Aging. Menopause. Nutrient deficiency. Which is the cause of forgetfulness?
For most of us, it's not really the above. It's not paying attention. Buddhists would say it was a lack of mindfulness.
Forgetfulness, lack of attention, whatever we call it, the cause is that we're simply trying to do too much. We joke about "multi-tasking" but it's the way a lot of us live. What can we do?
We don't need to add anything; that's what got us into this. We need to slow down, pay attention to what we're doing, and stop taking in all the useless information that bombards us everywhere we look and go. We keep getting hooked by all the things we're told are important when in reality they're all illusions. The activities, the ideas, the things don't make us happy. Rather, they make us forgetful by complicating our lives.
We need to simplify. And decide what is really important.