Fish Oil Benefits, Omega 3 and 6 EFAs, Doses and Tests

Content of this web page - manual

Salmon male and female fish Introduction
4.1 Omega 3 benefits
4.2 Side effects, risks and dangers of fish oil and other EFAs
4.3 Fish oil vs. flaxseed oil and other vegetable oils
4.4 What is the difference between DHA and EPA?
4.5 How much fish oil is recommended?
4.6 "3 day test"
4.7 What is the difference between fish oil and cod liver oil?
4.8 What is krill oil for (krill oil vs. fish oil)?
4.9 Salmon oil vs. fish oil
4.10. Sources of Fish oil, cod liver oil, salmon oil and krill oil: their EPA and DHA
4.11 Criteria and summary for choosing EFAs or omega 3 supplements


Quotes and references (dangers in fish oil and fish due to pollution)
Quotes and references about conversion rates of ALA (alpha-linolenic acid) to EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid)
Quotes and references (fish oil versus flaxseed oil)
Quotes and references (krill oil medical research)
Quotes and references (long-term use causes negative effects)


Woman meditating(This is Part 2 of the Major Nutrients Guide for Better Breathing and Body-Oxygen Level. Part 1 has a title Macrominerals (Ca, Mg, Zn) and Fish Oil. Note that it would be difficult to understand the ideas of this Guide (3 day test or how to practically check nutritional deficiencies) without knowledge of the following topics: how to measure body oxygenation; effects of breathing patterns and body oxygenation; CO2 uses in the human body; and web pages related to the Homepage of this website.)

Modern people, as it is proven by numerous studies, consume too much omega 6 EFAs (essential fatty acids), with too little omega 3 fats. This review focuses on omega 3 EFAs supplements, including fish oil, cod liver oil, salmon oil, krill oil, algae oil, and many other sources of these supplements. Note that the main signs of EFAs deficiency are considered in Part 1. Here we are going to consider more fine details of EFAs supplementation and related challenges.

4.1 Omega 3 benefits

While medical research continues to discover new health benefits of fish oil, cod liver oil, and other sources of EFAs, it is clear that replenishing any missing nutrient is ultimately useful against any chronic disease since all chronic diseases have one common cause: alveolar hyperventilation, which results in cellular hypoxia. Therefore, the previous list of related health problems (Coronary heart disease, High blood pressure, Angina pectoris, Epilepsy, Cancer, Crohn's disease, Diabetes, Rheumatoid arthritis,  Depression, Sinusitis, Acne, Asthma, Bronchitis, Cystic fibrosis, and Other inflammatory disorders) from Part 1 of this Guide can be extended to include 150-200 common or chronic health disorders. In short, when someone asks, “What is fish oil for?”, “What does fish oil do for the body?”, “What are fish oil health benefits?”, “Why take fish oil?”, “Why is fish oil good for you?”, the answer is simple: to improve breathing and body oxygenation, thus curing chronic diseases. Physiologically, fish oil reduces inflammation and, hence, is useful for so many seemingly unrelated health problems.

Therefore, when one is sick and starts breathing retraining, regardless of the chosen source of EFAs, when conditions are right (the process of breathing retraining is active and the CP or body oxygen level is steadily growing) and no damage is done to the body (e.g., due to allergic reaction or toxicity of the dietary supplement), then the deficient student will benefit from having this missing nutrient in the diet. Hence, for example, fish oil will help with weight loss, cholesterol, prostate cancer, depression, arteries, inflammation, and many other problems, provided that you improve your body oxygen level. Therefore, it is not a particular supplement, but one’s health state and the corresponding health zone in the Buteyko Table of Health Zones that matters most.

4.2 Side effects, risks and dangers of fish oil and other EFAs

Dangers and side effects of fish oil and other sources of EFAs relate to various mechanisms and interactions of numerous factors. They also depend on the health state of the person.


Pollution with fumes Contamination of the environment with mercury (mostly from burning coal), lead, nickel, arsenic, cadmium, dioxins and PBCs (polychlorinated biphenyls), and other toxins is present in oceans due to activities of humans. To avoid these poisons, use purified dietary supplements (e.g., molecular distillation) or pharmaceutical grade supplements.

Using fish oil, for example, is generally much safer than eating whole fish (see abstracts below). Children, pregnant and nursing women are more sensitive to mercury toxicity; avoiding contaminated fish and supplements is an especially high priority for these groups of people.

Concerns about safety and contamination of animal and fish products are legitimate. However, there is no indication in toxicological, nutritional, and environmental studies that there are dangers associated with purified fish oil or cod liver oil products. However, some studies warn of pollutants in whole fish.

Quotes and references (dangers in fish oil and fish due to pollution)

Allergic reactions

Many people are sensitive to fish (because of seafood allergy) and/or related products. It is crucial to avoid allergic reactions and to change the supplement source or brand or route of administration so as not to trigger any adverse side effects, including skin rashes. Algae oils may be a suitable alternative as they provide the most important essential fatty acid, DHA. If someone has adverse effects to all forms of EFAs when taken orally, omega fats can be successfully administered rectally or cutaneously (by rubbing small amounts of fish oil into arms and taking a shower afterwards).

Irritation of the stomach and other GI symptoms

GI system Since gastritis (inflammation of the stomach lining) is almost the norm for modern people, many omega fat supplements often produce incessant burping, upset stomach, aftertaste, or even nausea, especially when taken on an empty stomach. Fish oil, cod liver oil and other EFAs can also cause abdominal discomfort, diarrhea, heartburn and indigestion. The suggested solution is to start with a small dose, avoid taking supplements on an empty stomach, and chew your omegas mixed with food and do it very well (more will be absorbed in the mouth too). If the problem persists, try freezing the capsules and taking them on an empty stomach (so that they melt in your small intestine), consider changing the brand or buy enteric coated fish oil tablets (if your duodenum is in a normal state), or apply fish oil, cod liver oil, and other EFAs rectally or cutaneously. Rancid sources of omegas are more likely to cause these negative effects.


Polyunsaturated oils, including EFAs, are extremely susceptible to damage from oxygen, heat, and light. The unstable double bond between carbon atoms can easily attract oxygen atoms from air, forming free radicals, which can trigger chain reactions destroying many hundreds substances and/or structures of the human body. Rancidity changes the flavor and smell of the fish oil and other EFAs. Such supplements may still produce some positive effects on health, but excessive rancidity will increase one’s breathing and decrease the CP. Hence, all oils that are high in polyunsaturated fatty acids (including fish oil, krill oil, flaxseed oil, etc.) should be stored in dark tightly closed, glass containers in the refrigerator or freezer. Obviously, EFAs, as well as other unsaturated fats, should never be used for frying or in hot dishes. To avoid rancidity, it is wise to choose those EFAs supplements that are certified and organic, and have been refrigerated in a dark glass jar. Note that the same relates to capsules of fish oil and other supplements. Gelatin capsules do not protect unsaturated oils from oxidation since over periods of weeks or months, oxygen can easily penetrate through various plastic materials, while glass provides much better protection from oxygen damage. Presence of combinations of natural tocopherols (vitamin E) significantly reduces rancidity of these unstable oils.


Man sleeping with mouth openWhen the person has been practicing breathing technique exercises and has significantly improved his own CP, the temporary need for EFAs to reduce inflammation and do other useful jobs in the body can be much greater. In such conditions of deficiency, taking cod liver oil, fish oil, or krill oil supplements can produce a lasting invigorating effect (similar to barefoot walking) so that one can experience problems with sleep, if the supplement is taken in the second half of the day or especially just before sleep. To avoid this, take fish oil, krill oil and other omega supplements in the morning with your breakfast.

