Abstract
A three-year accumulation of data obtained from the analysis of more than 1,000 blood samples indicated that the average plasma ascorbic acid level of the patients in this hospital was less than .40 mg %. The lowest results, averaging .20 mg %, were obtained during the months of April, May and June and the highest during October and November when an average of .59 mg % was achieved. These data on ascorbic acid and others on various nutritional essentials which will be described in subsequent reports indicated that a large mental institution is an exceptional laboratory for conducting studies of human nutrition and a project has been started to make use of this opportunity. The regulated routine of the majority of the patients, the supervision of the dietary intake, and the choice of age and sex from the large numbers available make it possible to have better controls than is ordinarily so easily available.
A modification of the Mindlin and Butler 1 method was used to determine the plasma ascorbic acid. No cyanide was added to the blood but the plasma was separated from the cells and precipitated with metaphosphoric acid within 30 minutes after the blood was drawn in order to minimize ascorbic acid oxidation. All recent estimations have been made with the aid of a Cenco Spectrophotometer. Prior to January, 1941, a Cenco Photelometer was used with a green filter. All blood samples were taken in the morning before breakfast.
Table I presents the average ascorbic acid levels of different groups who were in residence at this hospital during the months March through June. The differences demonstrated are the direct results of differences in the diets.
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