Maintaining or even improving your powers of memory is something that can be achieved with effort. Looking after your nervous system is a wise strategy too with a good diet, enough exercise and sleep. Without getting these measures correct all other efforts will come to nothing. Good quality oils in the diet and measures to suport your circulation and detoxification will then help.
Mental exercise – reading, crosswords etc – is essential to maintain mental acuity, especially with age.
If the simple things do not help go and see your herbalist please.