Krill Oil: Potential Benefits, Known Risks, and More

Krill Oil: Potential Benefits, Known Risks, and More

Krill Oil: Potential Benefits, Known Risks, and More
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Published on September 19, 2022
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Note: The U.S. Food and Drug Administration (FDA) does not approve supplements for safety or effectiveness. Talk to a healthcare professional about whether a supplement is the right fit for your individual health, and about any potential drug interactions or safety concerns.

Plenty of research indicates that omega-3 fatty acids may help lower the risk of many chronic diseases.

 While eating fatty fish is one of the best ways to get these essential nutrients, nearly 90 percent of Americans don’t eat the two weekly servings of fish or seafood recommended in the U.S. Dietary Guidelines.

 Fish oil supplements have long been promoted as a way to bridge that nutritional gap in typical Western diets.
Still, they aren’t the only way to get your omega-3s in supplement form. In fact, there are claims that krill oil, which comes from tiny Antarctic prawn-like crustaceans, may be a better source of omega-3s.

Here’s what you need to know about krill oil and whether the supplement is right for you.

Potential Health Benefits of Krill Oil

Krill oil is a good source of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), two key types of omega-3 fatty acids. “Omega-3 fats are beneficial for heart, brain, and cell health,” says Chicago-based registered dietitian-nutritionist Vicki Shanta Retelny, RDN.

“Krill oil can be used as an alternative to fish oil and has some compelling benefits,” adds Sarah Kamely, RDN, an integrative registered dietitian nutritionist in Miami. Here are a few.

Krill Oil May Support Heart Health

As chronic inflammation is linked to several diseases, including heart disease, the anti-inflammatory effects of krill oil may help your heart stay healthy. Polyunsaturated fatty acids like omega-3s reduce the production of inflammatory proteins in the blood vessels and the heart itself.

Research suggests that krill oil may benefit the heart by helping to lower triglycerides, a type of fat in the blood that can increase your risk of heart disease and stroke if levels get too high. In one study of people with severe hypertriglyceridemia (a condition of high triglyceride levels), those who took krill oil supplements for 12 weeks saw a 26 percent decrease in triglycerides.

In addition, a review and meta-analysis of seven randomized controlled trials found that people who took krill oil for at least two weeks showed a significant reduction in low-density lipoprotein cholesterol (LDL), often called “bad” cholesterol, and a significant increase in high-density lipoprotein cholesterol (HDL), also known as “good” cholesterol, compared with a placebo group.

“If deemed appropriate on an individual client basis, I would feel comfortable recommending krill oil as a supplement for its heart-health benefits,” says Kamely. Be sure to discuss with your healthcare provider.

Krill Oil Provides Antioxidants

Krill oil contains astaxanthin, a pigment that gives krill its pink-red color. Astaxanthin also belongs to a group of antioxidants called carotenoids, which help battle free radicals.

Free radicals are unstable molecules that your body creates in response to certain foods in your diet, or when you’re exposed to harmful substances like cigarette smoke. High levels of free radicals can cause oxidative stress, leading to cell damage. Cell damage from oxidative stress may play a role in many health issues, including cancer and heart disease.

Astaxanthin may offer unique benefits. “This carotenoid has been shown to help fight off the negative effects of free radicals on both our brain and nervous system,” says Kimberlain. As an antioxidant, astaxanthin is 6,000 times more potent than vitamin C, and may protect the brain and nervous system against free radical damage that contributes to age-related issues like dementia (a decline in mental ability that affects daily tasks).

Krill Oil Might Promote Gut Health

Krill oil may support gut health by reducing inflammatory proteins and oxidative stress, two factors that can lead to intestinal inflammation.

 Uncontrolled intestinal inflammation is associated with inflammatory bowel disease (IBD, a group of chronic conditions that cause diarrhea, abdominal pain and cramping, loss of appetite, and other digestive symptoms). Though krill oil hasn’t been shown to prevent or treat these conditions.