Increased bleeding myth

It has been previously reported that fish oil components DHA and EPA can increase the chances of bruising and bleeding (e.g., nosebleeds, GI bleeding, strokes or blood in the urine). This myth has gained some popularity on various websites, including official medical sites, while medical research did not find any significant association between intake of fish oil and bleeding. Dr. Harris (see the reference and abstract below) analyzed about 20 medical studies where patients were given between 3 and 7 g of EPA. Most studies were very large (up to several hundred patients) and there were no reports of increased bleeding, while bleeding time increased moderately only in a few studies.

Quotes and References (Increased bleeding myth)

Concerns related to vitamin A toxicity

While there are many internet claims about too much vitamin A in cases of using cod liver oil, medical research does not support these claims. There are published cases of individuals taking too much cod liver oil and resultant liver problems, but these cases are confined to very large doses. The typical therapeutic dosage recommended is only between 1 teaspoon and 1 tablespoon daily. Additionally, inability of the organism to regulate vitamin A accumulation indicates very low CP (likely less than 10 s). Therefore, people taking therapeutic doses of cod liver oil and other EFAs sources do not need to worry about this effect. There are many published studies where doctors treated surgical patients with up to 7-8 g of DHA and EPA per day. In such cases they suggest using fish oil and other sources of these EFAs, to avoid overdoses of vitamin A in cod liver oil.

Other possible negative symptoms

Woman with anxiety Medical studies have revealed that fish oil may contribute to worsening of some health problems in certain patient population, for example: aggravation of symptoms of bipolar disorder and depression; drop in blood pressure due to reduction of inflammation in medicated hypertension; worsened blood sugar control in diabetes; possible contribution to some cancers in certain groups of people; lowered immune response in HIV/AIDS; and other similar situations. Such adverse effects would be expected for those people who improved their CPs (e.g., up to 5-10 s), but continue to use the same dose of their medication. This can be dangerous since, with higher CPs, most drugs have a much stronger effect. Hence, many such cases rather relate to interactions with medical drugs rather than to effects of fish or cod liver oil.

Interactions with medication

During breathing retraining, it is sensible to explain to your family doctor (or general practitioner) that your symptoms subsided (or disappeared) depending on your progress and previous health problems. Since most MDs and GPs have no time to follow alternative medicine developments and are bombarded with papers representing official doctrines, very few MDs know in detail about the Buteyko method. Hence, you can emphasize healthy changes in your lifestyle as the likely cause of your health improvement. [Doctors do know about the benefits of exercise, better diet, etc.] Then it will be easier to convince them to reduce your medication.

There have been many Buteyko students who could achieve up to 5-10 s higher morning CP just by taking fish oil. Such changes in breathing modify the effects of many medical drugs so that their efficiency is greatly increased. This relates to medication that control blood pressure, blood glucose level, blood clotting, blood thinning and some other physiological parameters. Thus, potentially, it is not the direct effect of fish oil, but changes in breathing, that alter the reactions to usual dosages of medical drugs. Hence, ask you MD or GP to reduce medication accordingly.

4.3 Fish oil vs. flaxseed oil and other vegetable oils

Should everyone use fish oil or other animal-derived omegas? This depends on your body oxygenation (or health state). For hundreds of generations, many human communities, groups and tribes could thrive without eating fish, provided that they had high CPs. EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) are normal components of the human blood and are necessary for numerous functions. These fatty acids can be synthesized from ALA (alpha-linolenic acid), which is also an omega fat, provided that the GI tract is healthy. ALA is abundant in various nuts and seeds. For example, flax oil and milled flax seeds are a rich vegetarian omega 3 source, but flax doesn’t have DHA or EPA. The same relates to hemp seed omega-3 oil, linseed oil, olive oil and sunflower oil. Among vegetarian sources, only algae oils have a high DHA content (see the Table below).

People with low CPs (less than 20 s) and/or GI problems are often unable to utilize vegetarian sources of EFAs, as it was confirmed by many published studies, provided 2 paragraphs below. Hence, when most people try flaxseed (linseed) oil, hemp oil, sunflower oil, and other oils (usually extracted from seeds and nuts), they still experience their symptoms and deficiency in essential fatty acids. When they try cod liver oil or fish oil for 3 days, their morning CP can increase by 3, 5 sometimes up to 10 s. Hence, this supplementation can greatly assist health recovery.

If you have any, even very mild digestive problems, vegetarian sources of omegas cannot not be used to build and repair the body as effectively as animal sources of EFAs. However, if you are reluctant to use animal products, try a 3-day test with flaxseed oil and later with animal omega sources and compare the results.

There are some people, even with low CPs, who do not experience any improvement after a 3 day fish oil trial and then there is no need for them to use this animal product. They can use flaxseed, linseed, hemp and other seed- or nut-based oils or just regularly consume nuts and seeds or sunflower and other food grade, better cold-pressed oils.

This question (What is better for you: fish oil or flaxseed oil?) can be also answered using 2 different scientific ways. First, we can consider studies related to conversion rates in modern humans, who, according to medical respiratory research, can be divided into sick (ordinary humans) and very sick people.

Quotes and references about conversion rates of ALA (alpha-linolenic acid) to EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid)

Why some people cannot convert EFAs or omega fats in their bodies

Man running The situation with synthesis of EFA and DHA in the human body is similar to synthesis of vitamin B12 (cobalamin) in the human gut. Theoretically, as modern researchers claim, it can take place, but practical evidence suggests that most people are not able to synthesize B12 in the body due to absence of the intrinsic factor.

This is how Dr. K. Buteyko described some of the effects of chronic hyperventilation:

c) Change in the activity of enzymes and vitamins: some of them increase their activity, while others decrease. And this inevitably leads to:
d) Abnormalities of the metabolism, which is the foundation of life, i.e. enzymes (there are about 700 of them which have already been discovered) and vitamins (there are more than 20). All these control units of the metabolism start to work abnormally. The metabolism is abnormal; the foundation of life is abnormal. If carbon dioxide decreases below the limiting norm, then there is a termination of the [normal] chemical processes, death of the cells and organism...”

Note that conversion of ALA into DHA and EPA depends on activity of enzymes.

Now we can also consider studies that compared supplementation with fish oil versus flaxseed oil and other vegetarian oils. Here are quotes from some recent research studies, most of which focus on fish oil vs. flaxseed oil effects and all claim higher efficacy of fish oil dietary supplementation.

Quotes and references (fish oil versus flaxseed oil)

Conclusion. Most people, due to low CP and tissue hypoxia, with the body’s inability to synthesize various vital substances (DHA and EPA included), do require supplementation with EPA omega 3 and DHA omega 3, which generally come from animal sources.

4.4 What is the difference between DHA and EPA?

Researchers agree that DHA is the most beneficial fatty acid for the human body. DHA is also the largest molecule among all considered EFAs. It has 22 carbon chain bonds and six double bonds. Furthermore, DHA is essential for infants. Quickly growing brains of babies constantly require large amounts of DHA. Apart from cardiovascular health, it is also crucial for cognitive and neurological function, learning ability, memory, focus, kidney function, etc..

EPA is another essential fatty acid, although it is not near as important as DHA. EPA has 20 carbon chain bonds and 5 double bonds. EPA is more involved in the work of the cardiovascular, hormonal and immune systems.

