Some Aspects of the Biochemistry of Malabsorption from the Upper Intestinal Tract

Abstract

method has been introduced which was suitable for the routine measurement of vitamin E levels in serum. It has been used to assess the vitamin E status of 220 patients with gastrointestinal diseases. These patients serum levels were found is be significantly lower than those of blood donor normals. The levels found correlated with the degree of ileal disease. Surgical intervention in any area of the gastrointestinal tract produced a lowering of serum levels. Vitamin E levels were not correlated with haemoglobin or MCV. There was a correlation with serum albumin and iron and with faecal fat excretion, all of which reflect gastrointestinal damage. When tritiated DL-α-tocopherol was given by mouth to rats, the major site of absorption was found to be in the jejunum and proximal ileum. The method used to monitor absorption of an oral dose of vitamin E by humans was not sensitive enough to follow accurately the small changes of level involved. The same methodological limitation applied when fasting levels of vitamin E were compared in serum from hepatic or hepatic portal with that from the ante-cubital vein; there was no significant correlation between serum vitamin E and cholesterol levels in these samples. The method used for the measurement of vitamin B6, in the form of pyridoxal-5'-phosphate (PLP), is convenient to use but further mechanisation is necessary to improve reproducibility. 182 gastrointestinal patients and 124 normals have had their serum PLP measured. Amongst normals, women had a statistically significant lower mean serum PLP. This sex difference was abolished when the subjects had gastrointestinal disease. The presence of an active disease process was found to have the most marked effect on the levels found. An attempt was made to correlate serum PLP level with the excretion of abnormal levels of tryptophan metabolites after an oral load of L-tryptophan.