Omega-3 Fatty Acids

Omega-3 fatty acids are polyunsaturated fatty acids, distinguished by having a double bond three carbons away from the end of the hydrocarbon tail. Examples of omega-3s are alpha-linolenic acid (ALA), Eicosapentaenoic Acid (EPA), and docosahexaenoic acid (DHA). This page covers evidence for omega-3s as a whole and is under construction. For mixed EPA and DHA, see fish oil.

Quick Answer

What it is

Omega-3 fatty acids are polyunsaturated fatty acids, distinguished by having a double bond three carbons away from the end of the hydrocarbon tail. Examples of omega-3s are alpha-linolenic acid (ALA), Eicosapentaenoic Acid (EPA), and docosahexaenoic acid (DHA).

Key findings

  • Grade B: C-Reactive Protein (CRP) (Type 2 Diabetes)
  • Grade B: High-density lipoprotein (HDL) (High Cholesterol)
  • Grade C: Depression Symptoms (Depression)

Safety

No specific caution or interaction language was detected in the current summary/outcome notes.

ℹ️ Quick Facts: Omega-3 Fatty Acids

Quick Facts: Omega-3 Fatty Acids

  • Best Evidence:Grade B
  • Conditions Studied:19
  • Research Outcomes:60
  • Grade B Findings:3
  • Key Effect:High Cholesterol
Outcomes by grade:
A0
B3
C3
D8
19 conditions · 60 outcomes

Detailed Outcomes

Grade:
Effect:
Size:
Sort:
|
B
C-Reactive Protein (CRP)
Small Decrease
16 studies
smallImproves
?
Oxidative Stress Biomarkers
11 studies
Improves
?
Total Antioxidant Capacity (TAC)
Improves
?
Superoxide Dismutase Activity
6 studies
Improves
?
Interleukin 6
Improves
?
TNF-Alpha
5 studies
Improves
B
High-density lipoprotein (HDL)
Small Improvement
12 studies
smallImproves
?
Triglycerides
14 studies
Improves
?
Total cholesterol
Improves
?
Low-density lipoprotein (LDL)
8 studies
Improves
B
C-Reactive Protein (CRP)
Small Decrease
4 studies
smallImproves
?
Vascular Function
7 studies
Improves
?
Interleukin 6
Improves
?
TNF-Alpha
5 studies
Improves
C
Depression Symptoms
Small Improvement
smallImproves
C
Anxiety Symptoms
Small Improvement
smallImproves
?
Quality of Life
Improves
C
Anxiety Symptoms
Small Improvement
smallImproves
?
Depression Symptoms
Improves
?
Sleep Quality
1 study
Improves
D
Infant Death Risk
No effect
none
?
Pregnancy Complications
15 studies
Improves
D
Blood glucose
No effect
none
?
Pregnancy Complications
15 studies
Improves
?
Infant Death Risk
Improves
?
Total cholesterol
Improves
?
Triglycerides
8 studies
Improves
?
High-density lipoprotein (HDL)
7 studies
Improves
?
Insulin
6 studies
Worsens
?
Low-density lipoprotein (LDL)
6 studies
Improves
?
C-Reactive Protein (CRP)
5 studies
Improves
?
Interleukin 6
Improves
?
Oxidative Stress Biomarkers
3 studies
Improves
?
Total Antioxidant Capacity (TAC)
Improves
D
6-Minute Walking Test Performance
No effect
5 studies
none
?
C-Reactive Protein (CRP)
4 studies
Improves
?
Interleukin 6
Improves
?
Quality of Life
Improves
D
Blood Flow
No effect
4 studies
none
?
Walking Ability
Improves
D
Seminal Motility
No effect
3 studies0
none
?
Sperm Count
2 studies0
Improves
?
Sperm Quality
2 studies0
Improves
D
Cardiovascular Disease Mortality
No effect
none
?
Risk of Hospitalization for Heart Failure
4 studies
Improves
D
Body Fat
No effect
1 study
none
?
Body Mass Index (BMI)
1 study
Improves
?
Muscle Mass
Improves
?
Weight
1 study
Improves
D
Body Fat
No effect
1 study
none
?
Body Mass Index (BMI)
1 study
Improves
?
Muscle Mass
Improves
?
Weight
1 study
Improves
?
Anxiety Symptoms
Improves
?
Anxiety Symptoms
Improves
?
Schizophrenia symptoms
Improves
?
Glycemic Control
Improves
?
Itching
Improves
?
Cognition
Improves
?
Cognition
Improves

Evidence by Condition

Best grade per condition (each condition may have multiple outcomes)

BHigh Cholesterol
1
High-density lipoprotein (HDL)ImprovesTriglyceridesImprovesTotal cholesterolImproves
BType 2 Diabetes
1
C-Reactive Protein (CRP)ImprovesOxidative Stress BiomarkersImprovesTotal Antioxidant Capacity (TAC)Improves
BCardiovascular Disease
1
C-Reactive Protein (CRP)ImprovesVascular FunctionImprovesInterleukin 6Improves
BUremic Pruritus
1
ItchingImproves
CDepression
1
Depression SymptomsImprovesAnxiety SymptomsImprovesQuality of LifeImproves
CMajor Depressive Disorder (MDD)
1
Anxiety SymptomsImprovesDepression SymptomsImprovesSleep QualityImproves
DPregnancy and Delivery Health
1
Blood glucosePregnancy ComplicationsImprovesInfant Death RiskImproves
DChronic Obstructive Pulmonary Disease (COPD)
1
6-Minute Walking Test PerformanceC-Reactive Protein (CRP)ImprovesInterleukin 6Improves
DInfertility
1
Seminal MotilitySperm CountImprovesSperm QualityImproves
DObesity
1
Body FatBody Mass Index (BMI)ImprovesMuscle MassImproves
DHeart Failure
1
Cardiovascular Disease MortalityRisk of Hospitalization for Heart FailureImproves
DOverweight
1
Body FatBody Mass Index (BMI)ImprovesMuscle MassImproves
DPeripheral Arterial Disease
1
Blood FlowWalking AbilityImproves
DPremature Birth
1
Infant Death RiskPregnancy ComplicationsImproves

Research Citations (21)

Effects of omega-3 fatty acids on chronic pain: a systematic review and meta-analysis.
(2025)
PMID: 41267881
Effect of omega-3 fatty acid supplementation on markers of inflammation and endothelial function in patients with chronic heart disease: A systematic review and meta-analysis.
PMID: 38836663
Efficacy and safety of omega-3 fatty acids supplementation for anxiety symptoms: a systematic review and dose-response meta-analysis of randomized controlled trials.
PMID: 38890670
Omega-3 fatty acids for depression in adults
PMID: 26537796
Effects of long-chain omega-3 polyunsaturated fatty acids on reducing anxiety and/or depression in adults; A systematic review and meta-analysis of randomised controlled trials
PMID: 37028202
Exploration of the optimized portrait of omega-3 polyunsaturated fatty acids in treating depression: A meta-analysis of randomized-controlled trials.
PMID: 40049535
Omega-3 for bipolar disorder: meta-analyses of use in mania and bipolar depression
PMID: 21903025
Omega-3 fatty acids for depression in adults
PMID: 34817851
Efficacy and Safety of Omega-3 Fatty Acids in Ameliorating Pruritus in Adult Patients With Chronic Kidney Disease: A Meta-Analysis of Randomized Controlled Trials.
PMID: 39246955
The effects of ω-3 fatty acids on inflammatory and oxidative stress markers in patients with Type 2 diabetes mellitus: A systematic review and meta-analysis of controlled trials.
PMID: 39243880

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