Another difference is that it is relatively easy for the human body to convert the larger DHA molecule (22 carbon chain bonds) into EPA (20 carbon chain bonds), but not the other way around. Moreover, low CPs make the inverse conversion (from EPA to DHA) more difficult or even impossible. [All these concerns are not important for those whose CP is about 40 s or preferably no less than the Buteyko norm (60 s).]

Hence, it is sensible for many people to use supplements with higher DHA absolute and relative content.

4.5 How much fish oil is recommended?

The officially recommended dosage for fish oil does not exist since fats are macronutrients, and, hence, they are not assigned recommended daily allowances.

Macronutrients have AI (Acceptable Intake) and AMDR (Acceptable Macronutrient Distribution Range) instead of RDAs. The AI for omega-3 is 1.6 g/day for men and 1.1 g/day for women. The AMDR is from 0.6% to 1.2% of total energy intake. As about nutritionists and experts, their fish oil supplements dosage can range from about 300 to 2,000 mg of DHA and EPA per day depending on the health state and many other parameters of the person. Medical doctors often use up to 5-8 g of DHA and EPA daily for their patients during and after surgery.

The experience of my students indicates that personal requirements depend on many factors. First of all, not all people require animal sources of omega 3 EFAs. While most people cannot convert vegetarian sources of EFAs, some of those people who have very good digestion and use, for example, flaxseed oil would not benefit from switching to cod liver or fish oil for a 3-day trial.

How much fish oil should I use?

In order to have a good understanding of your particular requirements, consider the main benefits of taking fish oil, cod liver oil, and other EFAs sources. What is fish oil good for? The main effect is to reduce inflammation. However, inflammation is naturally reduced when one has higher CP (the adrenal gland starts to recover and produce more cortisol when the CP is more than 20 s). Physical exercise with strictly nasal breathing and breathing exercises improve body oxygenation index and are the most powerful and common tools to fight inflammation. [Note that a small number of breathing students cannot improve their CPs at all without cortisol supplementation and this effect is considered elsewhere.] Hence, aspiring breathing students can easily compensate their seemingly large requirements in EPAs and DHAs by smart changes in their lifestyle.

4.6 "3 day test"

When a person applies various breathing retraining techniques and has a CP that is growing, it is relatively easy to define the optimum amounts and types of omega supplements. It can be done using the same 3-day test that is used to test and define correct dosages of minerals (Ca, Mg and Zn). Take the full or even double dose, if you have a lot of inflammation, of EPA and DHA for 3 days while monitoring your CP, especially the morning CP, and heart rate. Then do not use the supplement for 5 days and again record your parameters in your daily log. If there is a definite improvement at the end of the 3 day trial, while your parameters drop later, you need this supplement. If you are uncertain and there are other healthy lifestyle changes that could also influence the results, you can repeat this test 2, 3 or even many more times. If there are no changes in your parameters (especially the morning CP), do not waste your time and money for this supplement.

How much fish oil should you take a day after this trial or in a long run? The dosage during this trial can be much larger than your optimum requirements and your next step is to define the optimum dose, which produces the maximum effect. For example, if your morning CP is less than 20 s, your 3-day dose can be up to 2 tablespoons of fish oil or cod liver oil (or about 2-3 g of DHA and EPA daily). However, you may need only 1 tablespoon or even 1 teaspoon for a long term use later. If your morning CP is over 60 s, you may require only 1 teaspoon of cod liver or fish oil per day or you can even try to switch to nuts and seeds for 2-3 weeks, the most natural sources of omegas for healthy people. (The long term strategy is described at the end.)

4.7 What is the difference between fish oil and cod liver oil?

Cod liver oil is traditionally produced from livers of cod fish, while fish oil is produced from tissues of fatty fish. Cod liver oil has a fishy taste. Many companies now add peppermint, lemon or citrus flavors to make the taste more pleasant. Cod liver oil has a higher ratio of DHA to EPA (which is good for low CPs), while fish oils have a higher ratio of EPA to DHA (which is ok for high CP). If we take the same amount of both oils, fish oils have almost twice greater amount of total EPA plus DHA than cod liver oil. Cod liver oil, on the other hand, has additional vitamins A and D. Note that concerns about health problems due to excessive vitamin A consumption are reasonable for low CP people (especially for those with less than 10 s CP) and low CP pregnant women.

4.8 What is krill oil for (krill oil vs. fish oil)?

Krill: the source of krill oilIf we compare krill oil vs. fish oil, krill oil also contains EPA and DHA, but in a different form. In krill oil, the EFAs are linked in phospholipid form. It is the same structure as the fat cells in the human body. Hence, it is much easier for the human organism to absorb and use krill oil EPA and DHA for building human tissues. However, the most valuable components of krill oil are antioxidants, such as phospholipids, vitamins E, A and D, and astaxanthin, which is a very potent one.

Studies found benefits of krill oil in reducing inflammation and pain associated with rheumatoid arthritis, as well as other inflammatory conditions. It was useful to treat the symptoms associated with PMS and dysmenorrhea and to suppress autoimmune murine lupus. When the CP is over 30 s, the students generally require only one 500 mg capsule per day, while low CP students (with less than 20 s of oxygen in the body), usually require 2 capsules daily in order to prevent or reduce, for example, joint pain due to arthritis.

Krill oil benefits and advantages also include: a better absorption rate of its nutrients, less pollution (krills are at the bottom of the food pyramid and hence accumulate less toxins), excellent antioxidant supply, stability against rancidity due to naturally present antioxidant, and less side effects.

Conclusion (fish oil versus krill oil). Due to high antioxidant power, but low content of DHA and EPA, krill oil can rather be used as an additional source of antioxidants, while fish oil or cod liver oil can be used as sources of omega 3 fats.

Quotes and References (Krill oil medical research)

4.9 Salmon oil vs. fish oil

Which one is better? First of all, the supplement can have only salmon oil inside, while the main label and the name of the product can include “Fish Oil” words without any referral to salmon. Second, the choice depends on many factors that have been described above. Generally, salmon oil is better due to higher DHA content and higher DHA to EPA ratio, but this does not mean that any salmon oil supplement is better than any fish oil supplement. There are fish oil brands and varieties that can be much better than salmon oil. For more details on how to choose omega oils, see the summary of factors provided below.

4.10. Sources of Fish oil, cod liver oil, salmon oil and krill oil: their EPA and DHA contents

How much omega 3 do you need? For most people, the dose can range from about 500 to 2,000 mg depending on 3-day test results and factors described above. Hence, it is important to know what the DHA and EPA content in your supplements is and what the best sources of these omega 3 fats are. Here are some average or typical results.

