Cod Liver Oil: Benefits, Side Effects, Uses, Dosage, Warnings?


COD LIVER OIL: Benefits, Side Effects, Uses, Dosage, Warnings?
The cod liver oil is derived from the liver of cod (fish). In the past, this was an extra nutritional commonly given to children, to the problem of rickets and bone growth.

As food , the oil is one of the most effective sources of fatty acids omega-3 [ref. needed] , especially acid docosa hexaénoïque commonly called DHA and eicosapentaenoic acid, or EPA, which are polyunsaturated fatty acids called "essential" because they are not manufactured by the body and only provided by food. The cod liver oil is also an excellent source of vitamin A and vitamin D , which distinguishes it from other fish oils. The nutritional value of cod liver oil, through the EPA and DHA, has been validated by the European Commission to validate claims that confirms its effectiveness for his contribution:

the normal brain development of the fetus and infants 2 (EU Regulatory Commission No. 440/2011 of 16/05/2012)
maintenance of normal heart (EU Regulatory Commission No. 432/2012 of 16/05/2012)
maintenance of normal vision (EU commission regulation No. 432/2012 of 16/05/2012)
the maintenance of normal triglyceride concentration in the blood (EU Regulatory Commission No. 536/2013 of 11.06.2013)
the maintenance of normal blood pressure (EU Regulatory Commission No. 536/2013 of 11.06.2013)
3 4

In summary, cod liver oil plays a beneficial role for


It is traditionally recommended in cases of osteoporosis 11 or fracture (vitamin D) deficiency and vitamin A which has adverse consequences for the Vision 12 and the skin . This oil was also once used by sailors of northern Europe, applied to their skin for protection from the sun. [ref. needed]


Nutrient Value for 100g 13
Vitamin A 100,000 IU
Vitamin D 10,000 IU
Saturated fatty acids 22.608 g
Monounsaturated fatty acids 46.711
Polyunsaturated fatty acids 22,541g
Manufacturing [ change | change the code ]

Atlantic cod
This oil is made ​​by cooking cod livers with steam, then crushing and settling livers cooked to extract the oil. The bad taste of the oil is now largely mitigated by advances in extraction techniques and filtration process.

In contrast, fish oils are extracted from the whole bodies of fish, during the manufacture of flours fish. If the cod liver oil and fish oils may seem somewhat similar, their chemical composition is different: fish oil contains much less vitamin A and compared to cod liver D.

Dosage form [ change | change the code ]
There are two dosage forms for a dietary supplement, or as soft gelatin capsules either directly as a liquid bottle. The advantage of the capsule is its neutrality in taste but with the constraint of ingestion. The advantage of the cod liver oil in liquid form is its improved bioavailability.

Other names: marine omega-3, polyunsaturated fatty acids, fatty acids, long-chain omega-3 fatty acids, EPA, DHA.

The fish oil as krill oil are good sources of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), two substances that are part of the family of fatty acids omega-3 . . For more information, see our fact sheet Omega-3 and Omega-6
. Note seaweed supplements have appeared on the shelves: they are good sources of DHA, but do not contain EPA.

Reduce risk factors for cardiovascular disease; decrease the risk of reinfarction.
Relieve symptoms of rheumatoid arthritis.
See legend of symbols
Likely effectiveness
Treat depression.
Uncertain effectiveness
Alleviating the symptoms of ulcerative colitis, Crohn's disease, psoriasis. Relieve menstrual pain. Prevent allergies, asthma and eczema.
For details, see the Research section on fish oil.

Intake of fish oil
To reduce belching caused by the ingestion of fish oil, take it at the beginning of the meal. The oil and less likely to stay in the stomach. The capsules enteric coating also reduce belching, since they dissolve in the intestine rather than the stomach.

Cardiovascular protection
For people in good health : consume at least 500 mg of EPA / DHA per day, or taking a supplement of fish oil or eating from February to March meals of fatty fish per week (see table in Food sources section) or by combining the two inputs.
For people with heart disease : Consume 800 mg to 1000 mg of EPA / DHA per day, or taking a fish oil supplement or by eating fatty fish every day (see table in Food sources section) or by combining the two inputs.
The diagnosis and treatment of cardiovascular disorders, even with a natural counter product, require the intervention of a health professional.

Reduction of blood triglycerides
Take supplements of fish oil providing 2 g to 4 g per day of EPA / DHA. The beneficial effect may take 6 weeks to 3 months to show up. Start with a low dose and increase gradually.
Rheumatoid arthritis
Take supplements of fish oil providing 3 g to 6 g per day of EPA / DHA. The beneficial effect may take up to three months to appear. Start with a low dose and increase gradually.
Depression and mood disorders
Although the effectiveness of fish oil and the optimal dose is not prepared, this supplement is safe and may be helpful for depression, or not in conjunction with antidepressants. The standard dose is 1 g of EPA.
See the section on the shelves for purchase advice.

