Are Spirulina & Fish Oil Safe if Taken Together?

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Both spirulina and fish oil supplements provide essential nutrients and may have additional health benefits, although the research on this is still preliminary. While this combination is typically safe, check with your doctor before taking either supplement, because people with specific conditions or on certain medications may need to avoid one or both of these supplements.

Benefits of This Combination

Although research is still in the preliminary stages, taking both spirulina and fish oil may have health benefits. Taking these two supplements together may help limit inflammation and be beneficial for high cholesterol caused by diet, according to an animal study published in BMC Complementary & Alternative Medicine in December 2014. Further research is necessary to verify whether this combination has the same effect in people.

Nutrient Content

Taking spirulina and fish oil together adds a wider variety of nutrients to your diet. A tablespoon of spirulina provides significant amounts of copper, iron, riboflavin and thiamine, nutrients not typically present in fish oil. Some types of fish oil, such as cod liver oil, are good sources of vitamins A and E.

Proponents sometimes claim that spirulina is a good vegetarian alternative to fish oil for those who want to increase their intake of essential omega-3 fats. This isn't the case, however, because spirulina mainly provides the omega-6 fat gamma-linolenic acid. Some types of microalgae or seaweed do provide omega-3 fats, but spirulina only has about 58 milligrams of omega-3 fats per tablespoon. Fish oil, however, is an excellent source, with the exact amount of omega-3 fats depending on the type of fish oil. A teaspoon of herring oil has about 708 milligrams, while the same amount of cod liver has 1,034 milligrams, for example. The Academy of Nutrition and Dietetics recommends getting at least 500 milligrams per day of a combination of the omega-3 fats EPA and DHA.

Side Effects and Interactions

Fish oil can cause bad breath, bloating, belching, nausea, rash, nosebleeds, loose stools, diarrhea, nausea and heartburn. High doses may increase your risk for bleeding. Freezing your supplements or taking a time-release brand may minimize these effects. Spirulina is usually safe even at higher doses, although it may interact with medications that suppress immune function. Fish oil can have an immune-function-suppressing effect at high doses, which can be a problem for people taking these medications as well. It may also interact with blood thinners, the weight-loss drug orlistat, blood pressure medications and birth control pills.

Other Considerations

People with phenylketonuria, a genetic condition in which the amino acid phenylalanine can't be broken down, shouldn't take a spirulina supplement, because it could make their condition worse. Those with any autoimmune disease should also avoid these supplements. Spirulina may be contaminated with toxic substances, such as heavy metals like mercury, so it's important to purchase a reputable brand and to avoid this supplement during pregnancy. Fish oil supplements are usually purified to remove any such contamination. People with liver disease, bipolar disorder, an implanted defibrillator, HIV/AIDS, diabetes, high blood pressure or depression may need to avoid fish oil supplements, however.