Fish Oil vs Krill Oil: Which is Best for You?
July 8 2019
By Eric Madrid MD
In this article:
There is a lot of confusion out there concerning the health benefits of fish oil and krill oil. Many wonder if the difference between the two is significant and whether one is more beneficial than the other.
Both fish oil and krill oil contain omega-3 fatty acids, specifically docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). These essential fatty acids can help lower triglycerides and reduce pain and inflammation in those with arthritis.
- Docosahexaenoic acid (DHA) is an omega-3 fatty acid that’s a big component of the human brain, skin, and eye. Although important, it is not considered “essential” since it can be manufactured in the body if acid (ALA) is consumed in the diet.
- Eicosapentaenoic acid (EPA; or icosapentaenoic acid) is commonly found in fish oil, krill oil, and eggs (assuming the chickens were fed EPA).
A 2016 study showed a similar elevation in blood levels of DHA/EPA when equivalent doses of fish oil and krill oil were given to test subjects over a 4-week period.
Sources of DHA and EPA
Fish oil obviously comes from fish. Commonly, commercial fish oil comes from tuna, herring, and sardines. When extracted, fish oil generally has a white or yellow color. Overall, it has low antioxidant properties, meaning it does not work well as an anti-oxidant. When consumed, it is delivered to the body as a triacylglyceride (TAG). Commercial-quality fish oil needs to go through additional purification processes to eliminate heavy metals that may be present.
Likewise, krill oil comes from krill, crustaceans harvested from the Antarctic area. Krill feed on phytoplankton and marine algae and are at the bottom of the food chain. As a result, in their natural habitat krill have little to no heavy metal exposure, so extra purification is not required.
A krill is a small, red, lobster-like creature found in the southern Atlantic Ocean. Krill oil is an essential fatty acid with a distinctive red color. It tends to be more expensive than fish oil. When consumed, it is delivered to the body in phospholipids.
Worldwide, krill tend to be more plentiful than fish, so in total, extracting adequate DHA/EPA from krill has more long-term sustainability potential than extracting these oils from fish.
Is eating seafood a good alternative?
Ideally, one should get all their vitamins, minerals, and essential fatty acids from foods. This is what I advise my patients, but I know it’s not always possible. The American Heart Association recommends regular consumption of fish, at least twice per week, for heart health. For those who prefer vegetarian alternatives, consumption of certain foods can be a good source of alpha-linolenic acid (ALA), which can be converted into DHA. ALA can be found in foods such as flaxseed, walnuts, soy, chia seeds, and hemp seeds.
If relying solely on food, consumption of adequate DHA and EPA from animal sources can be a challenge due to the pollution of our oceans. For example, fish such as mackerel, swordfish, bass, shark, and tuna tend to have higher-than-average levels of mercury and should be eaten sparingly. Fish such as salmon, catfish, anchovies, sardine, herring, trout, and tilapia have lower levels of mercury, but the levels can add up if consumed more than two or three times per week.
Fish oil and krill oil can have an effect on the following common health conditions.
Osteoarthritis usually results from general wear and tear of the joints. It results from the destruction of cartilage, which acts as a cushion that covers the bone. Early signs of osteoarthritis may begin when an individual is around 40 years old and can progress as one ages. Symptoms include joint pain, swelling stiffens, and loss of joint function. Natural alternatives are sought by many to help with symptoms. Generally, doctors prescribe non-steroidal anti-inflammatory drugs (NSAIDS), such as ibuprofen, naproxen, and indomethacin.
Studies show essential fatty acids help improve joint pain and reduce the use of NSAIDs. Studies also show a reduction of joint stiffness when fish oil is taken daily at a minimum of 500 mg per day up to 2,000 mg per day.
A 2007 study in the American Journal of Clinical Nutrition showed that 300 mg of krill oil “significantly inhibits inflammation and reduces arthritic symptoms within a short treatment period of 7 and 14 days”. A 2016 double-blind, placebo-controlled study of patients with mild knee pain demonstrated that krill oil could reduce pain at daily doses of 2,000 mg per day.
