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Published on April 26, 2021

Krill Oil vs Fish Oil: Which Should You Take?

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Krill Oil vs Fish Oil: Which Should You Take?

Omega 3 fats are essential in our diet, and there are lots of different sources, such as oily fish, nuts, seeds, and also supplements. There are pros and cons of both food sources and also supplements. So, in this article, I will guide you through the advantages and disadvantages of Krill oil vs fish oil supplements. I’ll also cover who needs to take these supplements, and if krill oil is better than fish oil, and cod liver oil.

What Are Omega Fatty Acids?

There are two types of fats or fatty acids that are essential and can’t be produced in our bodies. These are omega 3 and omega 6. Omega 3 can be broken down into three main forms: alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA).

Where Are Omega Fatty Acids Found?

ALA is found in plant oils, such as flaxseed, soybean, and canola oils. DHA and EPA are found in oily fish, fish oils, and krill oils. DHA and EPA are actually synthesized by microalgae—not by the fish—but accumulate in the tissue when they are eaten by fish and shellfish further up the food chain.

Why Are Omega Fatty Acids So Important?

Omega-3 and -6 fatty acids have an important structural role needed for cell membranes. They are also energy sources and are used to form signaling molecules called eicosanoids, comprised of prostaglandins, thromboxanes, and leukotrienes.

There are many different prostaglandins with wide-ranging roles, such as the sensation of pain, inflammation, regulation of pregnancy and birth, control of blood pressure, secretion of stomach acid, contraction, and relaxation of smooth muscle.

Thromboxanes regulate blood clotting by causing constriction of blood vessels and the aggregation of platelets (so they stick together), which are early steps in blood clotting.

Leukotrienes are involved in immune function by attracting immune cells such as neutrophils to sites of inflammation. They also constrict bronchioles in the lungs and make capillary walls permeable.

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This is thought to be because the metabolic products of omega-3 fatty acids are less inflammatory than those produced from omega 6 fatty acids. Western diets are associated with an imbalance of omega-3, -6 such that instead of levels of omega 3 being higher than 6, the reverse is more commonly seen. This is associated with an increased risk of chronic inflammation.[1]

A large systemic review that combined 86 trials involving over 162,000 people looked at the effect of higher omega-3 intake versus lower omega-3 intake for at least a year. This was provided mostly by omega-3 supplements while a few trials gave oily fish. Omega-3 fatty acids have been shown to reduce blood pressure and can be incorporated into your diet by eating oily fish or seeds, such as chia seeds, flax seeds, and nuts.[2]

There are three types of omega-3: those found in oily fish called EPA and DHA and the plant-based ALA.

What Is Krill Oil?

Krill oil is extracted from the bodies of Antarctic krill, a tiny shrimp-like shellfish. Krill oil, fish oil, and cod liver oil are similar in that they all contain DHA and EPA.

Fish oil is extracted from the body of the fish and contains some vitamin A and vitamin D as well. Cod liver oil is extracted from the liver of the fish and contains higher levels of vitamin A and D.

High doses of vitamin A can be toxic as it is a fat-soluble vitamin that is stored by your body. This is why omega 3 supplements that contain vitamin A are to be avoided in pregnancy because high levels of this vitamin may damage the fetus.

Krill Oil Vs Fish Oil

Evidence surrounding krill oil is limited compared with fish oils and cod liver oils. A large portion of the EPA and DHA in krill comes in phospholipid form (whereas fish oil fatty acids are contained in triacylglycerols), which some claim has a higher rate of absorption in the body than fish oil.

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Previously, it was thought that Krill oil was more bioavailable than fish oil, but there were problems with this research with regards to dosing.[3] More recently, a randomized controlled trial in 66 people was performed to answer this question and compared the bioavailability of krill oil compared with fish oil. It found that there was no difference between blood measurements of DHA and EPA. Therefore, the evidence does not support krill oil being “better” or needing lower doses than fish oil.[4]

Krill Oil Vs Fish Oil in Terms of Cholesterol

A study in animals looked at gene expression after supplementation with either krill oil or fish oil. They found that fish oil upregulated (increased gene expression) the cholesterol synthesis pathway more than krill oil. Krill oil was found to upregulate (increase gene expression) more metabolic pathways than fish oil. This suggests that there might be different biological effects between krill and fish oil but more research is needed.[5]

In group (meta) analysis of seven trials totaling 662 participants, Krill oil supplementation was found to reduce low-density lipoprotein cholesterol and triglycerides but not total cholesterol.[6] Whether this translates to decreased risk of cardiovascular disease needs further research.

