Despite the presence of combined deficiency of
vitamins D and group B among the population of Russia, the intake of
cholecalciferol is often recommended without correcting the supply with B group
vitamins, which are involved in ensuring the
biological functions of
vitamin D. The aim of the study was to compare the effectiveness of
vitamin D deficit correction by replenishing its content in the diet to an adequate level without eliminating the deficit of
B vitamins and by restoring
vitamin D level in combination with
B vitamins. Material and methods. The experiment was carried out on male Wistar rats (n=33) with an initial
body weight of 69.5±0.8 g. Combined deficit of
vitamins D and B group in rats (n=24) was caused by a 5-fold decrease in their content in the
vitamin mixture of a semi-synthetic diet for 23 days. Over the next 7 days, in order to correct
vitamin deficiency, 12 rats (group «-B+D») were fed a diet, replenished up to 100% for
vitamin D with continued deficiency of B group
vitamins, and 12 rats (group «+B+D») were fed a diet replenished for all missing
vitamins. Animals of the control group (n=9) received a full semi-synthetic diet during the entire experiment. The concentration of
vitamins A and E in blood plasma and lyophilized liver and whole brain was determined by HPLC,
vitamins B1 and B2 in the liver, brain and urine,
riboflavin in plasma and
4-pyridoxic acid in urine - by fluorimetric methods, 25(
OH)D in blood plasma was determined by ELISA. The content of
calcium,
magnesium,
iron,
manganese,
zinc and
copper in freeze-dried liver and brain was determined by atomic absorption method, biochemical parameters of blood and urine were determined using a biochemical analyzer. Results. The only
vitamin D addition to the feed with a persisting deficiency of
B vitamins did not restore the concentration of 25(
OH)D and
osteocalcin to the level in control animals sufficiently provided with all
vitamins. In animals of the "-B+D" group, 25(
OH)D plasma level was reduced by 17.3% (p<0.10),
osteocalcin - by 11.7% (p<0.05), the activity of
aspartate aminotransferase was 1.5 fold less,
alanine aminotransferase - 2.3 fold (p<0.05),
lactate dehydrogenase - by 14.9% (p<0.10), while the concentration of
iron exceeded 2.7 times,
glucose - by 15.0%,
calcium - by 8.0%,
creatinine - by 8.7% (p<0.05),
urea - by 32.1%, direct
bilirubin - by 24.2% (p<0.10 ) compared with corresponding
indicator in rats of the control group. The level of
cholesterol and
HDL cholesterol was 14.7% and 15.9% higher (p<0.10) than in animals of the «+B+D» group. Conclusions. Deficiency of
B vitamins inhibits the restoration of adequate supply with
vitamin D. In the presence of a lack of
B vitamins in rats,
vitamin D deficit and its consequences cannot be completely eliminated. Adequate supply with
vitamins D and B group are synergistic factors in maintaining the level of
glucose,
cholesterol in blood plasma and other diagnostically significant parameters.