Cod Liver Oil: A Natural Source for Omega 3, and Vitamins A and D

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Along with providing information on whether cod liver oil supplements might be right for you, this article also links to Fullscript where you can buy cod liver oil supplements online through the secure healthcare formulary and get free shipping and 20% off the retail price of professional-grade supplements.

Cod liver oil is well known for its rich nutritional content, including omega-3 fatty acids, vitamins A and D. This article aims to provide insight into how these nutrients contribute to overall health.

What Is Cod Liver Oil?

Cod Liver Oil is obtained from the liver of cod fish, predominantly harvested in the North Atlantic. This dietary supplement is noted for its content of omega-3 fatty acids and vitamins A and D, which are associated with various health benefits. These benefits cover support for cardiovascular health, improvement in bone density, and enhancement of immune system function.

This supplement has a long history of use, valued for both its nutritional content and health-promoting properties. The process of extracting the oil ensures that it retains its beneficial components, making it a source of essential nutrients that may not be sufficiently consumed through the diet alone.

Nutrient Content of Cod Liver Oil

Here are the estimations for nutrients you will find in cod liver oil

NutrientPer Teaspoon Cod Liver Oil
(5 mL)
Recommended Daily Allowance
Upper Limit
EPA (Eicosapentaenoic Acid)300 mg
DHA (Docosahexaenoic Acid)370 mg
Vitamin A1500 IU700 – 900 mcg for adults10,000 IU
Vitamin D130 to 340 IU600 IU for most adults
These values are approximate.

Potential for Toxins In Cod Liver Oil

Although Cod liver oil is a good source of the omega-3 fatty acids EPA and DHA as well as vitamins A and D, there are some things to watch. Consumers need to be aware of concerns about the presence of contaminants such as mercury, PCBs (polychlorinated biphenyls), and dioxins in fish oil supplements. These environmental toxins accumulate in marine environments.

Large fish like tuna and cod tend to accumulate more toxins than smaller fish due to their position higher up in the food chain and their longer lifespan, which allows more time for bioaccumulation of substances like mercury and other pollutants from their prey.

Mercury, a heavy metal, is of particular concern due to its potential for causing neurological damage and other health issues. It tends to accumulate in the muscle portion of fish rather than fat portions. Dioxins and PCBs tend to concentrate in the fatty portions of fish. PCBs and dioxins, once widely used in industrial applications, are known for their persistence in the environment and potential to disrupt hormonal function in humans.

Quality supplement manufacturers are careful to take measures to reduce PCB contaminants although such efforts are largely voluntary. Molecular distillation and the use of activated carbon filters can effectively remove impurities without diminishing the oil’s nutritional value. While the FDA sets tolerances for PCBs in fish oil supplements, it does not specifically mandate testing for PCBs by manufacturers. Be careful to choose quality brands.

What Are the Benefits of Cod Liver Oil?

Cod liver oil is a rich source of omega-3 fatty acids, specifically EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid), which are known for their heart health benefits and ability to reduce inflammation. It is also high in vitamins A and D, which play crucial roles in maintaining healthy vision, immune function, and bone health. Vitamin A is essential for eye health and immune system function, while vitamin D is vital for calcium absorption and bone metabolism.

  • Rich in Omega-3 Fatty Acids: Supports heart health by reducing triglycerides and blood pressure.
  • High in Vitamins A and D: Essential for maintaining healthy eyesight, immune function, and bone health.
  • May Reduce Inflammation: Omega-3s and vitamin D in cod liver oil can help decrease inflammation, benefiting conditions like arthritis.
  • Supports Brain Health: Omega-3 fatty acids are vital for maintaining brain function and may improve mood disorders.
  • May Improve Bone Health: Vitamin D plays a crucial role in calcium absorption and bone metabolism.
  • Supports Healthy Skin: Vitamins A and D, along with omega-3 fatty acids, can promote skin health by enhancing hydration and elasticity.
  • Supports Eye Health: Omega-3 fatty acids and vitamin A in cod liver oil contribute to maintaining good vision and may prevent age-related macular degeneration.
  • Enhances Immune System Function: Vitamin D in cod liver oil plays a critical role in immune health, helping to protect against infections and illnesses.
  • May Reduce Risk of Autoimmune Diseases: Vitamin D has been linked to a lower risk of certain autoimmune diseases, such as type 1 diabetes and multiple sclerosis.
  • Supports Mental Health: The omega-3 fatty acids in cod liver oil are linked to a reduced risk of depression and anxiety.
  • May Improve Respiratory Health: Vitamin D can help reduce the risk of respiratory infections and may be beneficial for individuals with asthma or COPD.
  • Promotes Healthy Pregnancy: Omega-3 fatty acids are crucial for fetal brain development and may reduce the risk of premature birth.

