Possible Side Effects Of Cod Liver Oil

Cod liver oil has a variety of health benefits but has serious side effects as well. It should be taken with caution.

Cod liver oil has been touted as a remedy for everything from arthritis to heart disease. A steady stream of research has affirmed its ability to treat or prevent a number of health problems, and its popularity is growing rapidly. While the supplement appears to hold great promise, it also has numerous potential side effects and should be taken with caution.

Possible Adverse Effects

Cod liver oil's effectiveness stems mainly from its large amounts of omega-3 fatty acids, which seem to provide relief from a variety of ailments. However, in large amounts, these same acids can pose great health risks, particularly when taken in supplement form rather than included in the diet by eating foods rich in omega-3 acids. While many people may find great benefit from taking cod liver oil, anyone considering taking the supplement should be aware of these potential side effects:

Omega-3 fatty acids can interfere with the blood's ability to clot, thus increasing the risk of hemorrhagic strokes. By inhibiting clotting ability, it can also raise the risk for internal bleeding. Supplements should not be taken by anyone on anti-coagulant medication, anyone who has a bleeding disorder, or anyone with uncontrolled high blood pressure, a condition that already places them at greater risk for a stroke. Fish oils also should be discontinued two weeks before having surgery and one week after, to prevent complications from the blood's decreased ability to clot.

Omega-3 acids are fats, and like all fats they contain large amounts of calories. Following some of the recommended dosage guidelines would add 200 calories a day to a person's diet. People taking supplements rich in omega-3 fatty acids may need to change their diet to ensure they don't include too much fat, which could also cause health problems.

Cod liver oil, whether taken in liquid or capsule form, is the richest source of vitamins A and D, which can be dangerous when taken in large amounts. These vitamins are essential, and in fact, too little of either can cause health problems, but taking too much can also be risky. Too much vitamin A can cause birth defects, so amounts should be limited for women of childbearing age. It is also that believed that too much vitamin A can interfere with bone growth and make the bones prone to fractures. Vitamin D is also dangerous in large amounts, and overdosing on the vitamin can be toxic.

People with diabetes should only use cod liver oil under the close supervision of a doctor, because the supplement could make their condition worse. According to some research, fish oil supplements may make blood sugar levels harder to control in diabetic patients, which would raise the risk of complications and could cause life-threatening side effects.



In large doses, fish oils can suppress the immune system, leaving the body more vulnerable to infection and disease. Anyone whose immune system is already compromised should use caution when taking cod liver oil supplements.

Cod liver oil is derived from the liver, which filters and detoxifies the blood. Because of this, the liver could contain highly-concentrated levels of toxins, contaminating any supplements made from it. Because other fish oil supplements are made from other parts of the fish, they are less likely to be contaminated.

Not all of the side effects are potentially fatal, however. Cod liver oil can also cause less severe complications such as nausea, diarrhea, flatulence and bloating. Taking very large amounts could also cause the body to give off a fishy odor.

Potential Drug Interactions

Cod liver oil can cause potentially life-threatening complications when taken with certain medications, both over-the-counter and prescription. Fish oils can enhance the blood-thinning effects of many medications, leading to internal hemorrhaging or excess bleeding. Because of this, cod liver oil and other fish oils should never be taken in conjunction with anti-coagulant medications, including aspirin, dalteperin sodium, enoxaparin sodium injections and warfarin.

Cod liver oil is one of the most popular nutritional supplements on the market and holds promise in treating a wide range of medical conditions. However, it may not be the best option for everyone. Its rich supply of omega-3 fatty acids, the very things that make it so potent, are also what makes it so potentially dangerous. When taken in large amounts, these acids can lead to life-threatening complications, including increased risk for hemorrhagic stroke and internal bleeding. Before taking cod liver oil supplements, it is safest to research their potential side effects and consult a doctor to help lessen the risk of complications.

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