However, when directly compared, krill oil was not superior to fish oil supplementation and had very similar effects on cholesterol.[7]

Krill Oil Vs Cod Liver Oil

Cod liver oil contains higher levels of vitamin D and vitamin A, which may be toxic in excess. If you want to take a high dose of omega-3, this means you will also end up having higher doses of vitamin A and D. Both of these are fat-soluble vitamins that are stored by the body and can become toxic. Vitamin A supplementation should be avoided during pregnancy due to risks for the baby.

There is a risk that since the liver is used to filter out toxins, there is the possibility that cod liver oil contains more environmental contaminants than fish oil or krill oil.

Are There Risks With Krill Oil?

Less research has been performed on krill oil and although no side effects have been reported, the safe maximum dose of natural astaxanthin has not been determined.

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Krill make up a vital part of the Antarctic food chain and a huge number of species higher up the food chain depend on them. Fishing krill has the potential to catastrophically destabilize this important food chain. Therefore, fish oils are more sustainable than krill oil.

Why Is Krill Oil Red?

The deep red color of krill oil is due to a compound called astaxanthin found in krill. Astaxanthin is also found in other more sustainable sources such as red trout, crab, lobster, and wild salmon. Astaxanthin is a carotenoid antioxidant compound that mops up harmful free radicals.

When to Take Omega-3 Supplement

A large review of 86 trials combined—totaling over 162,000 people—looked to see what the effect of increased omega-3 had on cardiovascular risk. Increasing ALA made no significant difference to blood clots of the coronary arteries supplying the heart (coronary events) but slightly reduced cardiovascular events (diseases related to blood vessels such as clots and rhythm problems) while EPA and DHA reduced serum triglycerides and also reduced the risk of coronary heart disease, such as heart attacks.[8]

They found that EPA and DHA decreased triglycerides (a type of fat) by about 15% and reduced the risk of coronary artery death and coronary events, which are illnesses of arteries supplying the heart. However, they did not affect cardiovascular events (e.g., strokes, heart irregularities).[9]

While increasing ALA made no significant difference to coronary events, it slightly reduced cardiovascular events. This means that the three combined (ALA, EPA, and DHA combined) may reduce the risk of coronary, cardiovascular disease, and lower triglyceride levels, but the effects are small.

One of the ways of decreasing your risk of cardiovascular disease is by lowering your cholesterol—reducing saturated fats in your diet and eating ALA omega-3 (e.g., from walnuts). A grouped meta-analysis has not found any link between omega-3 and dementia, but more information is needed to see if omega-3 can prevent cognitive decline.[10]

Overall, if you aren’t pregnant or intending to get pregnant, then omega 3 supplements are probably unlikely to do you harm and might benefit your long-term cardiovascular risk. It isn’t possible to tell the difference in general between eating enough omega-3 in your diet versus supplementing, but whole foods have other benefits as well.

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Omega-3 supplements often have high levels of vitamin A, which can be harmful in pregnancy. Therefore, you should avoid supplementing or choose a pregnancy-safe version.

If you are vegan, you may consider taking an omega-3 supplement made from algae or seaweed, but these are unregulated and can contain significant quantities of iodine, which can be harmful. Therefore, it is better, where possible, to optimize your diet. There are concerns that part of the benefit of omega-3 is from a whole food effect that isn’t seen with taking a supplement instead.