Are Cod Liver Oil Supplements Safe?

Cod Liver Oil supplements are generally considered safe for most people when taken in recommended amounts. However, due to its high vitamin A content, excessive intake can lead to vitamin A toxicity, which emphasizes the importance of adhering to dosage guidelines. Additionally, since it’s derived from fish, there’s a concern about contaminants such as mercury or PCBs, though many manufacturers purify their products to eliminate these risks.

Medication Interactions with Cod Liver Oil

  • Blood Thinners (e.g., Warfarin, Heparin): Cod Liver Oil’s omega-3 fatty acids can enhance the blood-thinning effect, potentially increasing the risk of bleeding.
  • Antihypertensive Medications: Cod Liver Oil may lower blood pressure, potentially causing blood pressure to drop too low when taken with medications designed to reduce hypertension.
  • Nonsteroidal Anti-Inflammatory Drugs (NSAIDs, e.g., ibuprofen, aspirin): Cod Liver Oil can affect blood clotting, possibly amplifying the risk of bleeding when combined with NSAIDs that also affect clotting.
  • Orlistat: This weight loss medication can interfere with the body’s ability to absorb Cod Liver Oil, reducing the effectiveness of the supplement.
  • Vitamin A Supplements: Since Cod Liver Oil contains vitamin A, combining it with additional vitamin A supplements could increase the risk of vitamin A toxicity.
  • Vitamin D Supplements: Similar to vitamin A, taking Cod Liver Oil with additional vitamin D supplements may lead to excessive vitamin D intake.

Supplement Interactions with Cod Liver Oil

  • Vitamin A Supplements: Taking these in addition to Cod Liver Oil, which is rich in vitamin A, could lead to an excess intake of vitamin A, increasing the risk of toxicity.
  • Vitamin D Supplements: Cod Liver Oil also contains vitamin D; adding more through supplements might result in vitamin D excess, which could cause hypercalcemia and other health issues.
  • Omega-3 Fatty Acid Supplements: Since Cod Liver Oil is a source of omega-3s, combining it with other omega-3 supplements could lead to an excessive intake, potentially affecting blood clotting and increasing the risk of bleeding.
  • Antioxidant Supplements (e.g., Vitamin E): While antioxidants support health, taking them in high doses alongside Cod Liver Oil might amplify blood thinning effects, particularly in people on blood-thinning medication.
  • Calcium Supplements: High doses of vitamin D from Cod Liver Oil in combination with calcium supplements might lead to hypercalcemia, especially if intake exceeds recommended levels.

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Why Professionals Choose the Fullscript Formulary

Your health is on the line. Health professionals know that many other online and retail options set a very low bar for quality–sometimes amazingly low. The Fullscript formulary is the most secure online source for the highest quality brands securely sourced to assure freshness and purity. Here’s what makes Fullscript the best:

  • Meticulous vetting of brand quality. Health professionals trust Fullscript to continuously monitor the quality of each item on the platform. Other retailers operate with profit as their highest or only motive when choosing brands. Fullscript cares only about quality and reliability. Unlike discount stores, large online marketplaces, and other retailers you won’t find ingredients sourced from China or other questionable locations or companies.
  • Always 20% Discount off the manufacturer’s retail price. When you follow any link from, you will automatically get 20% off the retail price.
  • Free shipping over $50.
  • Freshness. Fullscript prioritizes freshness over bulk buying even if it means an increased risk of briefly being out of stock.
  • Top quality phone and online support. When you call, knowledgeable humans at Fullscript answer your questions.
  • How It Works:
    • Easy Sign-up & No Spam Email: Click the “View Product” button below to be taken to Fullscript’s login page where you can quickly create your secure account with just your name, email, and phone number. Then you will be taken directly to the product page.
    • Wide variety of supplement options: Once you sign in to your account, you are not limited to the products listed below. You will see similar items listed at the bottom of each product page on Fullscript.
    • Search For What You Want: Once inside Fullscript, you can search for the exact brands and products you want from their wide selection of quality brands.

