Undisputedly, one of the most popular products among nutraceuticals, cod liver oil is highly unlikely to be dislodged from its highly ranked global preference. A variety of benefits, and the age-old practice of making the supplement a regular part of intake during formative years of children, continue to drive its demand. Following subsections offer a detailed look at the nutritional supplement and the mechanism of action of various nutrients in the oil. Information also includes ideal dosage of cod liver oil for kids, apart from a compilation of possible undesirable effects of the oil. This is intended to help individuals prevent side effects and enjoy the complete benefits from the nutritional supplement.

Overview – why cod liver oil?

Cod liver oil is known to be one of the best sources of vitamins A, D and omega-3 fatty acid. Various benefits are attributed to the oil and supplements that contain the oil. For instance, the oil is known to prevent blood clotting, reduce pain, inflammation and is also used as a part of holistic treatment for diseases of the heart. It is also used as a form of supportive treatment regimen for patients diagnosed with depression, arthritis, and other various conditions. However, it is important to note that medically, the claims of benefits of cod liver oil in treating certain conditions, has not been fully proved.

Cod liver oil has been used over the ages as an important nutritional supplement for children, mainly because of the benefits in improving the cognitive functions of kids, apart from boosting immunity. It is used as a part of preventive therapy for conditions such as rickets, osteomalacia and osteoporosis.  It is also known to have proven benefits on helping enhance vision. The oil is extracted from the liver of cod fish, and the benefits are attributed to Vitamins A and D, omega-3 fatty acids, EPA, acronym for eicosapentaenoic acid and DHA, acronym for docosahexaenoic acid.

All-purpose nutritional supplement

Initially, the supplement was recommended due to the vitamin d content, which is known to help treat vitamin D deficiency and various conditions linked with the deficiency. This slowly expanded to include other conditions, and the supplement acquired huge popularity. While certain claimed benefits are yet to be medically supported with documented reports, it is considered as a useful supplement for patient’s post-heart attacks.

Mechanism of action of cod liver oil

To answer the question how does cod liver oil help? it is important to know more about the various nutrients and the mechanism of action of each nutrient – for instance, eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), vitamin A and vitamin D.  The manner in which EPA and DHA acids help to bring about a reduction in serum triglyceride levels is assumed to be the sequence of actions that result in increased fatty acid oxidation and reduced triglyceride synthesis. Additionally, the two acids are known to promote apolipoprotein B degradation, apart from speeding up the elimination of VLDL (very-low-density lipoprotein) particles. As a result of this, the volume of VLDL particles reduce, which in turn brings about reduction in triglycerides.

In addition to the above, the amoegaa-3 fatty acids in fish oil are known to possess or exert certain effects, that result in an increase in ventricular fibrillation threshold.  Omega-3 acids are also known to bring about a reduction in sodium and L-type calcium currents. The results of reduction in sodium ion current, and calcium ion current are antiarrhythmic effects.

Vitamin A and its mechanism of action 


As mentioned above, Vitamin A is present in cod liver oil in the right levels, and this delivers excellent outcomes for many functions, including retinal function.  The mechanism of action of Vitamin A is attributed to the conversion in the retina to a different form, which in turn has a function in the transduction of light, which is essential for vision, and the perceptions of light, from the nerve impulses.  Individuals with night vision problems experience improvement when on the supplement, mainly because of the binding of Vitamin A to different types of retinoid receptors.

Vitamin D and its mechanism of action

This is commonly available in various supplements and multivitamins. However, cod liver oil contains Vitamin A with Vitamin D, and it is this availability and synergistic relation between the two that gives it impressive outcomes. While vitamin D is available in dietary forms, such as eggs, cheese and fish, the most common and easiest availability is through photochemical conversion when exposed to the rays of the sun. While deficiency is typically attributed to less exposure to the sun and poor nutritional balance, it is important to bear in mind that vitamin deficiency could also be attributed to genetic inheritance, kidney ailments and liver disease. As a result of one of these reasons, the individual is at risk of developing rickets or osteomalacia. These conditions could then aggravate and result in one of many conditions.

