Vitamin A Toxicity

Most traditional fish oil supplements (from the oil in fish meat) do not contain significant amounts of vitamin A and should not be of concern when taken with a multivitamin. On the other hand, fish liver oils such as cod liver oil do contain significant amounts of vitamin A, which may be harmful if consumed in large quantities.

One tablespoon (14 grams) of cod liver oil, for instance, may provide up to 270% of your daily requirements for vitamin A in one serving. Dizziness, nausea, joint discomfort, and skin irritation are some of the negative symptoms that can result from a vitamin A overdose. Long-term effects might potentially include liver damage and even liver failure in severe cases. For this reason, it's important to keep your dosage of an omega-3 supplement reasonable and pay attention to the vitamin A content.