Tips on How to Get Enough Omega-3 in Your Diet

  • Aim to have oily fish twice a week if you aren’t pregnant or once a week if you are, as the benefit of omega-3 has to be offset by the risk of contamination with heavy metals.
  • Algae and seaweed are the only plant-based sources of EPA and DHA, but ALA can be converted in your body into EPA and DHA.
  • Vegan sources of omega-3 are chia seeds, linseed, hemp seeds, walnuts, and vegetable oils, such as rapeseed. To meet the current guidance for omega-3, you would need to eat about a tablespoon of chia or ground linseeds, or two tablespoons of hemp seeds, or six walnut halves a day.
  • Algae oil is an alternative to fish oil, which makes it an attractive option for vegetarians. But while algae oils do contain large amounts of DHA, most don’t contain any EPA fatty acids at all.

In Summary

Krill oil supplements appear to be safe and as effective as fish oil. They also have the bonus of containing the antioxidant astaxanthin.

However, harvesting krill is not sustainable, and there are risks regarding destabilizing the Antarctic food chain. Instead, aim to include foods rich in omega-3 in your diet to benefit from the “whole food effect,” and eat foods that are naturally rich in carotenoids, such as vegetables, crab, and lobster. Avoid taking high doses of cod liver oil, and avoid it completely during pregnancy due to the risk of vitamin A.

Featured photo credit: Anshu A via unsplash.com

Reference

More by this author

Dr. Harriet Holme

Registered Nutritionist, and doctor

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Published on August 27, 2021

Should Men Take Fish Oil? 4 Fish Oil Benefits for Men

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Should Men Take Fish Oil? 4 Fish Oil Benefits for Men

Fish oil is a well-known healthy food that fits in almost any diet. Most people who want to improve their diet usually try to include fish oil in their daily consumption. But some people may ask: what are the fish oil benefits for men? Is it really good for men’s health? Or is there something fishy about fish oil?

In this article, I will take a comprehensive look at why fish oil is recommended for everyone, especially men. Let’s start with the sources of fish oil and how it could be good for your health.

Fish Oil Sources and Why It Could Be a Good Catch

Fish oil is primarily found and extracted from oily fish varieties, such as salmon, tuna, mackerel, sardine, herring, and trout.[1] It contains two highly beneficial types of omega-3 fatty acids for many health conditions:[2]

  • Docosahexaenoic acid (DHA)
  • Eicosapentaenoic acid (EPA)

But here’s the catch: your human body cannot make omega-3 polyunsaturated fatty acids. You are dependent on food sources to supplement these vital nutrients.[3] But this is not a big deal since you could consume foods that are rich in omega-3 fatty acids, such as oily fish, or consume fish oil in the form of supplements.

As a side note, you can also find another type of omega-3 fatty acid called alpha-linolenic acid (ALA) in some plant sources, such as walnuts, flax seeds, pumpkin seeds, and chia seeds. You cannot find alpha-linolenic acid in fish oil, and interestingly, your body converts ALA into DHA and EPA, but in very small amounts.[4] So, if you want your Omega-3 in balance, you will have to consume DHA, EPA, and ALA via food sources or supplements or a combination of both.

Can Fish Oil Improve Your Health?

The American Heart Association (AHA) recommends consuming oily or fatty cold-water fish twice a week.[5] Fish is one of the best ways to get your omega-3 fatty acids intake and reap its numerous health benefits. It is an excellent source of protein and, in comparison to other fatty meat products, it has low saturated fat.

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However, if you’re a vegetarian or do not consume fish, you can consult your doctor for dietary alternatives to fish and fish oil.

Let’s look at some of the fish oil benefits for men, though some of these benefits also apply to everyone.[6]

1. Fish Oil Can Boost Male Fertility

Various research studies have suggested that Omega-3 improves semen quality, volume, erectile function and even prevents prostate cancer.[7]

Recently, the first observational study on the association between fish oil supplementation intake and improved testicular function conducted also showed these supplements to be beneficial to men’s health.[8] The study was conducted on 1,700 young, healthy Danish men who averaged around nineteen years of age. Those who took fish oil supplements reported higher semen volume and improved sperm quality. Those who took other supplements, such as multivitamins did not show the same effects, pointing to possible links between fish oil supplements and better sperm counts.

The study’s lead researcher Tina Kold Jensen, a professor of environmental medicine at the University of Southern Denmark who has been active in this research field for over 25 years, said that these male reproductive factors should lead to improved male fertility in men taking fish oil. Jansen was also optimistic that her research findings would have the same effect on older men who take fish oil supplements.

