One in five adults over age 60 takes fish oil, a supplement extracted from the tissues of fatty fish and rich in omega-3 fatty acids, which support heart, brain, eye, and joint health. But even though omega-3s have benefits, certain medications and supplements can interact with fish oil in potentially harmful ways. Here are five of them.
Omega-3 supplements can inhibit blood-clotting, which usually isn’t an issue when they’re taken on their own, Aaron Emmel, PharmD, a pharmacist and the founder and director of educational programs at Pharmacy Tech Scholar, told Health.
However, mixing omega-3s with medications that have similar effects, such as anticoagulants like warfarin or antiplatelet drugs like aspirin, could increase the risk of bleeding, he said.
If you take these medications, talk to your physician before adding fish oil. They may want to monitor your international normalized ratio, which measures how long it takes for your blood to clot, noted Amy Goldsmith, RDN, LDN, a registered dietitian and owner of Kindred Nutrition & Kinetics in Frederick, Maryland.
Ginkgo biloba, an herbal supplement often taken for brain health and conditions like anxiety or PMS, also has antiplatelet properties that make it more difficult for blood to clot, said Brynna Connor, MD, ABFM, a board-certified family medicine physician and healthcare ambassador at NorthWestPharmacy.com.
That’s why combining it with fish oil increases the risk of bruising or bleeding, she told Health.
Vitamin E—an antioxidant linked to immune, heart, and eye health—also thins the blood. When taken alongside fish oil, it can further raise the risk of bleeding or bruising.
Most adults can meet the recommended 15 milligrams (mg) per day of vitamin E through foods like vegetable oils, nuts, seeds, spinach, and broccoli. Supplements often provide more than you need, which may worsen the risk when combined with fish oil.
NSAIDs such as ibuprofen and naproxen reduce pain and inflammation but can increase the risk of internal bleeding, especially in the gastrointestinal tract. Because omega-3s have anticoagulant properties, taking both at the same time can be risky.
“NSAIDs have an increased bleeding risk with high fish-oil doses,” Goldsmith said, so the pairing should be supervised by your provider.
Omega-3s can slightly decrease blood pressure. When combined with blood pressure-lowering medications like ACE inhibitors, beta blockers, and calcium channel blockers, the effects may cause blood pressure to drop too low, Emmel said.
“This doesn’t mean that you absolutely can’t take fish oil with these supplements,” he noted. “However, if you take them together, do so with caution.”
Any adverse effects from fish oil usually happen with higher doses—more than 3,000 mg of combined EPA and DHA per day. “Generally, the standard OTC dose is 1,000 to 2,000 mg of total fish oil daily, and it should be safe as long as it’s monitored and guided by your doctor,” Emmel said.
That said, many people may not need to take fish oil at all. All three experts recommended getting omega-3s from your diet before turning to supplements. You can likely meet the recommended intake by eating two to three servings of fish per week (a 3-ounce serving of salmon, for example, has about 2,000 mg of DHA and EPA).
“Supplements are best for those individuals who don’t eat fish, or those who need therapeutic supplementation for conditions like high triglycerides, cardiovascular disease risk, and rheumatoid arthritis,” Connor told Health.
For those who do need supplements, Connor suggested choosing ones in triglyceride or re-esterified triglyceride form, which are more bioavailable than the ethyl ester form. Take them with a meal that includes some dietary fat to enhance absorption, she said.
