What are the recommended dietary sources and supplementation doses of essential fatty acids (omega‑3 fatty acids such as eicosapentaenoic acid [EPA], docosahexaenoic acid [DHA], and alpha‑linolenic acid [ALA]; and omega‑6 fatty acids) for adults, and what precautions should be taken for vegans, patients on anticoagulant therapy, and those with hypertriglyceridemia?

Essential Fatty Acids: Evidence-Based Dietary Sources, Supplementation Doses, and Special Population Precautions

Core Dietary Recommendations for Adults

Consume at least two servings of fatty fish per week to provide approximately 400–500 mg/day of EPA+DHA for general cardiovascular health. 1, 2 This dietary pattern reduces coronary heart disease mortality by 28–54% in observational cohorts. 3

Plant-Based Omega-3 Sources (Alpha-Linolenic Acid)

• For adults who do not consume fish, the adequate intake (AI) for alpha-linolenic acid is 1.6 g/day for men and 1.1 g/day for women. 1, 4 This amount supports normal growth and neural development without deficiency. 4

• Plant sources of ALA include flaxseeds, walnuts, soybeans, tofu, and canola oil, though ALA is significantly less potent than marine-derived EPA and DHA. 1, 2 The conversion of ALA to EPA and DHA in humans is minimal and inefficient. 5, 6

• A total ALA intake of 1.5–3 grams daily appears beneficial for cardiovascular health based on observational studies and randomized trials. 1, 2

Omega-6 Fatty Acids

• The adequate intake for linoleic acid (omega-6) is 17 g/day for adult men and 12 g/day for adult women. 1 Vegetables and vegetable oils are primary sources. 7

• The current Western diet provides an omega-6 to omega-3 ratio of approximately 10:1 to 25:1, whereas a ratio closer to 1:1 to 2:1 is considered optimal for homeostasis and disease prevention. 6, 7 This imbalance contributes to chronic inflammatory conditions. 7

Supplementation Dosing Algorithm by Clinical Indication

Healthy Adults (Primary Prevention)

• Prescribe 500 mg EPA+DHA daily for cardiovascular primary prevention in adults without established heart disease. 8, 2 This dose is supported by the American College of Cardiology. 8

• Up to 10% of the ALA adequate intake can be consumed as EPA and/or DHA, representing approximately 100 mg/day of current mean intake in the United States. 4 However, this amount is substantially lower than what most international organizations recommend. 4

Documented Coronary Heart Disease (Secondary Prevention)

• Prescribe 1 gram (850–1,000 mg) EPA+DHA daily for patients with established coronary heart disease. 1, 8, 2, 3 This dose reduces sudden cardiac death by 45% and total mortality by 15–21% in post-myocardial infarction patients. 8, 2

• The GISSI-Prevenzione trial demonstrated a 21% reduction in mortality with 850 mg EPA+DHA daily in post-MI patients, representing Level A evidence. 8, 2

Hypertriglyceridemia

• For moderate hypertriglyceridemia (200–499 mg/dL), prescribe 2–4 grams EPA+DHA daily under physician supervision, which lowers triglycerides by 20–40%. 8, 2, 3, 5

• For severe hypertriglyceridemia (≥500 mg/dL), prescribe 4 grams EPA+DHA daily under physician supervision, which reduces triglycerides by approximately 45% and VLDL cholesterol by more than 50%. 8, 3 This dose also mitigates pancreatitis risk. 3

• The triglyceride-lowering effect occurs through decreased hepatic VLDL-triglyceride production, increased fatty acid oxidation, and enhanced lipoprotein lipase activity. 3, 5

Special Population Precautions

Vegans and Vegetarians

• Vegans must rely exclusively on ALA from plant sources (flaxseeds, walnuts, chia seeds, hemp seeds, canola oil) to meet essential fatty acid requirements, as dietary DHA is not produced from EPA in meaningful amounts in humans. 2, 5 Dietary DHA is retroconverted to EPA, but the reverse does not occur. 5

