Влияние сочетанного недостатка витаминов D, группы В, кальция и магния в рационе крыс на обеспеченность микронутриентами и биохимические показатели плазмы крови

Abstract

The lack of vitamins D, B group, calcium and magnesium is common for the diet of the Russian population. It has been previously demonstrated that that the elimination of B vitamin deficiency is a necessary condition for the implementation of vitamin D biological functions. The aim of the research was to assess the effect of a combined deficiency of vitamins D and B group, calcium and magnesium in the diet of rats on biomarkers of micronutrient sufficiency and plasma biochemical indicators. Material amd methods. Male Wistar rats with an initial body weight of 66±1 g were randomly assigned to one of five groups. The rats of the 1st group (Control) were fed a standard semi-synthetic diet (SD) for 28 days. The combined deficit of vitamins D and B group, calcium and magnesium in rats of four experimental groups was caused by a 5-fold decrease in their content in the vitamin mixture and 2-fold decrease in their content in mineral mixture of the SD for 23 days. Over the next 5 days, the rats of 2nd group (+В+D+Ca+Mg) were fed a diet replenished for all missing vitamins and minerals, the rats of 3rd group (-В+D+Ca+Mg) were fed a diet with continued deficiency of B group vitamins, the rats of the 4th group (+В+D-Ca-Mg) were fed a diet with continued lack of calcium and magnesium, the diet of the 5th group (-B-D-Ca-Mg) was not replenished. Vitamins B1 and B2 in lyophilized liver and brain and urine, riboflavin in plasma and 4-pyridoxic acid in urine were determined by fluorimetric methods, 25(OH)D in plasma was determined by ELISA, the level of vitamins A and E in blood plasma and lyophilized liver, of vitamin E in whole brain - by HPLC. Biochemical parameters of blood plasma were determined using a biochemical analyzer. Results. In rats of the 5th group (-B-D-Ca-Mg), there were 3.4-fold increase (p<0.05) in iron plasma level, 1.7-fold elevation (p<0.10) in alkaline phosphatase activity, and 1.8-fold decrease (p<0.05) in alanine aminotransferase (ALT) activity on the background of the increase in α-tocopherol blood plasma level by 26.7% (p<0.05) and liver content by 2.0 fold (p<0.05) relative to the indicators in animals who hadn't passed the deficiency of micronutrients (Control) and / or from the 2nd group (+B+D+Ca+Mg). The lack of B group vitamins in the diet, which persisted during the correction of vitamin D, calcium and magnesium deficiency in rats of the 3rd group (-B+D+Ca+Mg), inhibited the recovery of diagnostically significant biochemical parameters of blood plasma (namely, an increased level of glucose, iron, triglycerides, cholesterol, α-tocopherol, increased alkaline phosphatase activity and reduced ALT activity) to the level in animals of the control group and/or rats fed the diet replenished for all missing micronutrients (+B+D+Ca+Mg). Conclusion. Combined deficiency of several micronutrients led to changes in biochemical blood parameters. Reduced intake of calcium and magnesium during the correction of the lack of vitamins D and B group in the diet can have a negative impact on vitamin B2 status. Even under normal dietary vitamin E intake the combined deficiency of several other micronutrients affected the metabolism of this vitamin (increased levels of vitamin E in the liver and blood plasma of animals). Chronic combined alimentary deficit of B vitamins, calcium and magnesium, which is characteristic in the diet of the Russian population, reduces vitamin D bioavailability, which justifies the expediency of using vitamin-mineral complexes.