The primary role of Vitamin D is to facilitate the absorption of serum calcium and phosphorous in the small intestines from dietary intake, so as to maintain the desired levels in the blood. The intake of cod liver oil supplements, delivers the right amount of vitamin D along with vitamin A to prevent the conditions linked to deficiency, arising out of the reasons mentioned above.

What is the difference between Cod Liver Oil & Fish Oil?

It is important to note the difference between fish oil and cod liver oil, as many are known to consider the two products as the same. Many users end up purchasing one, when the intent or the need was to purchase the other. Fish oil is extracted from the tissues of certain specie of fish, while cod liver oil is extracted from the liver of one specie of fish. The former is extracted from fish belonging to oily fish types, such as herring, tuna, anchovies, and mackerel. Cod liver oil, is extracted from demersal fish specie Gadus, that actually belongs to the family Gadidae.

Fish oil contains DHA and EPA, while oil of cod liver contains DHA, EPA and abundance vitamins A and D. This difference makes a huge impact nutritionally, and this is one of the reasons why the oil of doc liver is a huge hit among the health conscious. Vitamin A and Vitamin D are relatively difficult to be obtained through dietary sources, and this makes the two vitamins immensely important. This is because of the role of the two vitamins in regulating gene expression. This refers to the need of the body to function with maximum genetic potential and achieve the best or ideal biological outcome. This can only happen when hormones are regulated in the best possible manner. Vitamin D is known to have an impact over 2,000 genes. It is important to note here that Vitamins A and D have, what is called as a synergistic relation, and deliver best results when made available at the same time. Every single cell in the body contains vitamin A and D receptors, signalling the importance of the vitamins.

Apart from the presence of receptors on every cell, there is a unique arrangement, wherein a receptor permits both the vitamins to share or interchange information. This is essentially, one of the reasons for the impressive health benefits of the oil of cod liver. Both the vitamins need to be in perfect balance, and imbalance caused by excessive amounts of one, or excessive use of one, may result in triggering a deficiency of the other. Cod liver oil, as a rich source of both the vitamins, offers the best results, without opportunity for an imbalance among the two vitamins.

What are the different types of cod liver oil?

There are two different types of cod liver oil, and the types are classified on the basis of the extraction process. The first category is regular cod liver oil, wherein the extraction and processing of the oil is performed at high temperatures. Additionally, the oil is fortified with the inclusion of select synthetic vitamins that help to deliver enhanced nutrition. The second category is fermented cod liver oil, which refers to extraction processes that do not involve heat. After the extraction, the oil is typically fermented for a period that could be anywhere between six months to one year. This results in the creation of a natural product that is consumed as food.

Different forms of cod liver oil and nutritional information

The oil is available either as oil or is sold in the form of capsules. Regardless of the difference in forms, the nutritional breakup is more or less the same, with 10% EPA and 10% DHA available in both oil and capsule form.  

The nutritional breakup of the oil is as given below:

902 kcal of energy, 29000µg of Vitamin A, 29000µg of Retinol, 99,000 IU of Vitamin A, 250µg of Vitamin D (D2 and D3), 10000 IU of Vitamin D, 22 grams of total saturated fatty acids, 46 grams of total monounsaturated fatty acids, 22 grams of total polyunsaturated fatty acids, and 550 mg of cholesterol.

Cod liver oil capsules dosage for kids and adults

The typical dosage for adults is around 15 mL daily, while the dosage for kids differs depending upon nutrient requirements. For instance, children between the age of 3 to 12 require doses that deliver around 2500 IU of Vitamin A, which needs to be given either twice or thrice a week. Children above the age of 12 may require a lesser dose of 5000 IU Vitamin A, twice a week.  Pregnant women and breastfeeding mothers need a dose of around 10000 IU Vitamin A, twice a week. It is added, that these values are only a reference, and are not to be considered as the ideal or actual dosages. The actual dose will be as determined by the specialist, after assessing the kid or the adult, and level of nutrition.  