One study found that krill oil dampened the production of inflammatory molecules when human intestinal cells were exposed to harmful bacteria. However, the study was done in a test tube, so more research in humans is needed to confirm the potential benefits.

Krill oil may also support the health of the intestinal barrier (a layer of cells that protect the interior of the intestine from the outside environment) and improve the diversity of the gut microbiome (the microorganisms that live in the gut), says Kamely. Early research suggests that krill oil may dampen inflammatory proteins and promote bacteria-killing immune system cells. This may lead to greater microbial diversity in the intestines, a marker of gut health. But more research is needed.

Still, krill oil may be a worthwhile addition to your routine if you experience gut inflammation, IBD, or increased intestinal permeability (leaky gut, or the theory that the intestines can allow toxins from the digestive tract into the blood stream), Kamely says. Just be sure to talk with your doctor before using krill oil to help manage gut issues.

Krill Oil May Ease Arthritis and Joint Pain

Thanks to their ability to lower inflammation, the omega-3s in krill oil may reduce joint pain in people with inflammatory joint conditions like arthritis, says Kimberlain.

In one study in adults with mild to moderate knee osteoarthritis (a wear-and-tear condition that affects the knee joint), those who took 4 grams (g) of krill oil daily for six months saw greater improvements in knee pain, stiffness, and physical function than those who took a placebo.


However, talk to your doctor before adding krill oil supplements to your arthritis management plan.

Krill Oil May Provide PMS Pain Relief

In general, the omega-3s in krill oil have anti-inflammatory properties that may help ease pain, including menstrual pain.

Older research found that women taking krill oil used fewer pain relievers for premenstrual syndrome (PMS)-related pain after three menstrual cycles than women taking fish oil (though both groups saw improvements in symptoms).

While promising, this study is older and only included 70 participants. Newer studies with larger groups are needed to understand if and how krill oil may be helpful for managing PMS.

Still, Kamely notes that taking pain-relieving medications — specifically nonsteroidal anti-inflammatory drugs (NSAIDs) — too often can harm the gut lining. So, krill oil may be a safer alternative, especially if PMS symptoms are particularly painful, she notes. Ask your healthcare provider before starting krill oil supplements for PMS.

Weight Loss Effect of Krill Oil

There is not much research that explores whether krill oil leads to weight loss or changes in body composition — and the studies that do exist aren’t promising.

In a small study involving 26 women with a body mass index (BMI) that qualifies as overweight, supplementing with 3 grams (g) of krill oil per day for eight weeks did not result in a reduction in waist circumference.

Krill oil may have indirect benefits on weight loss by lowering inflammation, says Kathryn Durston, RDN, owner of Naturally Good Nutrition in Grand Rapids, Michigan. Chronic inflammation may promote weight gain or make it harder to lose weight by interfering with metabolism and hunger hormones, she says. For that reason, krill oil’s anti-inflammatory properties may be beneficial for weight loss.

“That being said, prioritizing a balanced diet, exercise routine, and stress management are more worthwhile habits for losing weight,” Durston says.

Potential Risks and Side Effects of Krill Oil

Krill oil isn’t for everyone. In addition, the U.S. Food and Drug Administration (FDA) doesn’t regulate supplements the way it does conventional medicines, so there are risks to be aware of.

Risks

Talk to your doctor before taking any marine supplement if you have a fish allergy.

Krill oil can cause blood thinning, so it’s important for people who take blood thinners, have a bleeding disorder, or are going to have surgery to consult with their doctor before taking them.

Some doctors might suggest that pregnant women take fish oil, as omega-3s may support fetal development, prevent preterm labor, lower the risk of developing high blood pressure during pregnancy (preeclampsia), and boost mood.

However, you might want to avoid krill 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 not take krill oil,” says Amy Kimberlain, RDN, CDCES, a Miami-based spokesperson for the Academy of Nutrition and Dietetics.

