A comparison of the amounts of phosphorus contained in the food of typical American families with the amounts metabolized in the experiments above mentioned indicates that a freely chosen diet does not always furnish an abundance of phosphorus compounds. In 150 American dietaries of families or larger groups believed to be fairly representative, the estimated amount of phosphorus furnished per man per day was below 0.96 gram in 7 cases, while in no case was there less than 50 grams of protein per man per day. If we allow a margin of 50 per cent for safety in both protein and phosphorus, we find 8 per cent of the dietaries below the protein standard of 75 grams and 41 percent below the phosphorus standard of 1.44 grams. These results indicate plainly that present food habits are more likely to lead to a deficiency of phosphorus compounds than to a deficiency of protein in the diet, and it is not improbable that many cases of malnutrition are really due to an inadequate supply of phosphorus compounds.

Approximate Amounts Of Phosphorus In Food Materials

Food

Phosphorus per 100 Grams

Edible Substance

Phosphorus per 100 Grams • Protein

Phosphorus per 3000 Calories

Beef, all lean.............................

0.218

0.96

5.2

Eggs.......

.180

1.35

3.66

Egg yolk......

.524

2.73

3.54

Milk........

.093

2.82

4.02

Cheese........................................

.683

2.58

4.68

Wheat, entire grain................

.423

3.25

3.54

White flour.............................

.092

.81

.78

Rice, polished............................

.096

1.19

.81

Oatmeal....................................

.392

2.36

2.97

Beans, dried.....

.471

2.20

4.11

Beets...........................................

.039

2.42

2.52

Carrots.......................................

.046

4.17

3.03

Potatoes...................................

.058

2.60

2.07

Turnips....................................

.046

3.55

3.51

Apples.......................................

.012

3.15

0.60

Bannans.....................................

.031

2.35

0.93

Oranges.....................................

.021

2.58

1.20

Prunes, dried.............................

.105

5.00

1.05

Almonds......

.465

2.25

2.16

Peanuts.......................................

.399

1.55

2.19

Walnuts......................................

.357

1.96

1.53

That the cases of low phosphorus dietaries are not to be ascribed simply to inadequacy of the total food supply of these families was shown by computing the amounts of phosphorus which would have been furnished in each case had the total amount of food been so increased or decreased as to furnish just 3000 Calories per man per day. On this basis only one of the 150 dietaries shows less than 0.96 gram, but 49 of them or 33 per cent show less than 1.44 grams of phosphorus, as against only 2 per cent with less than 75 grams of protein, per 3000 Calories.

The table on the preceding page compares some staple foods as sources of phosphorus.

It will be seen that, whether compared on the basis of weight, or of protein content or energy value, the different staple foods vary greatly in phosphorus content. In the planning of dietaries this fact should be kept in mind and care taken that foods fairly rich in phosphorus be adequately represented in each day's food.