Type of omega 3 supplement DHA, mg EPA, mg Additional substances
and other parameters
Typical fish oil capsule (1000 mg) 120 180
Ethyl ester* fish oil capsule (1000 mg) 350 490
LOVAZA omega-3 fish oil 375 465 Is the only FDA-approved medicine made from fish oil
Carlson Cod Liver Oil capsule (1000 mg) 120 90 80 to 100 mg ALA; 1600 IU v. A; 800 IU v. D; 20 IU v. E (natural d-alpha tocopherol and mixed tocopherols)
Carlson Cod Liver Oil capsule (10 ml) 1090 860  
Cod liver oil, Atlantic (10 ml) 1200 800 Vitamins A and D
Cod liver oil, Baltic (10 ml) 2000 900 Vitamins A and D
Extra-Virgin Salmon Oil capsule (1100 mg) 240 240 50 mg of mixed omega 3s; 40 mcg astaxanthin complex; antioxidant blend (natural lemon oil, rosemary extract, ascorbyl palmitate - fat-soluble vitamin C, natural tocopherols - vitamin E)
GNLD NeoLife Omega III Salmon Oil Plus capsule (1000 mg) 240 230 50 mg DPA and 40 mg of mixed omega 3s, including SDA, ETA(3), ETA, HPA and ALA
Salmon Oil Plus capsule (1000 mg) 160 90 17 mg DPA and 27 mg of mixed omega 3s, including SDA, ETA(3), ETA, HPA and ALA
Alaska Deep Fish Oil (Salmon Oil) capsule (1000 mg) 180 80
Salmon Oil Concentrate capsule (1000 mg) 120 80
DHA-Rich Omega-3 Algae Oil capsule (800 mg) 300 10 Vegetarian
Krill oil, 2 capsules (1000 mg in total) 90 150 420 mg phospholipids, omega-3 rich
(90% a phosphatidylcholine & lysophosphatidylcholine
10% as other phospholipids); 1.5 mg astaxanthin; lemon oil

* Ester forms of fish oil have better bioavailability and is more readily used by the body due to their optimum molecular geometrical configuration.

Other available products that you can buy include:
1. Enteric coated EPA and DHA capsules or tablets (for those whose stomachs are sensitive to fish oils). They are more concentrated in EPA and DHA.
2. Emulsions of fish oils (e.g., for salad dressings)
3. Functional foods with fish oil (e.g., snack bars)
4. Infant formulas with DHA.

4.11 Criteria and summary for choosing EFAs or omega 3 supplements

Scales to compare* Your current personal needs (consider your health conditions or CP and symptoms)
* Purity of the product (choose those with special molecular distillation processes or pharmaceutical grades)
* DHA content (the more the better)
* EPA content (the more the better)
* Presence of protective antioxidants (good fish oil products must contain antioxidants such as tocopherol to protect against their oxidation during storage and at other times)
* Date of production (go for newer products)
* Storage conditions (go for those stored in the fridge)
* Packaging (go for dark glass containers, since capsules provide poorer protection from oxygen).

As you can see that choosing a right supplement can be a headache especially when one's CP is low. Better get over 60 s for your body oxygen level and make a transition to nuts and seeds without all these cautions, warning, concerns and rules. With maximum possible CPs (about 3 min), as hatha yoga ancient books claim, one can eat only meat and remain healthy (with high CP). For modern people, eating only meat can be a disaster since the sick ones will die probably in some weeks, while more healthy individuals may last only for some months.

PS. There are very recent 2010 studies that found that long-term use (or lifetime) use of fish oil could cause more oxidative stress and cause other negative effects (see references below). The results could be generally true since it is not physiologically normal for humans to consume fish products on daily basis. After each 1 month course, you can take 1-2 week breaks and monitor your morning body-oxygenation index and other parameters during this break and when you resume supplementation. This is another reason to raise the CP, so that there are fewer complications with diet and supplements.

Quotes and references (long-term use causes negative effects)

Feel free to leave comments, questions and suggestions at the bottom of this page

All quotes and references for this web page

Quotes and references (dangers in fish oil and fish due to pollution)

“Five types of oil derived from various Baltic fish were purified. Reduction in the PCDD/Fs content was 77.0-93.6% on average, whereas in the dioxin-like polychlorinated biphenyls (dl-PCBs)-it was 42.7-50.5% on average, with insignificant changes in the total amount of EPA and DHA content. Furthermore, a significant reduction in the content of arsenic was noted (by about 62% on average), with insignificant changes in the content of organochlorine pesticides (OCPs), and marker polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), cadmium, lead, and mercury. Purification provided fish oil having standardized parameters that allow for its use as feed additives, whilst retaining its favorable fatty acid content.”

Usydus Z, Szlinder-Richert J, Polak-Juszczak L, Malesa-Ciecwierz M, Dobrzanski Z, Study on the raw fish oil purification from PCDD/F and dl-PCB-industrial tests, Chemosphere. 2009 Mar; 74(11): p. 1495-1501.

“This paper reviews the state of the science regarding recent literature on PCDD/F (polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans) and PCB (polychlorinated biphenyls) levels in marine species and human nutrients intake through fish and seafood consumption. The concentrations of these pollutants depend basically on the environment in which the respective species are caught. It is concluded that some groups of population frequently consuming high quantities of certain species could be significantly increasing health risks due to PCDD/F and PCB exposure.”

Domingo JL, Bocio A, Levels of PCDD/PCDFs and PCBs in edible marine species and human intake: a literature review, Environ Int. 2007 Apr; 33(3): p. 397-405.

“… Several studies have shown an inverse correlation between omega-3 fatty acids from fish in serum/adipose tissue and coronary heart disease. However, a high content of mercury in hair/toe nail had a negative effect, and in one study the odds ratio for myocardial infarction in those with the highest content of mercury was 2.16. A positive correlation between mercury in hair and the progression of carotid atherosclerosis has been found. Intake of fish is a major source of exposure to mercury, and a high content of mercury probably inhibits the beneficial effects of omega-3 fatty acids on the development of coronary artery disease.”

Landmark K, Aursnes I, Mercury, fish, fish oil and the risk of cardiovascular disease [Article in Norwegian], Tidsskr Nor Laegeforen. 2004 Jan 22; 124(2): p.198-200.

“… CONCLUSIONS: High content of mercury in hair may be a risk factor for acute coronary events and CVD, CHD, and all-cause mortality in middle-aged eastern Finnish men. Mercury may also attenuate the protective effects of fish on cardiovascular health.”

Virtanen JK, Voutilainen S, Rissanen TH, Mursu J, Tuomainen TP, Korhonen MJ, Valkonen VP, Seppänen K, Laukkanen JA, Salonen JT, Mercury, fish oils, and risk of acute coronary events and cardiovascular disease, coronary heart disease, and all-cause mortality in men in eastern Finland, Arterioscler Thromb Vasc Biol. 2005 Jan; 25(1): p. 228-233.

“The mercury content of fish oil was similar to the basal concentration normally found in human blood. CONCLUSIONS: Fish are rich in omega-3 fatty acids, and their consumption is recommended to decrease the risk of coronary artery disease. However, fish such as swordfish and shark are also a source of exposure to the heavy metal toxin, mercury. The fish oil brands examined in this manuscript have negligible amounts of mercury and may provide a safer alternative to fish consumption.”

Foran SE, Flood JG, Lewandrowski KB, Measurement of mercury levels in concentrated over-the-counter fish oil preparations: is fish oil healthier than fish? Arch Pathol Lab Med. 2003 Dec; 127(12): p. 1603-1605.

“CONCLUSIONS: For major health outcomes among adults, based on both the strength of the evidence and the potential magnitudes of effect, the benefits of fish intake exceed the potential risks. For women of childbearing age, benefits of modest fish intake, excepting a few selected species, also outweigh risks.”

Mozaffarian D, Rimm EB, Fish intake, contaminants, and human health: evaluating the risks and the benefits, JAMA. 2006 Oct 18; 296(15): p. 1885-1899.

“We studied 22 commercial fish oil and menhaden oil preparations in respect to accompanying substances that could be harmful. The substances measured were: cholesterol as determined by gas liquid chromatography, heavy metals measured by atomic absorption, and vitamin A as determined by high-performance liquid chromatography (HPLC). The contents of cholesterol and heavy metals were in ranges which can be regarded as negligible; the content of vitamin A in menhaden oils, however, was found in amounts which warrant that pregnant women do not exceed the dosage as recommended by the manufacturers.”

