Battle of the Fish Oils: Cod Liver Oil vs. Fish Oil

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    Finding the right supplement for your health requires knowing your options. Let’s take a look at some of the differences between cod liver oil and fish oil.

    The good news is that both cod liver oil and fish oil are a good way to get in omega-3s. Omega-3 fatty acids are essential, meaning they cannot be made in the body. This means that either food or supplements need to be consumed to get adequate levels for optimal health.

    There are three types of omega-3s:

    • EPA (Eicosapentaenoic Acid)
    • DHA (Docosahexaenoic Acid)
    • ALA (Alpha-Linolenic Acid)

    Each of these types of omega-3 fatty acids have distinct roles and benefits. EPA and DHA are the omega-3s that are predominantly found in fish oils. ALA must first be converted in the body, so it is an indirect source of these essential fats.

    Although there is no official recommended dietary allowance for omega-3s, the adequate intake has been established based on the generalized needs of healthy people. For adults born female, the adequate intake is 1.1 grams. For adults born male, it is 1.6 grams. The recommended intake during pregnancy is 1.4 grams. Healthcare providers may suggest a higher intake depending on a person’s individual health needs, family history, or dietary intake.

    Cod liver oil and fish oil both contain omega-3s, but there are some key differences. Fish oil comes from various parts of several types of fish. Cod liver oil comes entirely from the fish liver, usually from cod (hence the name).

    Finding the right supplements for your health requires knowing your options. Let’s take a look at some of the differences between cod liver oil and fish oil.

    Cod Liver Oil vs. Fish Oil: Which is Best?

    There are other differences between fish oil and cod liver oil. Where they are sourced from is a primary one. We’ll discuss the differences and similarities in detail.

    Where do the oils come from?

    Cod liver oil is made from Atlantic cod livers. It is often used as a nutritional supplement and is high in nutrients. The only source of cod liver oil is the liver of a cod fish. It has a higher concentration of vitamin A and vitamin D, but can have lower levels of omega-3 fatty acids than standard fish oil. However, it is a of DHA.

    Fish oils are derived from the tissues of numerous types of fish that live in cold water. Fish oils are extracted from fatty fish, usually salmon, trout, mackerel, tuna, herring, and/or sardines.

    Differences in Omega-3 Content

    One of the main reasons people choose to supplement with these oils is due to their omega-3 content. However, the exact concentration of omega-3s can differ between these two types of oils. An average fish oil supplement contains about 1,000 mg of fish oil, of which approximately 180 mg is EPA and 120 mg is DHA. Of course, these doses can vary widely depending on the brand and source of fish.

    On the other hand, cod liver oil is not just a source of omega-3s. It also contains significant amounts of essential vitamins like vitamins A, D, and E. Depending on the serving size and formulation, cod liver oil can sometimes contain as much omega-3s as some fish oil supplements.

    If you are looking to base your decision on the omega-3 content, you should read the labels and compare the EPA and DHA concentrations in different products.

    Taste and Palatability

    When it comes to the taste of fish oil versus the taste of cod liver oil, a lot boils down to your personal preference. Cod is considered a milder fish, and a result some people find it more palatable. If you’re new to fish supplements or sensitive to strong taste, cod liver oil might be better for you.

    On the flip side, the flavor of fish oil can vary significantly depending on the source of the fish and the processing methods used by the brand. Some fish oils might have a more robust fishy taste, while others might be milder, depending on the fish species and the purification processes used. Ultimately, the best choice is subjective and based on personal taste preferences.

    Cost and Affordability

    Generally, the price of these supplements is influenced by factors such as brand, extraction methods, and purity. However, cod liver oil tends to be a bit pricier than fish oil since it is sourced from a specific fish.

    Supplement forms

    Both cod liver oil and fish oil are available in softgel and liquid form. The nutrient content depends on the source and dose.

    Care/of’s fish oil supplement is in the form of a softgel and is sustainably harvested from wild-caught small fish that are high in nutrients. The oil undergoes a unique extraction and purification process that maintains abundant levels of omega-3 (EPA and DHA).

    Health Benefits of Cod Liver Oil

    Scientists have performed numerous studies on the benefits of cod liver oil. Let’s take a look at what some of these key benefits are.

    Immune System Health

    Cod liver’s concentration of vitamins A and D support a healthy immune system. These two vitamins play a role in developing immune cells, as well as maintaining the structural integrity of protective barriers in the skin and mucosal lining. In addition to these vitamins, the omega-3 content in cod liver oil helps support the communication between immune cells.

    Skin Health

    Cod liver oil supports skin health thanks to high vitamin A content. Vitamin A is known for playing an important role in skin membrane health. Additionally, its omega-3s are pivotal for supporting healthy keratin homeostasis, skin barrier function, and fluid balance.

    Joint Health

    Cod liver oil may support healthy joint and tissue responses. In clinical studies, cod liver oil has performed better in supporting joint comfort than a placebo. Other studies have shown similar results with fish oil, making it clear that these joint health benefits are likely due to the omega-3 content that these oils contain. Further, the omega-3 fatty acids found in cod oil have been shown to support healthy immune responses, including how cartilage is affected.

