Pantothenic acid deficiency and safe and adequate levels of intake
Prisoners of war in the Far East in the 1940s, who were severely malnourished, showed, among other signs and symptoms of vitamin deficiency diseases, a new condition of paresthesia and severe pain in the feet and toes, which was called the “burning foot syn-drome” or nutritional melalgia. Although it was ten-tatively attributed to pantothenic acid deficiency, no specific trials of pantothenic acid were conducted, rather the subjects were given yeast extract and other rich sources of all vitamins as part of an urgent program of nutritional rehabilitation.
Experimental pantothenic acid depletion, together with the administration of ω-methyl-pantothenic acid, results in the following signs and symptoms after 2–3 weeks:
● neuromotor disorders, including paresthesia of the hands and feet, hyperactive deep tendon reflexes, and muscle weakness. These can be explained by the role of acetyl-CoA in the synthesis of the neurotransmitter acetylcholine, and impaired formation of threonine acyl esters in myelin. Dysmyelination may explain the persistence and recurrence of neurological problems many years after nutritional rehabilitation in people who had suffered from burning foot syndrome
● mental depression, which again may be related to either acetylcholine deficit or impaired myelin synthesis
● gastrointestinal complaints, including severe vom-iting and pain, with depressed gastric acid secretion in response to gastrin
● increased insulin sensitivity and a flattened glucose tolerance curve, which may reflect decreased antag-onism by glucocorticoids
● decreased serum cholesterol and decreased urinary excretion of 17-ketosteroids, reflecting the impair-ment of steroidogenesis
● decreased acetylation of p-aminobenzoic acid, sul-fonamides and other drugs, reflecting reduced availability of acetyl-CoA for these reactions
● increased susceptibility to upper respiratory tract infections.
There is no evidence on which to estimate panto-thenic acid requirements. Average intakes are between 3 mg/day and 7 mg/day, and since deficiency does not occur, such intakes are obviously more than adequate to meet requirements.