Koller H, Luley C, Klein B, Baum H, Biesalski HK, Contaminating substances in 22 over-the-counter fish oil and cod liver oil preparations: cholesterol, heavy metals and vitamin A [Article in German], Z Ernahrungswiss. 1989 Mar; 28(1): p. 76-83.

Quotes and References (Increased bleeding myth)

“It has been suggested that the potential antithrombotic effect of fish oils may theoretically increase the risk for bleeding, which may be a safety concern for individual patients. However, clinical trial evidence has not supported increased bleeding with omega-3 fatty acid intake, even when combined with other agents that might also increase bleeding (such as aspirin and warfarin). Another potential safety concern is the susceptibility of omega-3 fatty acid preparations to undergo oxidation, which contributes to patient intolerance and potential toxicity. Finally, large amounts of fish consumption may result in adverse experiences due to the potential presence of environmental toxins such as mercury, polychlorinated biphenyls, dioxins, and other contaminants. The risks of exposure to environmental toxins and hypervitaminosis with fish consumption are substantially reduced through purification processes used to develop selected concentrated fish oil supplements and prescription preparations. Thus, in choosing which fish oil therapies to recommend, clinicians should be aware of available information to best assess their relative safety, which includes the US Food and Drug Administration (FDA) and Environmental Protection Agency (EPA) advisory statement regarding fish consumption, the meaning of certain labeling (such as "verification" through the US Pharmacopeia) and the differences in FDA regulatory requirements between nonprescription fish oil supplements and prescription fish oil preparations, and how all of this is important to the optimal treatment of patients.”

Bays HE, Safety considerations with omega-3 fatty acid therapy, Am J Cardiol. 2007 Mar 19;99(6A):35C-43C. Epub 2006 Nov 28.
Louisville Metabolic and Atherosclerosis Research Center, Louisville, Kentucky 40213, USA.

“Omega-3 fatty acid ethyl esters have well-known triglyceride-lowering properties and were shown >30 years ago to inhibit platelet function. With the recent US Food and Drug Administration (FDA) approval of these agents for treating severe triglyceride elevations, concerns about excess bleeding naturally arise. However, an objective assessment of the evidence for clinically significant bleeding reveals that such concerns are unfounded. As such, the benefits of triglyceride lowering with omega-3 fatty acids more than outweigh any theoretical risks for increased bleeding.”

Harris WS, Expert opinion: omega-3 fatty acids and bleeding-cause for concern? Am J Cardiol. 2007 Mar 19; 99(6A): 44C-46C.
Sanford School of Medicine of University of South Dakota, Sioux Falls, South Dakota 57105, USA.

Quotes and references about conversion rates of ALA (alpha-linolenic acid) to EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid)

“The use of ALA labelled with radioisotopes suggested that with a background diet high in saturated fat conversion to long-chain metabolites is approximately 6% for EPA and 3.8% for DHA. With a diet rich in n-6 PUFA, conversion is reduced by 40 to 50%... These findings indicate that future attention will have to focus on the adequate provision of DHA which can reliably be achieved only with the supply of the preformed long-chain metabolite.”

Gerster H, Can adults adequately convert alpha-linolenic acid (18:3n-3) to eicosapentaenoic acid (20:5n-3) and docosahexaenoic acid (22:6n-3)? Int Journal of Vitam Nutr Res. 1998; 68(3): p. 159-73.
Vitamin Research Department, F. Hoffman-Roche Ltd, Basel, Switzerland.

“… in vivo studies in humans show that asymptotically equal to 5 percent of ALA is converted to EPA and <0.5 percent of ALA is converted to DHA. … even large amounts of dietary ALA have a negligible effect on plasma DHA”

Plourde M & Cunnane SC, Extremely limited synthesis of long chain polyunsaturates in adults: implications for their dietary essentiality and use as supplements, Applied Physiology of Nutr Metab. 2007 Aug;32(4): p. 619-634.
Research Center on Aging, Departments of Medicine, and Physiology and Biophysics, Université de Sherbrooke, 1036 Belvedere St, South, Sherbrooke, QC J1H 4C4, Canada

“Stable isotope tracer studies indicate that conversion of alphaLNA to EPA occurs but is limited in men and that further transformation to DHA is very low.”

Burdge GC & Calder PC, Conversion of alpha-linolenic acid to longer-chain polyunsaturated fatty acids in human adults, Reproductive Nutrition Dev. 2005 Sep-Oct; 45(5): p. 581-597.
Institute of Human Nutrition, University of Southampton, Southampton, UK.

“… alphaLNA-feeding studies and stable-isotope studies using alphaLNA, which have addressed the question of bioconversion of alphaLNA to EPA and DHA, have concluded that in adult men conversion to EPA is limited (approximately 8%) and conversion to DHA is extremely low (<0.1%).”

Williams CM & Burdge G, Long-chain n-3 PUFA: plant versus marine sources, Proceedings of the Nutritional Society, 2006 Feb; 65(1): p. 42-50.
Hihj Sinclair Unit Human Nutrition, School of Food Biosciences, University of Reading, UK.

Quotes and references (fish oil versus flaxseed oil)

“PURPOSE: Evaluate the effect of flaxseed, olive and fish oil on the lipid profile, preservation of villosities and lymphocyte migration in the intestinal mucosa of Wistar rats… RESULTS: The group which was fed fish oil presented lower values when compared to the other treatments for Total Cholesterol, High-density Lipoprotein Cholesterol and Triacylglycerol (p<0.05). The animals treated with fish and olive oils presented better intestinal villosities preservation. Less deposition of lymphocytes was observed in the flaxseed group (p<0.001). CONCLUSIONS: This study demonstrated that flaxseed, olive and fish oils present different responses than soy oil for the intestinal mucosa preservation and lymphocyte proliferation in Wistar rats.”

Rosa DD, de Sales RL, Moraes LF, Lourenço FC, Neves CA, Sabarense CM, Ribeiro SM, Peluzio Mdo C, Flaxseed, olive and fish oil influence plasmatic lipids, lymphocyte migration and morphometry of the intestinal of Wistar rats, Acta Cir Bras. 2010 Jun;25(3):275-80.
Department of Nutrition and Health, UFV, Viçosa, MG, Brazil.

“The atheroprotective potential of n-3 alpha-linolenic acid (ALA) has not yet been fully determined, even in murine models of atherosclerosis. We tested whether ALA-derived, n-3 long chain polyunsaturated fatty acids (LCPUFA) could offer atheroprotection in a dose-dependent manner. Apolipoprotein B (ApoB)100/100LDLr-/- mice were fed with diets containing two levels of ALA from flaxseed oil for 16 weeks. Fish oil- and cis-monounsaturated-fat-enriched diets were used as positive and negative controls, respectively. The mice fed cis-monounsaturated fat and ALA-enriched diets exhibited equivalent plasma total cholesterol (TPC) and LDL-cholesterol (LDL-c) levels; only mice fed the fish-oil diet had lower TPC and LDL-c concentrations. Plasma LDL-CE fatty acid composition analysis showed that ALA-enriched diets lowered the percentage of atherogenic cholesteryl oleate compared with cis-monounsaturated-fat diet (44% versus 55.6%) but not as efficiently as the fish-oil diet (32.4%). Although both ALA and fish-oil diets equally enriched hepatic phospholipids with eicosapentaenoic acid (EPA) and ALA-enriched diets lowered hepatic cholesteryl ester (CE) levels compared with cis-monounsaturated-fat diet, only fish oil strongly protected from atherosclerosis. These outcomes indicate that dietary n-3 LCPUFA from fish oil and n-3 LCPUFA (mostly EPA) synthesized endogenously from ALA were not equally atheroprotective in these mice.”