The cod liver oil or halibut: avoid

The cod liver oil became popular in the XIX th century to fight against rickets. Although it is an omega-3 source inexpensive, high vitamin A content is problematic. Indeed, this vitamin accumulates in the body rather than being eliminated: a long-term excess can be toxic . Do not continuously exceed the tolerable upper intake level of 3,000 micrograms (10,000 IU) of vitamin A daily. But according to the sources of cod or halibut which was shot oil, and according to the extraction methods and packaging that the product was subjected, the vitamin A supplementation can vary from 250 mcg ( 833 IU) to 3,000 micrograms (10,000 IU) per 5 ml (1 tsp.).

Moreover, according to analyzes by the United States Department of Agriculture (USDA) on products purchased in the United States in 2001, the cod liver oils contain, in general, much of PCBs and DDT as liquid fish (see On the shelves ).

Description of fish oil
The oil most fish , like seafood and some algae, is a source of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), two fatty acids like omega-3 . The human body can make these long chain fatty acids from the omega-3 vegetable, alpha-linolenic acid (ALA), but in very small quantities. For more on this, see our record essential fatty acids (omega-3 and omega-6).

AEP participates in the development of eicosanoids Series 3, substances that play a central role in cell membranes. Series 3 eicosanoids are involved in many biochemical processes in the body: regulating blood pressure, maintaining the elasticity of blood vessels, immune responses and anti-inflammatory, blood platelet aggregation, development and brain function etc. DHA plays a minor role in terms of eicosanoids, but produces substances called resolvins protectins and contributing to the resolution of inflammation .

Much of the fish oil is a by-product of the fishing industry. It is derived from the remains of fish processing (fillets, steaks, canned, etc.).

Dietary sources of omega-3 marine
American and Canadian medical authorities have jointly determined the recommended nutrient intake for many vitamins and minerals, but not yet for EPA and DHA. In 2002, the Institute of Medicine of the United States had found insufficient data to determine the contribution. In Canada 's Food Guide , revised in 2007, does not provide specific recommendations for omega-3 marine and vegetable sources.

However, in light of much evidence now available, many experts recommend consuming 500 mg per day of EPA and DHA to benefit from the cardioprotective effects of omega-3 marine 1-5 . For people who are at risk or who suffer from coronary artery disease, the suggested daily intake is 800 mg to 1000 mg 1,3.4 . A group of North American experts agree that data are now compelling enough to set a specific recommended nutrient intake for EPA and DHA 5 .

Most fish and seafood contain EPA and DHA, in varying proportions. Generally recommends eating fatty fish such as rainbow trout, rainbows, herring, mackerel, sardines, tuna, salmon, etc. To take full advantage of the virtues attributed to omega-3 fatty acids include fish, avoid overcooking.

Amount of fish provides about 500 mg of EPA and DHA

  • 20 g of Atlantic mackerel

  • 25 g of Atlantic salmon (farmed)

  • 30 g of herring in the Atlantic or Pacific

  • 35 g of Pacific mackerel

  • 30 g of canned pink salmon

  • 40 g of sockeye salmon

  • 50 g of sardines

  • 50 g rainbow trout rainbow (livestock)

  • 65 g of white tuna (albacore or) canned

  • 100 g shrimp

Source: Wang C, Chung M, Lichtenstein A, Balk E, et al . Effects of Omega-3 Fatty Acids on Cardiovascular Disease. AHRQ Publication No. 04-E009-2. Rockville, MD: Agency for Healthcare Research and Quality. March 2004.
NB Levels of omega-3 vary according to season, weather conditions, age of the fish, because it is wild or not and preparation techniques and conservation.

Deficiency of omega-3 marine
Experts consider that not only most Westerners do not eat enough foods rich in fatty acids omega-3 , but their excessive omega-6 interferes with the metabolism of omega-3 consumption. For more information on the metabolism of these fatty acids, see our listing on the essential fatty acids .

In 2009, a panel of experts examined the mortality can be prevented by lifestyle changed. Of the 12 issues identified (smoking, alcohol, for example), a low intake of marine omega-3 comes in 6 th place in the United States. According to these experts in public health, an adequate intake could prevent each year from 63 000 to 97 000 deaths related to cardiovascular disease 6 .

