Define Clinical Trials for Changing nutrient requirements with age?

Several clinical trials provide evidence of changing nutrient requirements with age. The metabolic demand for vitamin B, to maintain glucose tolerance and normal cognitive function in older adults is higher than the earlier assumption. Vitamin B6 and vitamin E supplementation help to enhance the vigor of immune reactions which slow down with age. The efficiency in absorption of vitamin B12 and folic acid in the gut may be reduced with age owing to the decrease in secretion of hydrochloric acid in the stomach of many elderly people. The capacity of the skin to synthesize vitamin D from sunlight and also Lundy's ability to convert vitamin D to its biologically active from declines with ageing process.