Daily Recommendations. Recommendations for vitamin A are based on age. Infants between 0 and 6 months require 400 mcg per day, whereas infants between 7 and 12 months need 500 mcg per day. Toddlers between 1 and 3 need 300 mcg every day.
The twenty amino acids can be divided into two groups of 10 amino acids. Ten are essential and 10 are nonessential. However, this is really not an accurate dichotomy, as there is overlap between the two groups, as is indicated in the text accompanying the following two charts:
Of the 20 amino acids, how many are considered to be essential in that human body cannot synthesize them?