Air, water and food from a sanitary standpoint / by Ellen H. Richards and Alpheus G. Woodman.

  • Richards, Ellen H. (Ellen Henrietta), 1842-1911.
Date:
[1904], [©1904]
Catalogue details

Licence: Public Domain Mark

Credit: Air, water and food from a sanitary standpoint / by Ellen H. Richards and Alpheus G. Woodman. Source: Wellcome Collection.

Provider: This material has been provided by the Augustus C. Long Health Sciences Library at Columbia University and Columbia University Libraries/Information Services, through the Medical Heritage Library. The original may be consulted at the the Augustus C. Long Health Sciences Library at Columbia University and Columbia University.

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    of proteid and carbohydrates, and if completely converted into mechanical work would yield that amount of energy which would suffice to raise 156 pounds (taken as the weight of the average human body) 56,755 feet. But a portion of this energy is used up in chemical processes, a portion in physical changes, and a portion is undoubtedly wasted; a portion of the food may be of no use or even detrimental to the body, so that not more than one-third of this work can be counted as available. Hence 18,918 feet may be counted as a theoretical day's work in mountain-climbing. The fact remains, however, that all experiments yet made go to show that within practical limits we are safe in using the heat of combustion (expressed in Calories) of any food- substance as a controlling measure of food values. The re- quisite number of Calories must, however, be obtained by the utilization of such substances as contain all the elements needed by the body, and in such ratio as has been found avail- able for the balance of nutrition. In carrying on its multi- farious activities the body loses about 20 grams of nitrogen per day, which must be replaced by the same element in the food taken. Thus while the requisite number of Calories may be furnished by fat or starch, these substances alone will not suffice for complete nutrition. The nutritive ratio, or the proportion of nitrogenous to non-nitrogenous food, must be maintained in the proportion of 1 to 3, or at least 1 to 5. The following table of one hundred common food-mate- rials is arranged in the order of calorific or energy-giving power, but in considering the food value of any one substance its nitrogen content must also be considered, and such com- binations made as will yield the requisite elements for a well- balanced ration. From even a cursory examination of the table it will be seen how widely some of the foodstuffs differ under differing conditions of soil moisture, fertilization in the case of plants,