Before taking omega-3, safety precautions and warnings for the supplement should be discussed with your healthcare provider if you have a bleeding disorder, diabetes, or familial adenomatous polyposis. You should also tell your healthcare provider if you are pregnant or breastfeeding. Since fish oil omega-3 supplements may contain toxins, look for a product from a reputable manufacturer that has been purified and tested for toxins.
A normal dietary intake of omega-3 fatty acids (that is, from food sources) is safe and beneficial. However, omega-3 supplements may not always be safe. You should talk with your healthcare provider prior to taking omega-3 fatty acids if you have:
- A bleeding disorder
- Familial adenomatous polyposis, a genetic condition involving colon polyps
- Any allergies, including allergies to foods (especially fish), dyes, or preservatives.
Also, let your healthcare provider know if you are:
- Pregnant or thinking of becoming pregnant
You should also be sure to tell your healthcare provider about all other medicines you are taking, including prescription and non-prescription medicines, vitamins, and herbal supplements.
Warnings and precautions to be aware of concerning the safety of omega-3 fatty acids include the following:
- There is some concern that fish oil omega-3 supplements may contain toxins, such as heavy metals (like mercury) or dioxin, although it seems that taking fish oil supplements may actually be safer than eating fish in this regard. Look for an omega-3 fatty acid product from a reputable manufacturer that has been purified and tested for such toxins. It is a good sign if a manufacturer abides by the rules of Good Manufacturing Practices (GMP) for drugs. It is also a good sign if a product has the United States Pharmacopoeia (USP) seal, which means that the product has been independently tested and shown to contain the correct ingredients in the amounts listed on the label. Your pharmacist is a good resource for information about which manufacturers are most reputable.
- Omega-3 fatty acids may "thin" the blood, preventing blood platelets from sticking together (an important step in blood clotting). If you have a bleeding disorder, do not take omega-3 supplements without checking with your healthcare provider.
- Sometimes, omega-3 fatty acid supplements may increase the risk of high blood sugar (hyperglycemia) in people with diabetes. If you have diabetes, check with your healthcare provider before taking omega-3 supplements. You may need to monitor your blood sugar more closely, and your healthcare provider may need to adjust the dose of your diabetes medications.
- People with familial adenomatous polyposis have a high risk for colon cancer, and there is some concern that omega-3 fatty acids may make this risk even higher. Some healthcare providers recommend that people with this condition avoid omega-3 supplements.
- Omega-3 fatty acids can interact with some medications (see Omega-3 Drug Interactions).
- Omega-3 supplements that are free of toxins are probably safe for pregnant or breastfeeding women (see Pregnancy and Omega-3 and Omega-3 and Breastfeeding). However, omega-3 fatty acid supplements and fish that may contain toxins should be avoided.
- People who are allergic to fish or shellfish may also be allergic to omega-3 supplements.