Tests Of A Perfect Food

Milk is often called a perfect food. This is true, however, only in a limited sense. Hutchison gives five tests of a perfect food.

First, such a food must contain all the nutritive constituents required by the body; proteids, fats, carbohydrates, mineral matter and water.

Second, it must contain these in their proper relative proportions.

Third, it must contain, in a moderate compass, the total amount of nourishment required daily.

Fourth, the nutritive elements must be capable of easy absorption, and yet leave a certain bulk of un-absorbed matter to act as intestinal balance.

Fifth, it must be obtainable at a moderate cost.

Of these tests milk meets only the first perfectly. It contains the two proteids, casein and albumen. It contains the fat so familiar to us in the form of cream and butter. The carbohydrates are represented in it by milk sugar or lactose. The mineral salts are particularly valuable,- and consists chiefly of calcium compounds, including calcium phosphate.

Proportions Of Nutrients

When we come to the second test, we find a different condition. An average sample of milk contains 87 per cent of water, three and three-tenths per cent proteid, four per cent fat, and five per cent carbohydrate, with seven-tenths of one per cent mineral matter. This proportion is of course right for the young animal, who demands a large proportion of muscle-building food, but it is far from a desirable proportion for the adult.

Composition of a Glass of Milk.

(After Hutchison).

Composition of a Glass of Milk.

Nutrient Ratio

Remembering that the nutrient ratio is about one to five, or to put it in another form, that the adult requires approximately five times as much carbohydrate (or its equivalent) as proteid, we see that milk must be supplemented by some food containing a large proportion of carbohydrate before it can adequately supply the needs of the adult. As a matter of fact, experience has taught us to use with milk such a food as bread, thus supplying the needed starchy material.

The third condition is not met better than the second. At least four quarts of milk a day would be necessary for the complete nutrition of a healthy man doing a moderate amount of muscular work. Milk also is lacking in the bulk of unabsorbed matter that it leaves.

Cost

The fifth condition may or may not be fulfilled. In the city the price of milk is too high for it to be an economical source of food if used exclusively. On the other hand in the country the price of milk is often so low that this condition might be fulfilled.

A comparison of the food value obtained from one pound (a pint) of milk and from that of a similar weight of some common article of food, is given, with the cost of each at prices taken from two different sections of the country:

Comparative Food Value Of Milk

l lb.

of

milk furnishes

.033 lbs.

proteid

.04 lbs.

fat

.05 lbs

carbohydrate

1 "

"

sirloin steak "

.1(55 "

"

.161 "

"

no

"

1 "

"

eggs (8 eggs) "

.131 "

"

.093 "

"

no

"

1 "

"

bread "

.092 "

"

.013 "

"

.5311bs

"

1 "

"

potatoes " (one 60th bu).

.018 "

"

.001 "

"

.147 "

"

From

milk at (.01 per qt. or .02 per lb).

1 lb.

of

proteid

costs

$ .60

"

" " (.07 " " " .035 " " )

1 "

"

"

"

1.06

"

sirloin steak at .18 a lb.

1 "

"

"

"

1.09

"

" " .25 "

1 "

"

"

"

1.52

"

eggs at (.15 per doz. or .10 per lb).

1 "

"

"

"

.76

"

" " (.36 " " " .24 " " )

1 "

"

"

"

1.83

"

bread at .05 per lb.

1 "

"

"

"

.54

"

" " .08 " "

1 "

"

"

"

.87

"

potatoes at .60 per bu. or .01 per lb.

1 "

"

"

"

.56

"

" " $1.20 " " " .02 " "

1 "

"

"

"

1.11

In addition to the proteid, the money invested would have purchased, in the case of milk more than a pound of fat and of sugar; in that of meat an equal amount of fat; in the case of bread more than five pounds of starch; in that of potatoes nearly seven pounds of starch; while three-fourths of a pound of fat would be furnished by the eggs.