928 NUTRITION AND HEAT REGULATION. 



jurious effect upon the tissues, and moreover a material whose 

 consumption protects some of the other foodstuffs fats, carbo- 

 hydrates, and protein from destruction. In the first place, there 

 is no doubt that alcohol is oxidized in the body. Various observers 

 estimate that as much as 90 to 98 per cent, of the alcohol absorbed 

 is destroyed.* Since 1 gm. of alcohol, when burnt, yields 7 calories 

 of heat, it is evident that its oxidation in the body must yield a 

 large supply of heat energy. The question arises whether this 

 oxidation of the alcohol occurs in addition to the normal metab- 

 olism of the protein and non-protein foodstuffs, or whether it pro- 

 tects and takes the place of these foodstuffs. With regard to the 

 non-proteins a number of observers have attempted to determine 

 the point by ascertaining the total carbon excretion during an 

 alcohol period. If the usual amount of material is burnt, and the 

 alcohol in addition, it is evident that the carbon excretion should be 

 markedly increased. Most observers, however, find that it re- 

 mains practically the same. Such results as the following have 

 been obtained: 



Atwater and Benedict { A|cohol-fre^da ys .. j|| gms. carbon. 



13.4 " " 



r. / Alcohol-free days. .212.58 gms. carbon. 

 * jeri ' I Alcohol days 220.84 " 



+ 8.26 " " 



n i / Alcohol-free days. .214.83 gms. carbon. 

 C1 P att \Alcoholdays 220.87 " 



+ 6.04 " 



These results indicate that the alcohol is used by the body in place 

 of the other carbon-containing foodstuffs, and this conclusion is 

 corroborated by experiments reported by Atwater and Benedict 

 in which the total energy given off from the body as heat was 

 measured in a respiration calorimeter. The average of their ex- 

 periments gave for the alcohol days 2752 calories and for the alco- 

 hol-free days 2723 calories. 



Theoretically if the alcohol takes the place of the other material the 

 amount of carbon dioxid excreted should be diminished. One gram of 

 alcohol when oxidized furnishes as much heat as 1.7 gms. of sugar or 0.75 gm. 

 of fat. But 1 gm. of alcohol when burnt yields only 1.91 gms. of CO 2 , while 

 J.7 gms. of sugar yield 2.77 gms. CO 2 , and 0.75 gm. of fat, 2.13 gms. of CO 2 . 

 If fat were replaced by the alcohol the amount of COj should be reduced 

 about 10 per cent., while if the sugar were replaced the reduction should 

 amount to 31 per cent. That such a reduction is not actually observed is 

 explained by the fact that the alcohol leads to more muscular activity arid 

 a greater loss of heat from the congested skin, thus indirectly augmenting 

 the oxidations of the body. 



To determine whether the combustion of the alcohol protects the 

 protein material from metabolism to the same extent as is done by 



* See Atwater and Benedict, Bulletin 69, United States Department of 

 Agriculture, 1889; also Memoirs of the National Academy of Sciences, 8, 1902. 



