A clinical study of tests for vitamin C deficiency

Abstract

I. A review has been presented of the present state of knowledge with regard to the origin, distribution, chemistry and physiological functions of vitamin C. It was demonstrated that several gaps still exist in our knowledge of the processes of absorption, utilisation and excretion of the vitamin, and of the factors controlling and influencing these processes.II. A deficiency of vitamin C in the diet is known to be able to produce eventually symptoms of scurvy in adults or children. There is also considerable evidence to suggest that minor degrees of deficiency of the vitamin insufficient to cause symptoms are probably not uncommon.III. For the detection of vitamin C deficiency, various tests have been elaborated,, the history and present position of these tests has been studied and two tests selected which were thought to be sufficiently well established to justify their use (with reservations): these tests were (1) a method of estimating the resistance of the skin capillaries, and (2) a method for the estimation of vitamin C in the urine.IV. The two tests chosen have been applied to an unselected series of cases in a children's hospital and the results obtained have been tabulated and examined.V. The tourniquet test was found to be unreliable and it yielded no helpful information as to the state of vitamin C nutrition of any of thle cases to which it was applied.VI. The test for excretion of vitamin C in the urine, while taking rather a long time for its performance, was found to yield useful information.VII. The test for excretion of vitamin C in the urine, while taking rather a long time for its performance, was found to yield useful information.VIII. A further series of cases on similar diet but who were all suffering from some pathological condition, mostly a chronic infection, were found to be in a state of unsatisfactory vitamin C nutrition.IX. Further light has therefore been shed on the conditions which may cause an increased "utilisation" of vitamin C and it has been conclusively demonstrated that chronic, apparently afebrile, infective conditions may deplete the vitamin C reserves of the tissues.X. There is some evidence to suggest that a deficient intake of vitamin C, of itself, does not cause so great a depletion of the vitamin C reserves as when some mild, often unsuspected, infection is present at the same time.XI. The frequent combination of these two factors and the difficulty of assessing the relative importance of each has been shown in a group of in-patient cases and also in a small group of ex- in- patients re-tested some time after discharge from hospital.XII. In only a very small number of cases found to be in a poor state of vitamin C nutrition was it thought that the main cause was a previous dietary deficiency of vitamin C.XIII. The writer would therefore like to point out the need, in applying this test to any case or group of cases, for a very thorough clinical examination of the cases beforehand in order to eliminate any subacute or chronic or slowly healing infective condition.