Digestion and absorption of cereal proteins in the human alimentary tract.

Rapidity of digestion of the protein contained in different cereal breakfast foods was determined in human subjects, partly by the emptying time of the stomach as measured by the total nitrogen in its contents obtained at successive intervals after a cereal breakfast, and partly by the rate of nitrogen excretion through the kidney following the meal. The former method obviously gives information chiefly upon the motility of the stomach.

Each of four subjects ingested 25 grams of dry cereal, after cooking a uniform length of time, with cream and sugar and in some cases coffee. Before the meal a Rehfuss tube was introduced and the fact established that the stomach was empty. The tube was left in place and one hour after the meal the contents of the stomach were completely removed by the use of large amounts of wash water. Each subject repeated the experiment on the following morning with the same cereal and with exactly similar technique, except that the stomach was emptied at one and a half hours. On succeeding mornings the time was 2 hours, 2 1/2 hours, etc., until the stomach was empty. The next week each subject took a different cereal with another change for the third, and still another for the fourth week. The cereals employed were a milled wheat product, a whole wheat product and two oats products.

The differences in stomach emptying time amongst the four cereals were small, much less than those found amongst the different subjects for the same cereal. An average of all the subjects for all the cereals indicated that at the end of one hour 35 to 45 per cent of the ingested cereal protein had passed out of the stomach, at two hours about 75 per cent and at three hours the average stomach was empty.