Krill Oil 101: Health Benefits, Side Effects, Who Should Take It, and More
Before you rush out to your local drug store or pharmacy, know this: Krill oil isn’t for everyone. “If you have fish allergies or are on blood thinners, consult with your healthcare provider before taking krill oil supplements,” says Retelny.
Fish oil and krill oil can cause blood thinning for some, which is why it’s important for people who are on blood thinners (or have bleeding disorders or are going to have surgery) to consult with their doctor before taking them, the Cleveland Clinic notes. As for those with a fish allergy, the American College of Allergy, Asthma, and Immunity agrees that you should talk with your doctor before taking any marine supplement.
While doctors might suggest that pregnant women take fish oil (for example, the American Pregnancy Association notes that omega-3s can have a positive impact on pregnancy), you might want to stick to fish oil if you are pregnant or nursing. “As there isn’t much research on the effects of krill oil, it’s cautioned that women that are pregnant or breastfeeding should also not take krill oil,” Kimberlain says.
“Additionally, it may interact with other medications people are taking,” says Kimberlain. In people with diabetes, for instance, some classes of oral medication may not be as effective, so it’s important to discuss your plan with your doctor or dietitian prior to starting, she says.
Also, if you have a sensitive stomach and don’t care for fish, it might not be right for you. “I wouldn’t call this a risk, but many people note that krill oil supplements have a fishy taste,” says Kimberlain. Some other symptoms or side effects may also be possible, such as diarrhea, heartburn, or an upset stomach, she adds.
And a word of caution in general about dietary supplements: The U.S. Food and Drug Administration (FDA) does not approve supplements before they are marketed, and supplement companies don’t have to provide the FDA with information about why their products are safe, the organization notes. Thus, it’s important to take caution when using supplements, and to ask your doctor before you start.
Because of that, Kimberlain suggests that you try to up your seafood game before considering a supplement. “I always suggest a food-first approach,” she says. You can get omega-3 fatty acids by adding cold-water fatty fish, like salmon, trout, herring, mackerel, and sardines, to your weekly menu. If you don’t eat seafood, you can also obtain omega-3s from flaxseed, chia seeds, and walnuts, according to the NIH.
A study published in 2018 in the Journal of Nutritional Science had one group of study participants eat fish, while the other were assigned krill oil capsules. They found that eating fish increased study participants’ vitamin D levels, but those who were in the krill oil group did not see this benefit (however, eating fish and taking a krill supplement both provided their respective groups with beneficial health effects, the researchers note).
If you do decide to take krill oil, follow the dosage instructions on the box or bottle carefully. That’s because taking too much fish oil (or krill oil) can increase your risk of bleeding and potentially impact how your immune system responds, the Mayo Clinic notes.