Vitamins are a group of substances that are needed for normal cell function, growth, and development. There are 13 essential vitamins:
Vitamin A (retinol, retinal, 4 carotenoids)
Vitamin C (ascorbic acid)
Vitamin D (D3 - Cholecalciferol, D2 - Ergocalciferol)
Vitamin E (tocopherols, tocotrienols)
Vitamin K (phylloquinone, menaquinones)
Vitamin B1 (thiamine)
Vitamin B2 (riboflavin)
Vitamin B3 (niacin)
Vitamin B5 (pantothenic acid)
Vitamin B6 (pyridoxine, pyridoxal, pyridoxamine)
Vitamin B7 (biotin)
Vitamin B9 (folic acid)
Vitamin B12 (cyanocobalamin)
Fat-soluble vitamins are stored in the body's fatty tissue: vitamins A, D, E, K.
Water-soluble vitamins - the body must use almost all water-soluble vitamins right away - vitamins B1, B2, B3, B5, B6, B7, B9 and C. Vitamin B12 is the only water-soluble vitamin that can be stored in the liver for many years.
A sharp distinction between humans and “animals” is essential if we are to bend them to our will, make them work for us, wear them, eat them–without any disquieting tinges of guilt or regret. It is unseemly of us, who often behave so unfeeling toward other animals, to contend that only humans can suffer. The behavior of other animals renders such pretensions specious. They are just too much like us.
The protein digestibility-corrected amino acid score (PDCAAS) has been adopted by FAO/WHO as the preferred method for the measurement of the protein value in human nutrition.
PDCAAS = Amino Acid Score x Digestibility
The method is based on comparison of the concentration of the first limiting essential amino acid in the test protein with the concentration of that amino acid in a reference (scoring) pattern. This scoring pattern is derived from the essential amino acid requirements of the preschool-age child.
Although the principle of the PDCAAS method has been widely accepted, critical questions have been raised in the scientific community:
the validity of the preschool-age child amino acid requirement values (more than 4 times greater than the EAA requirement for an adult),
the validity of correction for fecal instead of ileal digestibility,
the truncation of PDCAAS values to 100%.
The reference scoring pattern was based on studies performed more than 25 years ago on a limited number of 2-year-old children recovering from malnutrition.
According to the current official recommendations, a 2-year old child needs ~ 3x higher essential-to-non-essential amino acid ratio, and needs essential amino acids in different proportions than adult. Methionine/cysteine is the limiting essential amino acids for adults, and for children it is lysine or tryptophan.
The use of fecal digestibility overestimates the nutritional value of a protein because amino acid nitrogen entering the colon is lost for protein synthesis in the body and is, at least in part, excreted in urine as ammonia.