Memory loss isn't a normal part of any process.
That means that it's also not a normal part of aging.
Memory loss can be associated with illness, with stress, with hidden pathology, with nutrient deficiencies, and with injury.
Traumatic Brain Injury, Nutrition, High levels of toxicity, autoimmunity, metabolic issues (like diabetes and sugar metabolism), food sensitivities, circulatory issues (like high blood pressure) and many other issues can lead to memory loss.

These issues often cause permeability of the blood brain barrier - the barrier that protects our brain and maintains its normal function.
Test for problems. Repair them.
Any of these problems can lead to memory loss and difficulties with concentration. And not surprisingly, most of these issues can be corrected.
Giving the proper nutrition, balancing blood sugar and sugar metabolism, supplementating with the best nutrients and amino acids to repair the blood brain barrier, detoxifying the body, and improving circulation go far to restore proper brain function and stall memory loss.