Cardiovascular disease is a major killer of people all over the world. There are various risk factors which contribute to one’s increased risk of heart and vascular disease. Omega-3 fatty acids may be beneficial.
Regular consumption of omega-3 fatty acids is important for heart and vascular health. A 2017 study showed it can help prevent atherosclerosis, or hardening of the arteries, while a 2013 study in the Journal of the American Heart Association showed that higher levels of DHA/EPA in the blood were associated with a lower risk of cardiovascular disease.
A 2015 study in the British Medical Journal concluded: “Krill oil may lead to moderate improvement of cardiovascular risks, specifically endothelial dysfunction and HDL in patients with type 2 diabetes.” However, the benefits also apply to those who do not have diabetes. A 2017 study in Nutrition Reviews also showed that krill oil could benefit the heart by reducing bad (LDL) cholesterol and triglycerides, both risk factors for heart disease when levels are elevated in the blood.
Inflammation results when there is an imbalance in the body—in a sense, the body is internally “on fire”. During times of stress, the body produces a steroid hormone called cortisol in excess. When cortisol is elevated, the body makes inflammatory chemicals called prostaglandins. Inflammation can also be evaluated by measuring C-reactive protein (CRP) levels in the blood.
Elevated levels of CRP increase the risk of cancer and heart disease, according to a 2017 study in the Journal of the American College of Nutrition. In 2008, the Jupiter study showed cholesterol-lowering statin drugs could reduce inflammation. Krill oil and fish oil may also play a role.
Fish oil is well known to help lower CRP levels. A 2016 study showed this to be the case but also showed that krill oil was more efficient than 2,000 mg of fish oil. However, another 2016 study in the Journal of Internal Medicine showed that when 1,400 mg of fish oil was consumed, CRP level was not lowered. Based on this, I would recommend a dose of at least 2,000 mg twice per day of omega 3 fish oil to lower CRP levels.
A 2016 study showed that krill oil at a dose of 500 mg twice per day could help reduce CRP levels more than fish oil at a dose of 2,000 mg twice per day. A 2007 study in the Journal of the American College of Nutrition demonstrated that krill oil at a dose of 300 mg per day could lower CRP levels by almost 20 percent.
As populations age, memory concerns become more common. Alzheimer’s disease, the most common form of dementia, has no specific cure and can cause enormous frustration and challenges to both patient and caretakers alike. Symptoms include forgetting names and confusion in the early stages, while late stage Alzheimer’s can give way to more severe issues, like paranoia and abusive behavior. Fewer thalate-stagen one percent of the Alzheimer’s disease cases occur prior to the age of 65, but scientists predict that after 65, one in nine people are at risk. Natural treatments, such as turmeric and Boswellia, appear to be helpful along with DHA and EPA.
A 2016 study of 44 patients with memory issues was conducted in which 22 were given fish oil, while 22 were given a placebo. Researchers noted that the memory was better in those given fish oil. Other studies have shown similar findings.
A 2017 study in the International Journal of Molecular Sciences showed that krill oil could help reduce oxidative stress in the brain and reduce beta-amyloid deposits, which is believed to be the cause of Alzheimer’s disease. More research is currently underway.
Triglycerides are a type of fat that circulates in the blood. Ideal levels should measure less than 150 mg/dl (or less than 1.7 mmol/L). Elevated levels are a risk factor for a heart attack and stroke. Lowering them by consuming a low-sugar, low-simple-carbohydrate diet can also be beneficial, but sometimes that is not enough. An EPA/DHA supplement can be considered.
Pharmaceutical drug companies have allegedly realized the benefit of lowering triglycerides and have, therefore, developed a pharmaceutical-grade fish oil. However, due to its high cost, many are unable to afford it.