Finally, getting too many omega-3 fatty acids may even weaken your immune system and increase your risk of bleeding problems.

 Be sure to take the dose recommended by your healthcare provider.

Side Effects

The potential side effects of krill oil supplements include, per Kimberlain:

In addition, krill oil supplements have a fishy taste, which may be unappetizing for some.

Forms of Krill Oil

Krill oil supplements are available in the following forms:

  • Capsules
  • Liquid drops
  • Soft gels
  • Gummies
  • Powders

Food Sources of Krill Oil

It is possible to purchase canned or frozen krill meat, but it’s not commonly found in grocery stores.

For alternative food sources of omega-3 fatty acids, add cold-water fatty fish, like salmon, trout, herring, mackerel, and sardines to your weekly menu. Kimberlain suggests that you try to up your seafood game before considering a krill oil supplement. “I always suggest a food-first approach,” she says.

If you don’t eat seafood, you can also obtain omega-3s from flaxseed, chia seeds, and walnuts.

How to Select and Store Krill Oil

Use these tips when shopping for and storing krill oil supplements.

Selection

When choosing a krill supplement, look for brands that have been tested by independent organizations, such as NSF International, ConsumerLab.com, or U.S. Pharmacopeia (USP). This means the product has undergone third-party testing for quality and purity.

In addition, look for where the krill oil supplement has been sourced. “The best krill supplements are thought to be of Antarctic origin, as these carry a lower risk of contaminants,” says Kamely.

She advises choosing a krill oil supplement that is transparent about information on the oil’s origin and harvesting practices. Consider brands that carry the following sustainability certifications:

  • International Krill Oil Standards (IKOS)
  • Marine Stewardship Council (MSC)
  • Friend of the Sea

Storage

Manufacturers frequently recommend storing krill oil in a cool, dry place. However, follow the storage instructions for your specific supplement.

Dosage of Krill Oil

“There isn’t enough research to determine a set amount of krill oil to take daily,” says Kimberlain. However, the FDA recommends that daily intake of EPA and DHA combined does not exceed 3 g per day, with no more than two of those grams coming from supplements.

Talk to your doctor before taking a krill oil supplement, especially if you’re allergic to seafood, take blood thinners, have a bleeding disorder, are preparing for surgery, or are pregnant or breastfeeding.

If your doctor gives you the go-ahead, follow their specific dosage instructions.

The Takeaway

  • Most Americans don’t get the two weekly servings of fish or seafood recommended in the U.S. Dietary Guidelines, which may mean they’re missing out on omega-3 fatty acids. Krill oil supplements may help bridge that gap.
  • Krill oil provides omega-3 fatty acids, which may have benefits for heart health, joint and menstrual pain, and reducing inflammation. Research is ongoing, but we need larger human trials to fully understand the potential benefits of krill oil and who would benefit most.
  • Krill oil supplements may not be recommended for people with allergies to fish and seafood, those taking blood thinners, those with a bleeding disorder, people who are preparing for surgery, or those who are pregnant or breastfeeding.
  • If you’re not a fan of fish or seafood, krill oil supplements may help you get the omega-fatty acids you need. Talk to your doctor about whether krill oil supplements are right for you.

