Supplements That Affect Blood Clotting Like Baby Aspirin
Several dietary supplements inhibit platelet function similarly to baby aspirin, with the most clinically significant being garlic, ginger, ginkgo biloba, turmeric, vitamin E, and fish oil/omega-3 fatty acids. 1, 2
Supplements with Documented Antiplatelet Effects
High-Risk Supplements (Should Be Held 2 Weeks Before Surgery)
Garlic inhibits platelet function through multiple mechanisms, particularly at doses of 12g daily, and has been documented to cause spontaneous bleeding events when combined with SSRIs. 2 The antiplatelet effect is clinically significant enough to warrant discontinuation before surgical procedures. 1
Ginkgo biloba affects platelet function and should be held for 2 weeks before surgery due to increased bleeding risk. 1, 2 Case reports document elevated INR and epistaxis with its use. 2
Ginger inhibits platelet aggregation in vitro and has been associated with case reports of elevated INR and epistaxis, requiring caution in patients at bleeding risk. 2 The mechanism involves inhibition of thromboxane synthesis. 1
Turmeric/Curcumin inhibits platelet aggregation via thromboxane metabolism and calcium channel inhibition, also inhibiting generation of thrombin and factor Xa. 1 It demonstrates anti-inflammatory and antiplatelet effects with prolongation of activated partial thromboplastin time. 2
Vitamin E has antiplatelet effects related to inhibition of protein kinase C, which are worsened when taken with aspirin. 1 Higher serum levels are associated with bleeding in non-valvular atrial fibrillation patients on warfarin. 1
Moderate-Risk Supplements
Fish oil/Omega-3 fatty acids inhibit platelet-to-platelet adhesion and platelet-stimulated thrombin generation in vitro. 2 However, the clinical bleeding risk appears minimal - a large placebo-controlled trial showed no increase in perioperative bleeding, and the 2021 Mayo Clinic guidelines recommend continuation through surgery. 2 Studies of patients taking omega-3 fatty acids with both aspirin and clopidogrel showed no increased major bleeding compared to aspirin and clopidogrel alone. 3 Omega-3 fatty acids alone do not inhibit platelet aggregation by standard testing, but do enhance aspirin's antiplatelet effect when combined. 4, 5
Flaxseed oil has been associated with decreased platelet aggregation in healthy men and may increase bleeding risk. 2
Green tea extract (containing EGCG) inhibits platelet aggregation and decreases fibrinogen binding to platelet surface GPIIb/IIIa, but may be continued until surgery despite theoretical bleeding risk. 2
Fenugreek aqueous extracts inhibit the coagulation process in vitro and significantly prolong prothrombin time. 2
Additional Supplements with Coagulation Effects
St. John's wort may decrease platelet aggregation and can cause serotonin syndrome when combined with other serotonergic agents. 1 It strongly induces CYP3A4, affecting warfarin metabolism. 1
Saw palmetto may increase bleeding time leading to increased risk of hematuria and operative bleeding through cyclooxygenase inhibition. 1
Vanadium (sodium orthovanadate) prolongs clotting time via inhibitory effects on both factor Xa and thrombin. 1
Critical Clinical Considerations
Perioperative Management
All supplements with antiplatelet effects should ideally be discontinued 1-2 weeks before elective surgery to minimize bleeding risk. 1, 2 A survey found that 19% of surgical patients were taking supplements with potential coagulation effects, and 12.5% of these patients had actual intraoperative hemorrhage. 2
Important Distinction from Aspirin
None of these supplements provide adequate antiplatelet protection comparable to aspirin for cardiovascular prophylaxis - their effects are too weak and too transient. 6 Patients should not substitute supplements for prescribed aspirin therapy.
Drug Interactions
Approximately 120 dietary supplements may interact with aspirin, clopidogrel, and dipyridamole, while 180 may interact with warfarin. 7 The combination of supplements with antiplatelet medications requires careful monitoring, though fish oil appears safe even with dual antiplatelet therapy. 3
Common Pitfall
Do not assume supplements are safe simply because they are "natural" - many have clinically significant antiplatelet effects that can cause bleeding complications, particularly in the perioperative setting or when combined with antiplatelet medications. 1, 2