She concluded that she recommends fish oil supplements for those who want to improve their male fertility. However, she adds that your best options are to increase your fish intake like codfish and follow your doctor’s dietary advice.

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Other studies have also found positive associations between fish oil supplements and sperm quality.[9]

While these results have certainly been encouraging, the findings from these observational studies need to be corroborated by more rigorous randomized clinical experiments. Therefore, I encourage patients to discuss their individual cases with their doctors to ensure safety and maximize benefits from fish oil supplements.

2. Fish Oil Helps Maintain a Healthy Heart

Heart disease is the leading cause of death among men, according to the Centers for Disease Control and Prevention (CDC).[10] Overall, it accounts for one in four deaths in America every year.

Fish oil is a heart-friendly nutrient as it is a good source of omega-3 fatty acids. It protects your heart by reducing many of the risk factors for heart disease. Some benefits of fish oil include:[11][12][13]

  • Reduction of triglyceride levels
  • Lowering your blood pressure
  • Reducing your bad cholesterol
  • Preventing blood from clotting
  • Slowing or hindering plaque formation in your arteries
  • Reducing the risk of an abnormal heart rhythm
  • Decreasing your risk of a heart attack and stroke

There is also research that suggests that fish oil supplements reduce adverse situations, such as hospital admissions and death in people with heart failure.[14]

The American Heart Association (AHA) recommends that people without heart disease have at least two servings of fish every week to reduce cardiovascular events. It suggests eating a variety of cold-water, wild fish like tuna, mackerel, salmon, and sardines for their high levels of omega-3 fatty acids. The AHA does not recommend omega-3 supplements for people who don’t have a high risk for cardiovascular disease.[15]

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However, if you have heart disease, it’s best to consult your doctor before you decide to take fish oil supplements. Depending on your condition, they might recommend eating more foods rich in omega-3 fatty acids and/or taking an FDA-approved fish oil supplement.

Sometimes, higher doses of omega-3 are given to lower triglycerides. But it should be strictly under the care of a doctor because it can cause complications such as bleeding and affect the immune system.

3. Fish Oil Gives You Clear and Focused Vision

The American Academy of Ophthalmology (AAO) recommends fish oil to optimize your eye health. While there are some conflicting reports, some findings show how fish oil helps treat eye diseases like dry eye and age-related macular degeneration (AMD).[16]

A recent 2019 study supported findings that people who consumed fresh fruits, vegetables, and fish were less likely to develop eye diseases than those who did not.[17] Another study published in Investigative Ophthalmology & Visual Science suggests omega-3 fatty acid DHA for vision protection.[18]

Various studies have found similar findings of fewer dry eye symptoms in those who consumed fish oil. The omega-3 fatty acids in fish oil improved the eye’s oil film produced by meibomian glands situated on the edge of the eyelid.[19] Other studies also found that fish oil reduces pain and swelling, making it an effective treatment for dry eyes.[20]

4. Fish Oil Helps You Become Healthy From the Inside-Out

Fish oil is a versatile nutrient that seems to contribute to several other health benefits. These include:

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  • Lowering your depression[21]
  • Boosting your memory[22]
  • Preventing disease-causing inflammation with enhanced B cell activity or white blood cells[23]
  • Aiding in weight loss
  • Giving you healthier skin by clearing your acne and psoriasis[24][25][26]

Why You Need to Stay Cautious About Fish Oil

Fish oil has some possible risks associated with its consumption. Fish oil supplements have common temporary side effects, such as foul taste, smell, belching, heartburn, nosebleeds, rash, nausea, flatulence, and diarrhea.

While fish oil can prevent prostate cancer, excess consumption can increase your risk for high-grade prostate cancer.[27] Fish oil in high doses can cause bleeding, affect your immune system, and reduce your body’s ability to fight off infection.[28]

Certain combinations of medications can cause serious health risks when you take them regularly alongside fish oil. Hence, it would be best if you first discussed with your doctor about taking fish oil along with your prescribed medications.

While fish oil from the source is preferable, some fish meats are prone to mercury contamination and other toxic industrial and environmental chemicals.[29] Mercury contaminated fish meats can cause blindness, brain damage, and mental retardation in children.[30]

What’s the Verdict on Fish Oil?