• Algal oil supplements provide the only direct vegan source of EPA and DHA without animal products, offering 500 mg–2 grams EPA+DHA per dose depending on formulation. 3 Algal oil is free from methylmercury, PCBs, and dioxins found in fish. 3

• For vegans requiring cardiovascular protection, prescribe algal-derived EPA+DHA at 500 mg daily for primary prevention or 1 gram daily for documented coronary disease. 3

Patients on Anticoagulant or Antiplatelet Therapy

• Up to 5 grams EPA+DHA daily does not increase spontaneous bleeding episodes or bleeding complications, even with concurrent anticoagulation or antiplatelet therapy. 8, 2, 3 This safety threshold is established by the European Food Safety Authority. 8, 2

• No additional bleeding-time monitoring is required for doses up to 4 grams daily when combined with warfarin, aspirin, or other anticoagulants. 8, 2

• Patients receiving ibrutinib (BTK inhibitor) should completely avoid fish oil supplements due to elevated epistaxis risk. 8, 2 This is the only absolute contraindication. 8

• For patients with documented coronary heart disease on anticoagulation, prescribe 850–1,000 mg EPA+DHA daily with a fatty meal (10–15 g dietary fat) to optimize absorption of ethyl-ester formulations. 8

Hypertriglyceridemia with Concurrent Anticoagulation

• Prescribe 2–4 grams EPA+DHA daily under physician supervision for moderate hypertriglyceridemia in patients on anticoagulation, with no increased bleeding risk. 8, 2

• Monitor for atrial fibrillation when using doses ≥4 grams daily, as higher doses increase AF risk by approximately 25%. 8, 2, 3 The REDUCE-IT trial reported AF hospitalization in 3.1% versus 2.1% in controls. 8

Critical Safety Considerations and Monitoring

Upper Safety Limits

• Long-term supplementation up to 5 g/day combined EPA+DHA is safe without increased bleeding risk. 8, 2, 3 EPA alone up to 1.8 g/day has been specifically validated as safe. 8, 2

• Doses above 3 grams daily require physician supervision due to theoretical bleeding concerns, though actual evidence does not support increased bleeding. 8, 2, 3

Lipid Parameter Effects

• Omega-3 supplementation may increase LDL cholesterol by 5–10% in some patients, especially at high doses (≥2 grams daily). 8, 2, 3 This effect is not observed with pure EPA formulations (icosapent ethyl). 3

• HDL cholesterol typically increases modestly by 1–3% with EPA+DHA formulations. 8, 3

• Combining omega-3s with statins addresses both triglycerides and LDL cholesterol simultaneously, preventing the LDL rise from becoming clinically problematic. 3

Pregnancy and Mercury Exposure

• Pregnant and nursing women should avoid high-mercury fish (shark, swordfish, king mackerel, tilefish) and may safely consume up to 12 oz (340 g) per week of low-mercury fish such as salmon, pollock, canned light tuna, or catfish. 3

• For middle-aged and older adults, the cardiovascular benefits of fish consumption outweigh potential mercury risks when following FDA recommendations. 2, 3

• Removing skin and surface fat before cooking further reduces mercury and contaminant intake. 3

Common Clinical Pitfalls

• Do not prescribe omega-3 supplements for blood sugar control in diabetes—evidence shows no benefit for glycemic control. 8 However, omega-3s remain appropriate for triglyceride management in diabetic patients. 3

• Low-dose EPA+DHA mixtures (≤1 gram daily) showed no significant cardiovascular benefit in modern trials (ASCEND, VITAL, OMEMI) with contemporary statin therapy. 8, 3 These neutral results reflect the background use of statins, not a lack of omega-3 efficacy. 3

• Do not rely on plant-based omega-3 sources (ALA) for therapeutic triglyceride reduction—only marine-derived EPA and DHA demonstrate consistent triglyceride-lowering effects. 3, 5

• Prescription omega-3 formulations are required for consistent dosing and purity at therapeutic doses (≥2 grams daily); over-the-counter fish oil supplements have variable EPA+DHA content. 3