Increased Nerve Growth Factor by Zinc Supplementation with Concurrent Vitamin A Deficiency Does Not Improve Memory Performance in Mice

Abstract

SummaryWe investigated the effects of dietary supplementation of zinc (Zn) with or without vitamin A (Vit. A), to elucidate any cross activity between the two micronutrients, on memory and nerve growth factor (NGF) production in ddY male mice depleted for the two elements. After 3 mo-feeding with a Zn and Vit. A deficient (VAD) diet, mice were divided into three groups and replenished with normal Zn with VAD diet (NZ-VAD), high Zn with VAD diet (HZ-VAD) or normal Zn ϩ normal Vit. A (NZ-NVA) for additional 2 mo. One more group was made and given the normal diet for the same period (Control group). Levels of NGF were measured from extracts of hippocampus, cerebellum and cortex at the end of the 3rd and 5th month. In addition, a radial arm maze task was performed at the end of the 5th month. The two Zn supplemented groups (NZ-VAD and HZ-VAD) tended to show high NGF concentration but memory was not improved. However, improved memory was observed in the NZ-NVA group. From these results we concluded that Zn may increase NGF; however, memory was improved only when Vit. A was sufficient.

Zinc and glutamine improve brain development in suckling mice subjected to early postnatal malnutrition

“…For example, zinc supplementation given chronically to vitamin A-deficient mice improved nerve growth factor levels in the hippocampus, cerebral cortex and cerebellum extracts, however did not enhance mouse memory outcomes when vitamin A was deprived [35]. Zinc deficiency during lactation in rats was found to have lasting growth deficits after dietary rehabilitation and delay the first-week post-natal reflexes, including auditory startle, air righting and rope descent as compared to nourished controls [36].…”

Effects of zinc supplementation on parent and teacher behaviour rating scores in low socioeconomic level Turkish primary school children

“…However, it should also be noted that receiving multivitamins could alter neuropsychological performance. In an animal study it was shown that dietary supplementation of zinc may increase nerve growth factor; however, memory was improved only when vitamin A was sufficient (28).…”

The inorganic perspectives of neurotrophins and Alzheimer's disease

“…Levels of BDNF and NGF have been shown to decrease in zinc(II) deficient mice [125], hence zinc(II) dietary supplementation seems to replenish the NGF [126], as well as the BDNF, level [127]. Moreover, chronic treatments with zinc(II) ion induced a BDNF mRNA upregulation in the cortex and hippocampus [128], strongly suggesting a more direct role of this metal ion in the neurotrophins expression.…”