The existence of a relation between
vitamin A and
vitamin E and human
cancers is supported by epidemiologic investigations. The aim of this study is to link the level of these
vitamins to those of plasmatic
protein carriers like
retinol binding protein (RBP) and
prealbumin (TTR), in three groups of subjects: healthy patients (n = 78),
polyp (n = 34) and digestive
cancer patients (n = 70). A paired t-test did not reveal any significant variation in any parameter between the
polyp group and controls, but did evidence a significant decrease in serum levels of
retinol (p less than 2.10(-4], RBP (p less than 2.10(-4), TTR (p less than 10(-5), and
alpha-tocopherol (p less than 2.10(-3), in
cancer cases as against control subjects. Comparison of RBP renal clearance and
retinol tissue clearance in
cancer and healthy patients indicates that the decrease in circulating
retinol levels cannot be attributed to an increase in peripheral consumption. The simultaneous reduction of RBP and TTR serum levels is to be considered as a sign of
protein denutrition. Thus our results suggest that the decrease serum levels of
vitamins A and E observed in digestive
cancers are a consequence of this
nutritional deficiency.