Physiological economy in nutrition, with special reference to the minimal proteid requirement of the healthy man: an experimental studyChittenden, R. H. (Russell Henry)
Science
Physiological economy in nutrition, with special reference to the minimal proteid requirement of the healthy man: an experimental study
Chittenden, R. H. (Russell Henry)
Metabolism; Nutrition
|Daily average from | | | | | |
| Oct. 26, 1903 | 833 | 1018 | 7.43 | 0.516 | 1.28 |
+-------------------+-------+------+-----------+-----------+-----------+
It will be seen by a study of the analytical data that Dr. Underhill had
an average daily excretion of nitrogen through the kidneys from October
26, 1903, to June 23, 1904, of 7.43 grams. From October 26 to April 13, a
period of nearly six months, the average daily excretion was 7.81 grams
of nitrogen, while from the latter date to June 23 the average daily
excretion amounted to 6.68 grams of nitrogen. Taking the body-weight at
65 kilos, the lower nitrogen figure would mean a metabolism of 0.102 gram
of nitrogen per kilo of body-weight, closely akin to the figures obtained
with the two preceding subjects.
An excretion of 6.68 grams of nitrogen corresponds to the metabolism
of 41.75 grams of proteid matter, while the excretion of 7.43 grams of
nitrogen implies the metabolism of 46.4 grams of proteid, being less than
one-half the ordinarily accepted requirement for the healthy adult.
During this long period of eight months the body-weight was stationary,
carrying with it the assumption that the body was in a condition of
nitrogen equilibrium. It should be emphasized in connection with Dr.
Underhill’s case, that throughout the entire period of eight months,
and more, there was perfect freedom in the choice of food. Further, it
will be noticed by a study of the dietary made use of in the balance
experiments that Dr. Underhill did not reduce his nitrogen intake by any
exclusion of meat. He practically made use of his ordinary diet, such as
he had always been accustomed to, but with a decided diminution of the
amount of proteid food, accompanied by a gradual reduction in the total
amount of food consumed each day. His diet, therefore, was in no sense a
vegetable diet. Meat was conspicuous in his daily food, but naturally in
reduced quantities.
On February 9 a nitrogen balance was attempted, in which a careful
comparison of the nitrogen content of all intake and output was made for
a period of six days. By a study of the results of this balance period,
shown in the accompanying tables, it will be noticed that not only was
there no deficiency of nitrogen, but the body was laying on nitrogen at
the rate of 0.158 gram per day. Further, it will be observed that the
fuel value of the food per day averaged only a little over 2000 calories.
Yet this amount of food, with its comparatively low fuel value, carried
with it only 8.83 grams of nitrogen per day. Upon this quantity of food
the body was able to maintain itself, with a little nitrogen to spare and
with sufficient fuel value in the food to supply all the energy required
for muscular contraction, mental effort, and the maintenance of body
temperature.
_Tuesday, February 9, 1904._
Breakfast.—Bread 22 grams, tea 146 grams.
Public-domain text, read in full here on John Shaqi.
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