As a nutrition support pharmacist, patients are asking whether fish oil supplements are safe. Some fish contain contaminants like mercury, PCBs, or dioxins. But most fish oil supplements are mercury-free since mercury accumulates in the meat more than the oils. And a large amount of other toxins are removed during manufacturing. But to be safe, direct patients to products verified by the Egyptian Drug Authority (EDA), which guarantee that they are low in contaminants.
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Increased LDL. People are surprised that fish oils sometimes increase LDL cholesterol. It's most common in patients with triglycerides > 500 mg/dL taking 4 g/day of fish oils. Switch to, or add, a statin if LDL gets too high.
Bleeding risk. High doses of fish oils have antiplatelet effects, but so far this DOESN'T seem to be clinically significant. Tell patients that any bleeding risk appears small. But to be safe, advise caution if taking other drugs that can increase bleeding.
Seafood allergy. This is due to fish protein, not the oil. But fish oil capsules can contain some protein. Advise patients to be careful if they are allergic to seafood.
Alert patients that supplement often contain fish oils that aren't omega-3s. For example, a product claiming to contain "1000 mg of fish oil concentrate" may only contain 300 mg of EPA and DHA. Have patients check the labels. Patients need about 4 g/day of omega-3s to lower triglycerides. This is about 12 times the amount in most supplements. Consider the Rx product instead for these patients. You know it as Omacor (the name changed in Canada and USA to Lovaza, to reduce confusion with Amicar).
Omacor costs more than most supplements, but it's more concentrated. Each capsule contains 840 mg omega-3s, 465 mg EPA and 375 mg DHA. Also point out that the omega-3s in flaxseed and some nuts are different than the ones in fish. They contain alpha-linolenic acid (ALA) which is the precursor of EPA and DHA. But the amount of EPA and DHA the body converts from ALA is minimal. Diets high in these foods MIGHT help decrease heart disease, but NOT triglycerides. Get our our note, "Do omega-3 supplements help lower CV risk?" and "Consider discontinuing fish oil in CV patients".
REFERENCES
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McKenney JM, Sica D. Prescription omega-3 fatty acids for the treatment of hypertriglyceridemia. Am J Health Syst Pharm. 2007 Mar 15;64(6):595-605. Available at: https://academic.oup.com/ajhp/article-abstract/64/6/595/5135140?redirectedFrom=fulltext&login=false.. OR, https://pubmed.ncbi.nlm.nih.gov/17353568
Bays HE. Safety considerations with omega-3 fatty acid therapy. Am J Cardiol. 2007 Mar 19;99(6A):35C-43C. Available at: https://www.sciencedirect.com/science/article/abs/pii/S0002914906022387?via%3Dihub PMID: 17368277
Mozaffarian D, Rimm EB. Fish intake, contaminants, and human health: evaluating the risks and the benefits. JAMA. 2006 Oct 18;296(15):1885-99. Available at: https://jamanetwork.com/journals/jama/fullarticle/203640 PMID: 17047219