Vitamin A, Vitamin D and Cod Liver Oil: Some Clarifications

Vitamin A, Vitamin D and Cod Liver Oil: Some Clari...

Vitamin A, Vitamin D and Cod Liver Oil: Some Clarifications

By: Sally Follon and Mary G. Enig, PhD

Several visitors to our website have noted inconsistencies in various statements about vitamin A, vitamin D and cod liver oil. These issues revolve around questions of dosage and safety.

Vitamin A Dosage:

We have pointed out that concerns about vitamin A toxicity are exaggerated. Synthetic vitamin A can indeed be toxic but natural vitamin A found in foods like cod liver oil, liver and butterfat does not cause problems except in very large amounts, and side effects from large doses of natural vitamin A promptly resolve when the dosage is reduced.

As a general guideline, we recommend the following doses of vitamin A from cod liver oil, along with a nutrient-dense diet that contains other vitamin A-rich foods:

Children age 3 months to 12 years: A dose of cod liver oil that provides about 5000 IU vitamin A daily

Children over 12 years and adults: A maintenance dose of cod liver oil that provides about 10,000 IU vitamin A daily

Pregnant and nursing women: A dose of cod liver oil that provides about 20,000 IU vitamin A daily

Individuals under stress or wishing to use cod liver oil to treat a disease condition may take much larger doses, even up to 90,000 IU vitamin A per day, for a period of several weeks.

Vitamin D:

The recommended dosages for cod liver oil provide about 500 IU vitamin D for children, 1000 IU vitamin D for adults, 2000 IU vitamin D for pregnant and nursing women and up to 9000 IU for those taking large amounts of cod liver oil to deal with stress and disease.

One of our writers has expressed the opinion that dosages over about 2000 IU per day can be toxic, especially for individuals who spend a lot of time in the sun, and recommends routine testing if they are also taking cod liver oil or vitamin D supplements.

Yet a number of studies show that a brief full-body dose of noonday summer sun is comparable to taking between 10,000 and 25,000 IU of vitamin D. Thirty minutes of exposure to noonday summer sun releases 50,000 IU into the blood stream. Obviously, humans are designed to tolerate such large amounts of vitamin D.

If you are a lifeguard or spend a lot of time in the sun, you do not need to take supplemental vitamin D; however you still need to consume adequate vitamin A. So, if you cut back or eliminate cod liver oil in the summer, be sure to consume plenty of oily fish, liver and butterfat and egg yolks from grass fed hens to ensure adequate vitamin A.

For a discussion of Vitamin D Toxicity, see

This does not mean we do not recommend that some individuals have their vitamin D levels tested. Such testing can be very useful in determining vitamin D status and the effectiveness of cod liver oil or vitamin D supplements.

Cod Liver Oil

As of February, 2005, we recommend the following brands of cod liver oil:

In Stores: Garden of Life, regular dose cod liver oil

By Mail Order:

* Radiant Life, high vitamin cod liver oil, (888) 593-8333,

* Blue Ice, high vitamin cod liver oil, (402) 338-5551,

* In Europe, Healthspan Ltd., 0800 73 123 77,

* In Australia, Melrose cod liver oil, email:

Note that 1 scant teaspoon of regular dose cod liver oil provides about 5,000 IU vitamin A while 1 scant teaspoon of high vitamin cod liver oil provides about 10,000 IU vitamin A.

Some of the brands recommended in various articles on our website we no longer endorse because the manufacturer is removing vitamin A out of concerns of toxicity. An adequate dose of vitamin A-reduced cod liver oil may supply more unsaturated fatty acids than is considered safe.

Warning: Many brands of cod liver oil are processed to remove all the vitamins A and D and then have synthetic vitamins A and D added back in. These products should be completely avoided as the synthetic versions of A and D are toxic. For those living in Canada or overseas, where our recommended brands are not available, be sure to contact the manufacturer and inquire whether the A and D in their cod liver oil is naturally occurring or synthetic.

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