The fish oil benefits for men and women far outweigh the risks, especially for middle-aged and older people who follow the recommendations by the FDA, AHA, and EPA.

Make fish oil your friend by:

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  • Choosing more from food sources than supplements.
  • Following AHA’s recommendation of eating one to two servings of non-fried fish every week.
  • Eating a variety of fish higher in EPA and DHA and lower in methylmercury to minimize potentially adverse effects due to environmental pollutants.
  • Consuming fish along with other vital aspects of a healthy diet, such as fruits, vegetables, dairy products, and whole grains that ensure balanced omega.
  • Getting your doctor’s approval and prescribed fish oil supplement and following their instructions.
  • Following the AHA’s recommendations of consuming no more than 3 grams of fish oil supplement daily, as taking more can cause bleeding.
  • Taking your fish oil supplements into two doses in the morning and night to decrease side effects.
  • Taking fish oil supplements with food to increase absorption and decrease side effects.
  • Freezing and consuming them to decrease side effects.
  • Following the US federal government’s 2020–2025 Dietary Guidelines for Americans recommendations of seafood for pregnant and nursing women. Safe fish options for pregnant and nursing women include sardines, trout, salmon, herring, and anchovies because of higher EPA and DHA and lower mercury.

On a final note, your health is in your hands. Choose wisely, and use fish oil for your health benefit today. But first, consult your doctor for medical advice before making an informed decision on fish oil and taking action.

More About the Benefits of Fish Oil

Featured photo credit: Sam Moqadam via unsplash.com

Reference

[1] National Institutes of Health: Omega-3 Fatty Acids
[2] WebMD: The Facts on Omega-3 Fatty Acids
[3] Harvard School of Public Health: Omega-3 Fatty Acids: An Essential Contribution
[4] National Institutes of Health: Omega-3 Fatty Acids
[5] American Heart Association: Fish and Omega-3 Fatty Acids
[6] WebMD: What to Know About Omega-3s and Fish
[7] NCBI: Prostate Cancer Risk And Omega-3 Fatty Acid Intake From Fish Oil
[8] JAMA Network: Associations of Fish Oil Supplement Use With Testicular Function in Young Men
[9] PubMed.gov: Dietary supplementation with docosahexaenoic acid (DHA) improves seminal antioxidant status and decreases sperm DNA fragmentation
[10] Centers for Disease Control and Prevention: Men and Heart Disease
[11] MayoClinic: Omega-3 in fish: How eating fish helps your heart
[12] Cleveland Clinic: Omega-3 Fatty Acids
[13] Harvard Health Medical School: The complicated relationship between fish oil and heart health
[14] WebMD: Fish Oil
[15] National Institutes of Health: Omega-3 Fatty Acids
[16] American Academy of Ophthalmology: The Benefits of Fish Oil for Dry Eye
[17] NCBI: Nutrients for Prevention of Macular Degeneration and Eye-Related Diseases
[18] Harvard Health Publishing: Omega-3 for your eyes
[19] Mayo Clinic: Mayo Clinic Q and A: Fish oil supplements and dry eyes
[20] WebMD: Fish Oil
[21] Translational Psychiatry: Efficacy of omega-3 PUFAs in depression: A meta-analysis
[22] WebMD: Fish Oil Supplements Boost Memory
[23] Science Daily: Nothing fishy about it: Fish oil can boost the immune system
[24] NCBI: Cosmetic and Therapeutic Applications of Fish Oil’s Fatty Acids on the Skin
[25] PubMed.gov: Effect of dietary supplementation with omega-3 fatty acid and gamma-linolenic acid on acne vulgaris: a randomized, double-blind, controlled trial
[26] Oxford Academic: Efficacy of fish oil and its components in the management of psoriasis: a systematic review of 18 randomized controlled trials
[27] NCBI: Prostate Cancer Risk And Omega-3 Fatty Acid Intake From Fish Oil
[28] Mayo Clinic: Fish Oil
[29] American Heart Association: Fish and Omega-3 Fatty Acids
[30] World Health Organization: Mercury and health

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