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.

Date of Award	1973
Original language	English