History of fish oil
By studying the habits of the Inuit people of Greenland it was first interested in marine omega-3 . Indeed, although their diet is rich in fat (meat and fish oil, seal and whale), they rarely suffer from heart disease or rheumatoid arthritis. Subsequently, research has demonstrated that regular consumption of this type of fat - primarily the EPA and DHA - lowers blood triglyceride levels, "lightens" the blood, ensures the regularity of the beating heart muscle and fight the inflammation .

In the late 1990s and early XXI th century was multiplied epidemiological studies and clinical trials on the therapeutic efficacy of fish oil . This abundance of research has contributed to a better understanding of the role of omega-3 EPA and DHA. The medical authorities of the majority of developed countries have started to recommend people to eat more fish, especially oily fish , to reduce the risk of cardiovascular diseases, among others.

Prescription fish oil (not available in Canada.) In Japan, a product containing EPA purified (Epadel®) is approved as a prescription drug for treating hyperlipidemia and some symptoms of peripheral arterial disease, a condition that causes obstruction of the arteries.

In the United States, the drug Lovaza (47% EPA, 38% DHA), is approved for reducing high blood triglyceride levels. In Europe, it is marketed under the name Omacor for the adjuvant treatment of myocardial infarction secondary prevention and for the treatment of hypertriglyceridemia resistant to standard treatment (alone or in combination with statins).

Since the early 2000s, omega-3 is also a certain popularity as a treatment adjunct for depression.

Note. Fish oil is an interesting extra, but the fish does not consist of EPA and DHA. It contains many other nutrients that have together a protective effect on the heart: amino acid (taurine, arginine and glutamine) and trace elements (selenium, zinc and others), for example.

Research on fish oil
A great deal of research and synthesis focused on the effects of fish oil . We mention below the main well documented uses.

Effective Cardiovascular protection. In this regard, the roadmap fish oil is impressive 7.8 . The point where it is the only natural health product recommended by the American Heart Association for patients with coronary artery disease or high resistant to standard treatments triglycerides 1 . See Dosage section to learn more about the recommended dosages.

In primary prevention , that is to say, to reduce the risk of cardiovascular disease in healthy people, the American Heart Association recommends eating fatty fish at least 2 times per week 1 , the data are convincing that not unanimous on this point 9-12 . 2 to 3 servings per week equivalent to about 500 mg of EPA / DHA per day.

When the risk of relapse and death after a heart attack decreases, it is called secondary prevention . Some clinical studies of very large scale have shown that supplementation with fish oil , in conjunction with conventional treatments, reduced deaths, relapses of heart attack and heart attack in people who have already suffered a heart attack 13,14 . This combined treatment also reduces sudden cardiac death in patients with coronary artery disease 15 . This has been challenged by more recent tests, which indicate that the addition of fish oil does not increase the benefits of treatment including antihypertensive effects, anticoagulants, and statins 16.17 . However, the weight of evidence is clearly in favor of the effectiveness of fish oil in secondary prevention.

It is well established that fish oil has beneficial effects against several risk factors and markers of cardiovascular disease: blood lipids, blood pressure, vascular function, platelet function, inflammation, etc. 18-20 . The most notable and best documented is the reduction of too high triglycerides effect 4,21,22 . In addition, fish oil increasing the beneficial effects of statins 4.22 . It does not, however, significant effect on cholesterol levels 21 .

The JELIS study . In 2007, the first results of a huge Japanese study were published in the prestigious Lancet . The Japan eicosapentaenoic acid Lipid Intervention Study (JELIS) ​​followed, during five years, more than 18 000 subjects whose cholesterol was high: half of them took statins, the other half of statins and supplement containing 1.8 g of purified EPA. There was no placebo group. In the group taking the supplement of EPA, there were fewer coronary events in primary prevention as 23 secondary 24 .

An analysis of a subset of this large trial also indicates that the risk of recurrence of stroke was reduced by 20% 25 . These results are even more interesting than the Japanese consume initially more fish than Europeans and North Americans. They indicate that to have a beneficial effect, the dosage of fish oil, particularly the EPA, should be high.

Effective Rheumatoid arthritis. Consuming high doses of fish oil supplements can relieve some of the symptoms of this autoimmune disease. In fact, one published in 2007 meta-analysis and synthesis (2008) indicate that fish oil can relieve morning stiffness and the number of tender joints of people with rheumatoid arthritis 26 . It also reduces the dosage of anti-inflammatory medications 26.27 , a significant advantage, given their adverse effects. Indeed, diclofenac and celecoxib cause stomach irritation and increased risk of ulcers and the risk of cardiovascular disorders. Note that the relief provided by the fish oil may take 2 to 3 months to manifest, whereas the effect of anti-inflammatory drugs is immediate.