Degirolamo C, Kelley KL, Wilson MD, Rudel LL, Dietary n-3 LCPUFA from fish oil but not alpha-linolenic acid-derived LCPUFA confers atheroprotection in mice, J Lipid Res. 2010 Jul;51(7):1897-905. Epub 2010 Feb 11.
Department of Pathology, Wake Forest University School of Medicine, Winston-Salem, NC, USA.

“Whether preformed dietary docosahexaenoic acid (DHA) is required for brain accretion has not been clearly determined. In this study, we investigated in mice the different effects of dietary longer-chain n-3 polyunsaturated fatty acids (PUFAs) and alpha-linolenic acid (LNA) on brain accretion of DHA and the expression of associated desaturases and transcription factors. C57 BL/6J mice were fed for 3 months with four fish oil n-3 PUFA diets - lower, low, high and higher (0.46%, 0.91%, 1.73% and 4.29% total energy, respectively); a flaxseed oil n-3 PUFA (5.01% total energy) diet; and an n-3 PUFA-deficient diet, respectively. Either fish oil or flaxseed oil n-3 PUFA diets increased DHA concentrations in the brain. However, the flaxseed oil n-3 PUFA diet was less effective than the fish oil diet with higher amount of n-3 PUFA in increasing brain DHA content. Furthermore, the expressions of delta-6 desaturase (D6D) and sterol regulatory element binding protein 1 (SREBP-1) in the liver were down-regulated by all fish oil diets with different amounts of n-3 PUFAs, as well as by the flaxseed oil n-3 PUFA diet, whereas in the brain, D6D, delta-5 desaturase (D5D) and SREBP-1 expressions were down-regulated by the higher fish oil n-3 PUFA diet rather than by other fish oil n-3 PUFA and the flaxseed oil n-3 PUFA diets. These results suggest that preformed dietary DHA, different from those converted by LNA inside the body, is better for brain accretion. Dietary longer-chain n-3 PUFAs affect expressions of D6D, D5D and SREBP-1 in the brain differently from their precursor LNA.”

Zhu H, Fan C, Xu F, Tian C, Zhang F, Qi K, Dietary fish oil n-3 polyunsaturated fatty acids and alpha-linolenic acid differently affect brain accretion of docosahexaenoic acid and expression of desaturases and sterol regulatory element-binding protein 1 in mice, J Nutr Biochem. 2009 Nov 30.
Clinical Nutrition Center, Beijing Pediatric Research Institute, Beijing Children's Hospital, Capital Medical University, Beijing 100045, China.

“Thirty adults with ADHD were randomized to 12 weeks of supplementation with olive oil (< 1% omega-3 fatty acids), flax oil (source of alpha-linolenic acid; 18:3n-3; alpha-LNA) or fish oil (source of EPA and docosahexaenoic acid; 22:6n-3; DHA). Serum PL fatty acid levels were determined at baseline and at 12 weeks. Flax oil supplementation resulted in an increase in alpha-LNA and a slight decrease in the ratio of AA/EPA, while fish oil supplementation resulted in increases in EPA, DHA and total omega-3 fatty acids and a decrease in the AA/EPA ratio to values seen in the Japanese population. These data suggest that in order to increase levels of EPA and DHA in adults with ADHD, and decrease the AA/EPA ratio to levels seen in high fish consuming populations, high dose fish oil may be preferable to high dose flax oil.”

Young GS, Conquer JA, Thomas R, Effect of randomized supplementation with high dose olive, flax or fish oil on serum phospholipid fatty acid levels in adults with attention deficit hyperactivity disorder, Reprod Nutr Dev. 2005 Sep-Oct; 45(5): p.549-558.

“Fish oil caused a significant reduction (mean decline: 48%) in NK (natural killer) cell activity that was fully reversed by 4 wk after supplementation had ceased. CONCLUSION: A moderate amount of EPA (eicosapentaenoic acid; i.e. fish oil component) but not of other n-6 or n-3 polyunsaturated fatty acids (i.e, components of flaxseed oil) can decrease NK cell activity in healthy subjects.”

Thies F, Nebe-von-Caron G, Powell JR, Yaqoob P, Newsholme EA, Calder PC, Dietary supplementation with eicosapentaenoic acid, but not with other long-chain n-3 or n-6 polyunsaturated fatty acids, decreases natural killer cell activity in healthy subjects aged >55 y, Am J Clin Nutr. 2001 Mar; 73(3): p. 539-548.

“The results of prospective cohort studies indicate that consuming fish or fish oil containing the n-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) is associated with decreased cardiovascular death, whereas consumption of the vegetable oil-derived n-3 fatty acid a-linolenic acid is not as effective.”

Breslow JL, n-3 fatty acids and cardiovascular disease, Am J Clin Nutr. 2006 Jun; 83(6 Suppl): p. 1477S-1482S.

“CONCLUSIONS: Long-chain n -3 PUFA (polyunsaturated fatty acids) from fish are possible promising nutrients for the dietary prevention of PCa (prostate cancer), but to-date with little epidemiological support. In contrast, studies suggest that alpha-linolenic acid intake might be a risk factor.”

Astorg P, Dietary N-6 and N-3 polyunsaturated fatty acids and prostate cancer risk: a review of epidemiological and experimental evidence, Cancer Causes Control. 2004 May; 15(4): p. 367-386.

Quotes and References (Krill oil medical research)

J Am Coll Nutr. 2007 Feb;26(1):39-48.
Evaluation of the effect of Neptune Krill Oil on chronic inflammation and arthritic symptoms.
Deutsch L.
Sciopsis Inc. Evidence Based NutraMedicine, 18 Corso Court, Richmond Hill, Ontario L4S 1H4, CANADA.
OBJECTIVES: a) To evaluate the effect of Neptune Krill Oil (NKO) on C-reactive protein (CRP) on patients with chronic inflammation and b) to evaluate the effectiveness of NKO on arthritic symptoms.
METHODS: Randomized, double blind, placebo controlled study. Ninety patients were recruited with confirmed diagnosis of cardiovascular disease and/or rheumatoid arthritis and/or osteoarthritis and with increased levels of CRP (>1.0 mg/dl) upon three consecutive weekly blood analysis. Group A received NKO (300 mg daily) and Group B received a placebo. CRP and Western Ontario and McMaster Universities (WOMAC) osteoarthritis score were measured at baseline and days 7, 14 and 30.
RESULTS: After 7 days of treatment NKO reduced CRP by 19.3% compared to an increase by 15.7% observed in the placebo group (p = 0.049). After 14 and 30 days of treatment NKO further decreased CRP by 29.7% and 30.9% respectively (p < 0.001). The CRP levels of the placebo group increased to 32.1% after 14 days and then decreased to 25.1% at day 30. The between group difference was statistically significant; p = 0.004 at day 14 and p = 0.008 at day 30. NKO showed a significant reduction in all three WOMAC scores. After 7 days of treatment, NKO reduced pain scores by 28.9% (p = 0.050), reduced stiffness by 20.3% (p = 0.001) and reduced functional impairment by 22.8% (p = 0.008).
CONCLUSION: The results of the present study clearly indicate that NKO at a daily dose of 300 mg significantly inhibits inflammation and reduces arthritic symptoms within a short treatment period of 7 and 14 days.

