Fish oil supplements, a common source of omega-3 fatty acids like eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are often taken for heart and brain health. However, patients are required to stop taking these supplements before any surgical procedure. This mandatory pause is rooted in the potential of omega-3s to alter the body’s natural blood-clotting process. This alteration could lead to complications during an operation, as the fatty acids interact with the cellular components responsible for forming a stable clot.
How Omega-3s Affect Blood Clotting
The primary concern regarding fish oil and surgery stems from its effect on platelets, which are the small, sticky cells in the blood that clump together to initiate a clot. Omega-3 fatty acids, once consumed, are incorporated into the cell membranes of these platelets. This incorporation alters the raw materials the platelet uses to signal for help.
Specifically, the omega-3s compete with another fatty acid, arachidonic acid, which is typically used to create a potent clot-promoting molecule called Thromboxane A2 (TXA2). When EPA is available, it is preferentially converted into Thromboxane A3 (TXA3), which is significantly less effective at causing platelets to aggregate. This biological shift reduces the overall stickiness and activation of platelets, effectively acting as a mild anti-platelet agent.
By reducing the efficiency of platelet aggregation, omega-3s extend the time it takes for a clot to form. This is why they are considered to have a blood-thinning effect, a beneficial quality for managing cardiovascular risk over the long term. However, this same mechanism historically raised alarms for surgical teams who rely on a swift and robust clotting response to manage bleeding.
Surgical Complications from Increased Bleeding
When the natural process of hemostasis, or blood clotting, is impaired, the risk of excessive bleeding during and after surgery increases. The consequence of omega-3-impaired platelet function is a greater volume of intraoperative blood loss. Surgeons must be able to control bleeding quickly to maintain visibility and ensure patient stability throughout the procedure.
A major concern following the operation is the development of a hematoma, which is a collection of clotted blood outside the blood vessel. A hematoma can put pressure on surrounding tissues and cause pain. Depending on the surgical site, it can delay healing or even necessitate a second surgical procedure to drain the blood. For procedures involving confined spaces, such as brain or spinal surgery, even a small increase in bleeding risk is considered a serious complication.
Pre-Operative Cessation Guidelines
The traditional guideline for stopping fish oil supplements was based on the need to replace the affected platelets with new, fully functional ones. Platelets have a typical lifespan of about seven to ten days. This led to the common recommendation to discontinue fish oil 7 to 14 days before an operation. This period was thought to be sufficient to ensure the majority of circulating platelets were no longer affected by the omega-3 fatty acids.
However, the necessity of this strict cessation period has been questioned by more recent, high-quality clinical studies. Several systematic reviews and a 2021 consensus statement from the Society for Perioperative Assessment and Quality Improvement (SPAQI) suggest that over-the-counter fish oil supplements do not increase the risk of clinically significant bleeding during or after surgery. Some research even indicates that continuing omega-3s might be safe and potentially beneficial due to their anti-inflammatory properties, with some studies showing no increase in blood loss or even a reduced need for blood transfusions.
Despite this evolving evidence, many surgical teams still adhere to the two-week cessation protocol as a precaution to minimize potential risks. Patients must consult directly with their surgeon or physician to determine the exact timeline for their specific procedure. The protocol can vary based on the type of surgery and the individual’s overall health profile, especially for those taking high-dose prescription omega-3 formulations, which may have specific and stricter guidelines.
Other Supplements That Require Stopping
Fish oil is not the only supplement that can affect blood health and require pre-operative cessation. A variety of other common over-the-counter and herbal remedies also possess anti-platelet or anticoagulant properties. These properties pose a similar risk of increased bleeding by interfering with the body’s ability to form a clot.
High-dose Vitamin E should typically be stopped because it acts as a mild anti-platelet agent.
Common Supplements to Discontinue
- Garlic
- Ginger
- Ginkgo Biloba
- Ginseng
Non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen, also inhibit platelet function and must be discontinued well before surgery.