Benefits of cod liver oil for kids and adults

The oil is known to deliver multiple health benefits to children as well as adults. The benefits include prevention of certain conditions that are attributed to deficiency of nutrients, in addition to being a part of treatment options for certain diseases. The most popular benefit is prevention of rickets, a condition that is known to develop due to vitamin D deficiency. The ideal source of Vitamin D is exposure to sunlight, but entire societies in certain parts of the world do not get adequate exposure, which results in possible deficiency. This resulted in the condition; however, with cod liver oil, the prevalence rates in affected communities dipped considerably. The symptoms linked to the condition include typical bowed legs, and abnormally projected breastbone. Other symptoms that are indicative of the condition include thickened wrists and ankles. Over the ages, parents have supplemented children’s diet and nutrition with a single teaspoon of cod liver oil.  

The supplement is also known to prevent development of upper respiratory tract illnesses. Certain specific respiratory tract illnesses are typically seasonal in nature, with increased prevalence either during winters or during spring. The use of cod liver oil supplements has been traditionally practiced over the ages, and is believed to help either prevent or reduce the onset of these conditions. The supplement is also known to help prevent or reduce prevalence of ear infections. This is achieved in combination with multivitamins, and is also considered as an alternative treatment or preventive method for allergic rhinitis and ocular disease.

By virtue of being a rich source of Vitamin A with high bio-availability, the oil is also known to help improve vision, including night vision. It is also known to help kids fight eye infections better, and this keeps the children more active and healthier. In addition to these properties and benefits, the oil of cod liver is known to help reduce symptoms linked to ADHD in kids. This is known to have an impact on kids between the ages of seven and twelve. There are other studies that claim other health benefits, and this includes a study that suggests that the use of cod liver oil in kids will help reduce the possibility of type-1 diabetes in the future. Results of this study and other studies have concluded that there is a direct link between vitamin D supplementation and lowered risk of type-1 diabetes in later years. This has been attributed to lesser vitamin D levels in mothers, which in turn had an impact on exposing the child to the risk of diabetes.

The supplement is also known to have an overall impact on immunity levels. Children on cod liver oil supplements are known to have lesser instances of common cold and flu. The oil is also known to be rich in antioxidants and this makes it useful in preventing glaucoma, a condition that is known to affect the optic nerve. When the condition aggravates or turns severe, it is known to result in loss of vision.

Proven benefits of Omega-3 Fatty Acids 

More than half of the brain contains fat, which also has a role in powering neurons. This proves that omega-3 fatty acids, including DHA and EPA deliver a range of benefits to children.  The ability of the brain to perform well and the structure are determined to a great extent by fatty acids, which are considered as among the most important molecules in the brain. With the right amount of fatty acids, kids can benefit with enhanced intelligence, apart from improved vision. Various functions and abilities that develop during formative years of children, including functions such as focus, attention and the ability to solve problems apart from planning are linked to the brains structure. With the right amount of omega-3 fatty acids, children get the benefit of better cognitive abilities from ideal nutrition. Other qualities linked to Omega-3 is social and emotional development parameters of kids.

Apart from the very vital role in the structure of the brain, fatty acids also perform the job of messengers. The role in the synthesis and actions of the neurotransmitters in the brain, and its resultant effect on the immune system make essential fatty acids extremely important for overall health.  Most children are known to have inadequate levels of DHA, and the best way to deliver sufficient levels is through special dietary sources or supplements. This includes fatty fish varieties such as salmon, sardines apart from caviar and poultry eggs. The use of cod liver oil supplements is known to help boost the levels of DHA in the most effective manner.

Commonly reported side effects of cod liver oil

Health supplements are intended to deliver additional, targeted nutrients, for the desired benefits. However, there is a possibility of potential downsides to supplements. This could be either because of the mechanism of action of the nutrients or it could be because of the impact of increased nutrients that could affect the balance of other essential nutrients. However, the potential undesirable effects of all supplements, including cod liver oil is relatively less in terms of severity. Most of the effects may typically be mild in nature or could be short term in nature. These effects are likely to resolve naturally, or may resolve quickly with symptomatic intervention.

