PATHOLOGIC FACTORS ALTERING DIGESTIBILITY OF FATS 24 L 



of defective fat absorption upon a determination of the level of fecal fat 

 or upon histological examination of a single sample of feces. When fat is 

 determined by one of the chemical procedures, it is expressed as the percent 

 fat on the wet or dry basis. This index has been shown to give entirely 

 unreliable results when compared with a more satisfactory procedure such 

 as the fat balance. 



A straight line relationship has been shown to be absent. French 128 

 showed that the scatter is so wide that the percentage of fecal fat is not 

 only unreliable as an index of defective fat absorption but may lead to 

 totally erroneous conclusions in the detection of both normal and abnormal 

 fat absorption. 



b. By the Use of the Fat Balance. Van de Kamer, Huinink, and Wey- 

 ers 44 described a method of determining the state of fat absorption by the 

 use of fat balances which has proved exceedingly useful and reliable in the 

 diagnosis of impaired fat utilization. In this technic, a known amount of 

 fat is introduced into the diet daily, as determined by calculation from 

 diet tables; 50 g. is usually employed. 128 The daily output of fat is 

 estimated by a method of total saponification on an aliquot from the entire 

 twenty-four hour collection of feces. After saponification of the aliquot 

 with alcoholic potassium hydroxide, the sample is acidified with hydro- 

 chloric acid and the freed fatty acids are extracted with petroleum ether. 

 This extract is titrated with standard base and the fatty acid content ex- 

 pressed as stearic acid. 128 French 128 -considers that an absorption of 90% 

 or above is normal, one of 85 to 90% is borderline, while a value below 

 85% is to be considered definitely abnormal. 



The use of the fat balance procedure gives certain advantages. In the 

 first place, a continuous fat balance is of far greater use than a single 

 determination. Thus, in the case of celiac disease, only variations in 

 the trends upward or downward over a ten-day interval can be considered 

 significant. The simple estimation of fatty acids may be carried out in 

 thirty to forty minutes after hydrolysis by this procedure. 128 The results 

 based upon the intake and excretion of fat over a period of twenty-four 

 hours are likewise comparable with values in the literature. 



c. By the Use of Labeled Fats. Another procedure which has been 

 proposed for assessing the capacity for absorption of fats involves the use 

 of fats containing Sudan III or having fatty acids in the glycerides tagged 

 with elaidic acid, conjugated dienoic acids, or labeled with C 14 , I 127 , or I 131 . 

 However, there are certain objections to the use of this method. Since, 

 in the case of celiac disease, there is a preferential rejection of saturated 

 fatty acids concomitantly with a practically complete digestion of the un- 



