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.
Cod itself isn't a very good source of omega-3 fats, with a 3-ounce serving providing 134 milligrams of the recommended 500 milligrams per day. Cod liver oil does provide these healthy fats, however, with each teaspoon containing 1,034 milligrams. Other types of fish oil are better sources of omega-3s. For example, a teaspoon of salmon oil has 1,905 milligrams and a teaspoon of menhaden oil has 1,544 milligrams.