    Respiratory Health

    Cod liver oil may also support healthy lung function, largely due to its omega-3 fatty acid content. A higher intake of omega-3s, especially from DHA, was linked with healthier long-term lung function in more than 15,000 participants. Data gleaned from a prospective cohort study with over 152,000 individuals underscored the significance of these fatty acids, revealing that regular fish oil supplement intake is strongly associated with long-term healthy lung function. Since both fish oil and cod liver oil provide abundant omega-3s, potentially promoting healthy lung and respiratory support.

    Who should take cod liver oil?

    The nutrient profile of cod liver oil makes it particularly beneficial for those seeking immune support, joint health benefits, and healthy skin. It is also a great supplement to use if you live in an area with limited sunlight, since it can be a good source of vitamin D.

    Benefits of Fish Oil Supplements

    Cod liver oil and fish oil mainly differ in their nutritional composition. While these two vitamins both contain omega-3s, their concentrations of particular omega-3 can differ.

    Bone Health

    The EPA and DHA in fish oil may support healthy bones. Animal research has found that both moderate and high dose fish oil supplements can support healthy bone density, especially as part of the aging process. However, this needs to be replicated in humans to know if the results hold.

    Another study suggests that fish oil is best for bone health support when supplemented with calcium.

    Age-related Eye Health

    Some researchers found that omega-3 fatty acids in fish oil may benefit eye health. A study of 478 people who used computers frequently and experienced dry eyes found that oral omega-3 supplements supported healthy eyes by decreasing tear evaporation rate and helping with overall healthy eye lubrication.

    Heart Health

    Omega-3s from fish oil have been extensively researched for heart health benefits. The American Heart Association recommends consuming at least 2 servings of fish weekly or using fish oil supplements for healthy omega-3 intake. Studies have shown that fish oil helps maintain healthy triglyceride levels already within normal range along with other heart health-related markers.

    Brain Health

    A meta-analysis done in 2018 found that taking omega-3 supplements was generally linked to better brain function, especially in people with low levels of fatty acids. A 2005 clinical study found that omega-3 supplementation was associated with an improvement in attention and mood for the omega-3 group versus the placebo group. More recent research has confirmed that omega-3 fatty acids support healthy learning, memory, cognitive well-being, and healthy circulation in the nervous system.

    Who should take fish oil supplements?

    Fish oil supplements, known for their omega-3 content, might be ideal for those looking to support heart health, cognitive function, or healthy bones and joints. Those who are pregnant or breastfeeding might also benefit from a fish oil supplement since DHA is vital for fetal brain development.

    Safety Concerns of Cod Liver Oil and Fish Oil

    Based on the vitamin A content in cod liver oil, those who are pregnant or breastfeeding should avoid supplementing to prevent potential toxic levels of vitamins. Cod liver oil has vitamins A and D in addition to the omega-3s. High doses of vitamin A during the first trimester of pregnancy may have teratogenic impacts that can negatively impact the pregnancy. The upper limit of vitamin A for all adults, including during pregnancy, is 3000 mcg RAE. The upper limit for vitamin D is 4,000 IU or 100 mcg.

    If you take any blood thinning medication, always discuss supplementation options with your healthcare provider.

    Potential symptoms people report with either fish oil or cod liver oil include discomfort related to the digestive system. The best way to prevent symptoms is to have the oil with food or right before bed.

    Consult with your healthcare provider before starting a supplement regimen.

    The Bottom Line

    The nutrient content of cod liver oil and fish oil supplements is a major difference between the two. Many nutrients in both fish oil and cod liver oil are beneficial to health. As we have discussed, omega-3 fatty acids are the primary component of both cod liver and fish oil. However, vitamins A and D are also present in cod liver oil.

    This may seem like a minor distinction, but it has far-reaching implications for your health. That's why comparing fish oil and cod liver oil is essential before deciding to use either. What is best for you depends on your health needs and goals. Fish oil may be best if you are already supplementing with Vitamin A and D from other sources.

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    Mia McNew, MS
    Medical Content Reviewer
    Mia McNew is a nutrition science researcher with bachelor's and master's degrees in nutrition science and biochemistry. She holds additional certifications in clinical nutrition and formerly managed a private nutrition practice focusing on fertility and the management of chronic health and autoimmune disorders. She is currently pursuing a PhD in human nutrition with a research focus on disability, underserved populations, and inequities in popular nutrition therapy approaches. She has extensive experience as a fact-checker, researcher, and critical research analyst and is passionate about science and health communications that provide practical support.
    Jordana Tobelem, RD
    Freelance Contributor
    Jordana Tobelem is a Registered Dietitian who enjoys helping others become the best versions of themselves through proper nutrition education. Jordana is passionate about promoting lifestyle changes through nutrition, physical activity, and behavior to create a superior quality of life. She uses her experience in the clinical field of dietetics to provide consulting services to an array of healthcare brands and companies. Jordana loves finding the most current research in nutrition to create meaningful content to share with her clients. Jordana has been a member of the Academy of Nutrition and Dietetics since 2018 and also holds certifications in both Personal Training and Health Coaching.