A 2016 study in Lipids in Health and Disease concluded that omega-3 fatty acids are helpful in lowering triglycerides. Likewise, a 2017 meta-analysis study in Atherosclerosis, which studied 1,378 people, showed, that consuming oily fish helped lower triglycerides while increasing HDL (good cholesterol) levels, two important biomarkers for cardiovascular disease.
A 2014 study showed a 10-percent reduction in triglycerides in response to krill oil. A 2017 study in Nutrition Reviews of 662 patients showed similar results in those who consumed krill oil. Other studies have supported these findings.
Those with allergies to fish or shellfish should be cautious as they may have an allergic reaction. Consult with your physician prior if you have any questions.
- Yurko-Mauro et al. Lipids in Health and Disease (2015) 14:99 DOI 10.1186/s12944-015-0109-z
- Arch Med Res. 2012 Jul;43(5):356-62. doi: 10.1016/j.arcmed.2012.06.011. Epub 2012 Jul 24.
- Journal of the American College of Nutrition. 2007 Feb;26(1):39-48.
- Suzuki Y, Fukushima M, Sakuraba K, Sawaki K, Sekigawa K. Krill oil Improves Mild Knee Joint Pain: A Randomized Control Trial. Gagnier JJ, ed. PLoS ONE. 2016;11(10):e0162769. doi:10.1371/journal.pone.0162769.
- Yagi S, Fukuda D, Aihara KI, Akaike M, Shimabukuro M, Sata M. n-3 Polyunsaturated Fatty Acids: Promising Nutrients for Preventing Cardiovascular Disease. J Atheroscler Thromb. 2017;24(10):999–1010. doi:10.5551/jat.RV17013
- J Am Heart Assoc. 2013 Dec 18;2(6):e000506. doi: 10.1161/JAHA.113.000506.
- Lobraico JM, DiLello LC, Butler AD, Cordisco ME, Petrini JR, Ahmadi R. Effects of krill oil on endothelial function and other cardiovascular risk factors in participants with type 2 diabetes, a randomized controlled trial. BMJ Open Diabetes Res-Care. 2015;3(1):e000107. Published 2015 Oct 14. doi:10.1136/bmjdrc-2015-000107
- Nutr Rev. 2017 May 1;75(5):361-373. doi: 10.1093/nutrit/nuw063.
- Paul M Ridker, M.D., Eleanor Danielson, M.I.A., Francisco A.H. Fonseca, M.D.,et. Al * Rosuvastatin to Prevent Vascular Events in Men and Women with Elevated C-Reactive Protein N Engl J Med 2008; 359:2195-2207 November 20, 2008
- Journal of Internal Medicine. 2016 Jan;279(1):98-109. doi: 10.1111/joim.12442. Epub 2015 Oct 26.
- Arch Med Sci. 2016 Jun 1;12(3):507-12. doi: 10.5114/aoms.2016.59923. Epub 2016 May 18.
- J American College of Nutrition. 2007 Feb;26(1):39-48.
- Int J Mol Sci. 2017 Nov 28;18(12). pii: E2554. doi: 10.3390/ijms18122554.
- Lipids Health Dis. 2016 Jul 22;15(1):118. doi: 10.1186/s12944-016-0286-4.
- Atherosclerosis. 2017 Nov;266:87-94. doi: 10.1016/j.atherosclerosis.2017.09.028. Epub 2017 Sep 28.
- Nutrition Research. 2014 Feb;34(2):126-33. doi: 10.1016/j.nutres.2013.12.003. Epub 2013 Dec 18.
- Sorin Ursoniu, Amirhossein Sahebkar, Maria-Corina Serban, et. al. for the Lipid and Blood Pressure Meta-analysis Collaboration Group; Lipid-modifying effects of krill oil in humans: systematic review and meta-analysis of randomized controlled trials, Nutrition Reviews, Volume 75, Issue 5, 1 May 2017, Pages 361–373