Here is a compilation of some of the commonly reported side effects of the oil. It is added, that this is only a short compilation and is intended to only serve as a reference and is not to be treated as an exhaustive or complete list of unwanted effects. The most common effect is typically bad breath, due to the strong oil content. Additionally, children are known to report symptoms of heartburn when on the supplement. Burping occurs quite normally to most individuals and children on the oil supplements are more likely to burp with a strong fish smell. There is also the likelihood of kids experiencing loose stools, while some are known to end up with feelings of nausea.

Possible serious effects 

As mentioned earlier, most of the effects are typically mild in nature. However, there is a possibility of a severe and adverse reaction among kids. This is limited to kids who have a history of allergic reactions to seafood, or who are sensitized to seafood for the first time. It is extremely important to understand if the kid is allergic to seafood, and it is also necessary to check the ideal dosage to prevent over dose related conditions or effects. Commonly reported symptoms of such effects include bouts of diarrhea and possible vomiting. Other symptoms that are indicative of reactions include outbreak of rashes that are itchy in nature, with inflammation, apart from the formation of red inflamed welts. These conditions are medically known as Urticaria.

The oil could also cause aggravation of eczema and asthma among children diagnosed with the conditions.  Another possible serious condition is the likelihood of increased risk of bone fractures; however, this is limited to a very small percentage of users.  Excessive vitamin D could trigger an increase of calcium in the blood, resulting in a condition medically known as hypercalcemia. This could cause feelings of nausea and could also result in vomiting, apart from increased urination and fatigue. This could slowly, over a period of time develop into pain in the bone apart from renal conditions. For instance, formation of stones in the kidney may result from this, and would require treatment, including surgery in some cases.

Handling children who dislike the taste

By virtue of the source of the supplement, it has a distinct smell and taste, that is more often than not, disliked by children and adults alike. It may be therefore necessary to employ methods to ensure that the supplement is taken routinely. There are simple tips that can be used to ensure that kids consume the supplements without too much of a fuss. The best time saving option, would be to choose supplements that come as chewable tablets, which come in different flavors to help mask the taste. The supplement can also be added to juices that are acidic, as this will neutralize the taste and smell. Parents are also known to mix the supplements with favorite food products of kids; however, it is necessary to choose the product, as the right combination is essential, or it may actually end up being more repulsive or causing more distaste.

Interactions with other medications

Health supplements are also known to interact with other medications or products. This is again due to the conflict in mechanisms of action, when two or more products are taken together, often for the same condition or for different conditions. The resultant effect of contraindications is either an increase in the potency of one product, or a reduction in the efficacy of one product or it could also result in aggravation of side effects of either or both products. Interactions could occur between medications, health supplements, herbal remedies, alternative medicine, and food products. Typically, specialists identify such interactions and either temporarily suspend or permanently discontinue either of the products, replacing it with other products that do not interact.

In the event that both the products are equally important, the best option is to stagger the intake of the two interacting substances, and alter the dosage so as to minimise the impact. Medications that may interact with cod liver oil include drugs that are recommended for treating hypertension. This is because the oil is known to cause a decrease in blood pressure levels. Consequently, this may result in lesser efficacy of certain blood pressure drugs. Additionally, this reduction of blood pressure levels may also impact drugs recommended for lowering blood pressure. It is therefore necessary to intimate the doctor about use of such drugs.

Similarly, the oil is also known to have an impact on blood clotting, by slowing down the process of blood coagulation. Therefore, medications that are prescribed for slowing down blood clotting may end up with more than desired outcomes. This could, in turn result in increased possibilities of injuries and bleeding from bruises. The supplement is also known to have an impact on medications prescribed for diabetes. This is because cod liver oil is known to bring down blood sugar levels, and the combined effect of medications and cod liver oil may bring down blood glucose levels to extremely low levels.

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