BMC Musculoskelet Disord. 2010 Jun 29;11:136.
Supplementation of diet with krill oil protects against experimental rheumatoid arthritis.
Ierna M, Kerr A, Scales H, Berge K, Griinari M.
MD Biosciences Gmbh Postfach, Gewerbestrasse 9, 8132 Egg b Zürich, Switzerland.
BACKGROUND: Although the efficacy of standard fish oil has been the subject of research in arthritis, the effect of krill oil in this disease has yet to be investigated. The objective of the present study was to evaluate a standardised preparation of krill oil and fish oil in an animal model for arthritis.
METHODS: Collagen-induced arthritis susceptible DBA/1 mice were provided ad libitum access to a control diet or diets supplemented with either krill oil or fish oil throughout the study. There were 14 mice in each of the 3 treatment groups. The level of EPA + DHA was 0.44 g/100 g in the krill oil diet and 0.47 g/100 g in the fish oil diet. Severity of arthritis was determined using a clinical scoring system. Arthritis joints were analysed by histopathology and graded. Serum samples were obtained at the end of the study and the levels of IL-1alpha, IL-1beta, IL-7, IL-10, IL-12p70, IL-13, IL-15, IL-17 and TGF-beta were determined by a Luminex assay system.
RESULTS: Consumption of krill oil and supplemented diet significantly reduced the arthritis scores and hind paw swelling when compared to a control diet not supplemented with EPA and DHA. However, the arthritis score during the late phase of the study was only significantly reduced after krill oil administration. Furthermore, mice fed the krill oil diet demonstrated lower infiltration of inflammatory cells into the joint and synovial layer hyperplasia, when compared to control. Inclusion of fish oil and krill oil in the diets led to a significant reduction in hyperplasia and total histology score. Krill oil did not modulate the levels of serum cytokines whereas consumption of fish oil increased the levels of IL-1alpha and IL-13.
CONCLUSIONS: The study suggests that krill oil may be a useful intervention strategy against the clinical and histopathological signs of inflammatory arthritis.

Altern Med Rev. 2003 May;8(2):171-9.
Evaluation of the effects of Neptune Krill Oil on the management of premenstrual syndrome and dysmenorrhea.
Sampalis F, Bunea R, Pelland MF, Kowalski O, Duguet N, Dupuis S.
Department of Experimental Surgery, University of Montreal, Montreal, Quebec, Canada.
PRIMARY OBJECTIVE: To evaluate the effectiveness of Neptune Krill Oil (NKO) for the management of premenstrual syndrome and dysmenorrhea. SECONDARY
OBJECTIVE: To compare the effectiveness of NKO for the management of premenstrual syndrome and dysmenorrhea with that of omega-3 fish oil. METHODS/
DESIGN: Double-blind, randomized clinical trial.
SETTING: Outpatient clinic.
PARTICIPANTS: Seventy patients of reproductive age diagnosed with premenstrual syndrome according to the Diagnostic and Statistical Manual of Mental Disorders, Third Edition, Revised (DSM-III-R).
INTERVENTIONS: Treatment period of three months with either NKO or omega-3 fish oil.
OUTCOME MEASURES: Self-Assessment Questionnaire based on the American College of Obstetricians and Gynecologists (ACOG) diagnostic criteria for premenstrual syndrome and dysmenorrhea and number of analgesics used for dysmenorrhea.
RESULTS: In 70 patients with complete data, a statistically significant improvement was demonstrated among baseline, interim, and final evaluations in the self assessment questionnaire (P < 0.001) within the NKO group as well as between-group comparison to fish oil, after three cycles or 45 and 90 days of treatment. Data analysis showed a significant reduction of the number of analgesics used for dysmenorrhea within the NKO group (comparing baseline vs. 45- vs. 90-day visit). The between-groups analysis illustrated that women taking NKO consumed significantly fewer analgesics during the 10-day treatment period than women receiving omega-3 fish oil (P < 0.03).
CONCLUSION: Neptune Krill Oil can significantly reduce dysmenorrhea and the emotional symptoms of premenstrual syndrome and is shown to be significantly more effective for the complete management of premenstrual symptoms compared to omega-3 fish oil.

Altern Med Rev. 2004 Dec;9(4):420-8.
Evaluation of the effects of Neptune Krill Oil on the clinical course of hyperlipidemia.
Bunea R, El Farrah K, Deutsch L.
Department of Internal Medicine, McGill University, Montreal, Quebec, Canada.
OBJECTIVE: To assess the effects of krill oil on blood lipids, specifically total cholesterol, triglycerides, low-density lipoprotein (LDL), and high-density lipoprotein (HDL).
METHODS: A multi-center, three-month, prospective, randomized study followed by a three-month, controlled follow-up of patients treated with 1 g and 1.5 g krill oil daily. Patients with hyperlipidemia able to maintain a healthy diet and with blood cholesterol levels between 194 and 348 mg per dL were eligible for enrollment in the trial. A sample size of 120 patients (30 patients per group) was randomly assigned to one of four groups. Group A received krill oil at a body mass index (BMI)-dependent daily dosage of 2-3 g daily. Patients in Group B were given 1-1.5 g krill oil daily, and Group C was given fish oil containing 180 mg eicosapentaenoic acid (EPA) and 120 mg docosahexaenoic acid (DHA) per gram of oil at a dose of 3 g daily. Group D was given a placebo containing microcrystalline cellulose. The krill oil used in this study was Neptune Krill Oil, provided by Neptune Technologies and Bioresources, Laval, Quebec, Canada.
OUTCOME MEASURES: Primary parameters tested (baseline and 90-day visit) were total blood cholesterol, triglycerides, LDL, HDL, and glucose.
RESULTS: Krill oil 1-3 g per day (BMI-dependent) was found to be effective for the reduction of glucose, total cholesterol, triglycerides, LDL, and HDL, compared to both fish oil and placebo.
CONCLUSIONS: The results of the present study demonstrate within high levels of confidence that krill oil is effective for the management of hyperlipidemia by significantly reducing total cholesterol, LDL, and triglycerides, and increasing HDL levels. At lower and equal doses, krill oil was significantly more effective than fish oil for the reduction of glucose, triglycerides, and LDL levels.

Nutr Res. 2009 Sep;29(9):609-15.
Krill oil supplementation increases plasma concentrations of eicosapentaenoic and docosahexaenoic acids in overweight and obese men and women.
Maki KC, Reeves MS, Farmer M, Griinari M, Berge K, Vik H, Hubacher R, Rains TM.
Provident Clinical Research, Bloomington, IN 47403, USA; Provident Clinical Research, Glen Ellyn, IL 60137, USA.
Antarctic krill, also known as Euphausia superba, is a marine crustacean rich in both eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). We tested the hypothesis that krill oil would increase plasma concentrations of EPA and DHA without adversely affecting indicators of safety, tolerability, or selected metabolic parameters. In this randomized, double-blind parallel arm trial, overweight and obese men and women (N = 76) were randomly assigned to receive double-blind capsules containing 2 g/d of krill oil, menhaden oil, or control (olive) oil for 4 weeks. Results showed that plasma EPA and DHA concentrations increased significantly more (P < .001) in the krill oil (178.4 +/- 38.7 and 90.2 +/- 40.3 micromol/L, respectively) and menhaden oil (131.8 +/- 28.0 and 149.9 +/- 30.4 micromol/L, respectively) groups than in the control group (2.9 +/- 13.8 and -1.1 +/- 32.4 micromol/L, respectively). Systolic blood pressure declined significantly more (P < .05) in the menhaden oil (-2.2 +/- 2.0 mm Hg) group than in the control group (3.3 +/- 1.5 mm Hg), and the response in the krill oil group (-0.8 +/- 1.4 mm Hg) did not differ from the other 2 treatments. Blood urea nitrogen declined in the krill oil group as compared with the menhaden oil group (P < .006). No significant differences for other safety variables were noted, including adverse events. In conclusion, 4 weeks of krill oil supplementation increased plasma EPA and DHA and was well tolerated, with no indication of adverse effects on safety parameters.

