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Stages of Nutritional Vitamin Deficiency

In our days certain typical disease patterns have been shown to be due to vitamin deficiency. It is particular noticed in countries where diets are unbalanced and inadequate, or where there are particular dietary customs. Examples of the most commonly observed diseases are xerophthalmia, rickets, beriberi, pellagra and scurvy, which result from deficiencies of vitamin A, vitamin D, thiamin, niacin and vitamin C, respectively. In meantime deficiency of a single member of the vitamin B group is rare in humans.

As these vitamins are largely found together in nature, and foodstuffs lacking in one member of the complex are likely to be poor in the others. In addition, the obvious manifestations of deficiency of this group overlap to some extent.
Subclinical deficiency and marginal deficiency are synonymous terms used to describe conditions in ipeople who are not clinically nutrient deficient, but who appear to be close to it.
By reference to the sequence of events in the development of vitamin deficiency, scientists emphasized the importance of preventing functional metabolic disturbances that can evolve into overt clinical symptoms. This sequence can be subdivided into six stages as follows.

Stage 1
Body stores of the vitamin are progressively depleted. A decreased vitamin excretion in the urine is often the first symptom. Normal blood levels are maintained by homeostatic mechanisms in the very early stages of deficiency.

Stage 2
The urinary excretion of the vitamin is further decreased and vitamin concentrations in the blood and other tissues are lowered. A diminished concentration of vitamin metabolites might also be observed.

Stage 3
There are changes in biochemical parameters such as low concentrations of the vitamin in blood, urine and tissues, and a low activity of vitamin- dependent enzymes or hormones. Immune response might also be reduced. Non-specific subclinical symptoms such as general malaise, loss of appetite and other mental changes appear.

Stage 4
The biochemical alterations become more severe and morphological or functional disturbances are observed. These disturbances might be corrected by vitamin dosing in therapeutic amounts within a relatively short time or vitamin supplementation in amounts of (or exceeding) the recommended dietary allowances over a longer period. Malformation of cells is reversible at this stage.

Stage 5
The classical clinical symptoms of vitamin deficiency will appear. Anatomical alterations characterizedby reversible damage of tissues might be cured in general by hospitalization of the patient. In most cases there are deficiencies of several nutrients and a complicated dietetic and therapeutic regimen has to be followed.

Stage 6
The morphological and functional disturbances will become irreversible, finally leading to death in extreme cases. From the health point of view, clinical studies have shown that the borderline vitamin deficiency is represented by the transition from the third to the fourth stage.

by materials: Vitamins: Their Role in the Human Body. G.F.M. Ball Consultant, London, UK