/day for 5 months 5 months Some
C 2015 FT rct 40 clinical 3000 mg/day for 1 year 1 year Low
C 2015 FT rct 24 clinical 1080 mg daily (3 capsules/day) for 10 weeks 42 weeks (three 10-week treatment periods with two 6-week washouts) Some
A 2015 FT rct 25 clinical 3.4 g/day for 8 weeks 8-week treatment periods with 6-week washout periods (3-period crossover). Some
Y 2015 FT rct 80 clinical 4 g/day (728 mg EPA + 516 mg DHA) for 3 months 3 months Some
U 2015 FT rct 85 clinical 1.8 g/day DHA+EPA for 3 months 3 months High
M 2016 FT rct 261 healthy 1400 mg daily for 18 weeks 18 weeks (mean 129 days) Low
Y 2016 FT rct 24 healthy 600 mg EPA + 260 mg DHA daily for 8 weeks 62 days (8 weeks prior to exercise + 5 days post-exercise) Low
M 2017 FT rct 58 healthy 3 g fish oil daily (2.1 g EPA + 0.6 g DHA) for 18 weeks 18 weeks Some
F 2017 FT rct 100 clinical 4 g fish oil daily for 6 months 6 months Some
M 2017 FT rct 76 clinical 1 g EPA + 1 g DHA daily for 3 months 3 months Low
M 2017 FT rct 65 clinical 520 mg/day EPA+DHA for 24 weeks 24 weeks (six months) Some
E 2018 FT rct 1516 clinical Loading 8 60 g pre-op, then 2 g/day post-op Loading 8 60 g over 2 5 days preoperatively (including 2 g on morning of surgery), then 2 g/day postoperatively until discharge or postoperative day 10 Low
H 2019 FT rct 50 healthy ≈1.7 g fish oil (588 mg EPA + 412 mg DHA) daily for 12 weeks 12 weeks Low
B 2019 FT controlled trial 108 clinical 2 g/day EPA+DHA for 12 weeks 12 weeks Some
Y 2022 FT rct 1054 healthy 2000 IU daily for 2 years 4 years (follow-up visits at baseline, year 2, and year 4); full trial median treatment 5.3 years High
S 2023 FT rct 20 healthy ≈2.8 g EPA+DHA per day (3 capsules) for 8 weeks 8 weeks Low
E 2024 FT rct 47 clinical 2 g/day (two 1 g capsules) for 12 weeks 12 weeks Low
S 2025 FT rct 22 healthy 3 capsules daily (total 2820 mg omega-3/day) 72 hours (assessments through 72 h post-exercise) Some
P 2026 FT rct 415 clinical 3.0 g/day (four capsules daily) for 14 months 14 months Low

Sources

  1. 1. P 2000. Lipid-lowering effect of polyunsaturated fatty acids in hemodialysis patients. (2000)
  2. 2. D 2003. Randomized controlled trial of the effect of n-3 fatty acid supplementation on the metabolism of apolipoprotein B-100 and chylomicron remnants in men with visceral obesity. (2003)
  3. 3. H 2003. Influence of fish oil supplementation on in vivo and in vitro oxidation resistance of low-density lipoprotein in type 2 diabetes. (2003)
  4. 4. R 2009. Effects of omega-3 fatty acid supplementation on lipid levels in endstage renal disease patients. (2009)
  5. 5. N 2010. Dose-dependent increases in heart rate variability and arterial compliance in overweight and obese adults with DHA-rich fish oil supplementation. (2010)
  6. 6. M 2009. Effect of fish oil (n-3 polyunsaturated fatty acids) on plasma lipids, lipoproteins and inflammatory markers in HIV-infected patients treated with antiretroviral therapy: a randomized, double-blind, placebo-controlled study. (2009)
  7. 7. P 2012. No effect of 12 weeks' supplementation with 1 g DHA-rich or EPA-rich fish oil on cognitive function or mood in healthy young adults aged 18-35 years. (2012)
  8. 8. S 2012. Different gene expression profiles in normo- and dyslipidemic men after fish oil supplementation: results from a randomized controlled trial. (2012)
  9. 9. D 2012. Fish oil and postoperative atrial fibrillation: the Omega-3 Fatty Acids for Prevention of Post-operative Atrial Fibrillation (OPERA) randomized trial. (2012)
  10. 10. A 2012. Effects of supplementation with n-3 polyunsaturated fatty acids on cognitive performance and cardiometabolic risk markers in healthy 51 to 72 years old subjects: a randomized controlled cross-over study. (2012)
  11. 11. K 2013. Effects of omega-3 fatty acid supplementation on heart rate variability at rest and during acute stress in adults with moderate hypertriglyceridemia. (2013)