Common Questions & Answers

What does krill oil do for your body?
There’s evidence that the omega-3 fatty acids in krill oil may help your heart by lowering triglycerides and increasing high-density lipoprotein (HDL, or “good”) cholesterol. Also, krill oil contains antioxidants that may battle free radicals, unstable molecules associated with disease and aging.
Research shows that krill oil may help reduce knee joint pain. Study participants with mild knee pain who took 2 g of krill oil per day for six months experienced less knee joint pain and stiffness. Other research shows krill oil may ease knee pain in people with osteoarthritis.
Krill oil may have a blood thinning effect, so people who use blood-thinners or have a bleeding disorder should avoid taking it. People with fish and seafood allergies, and those who are pregnant, breastfeeding, or preparing for surgery should talk to their doctor before taking krill oil.
It’s okay to take a krill oil supplement every day provided you’ve gotten the go-ahead from your doctor. Follow your doctor’s dosage instructions.
There is some evidence showing that omega-3 fatty acid supplementation may help improve hair thickness — and krill oil is a great source of omega-3 fatty acids. However, studies have not looked at the effects of krill oil on hair specifically.
EDITORIAL SOURCES
Everyday Health follows strict sourcing guidelines to ensure the accuracy of its content, outlined in our editorial policy. We use only trustworthy sources, including peer-reviewed studies, board-certified medical experts, patients with lived experience, and information from top institutions.
Resources
  1. Omega-3 Fatty Acids Fact Sheet for Consumers. National Institutes of Health Office of Dietary Supplements. July 18, 2022.
  2. Love DC et al. Affordability influences nutritional quality of seafood consumption among income and race/ethnicity groups in the United States. The American Journal of Clinical Nutrition. June 13, 2022.
  3. A Look at Krill Oil’s Benefits. Cleveland Clinic. November 17, 2021.
  4. Banaszak M et al. Role of Omega-3 fatty Acids Eicosapentaenoic (EPA) and Docosahexaenoic (DHA) as Modulatory and Anti-Inflammatory Agents in Noncommunicable Diet-Related Disease - Reports From the Last 10 Years. Clinical Nutrition ESPEN. October 2024.
  5. Mozaffarian D et al. Effectiveness of a Novel w-3 Krill Oil Agent in Patients With Severe Hypertriglyceridemia. JAMA Network Open. January 2022.
  6. Ursoniu S et al. Lipid-Modifying Effects of Krill Oil in Humans: Systematic Review and Meta-Analysis of Randomized Controlled Trials. Nutrition Reviews. May 1, 2017.
  7. What Are Free Radicals? A Dietitian Explains. MD Anderson Cancer Center. August 6, 2024.
  8. Bjorklund G et al. The Role of Astaxanthin as a Nutraceutical in Health and Age-Related Conditions. Molecules. October 23, 2022.
  9. Costanzo M et al. Krill Oil Reduces Intestinal Inflammation by Improving Epithelial Integrity and Impairing Adherent-Invasive Escherichia coli Pathogenicity. Digestive and Liver Disease. January 2016.
  10. Camba-Gómez M et al. New Perspectives in the Study of Intestinal Inflammation: Focus on the Resolution of Inflammation. International Journal of Molecular Sciences. March 5, 2021.
  11. Liu F et al. Mechanistic Insights Into the Attenuation of Intestinal Inflammation and Modulation of the Gut Microbiome by Krill Oil Using in Vitro and in Vivo Models. Microbiome. June 4, 2020.
  12. Stonehouse W et al. Krill Oil Improved Osteoarthritic Knee Pain in Adults With Mild to Moderate Knee Osteoarthritis: a 6-month Multicenter, Randomized, Double-Blind, Placebo-Controlled Trial. The American Journal of Clinical Nutrition. September 2, 2022.
  13. Sampalis F et al. Evaluation of the Effects of Neptune Krill Oil on the Management of Premenstrual Syndrome and Dysmenorrhea. Alternative Medicine Review. May 2003.
  14. Lobo PCB et al. Krill Oil Supplementation Does Not Change Waist Circumference and Sagittal Abdominal Diameter in Overweight Women: A Pilot Balanced, Double-Blind, and Placebo-Controlled Clinical Trial. International Journal of Environmental Research and Public Health. October 20, 2022.
  15. Fish. American College of Allergy, Asthma, & Immunology. March 21, 2019.
  16. Omega-3 Fish Oil and Pregnancy. American Pregnancy Association.
  17. Krupa KN et al. Omega-3 Fatty Acids. StatPearls. February 28, 2024.
  18. Omega-3 Fatty Acids. National Institutes of Health Office of Dietary Supplements. December 17, 2024.
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