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.
This is why I feel Carlson's cod liver oil is a good choice among the many brands out there-the ratio between vitamin A and vitamin D in Carlson's brand is about 2 to 1. Apparently, there are some brands of cod liver oil that are at 5 to 1 and even 10 to 1.arlson cod liver oil contains approximately 800 IU of vitamin A per teaspoon. Physicians and scientists aren't in agreement on what a safe upper level of vitamin A is for the average adult.