In addition, people with rheumatoid arthritis have a significantly higher risk of heart attack and sudden cardiac death 28 . The protective effects of fish oil on the cardiovascular system are in addition to reducing the symptoms of rheumatoid arthritis.

Likely effectiveness Depression. Conclusive clinical studies accumulate on the antidepressant effects of fish oil, but they generally rely few subjects and are heterogeneous (different diagnoses, dosages, methods, etc). For now, although we obtained very promising results, it remains difficult to estimate the actual effect of fish oil on depression, according to a meta-analysis published in March 2010 29 . since conducted a clinical trial in Quebec examined 432 depressed patients. The results indicate that concentrated fish oil EPA (1050 mg EPA / DHA 150 mg) was significantly more effective than placebo in relieving symptoms of depression, but only in people who did not have in Moreover, an anxiety disorder 30 . The lead researcher believes that this efficiency is comparable to that of antidepressants. For more information on this test, read our news in question: The omega-3 supplements have proven themselves against depression .

EPA or DHA or 2?
Some data point to a more pronounced effect than EPA DHA on depression 32,33,36 , but that remains to prove more convincingly 37 .

Interestingly, a working group of the American Psychatric Association (APA) has looked at the effects of omega-3 and other alternative approaches to major depression . He concluded that this treatment has promising benefits for depression, is safe and inexpensive. Before advising the marine omega-3 in case of major depression, however, the APA wants more rigorous testing with more than patients be made ​​31 . Many researchers still recommend fish oil as an adjuvant treatment of major depression 32,33 .

Furthermore, according to two recent clinical trials, the intake of fish oil was more effective than placebo in reducing symptoms of depression in the elderly. However, in one case there was used a low-dose (300 mg DHA 300 mg EPA +) 34 and in the other, a high dose (1670 mg 830 g EPA + DHA) 35 .

Multi-tasking. Since depression is common in people with heart disorders or metabolic syndrome, fish oil would therefore provide a double benefit: cardiovascular protection and prevention or treatment of depression.

Note. Despite encouraging initial tests, the data are not convincing with regard to the prevention and treatment of depression during or after pregnancy, according to two recent syntheses 38.39 . For example, a clinical trial involved 2,399 pregnant women who took a placebo or 800 mg of DHA during pregnancy: treatment was not more effective than placebo in preventing postpartum depression 40 or for promote cognitive development of children in infancy. The use of a supplement containing DHA only seems to confirm that if depression is the ASP would be the main active ingredient. According to the authors of a summary, fish oil may still be beneficial and safe for women with postpartum major depression 38 . Indeed, safety is an important advantage in pregnant or nursing women.

Other areas of research. Besides thousands of already published on the effects of fish oil, at least 200 studies are under way on a variety of subjects, cardiovascular, mental and mood being head studies List 41 . Here are some other diseases on which the researchers believe that fish oil may have beneficial effects:
- Alzheimer's disease, cognitive decline 42-44 ;
- allergies, asthma and eczema 45-50 ;
- Breast Cancer 51
- macular degeneration 52 ;
- menstrual pain 53-56 .

The VITAL trial (Vitamin D and Omega-3 Trial), funded by the National Institutes of Health in the United States, was conducted among 20,000 people aged 60 and over. Its purpose is to check if the daily intake of 1 g of fish oil and 2,000 IU of vitamin D may reduce the risk of heart disease, stroke and cancer in subjects having no history of these diseases.

Watch out
The diagnosis and treatment of heart disease , even with a natural counter product, require the intervention and follow-up of a health professional.
Cod liver oil or halibut. liver oils fish are not recommended as a source of omega-3, because of their high content of vitamin A. If used regularly, it must be ensured not continuously exceed the tolerable upper intake level of vitamin A (3000 mcg or 10,000 IU per day). Check the label on the supplement.
Persons sensitive to bruising and those who suffer from blood disorders or taking anticoagulant drugs should avoid high doses of fish oil.
People suffering from hemophilia acquired or inherited should consult their doctor before taking fish oil supplements.
Mercury and other contaminants. According to the results of analyzes carried out in recent years, it seems that fish oil does not contain significant amounts of mercury, polychlorinated biphenyls (PCBs) and dioxins (toxic pollutants ), probably due to the quality control of the raw material provided to supplement manufacturers 57-59 .
Fish allergy. Persons with a severe allergy, that is to say, like anaphylaxis , fish should not take fish oil. However, if it is an allergic skin reaction, we can give it a try. Indeed, allergies are caused by the fish they contain proteins and not by their oils. These are highly purified and free of proteins.

