The protein content of cereal grains is small relative to their carbohydrate content. For example, white wheat contains 75.4% carbohydrate but only 9.4% protein. For wheat made into flour, the ratio is even more in favor of carbohydrate.
An adult woman requires about 50 g of protein per day, whereas an adult man needs slightly more about 63 g, The breakfast cereal can easily supply this quantity of protein.
Protein quality varies in protein, as cereals tend to have lower amounts of certain essential amino acids. All cereal products are deficient in the amino acid lysine, but breakfast cereal generally consumed with milk which is a good source of lysine.
Protein is essential for growth and repair of body tissue, and an adequate supply of protein can lower resistance to disease and infection. Although the protein quality of breakfast cereals as individual foods does not compare favorably with that of animal products like meat and milk, this is not to say that cereal grain proteins in general are devoid of specific amino acids as gelatin is devoid tryptophan.
When breakfast cereal are eaten together with other foods containing ample levels of amino acids, which are low in grains, the overall quality of the combined protein increase and satisfies daily protein requirements.
Their diets were sometimes supplemented with legumes and only occasionally with sources of animal protein, from meat, fish and milk.
It is reasonable to assume that breakfast cereals can make the same contributions as the cereal grains did, provided the protein is not significantly diminished or damaging by processing.
Breakfast Cereals as a Source of Protein