Arctic Cod Liver Oil Lemon by Nordic Naturals

  • Supports heart and brain health*
  • Essential for proper function of the immune and nervous systems*

Nordic Naturals has always used 100% Arctic cod livers in our cod liver oil (CLO) formulas—no fish body oils or synthetic additives are ever used. Arctic cod (Skrei) has the highest DHA, vitamin A, and vitamin D content of any cod species. Each serving provides approximately 600 mg of the essential omega-3 fatty acids, EPA and DHA, fulfilling the expert recommendation of a minimum of 500 mg per day.

Three soft gels daily, with food, or as directed by your health care professional or pharmacist.

Amount Per Three Softgel Serving
Calories … 25
Calories from Fat … 25
Total Fat … 3.0g
Saturated Fat … 0.6g
Trans Fat … 0g
Cholesterol … 10mg
Vitamin A … 150-600IU
Vitamin D … 0-12IU
Total Omega-3s … 750mg
EPA … 240mg (Eicosapentaenoic Acid)
DHA … 360mg (Docosahexaenoic Acid)
Other Omega-3s … 150mg

Ingredients: purified arctic cod liver oil, soft gel capsule (gelatin, glycerin, water, natural lemon flavor), natural lemon flavor, d-alpha tocopherol, rosemary extract (a natural preservatives).

Arctic Cod Liver Oil Lemon by Nordic Naturals

The fish oil that started it all, Nordic Naturals classic Arctic Cod Liver Oil is made from 100% wild Arctic cod from the Norwegian Sea. No fish body oils or synthetic vitamins or additives are ever used. This non-concentrated formula surpasses strict international standards for freshness and purity set by the European Pharmacopoeia, and is considered the gold standard for cod liver oil. Available in both liquid and soft gels, and in flavored and unflavored formulas.
Take one teaspoon daily, with food, or as directed by your healthcare professional or pharmacist. For best results, please refrigerate and use within three months after opening.

Amount Per 1 Teaspoon (5ml) Serving
Calories … 40
Total Fat … 4.5g
Saturated Fat … 1g
Trans Fat … 0g
Cholesterol … 20mg
Vitamin A … 40mcg RAE
Total Omega-3s … 1060mg
EPA … 340mg (Eicosapentaenoic Acid)
DHA … 510mg (Docosahexaenoic Acid)
Other Omega-3s … 210mg

Ingredients: purified arctic cod liver oil, natural lemon flavor, d-alpha tocopherol (antioxidant), rosemary extract (a natural preservative).

Food First!

Although this article discusses supplements in detail, don’t forget that we are absolutely committed to the “Food First” approach to nutrition. When it comes to your health, the totality of your eating habits far surpasses the impact of individual nutrients or any single supplement you consume. Even though this article doesn’t delve into the broader picture of your overall diet, it’s crucial to keep this element at the forefront of our minds. Your food needs to provide all the vitamins, minerals, fiber, and phytochemicals to nourish your body systems down to the cellular level.

Food choices, rather than supplements, are the most critical factors for a healthy gut microbiome. These trillions of tiny inhabitants in your gut affect your brain waves; they orchestrate your immune system. They possess the power to create molecules that can switch genes on or off and are even capable of synthesizing neurotransmitters. Opting for organic foods and steering clear of plastic packaging (including those labeled BPA-free) is a smart move to limit toxin exposure. The sum of all these parts leads to a powerful conclusion: the ultimate key to your health lies in the quality and balance of the food you consume. Supplements are secondary.

To Sum It Up

Cod Liver Oil supplements offer a variety of health benefits due to their rich content of omega-3 fatty acids, vitamins A and D. These nutrients support heart health, bone density, and immune function. While beneficial, it’s important to be mindful of dosage and potential interactions with medications and other supplements. Balancing Cod Liver Oil intake with other nutrient sources can contribute to overall well-being.

This Article is Not a Substitute for Medical Advice

Dietary supplements are not designed to diagnose, treat, cure, or prevent any disease. The Supplement Sciences website seeks to provide comprehensive access to the most relevant supplement information along with convenient online ordering. We do not provide medical advice and cannot guarantee that every product suggested is completely without risk. Since each person is unique in their health history and medication use, it is important to discuss supplements with your personal physician. Specifically, pregnant women and individuals being treated for cancer or liver or kidney problems must consult their physician about every nutritional supplement they plan to take. People taking medications for the treatment of HIV or with a history of organ transplant must not take supplements without consulting with their physician.

About the Author

Stephanie Figon, MS, RDN, LD

Founder of NutriScape.NET. As a dietitian since 1992, Steph Figon has had experiences in consulting, 15 years in clinical, and has operated a private practice nutrition counseling office for since 2011. Connect on Linkedin

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