  12. 12. J 2014. Omega-3 PUFA supplementation and the response to evoked endotoxemia in healthy volunteers. (2014)
  13. 13. M 2013. Determinants of erythrocyte omega-3 fatty acid content in response to fish oil supplementation: a dose-response randomized controlled trial. (2013)
  14. 14. S 2014. A double-blind randomized trial of fish oil to lower triglycerides and improve cardiometabolic risk in adolescents. (2014)
  15. 15. M 2014. Effects of supplemental long-chain omega-3 fatty acids and erythrocyte membrane fatty acid content on circulating inflammatory markers in a randomized controlled trial of healthy adults. (2014)
  16. 16. C 2015. Effects of n-3 fish oil on metabolic and histological parameters in NASH: a double-blind, randomized, placebo-controlled trial. (2015)
  17. 17. C 2015. Fish oil (n-3 fatty acids) in drug resistant epilepsy: a randomised placebo-controlled crossover study. (2015)
  18. 18. A 2015. Dose-response effects of marine omega-3 fatty acids on apolipoproteins, apolipoprotein-defined lipoprotein subclasses, and Lp-PLA2 in individuals with moderate hypertriglyceridemia. (2015)
  19. 19. Y 2015. Fish Oil Supplements Lower Serum Lipids and Glucose in Correlation with a Reduction in Plasma Fibroblast Growth Factor 21 and Prostaglandin E2 in Nonalcoholic Fatty Liver Disease Associated with Hyperlipidemia: A Randomized Clinical Trial. (2015)
  20. 20. M 2016. Fish oil supplementation does not lower C-reactive protein or interleukin-6 levels in healthy adults. (2016)
  21. 21. U 2015. Effect of caloric restriction with or without n-3 polyunsaturated fatty acids on insulin sensitivity in obese subjects: A randomized placebo controlled trial. (2015)
  22. 22. Y 2016. Eicosapentaenoic and docosahexaenoic acids-rich fish oil supplementation attenuates strength loss and limited joint range of motion after eccentric contractions: a randomized, double-blind, placebo-controlled, parallel-group trial. (2016)
  23. 23. M 2017. Sex differences in the effect of fish-oil supplementation on the adaptive response to resistance exercise training in older people: a randomized controlled trial. (2017)
  24. 24. F 2017. Treatment for 6 months with fish oil-derived n-3 polyunsaturated fatty acids has neutral effects on glycemic control but improves dyslipidemia in type 2 diabetic patients with abdominal obesity: a randomized, double-blind, placebo-controlled trial. (2017)
  25. 25. M 2017. Treatment with high-dose n-3 PUFAs has no effect on platelet function, coagulation, metabolic status or inflammation in patients with atherosclerosis and type 2 diabetes. (2017)
  26. 26. M 2017. Effect of n-3 Polyunsaturated Fatty Acid Supplementation on Metabolic and Inflammatory Biomarkers in Type 2 Diabetes Mellitus Patients. (2017)
  27. 27. E 2018. Fish Oil and Perioperative Bleeding. (2018)
  28. 28. H 2019. Effect of Fish Oil Supplementation on Hepatic and Visceral Fat in Overweight Men: A Randomized Controlled Trial. (2019)
  29. 29. B 2019. Effects of n-3 fatty acid supplements on cardiometabolic profiles in hypertensive patients with abdominal obesity in Inner Mongolia: a randomized controlled trial. (2019)
  30. 30. Y 2022. Effects of Vitamin D3 and Marine Omega-3 Fatty Acids Supplementation on Biomarkers of Systemic Inflammation: 4-Year Findings from the VITAL Randomized Trial. (2022)
  31. 31. S 2023. Fish Oil Supplementation with Resistance Exercise Training Enhances Physical Function and Cardiometabolic Health in Postmenopausal Women. (2023)
  32. 32. E 2024. Feasibility of Fish Oil Supplementation on Headache Symptoms and Blood Lipids in Migraine Patients. (2024)
  33. 33. S 2025. Effects of Acute Fish Oil Supplementation on Muscle Function and Soreness After Eccentric Contraction-Induced Muscle Damage. (2025)
  34. 34. P 2026. Marine n-3 fatty acid treatment for carotid plaques in patients with type 2 diabetes. (2026)
  35. 35. F 1995. Controlled trial of fish oil for regression of human coronary atherosclerosis. HARP Research Group. (1995)