. Serious one species of fish allergy In severe a type of fish allergy in particular, such as salmon, things get a little complicated: Despite labels that claim that fish are selected (anchovy or sardine, by example), the consumer can never be sure that it is only those fish. Indeed, much of the fish oil is in fact a by-product of the fishing industry. It is derived from the remains of fish processing (fillets, steaks, canned, etc.). Even if there is a larger amount of these fish, there may also have moieties derived from other types of fish.

Jean-Yves Dionne, pharmacist
April 2011

Adverse effects
Apart from the taste, which many find unpleasant, and hints of fish, side effects are rare in the usually recommended and usually limited to mild gastrointestinal assays. To reduce the smell of fish, take the supplements before meals or purchase supplements with enteric coating.
In high doses, the fish oil can cause nausea, loose stools and nosebleeds.
With plants or supplements
The effects of fish oil at a rate of more than 4 grams of EPA / DHA per day, can be added to those of plants or supplements that have antiplatelet or anticoagulant action.
With drugs
The effects of fish oil at a rate of more than 4 grams of EPA / DHA per day, can be added to those of synthetic drugs that have antiplatelet or anticoagulant action.
It was believed that fish oil might interfere with drugs that control blood sugar in diabetics, but the dosages used in the study, this treatment had no effect on sugar levels in the blood of participants 61 .
The opinion of our pharmacist
The use of fish oil for cardiovascular indications is probably the most important. Omega-3s help significantly lower blood triglycerides and have an effect on several other cardiovascular risk factors. These effects are not always very marked, but the sum of them helps reduce cardiac mortality significantly.

Dosage and report

A notion about the fish oil is particularly overused by marketing: the concentration ratio of EPA and DHA. In fact, the EPA / DHA ratio is really important for indications related to the nervous system, mood disorders, depression, resistance to stress, anxiety, etc. In these cases, the amount of EPA must be high while that of DHA must be low. Search for products having ratios EPA / DHA between 20: 1 and 7: 1. The recommended total dose of EPA is about 1000 mg per day, while the DHA should not exceed 150 mg per day.

For all other indications, the current data do not allow us to determine which fatty acid, EPA or DHA, is critical. Experts agree that the total dose of 2 is more important than their relationship. It is known that DHA has an important effect on brain development, that is to say the fetal period through early adolescence. No clinical research has shown other specific effect DHA alone.

Regular consumption

Even if they are recognized in health applications, omega-3s are not drugs, but many nutrients. It is therefore not expect rapid effects. As healthy eating is not the story of a meal, but a way of life, the omega-3 consumption should be regular and occur over a long period to bring benefits. And omega-3 are not a panacea. This is not because we are starting to take a fish oil supplement that cures rheumatoid arthritis! But one can expect some relief of symptoms if taken long term and in a sufficient amount.

Jean-Yves Dionne, pharmacist
April 2011

On the shelves
Read the labels

The concentration of omega-3 fish oil supplements may vary widely. It is important to read the label because it is necessary to differentiate the dose of omega-3 dose of oil. For example, the majority of supplements currently available on the market contain only 300 mg of omega-3 per capsule of 1 g (180 mg of EPA and 120 mg DHA), but some contain more. Some oils are available in liquid form rather than capsules: the label should clearly indicate the amount of EPA and DHA that provides 1 c. Tea or 1 tsp. Product table.

Check how oil volume or how many capsules represent the amounts of EPA and DHA displayed on the label. Some manufacturers fit the quantities supplied by several capsules, which can be confusing when comparing products. In the case of liquid supplements, it is normal dosage posted by spoonful tea is higher than a capsule, since this dose is approximately 5 capsules.

The liquid fish oil

The fish oil in liquid form is sometimes offered at a lower price than the capsules. When taking large amounts of fish oil, this presentation may be more convenient than swallowing many capsules. Because fish oil has a strong taste, most manufacturers offer liquids flavored with lemon or orange.

Capsule size

When you buy fish oil capsules for the first time, make sure the format you need. In fact, most are quite large and may be difficult to swallow.

According to analyzes by the United States Department of Agriculture (USDA), 14 fish oils purchased in the United States in 2001, of which 7 were cod liver oil , the latter contain, in general, significantly more PCBs and DDT. Moreover, while the concentrations of PCBs and DDT in fish oil had decreased from an analysis conducted eight years earlier, that of cod liver oil had remained similar 57 .
According to analysis done by Health Canada on 30 Omega-3 marine sold in countries all contain minimal residue of PCBs and pesticides quantities except oils shark and seal. The products based on fish oil contained considerably fewer residues that fish portion 58,59 .

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