Publications and Resources. Read the groundbreaking 1977 publication â Phylogenetic structure of the prokaryotic domain: The primary kingdoms ,â by Carl R. Woese and George E. Fox, in which Archaea, the third domain of life, is identified.
Youâre quite right that cod liver oil is a good source of vitamin D. According to the National Institutes of Health, it gives you 1,360 IU per tablespoon (I now recommend 2,000 IU daily). However, at least some kinds of cod liver oil provide as much as 13,500 IU of vitamin A, and thatâs way too much. The Upper Limit of vitamin A set by the Food and Nutrition Board of the National Academy of Sciences is 10,000 IU per day.
And women of childbearing age should not exceed 10,000 IU of vitamin A because of the risk of birth defects. Just one teaspoon of cod liver oil may have 4,500 IU of vitamin A, and the standard dose is one to three teaspoons a day. Capsules of cod liver oil contain less oil, but the vitamin can still add up, especially on top of the amount you get from foods and from a multivitamin, if you take one.