Alterntive Medicine Review 2010 Apr;15(1): p.84-86.
Krill oil. Monograph.

Quotes and references (long-term use causes negative effects)

"OBJECTIVE: The effects of fish oil including omega-3 polyunsaturated fatty acids on aging and lifespan arXu X, Jiang M, Wang Y, Smith T, Baumgarten C, Wood M, Tseng G, Long-term fish oil supplementation induces cardiac electrical remodeling by changing channel protein expression in the rabbit model, PLoS One. 2010 Apr 13; 5(4): e10140.
Department of Physiology and Biophysics, Virginia Commonwealth University, Richmond, Virginia, USA.
e not well understood. In this study, the influence of long-term ingestion of fish oil on lifespan was examined in senescence-accelerated (SAMP8) mice. METHODS: We investigated the effects of dietary fish oil on lifespan and on lipid composition and oxidative stress in plasma and liver in SAMP8 mice. Male mice were fed a fish oil diet (5% fish oil and 5% safflower oil) or a safflower oil diet (10% safflower oil) from 12 wk of age. RESULTS: The SAMP8 mice fed fish oil did not have a longer maximum lifespan and had a shorter average lifespan than mice fed safflower oil. To examine the mechanism underlying these results, the effects on oxidative stress of long-term ingestion of fish oil were also examined. SAMP8 mice fed fish oil for 28 wk showed strong oxidative stress that caused hyperoxidation of membrane phospholipids and a diminished antioxidant defense system due to a decrease in tocopherol compared with mice fed safflower oil. CONCLUSION: These findings suggest that intake of fish oil increases oxidative stress, decreases cellular function, and causes organ dysfunction in SAMP8 mice, thereby promoting aging and shortening the lifespan of the mice."

Tsuduki T, Honma TD, Nakagawa KH, Ikeda I, & Miyazawa T, Long-term intake of fish oil increases oxidative stress and decreases lifespan in senescence-accelerated mice, Nutrition. 2010 Jul 10. [Epub ahead of print] Laboratory of Food and Biomolecular Science, Graduate School of Agriculture, Tohoku University, Sendai, Japan.

"Hypothalamic serotonin inhibits food intake and stimulates energy expenditure. High-fat feeding is obesogenic, but the role of polyunsaturated fats is not well understood. This study examined the influence of different high-PUFA diets on serotonin-induced hypophagia, hypothalamic serotonin turnover, and hypothalamic protein levels of serotonin transporter (ST), and SR-1B and SR-2C receptors. Male Wistar rats received for 9 weeks from weaning a diet high in either soy oil or fish oil or low fat (control diet). Throughout 9 weeks, daily intake of fat diets decreased such that energy intake was similar to that of the control diet. However, the fish group developed heavier retroperitoneal and epididymal fat depots. After 12 h of either 200 or 300 mug intracerebroventricular serotonin, food intake was significantly inhibited in control group (21-25%) and soy group (37-39%) but not in the fish group. Serotonin turnover was significantly lower in the fish group than in both the control group (-13%) and the soy group (-18%). SR-2C levels of fish group were lower than those of control group (50%, P = 0.02) and soy group (37%, P = 0.09). ST levels tended to decrease in the fish group in comparison to the control group (16%, P = 0.339) and the soy group (21%, P = 0.161). Thus, unlike the soy-oil diet, the fish-oil diet decreased hypothalamic serotonin turnover and SR-2C levels and abolished serotonin-induced hypophagia. Fish-diet rats were potentially hypophagic, suggesting that, at least up to this point in its course, the serotonergic impairment was either compensated by other factors or not of a sufficient extent to affect feeding. That fat pad weight increased in the absence of hyperphagia indicates that energy expenditure was affected by the serotonergic hypofunction."

Watanabe R, Andrade I, Telles M, Albuquerque K, Nascimento C, Oyama L, CaXu X, Jiang M, Wang Y, Smith T, Baumgarten C, Wood M, Tseng G, Long-term fish oil supplementation induces cardiac electrical remodeling by changing channel protein expression in the rabbit model, PLoS One. 2010 Apr 13; 5(4): e10140.
Department of Physiology and Biophysics, Virginia Commonwealth University, Richmond, Virginia, USA.
sarini D, & Ribeiro EB, Long-Term Consumption of Fish Oil-Enriched Diet Impairs Serotonin Hypophagia in Rats, Cellular and Molecular Neurobiology, 2010 Jun 5. [Epub ahead of print]
Departamento de Fisiologia, Universidade Federal de São Paulo, Rua Botucatu, 862, 2 masculine andar, São Paulo, SP, Brazil.

"Clinical trials and epidemiological studies have suggested that dietary fish oil (FO) supplementation can provide an anti-arrhythmic benefit in some patient populations. The underlying mXu X, Jiang M, Wang Y, Smith T, Baumgarten C, Wood M, Tseng G, Long-term fish oil supplementation induces cardiac electrical remodeling by changing channel protein expression in the rabbit model, PLoS One. 2010 Apr 13; 5(4): e10140.
Department of Physiology and Biophysics, Virginia Commonwealth University, Richmond, Virginia, USA.
echanisms are not entirely clear. We wanted to understand how FO supplementation (for 4 weeks) affected the action potential configuration/duration of ventricular myocytes, and the ionic mechanisms/molecular basis for these effects. The experiments were conducted on adult rabbits, a widely used animal model for cardiac electrophysiology and pathophysiology. We used gas chromatography-mass spectroscopy to confirm that FO feeding produced a marked increase in the content of n-3 polyunsaturated fatty acids in the phospholipids of rabbit hearts. Left ventricular myocytes were used in current and voltage clamp experiments to monitor action potentials and ionic currents, respectively. Action potentials of myocytes from FO-fed rabbits exhibited much more positive plateau voltages and prolonged durations. These changes could be explained by an increase in the L-type Ca current (I(CaL)) and a decrease in the transient outward current (I(to)) in these myocytes. FO feeding did not change the delayed rectifier or inward rectifier current. Immunoblot experiments showed that the FO-feeding induced changes in I(CaL) and I(to) were associated with corresponding changes in the protein levels of major pore-forming subunits of these channels: increase in Cav1.2 and decrease in Kv4.2 and Kv1.4. There was no change in other channel subunits (Cav1.1, Kv4.3, KChIP2, and ERG1). We conclude that long-term fish oil supplementation can impact on cardiac electrical activity at least partially by changing channel subunit expression in cardiac myocytes."

Xu X, Jiang M, Wang Y, Smith T, Baumgarten C, Wood M, Tseng G, Long-term fish oil supplementation induces cardiac electrical remodeling by changing channel protein expression in the rabbit model, PLoS One. 2010 Apr 13; 5(4): e10140.
Department of Physiology and Biophysics, Virginia Commonwealth University, Richmond, Virginia, USA.

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