Fish Oil

Who Cannot Take Omega-3 Fish Oil Capsules?

Who Should Take Omega-3 Fish Oil

Omega-3 fish oil is a fantastic nutrient. From before we’re born through to our golden years, this essential fatty acid has a role to play at every stage of our lives.

And while other supplements fall in and out of fashion faster than you can say “activated charcoal”, omega-3 is here to stay. First discovered in the late 1920s, the essential fatty acid really entered the public consciousness in the 1970s when researchers discovered that Greenland Inuits, who consumed vast amounts of oily fish, didn’t have the levels of cardiovascular disease we suffered from in the West.

These days omega-3 is one of the best-researched supplements on the planet. With benefits that range from the cosmetic (who doesn’t want younger-looking skin?) to the physiological (from maintaining normal blood pressure to keeping your eyes healthy), it’s tempting to think we should all be taking omega-3 by the tablespoon. But is that really the case?

So who needs omega-3 fish oil in their lives and is there anyone who really shouldn’t be taking it? Read our guide to find out.

5 Things To Know About Omega-3s for Heart Disease

Experts agree that fish rich in omega-3 fatty acids should be included in a heart-healthy diet. Much research has been done on fish and heart disease, and the results provide strong, though not conclusive evidence that people who eat fish at least once a week are less likely to die of heart disease than those who rarely or never eat fish.

Omega-3s in supplement form have not been shown to protect against heart disease. While there has been a substantial amount of research on omega-3 supplements and heart disease, the findings of individual studies have been inconsistent. In 2012, two combined analyses of the results of these studies did not find convincing evidence that omega-3s protect against heart disease.

Omega-3 supplements may interact with drugs that affect blood clotting. Omega-3 supplements may extend the time it takes for a cut to stop bleeding. People who take drugs such as anticoagulants (“blood thinners”) or nonsteroidal anti-inflammatory drugs should discuss the use of omega-3 fatty acid supplements with a health care provider.

Fish liver oils (which are not the same as fish oils) contain vitamins A and D as well as omega-3 fatty acids; these vitamins can be toxic in high doses. Fish liver oils contain vitamins A and D as well as omega-3 fatty acids. Both of these vitamins can be toxic in large doses. The amounts of vitamins in fish liver oil supplements vary from one product to another.

Who Cannot Take Omega-3 Fish Oil Capsules?

Omega-3 fatty acids have anti-inflammatory properties and heart-healthful benefits. You can get fatty acids either from food or fish oil supplements. Fish such as mackerel, salmon, tuna, sardines and halibut are rich in omega-3 fatty acids, as are plant oils such as flaxseed and canola oil. Fish oil capsules are another way to get your omega-3 fatty acids. Fatty acids in fish oil are docosahexaenoic and eicosapentaenoic acid. Fish oil should not be taken without medical supervision because it is not suitable for some people.


Fish oil capsules usually contain 120 milligrams of DHA and 180 milligrams of EPA per capsule. No more than 3,000 milligrams, or 3 grams, of omega-3 fatty acids from capsules should be taken without medical supervision, reports the University of Maryland Medical Center. Ensure that you get your fish oil capsules from a reputable company whose products don't contain any pesticides, mercury, cadmium or lead.

Blood Disorders

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Taken in high doses, fish oil can increase the risk of bleeding, according to the National Center for Complementary and Alternative Medicine. Persons who have bleeding disorders, bruise easily or take blood thinners such as aspirin, warafin or clopidogrel should seek medical advice before taking fish oil capsules.

Pregnant Women

Pregnant or lactating women should not take fish oil capsules without consulting their doctor. However, the likelihood of ingesting mercury is much lower with fish oil capsules than with fish. According to the Food and Drug Administration, mercury can harm the developing baby's nervous system. Also, fish oil might contain polychlorinated biphenyls -- PCBs -- and dioxins, which are harmful to human health.


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Fish oil can raise fasting blood sugar level in some Type 2 diabetics, so it should not be taken without medical supervision, according to the University of Maryland Medical Center. This is especially crucial if you are taking blood sugar medications such as insulin, glipizide, gluchophage or glyburide. Your doctor might increase your medication if you wish to take fish oil capsules.

People With Allergies

Don't take fish oil capsules if you are allergic to fish or nuts. Rare incidences of skin rashes have been reported among persons taking supplements that had other food allergies.


People 18 years of age and younger should not be given fish oil capsules unless under the supervision of a doctor, according to the University of Maryland Medical Center. Children also should not eat fish with a possibly high mercury content, such as swordfish, shark or tilefish.

Eric Carter