Highly Purified Norwegian Cod Liver Oil
Also known as: Cod liver oil, Norwegian cod liver oil, Gadus morhua oil, Cod Liver Oil
Overview
Cod liver oil is an oil extracted from the liver of codfish (Gadus morhua), traditionally used as a dietary supplement. It is particularly rich in omega-3 fatty acids such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), as well as fat-soluble vitamins A, D, and E. This supplement is commonly utilized to support cardiovascular health, reduce inflammation, and maintain adequate vitamin D levels, especially in regions with limited sunlight during certain months. It is available in liquid and capsule forms. A substantial amount of research backs its efficacy, showcasing positive implications for various health outcomes, particularly related to heart health. The collective body of evidence is bolstered by well-conducted randomized controlled trials (RCTs) and meta-analyses demonstrating its favorable safety and efficacy profile.
Benefits
Cod liver oil has several evidence-based benefits that primarily support cardiovascular health. Systematic reviews and meta-analyses demonstrate that its omega-3 fatty acids reduce the risk of cardiovascular events, with one analysis showing a reduction in non-fatal myocardial infarction (relative risk 0.87) and coronary heart disease events (RR 0.91). Furthermore, individuals with pre-existing cardiovascular disease may experience greater benefits. While there are indications that omega-3 fatty acids have anti-inflammatory properties, the evidence specific to cod liver oil is less prevalent. Secondary benefits may include potential positive effects on brain health, though robust evidence is lacking. Overall, the most clinically significant benefits occur after prolonged supplementation over several months.
How it works
The omega-3 fatty acids EPA and DHA in cod liver oil are incorporated into cell membranes, enhancing membrane fluidity and influencing cellular signaling pathways. They aid in reducing inflammation by inhibiting pro-inflammatory molecules and cytokines. Additionally, they positively affect cardiovascular health by lowering triglyceride levels, reducing blood pressure, and enhancing platelet function. These fatty acids engage various molecular pathways, particularly those involved in inflammation and cardiovascular health, exhibiting effects on the arachidonic acid cascade and gene expression related to these processes.
Side effects
Cod liver oil is generally safe when consumed at recommended doses, but high doses can lead to certain adverse effects. Common side effects, occurring in more than 5% of users, include mild gastrointestinal issues such as fishy aftertaste, nausea, and diarrhea. Uncommon side effects affecting 1-5% of users may involve increased bleeding risk, especially at elevated doses due to the oil's antiplatelet properties. Rarely (less than 1% incidence), allergic reactions may occur. Caution is advised for individuals on anticoagulant medications or those with bleeding disorders. Pregnant or breastfeeding women should seek medical advice regarding high doses to mitigate any potential risks to the fetus or child.
Dosage
For cardiovascular health, a minimum effective dose of around 1 gram of combined EPA and DHA per day is recommended. Optimal dosages typically range between 1 to 3 grams per day, with a generally accepted upper limit of around 3 grams, unless under medical supervision. Cod liver oil can be taken at any time, though absorption may be enhanced when ingested with a fatty meal. Both liquid and capsule forms can be effective, but liquid forms may offer better bioavailability. There are no specific cofactors required for optimal absorption, but maintaining a balanced diet is advisable.
FAQs
How can I minimize the fishy aftertaste?
Taking cod liver oil with meals or opting for flavored varieties can mitigate the fishy aftertaste.
Can it be used during pregnancy?
Consult a healthcare provider before using high doses during pregnancy to ensure safety.
How long does it take to see benefits?
Cardiovascular benefits from cod liver oil are typically observed over several months to years.
Is it safe to take with other medications?
Generally safe, but caution should be observed when taken with anticoagulant medications due to increased bleeding risk.
Does cod liver oil prevent respiratory infections?
No, there is no significant evidence that cod liver oil prevents SARS-CoV-2 infection or other acute respiratory infections.
Research Sources
- https://www.bmj.com/content/378/bmj-2022-071245 – This randomized controlled trial with over 34,000 adults examined the efficacy of cod liver oil in preventing SARS-CoV-2 infections, finding no significant benefits in terms of infection rates or acute respiratory illnesses.
- https://www.thelancet.com/journals/eclinm/article/PIIS2589-5370(21)00277-7/fulltext – A systematic review and meta-analysis including 38 RCTs demonstrated that omega-3 fatty acids from sources like cod liver oil significantly reduce cardiovascular mortality and risk of non-fatal myocardial infarction, showcasing high-quality evidence.
- https://pubmed.ncbi.nlm.nih.gov/14679378/ – This study examined the use of fish oil supplements in over 400,000 participants, linking regular intake to reduced events of major cardiovascular risk and mobility enhancements in users free from cardiovascular diseases.
- https://www.tandfonline.com/doi/full/10.1080/10408398.2018.1425978 – The study assessed the influence of omega-3 fatty acids on cardiovascular disease, concluding that their consumption can reduce the transition from atrial fibrillation to serious cardiovascular events, emphasizing their preventative potential.
- https://bmjmedicine.bmj.com/content/3/1/e000451 – This meta-analysis focused on the adverse effects of omega-3 supplementation, highlighting bleeding risks associated with excessive dosages while affirming the general safety of recommended doses.