The chief reason for the lessened activity of the bowels on a milk diet is because the nourishment in milk is practically all absorbed—there is very little residue and milk gives little rough surface to excite peristaltic action and stimulate the walls of the intestine to activity.
The calcium, one of the constituents of milk, tends to lessen the peristaltic action of the intestines and this is one of the causes of constipation. Fruit and coarse bread containing much bran, should be used with a milk diet.
Constipation may also be occasioned by drinking milk rapidly. When the hydrochloric acid is very active coagulation may take place so quickly as to cause hard tough curds to form; these enter the intestine undissolved because the gastric juice can act only on the exterior portion; the stomach retains the curds in its effort to dissolve them and fermentation may occur, with irritation and constipation from irregular action. In this case the constipating effect may be overcome by taking the milk in small sips or by the addition of one part of limewater to six parts milk. The limewater causes the curds to be precipitated in small flakes.
Limewater may be prepared by putting a heaping teaspoon of unslaked lime with a quart of boiled or distilled water into a corked bottle or Mason jar. Shake thoroughly two or three times during the first hour; then allow the lime to settle, and after twenty-four hours pour or siphon off the clear fluid. Be careful not to allow the lime to be poured off with the water.
Barley water or oatmeal water added to milk also prevents the formation of large curds.
Milk may also be taken with any variety of gruel—oatmeal, sago, arrowroot, or tapioca.
If there is much mucus in the stomach, mucous fermentation may occur in milk because of the lack of hydrochloric acid. The partially digested curds are tough, stringy, and slimy and the intestinal walls find no resistance in the mass. In this case constipation may be followed by diarrhea.
If the stomach is deficient in hydrochloric acid the juice of half an orange or a little lemon juice may be taken a half hour before the glass of milk.
Constipation and, later, diarrhea may also result when stomach digestion is weak, the curds passing through the stomach and intestines undissolved.
When there is any tendency to torpidity of the liver, daily exercise should be directed to the liver, stomach, and intestines or milk may cause biliousness, because the excess of fat and protein taken overstimulates the liver, causing an excess of bile. The bile may enter the stomach and cause nausea and vomiting. Constipation results from the disordered digestion. This will not often occur if one exercises daily and cuts down the quantity of solid food as the amount of liquid is increased.