There are many causes of memory loss. As we age, we become more prone to having problems with remembering things. This can lead to a fear of developing dementia. But there is a big difference between becoming forgetful, and dementia.
Normal memory loss may cause some inconvenience and embarrassment, but does not get in the way of day to day functioning to any great degree. We may become slower to process information, but this is not the same thing as a breakdown in brain function.
Ironically, those who are most concerned about their diminishing power of recall are the ones with the least need to worry. A person moving into Alzheimer's or other form of dementia, may have the sense that something is not quite right but they are not aware of the changes in their cognitive ability. It is the people around them who will be noticing the impairment, not the individual actually experiencing this decline.
Aside from the problem that results from the normal aging process, there are many other causes for memory loss.
Diseases of many kinds can hinder one's ability to remember. Dementia such as Alzheimer's is one cause. One symptom of Parkinson's disease may be memory loss resulting from a genetic defect. This is also true of Down Syndrome. Huntington's, an inherited disease, may be accompanied by memory loss. Some types of mental illness, e.g., Dissociative Identity Disorder, may exhibit this problem with memory.
Traumatic brain injury, e.g., concussion, may alter one's capacity for recall. Nutritional deficiencies and depression may affect one's memory. Chronic diseases like diabetes and Chronic Fatigue Syndrome can reduce the cognitive process. Central nervous system infections and inflammation of the brain, like encephalitis, also low blood sugar, or low estrogen in women, can all hinder the ability to remember.
Dietary changes can make a difference. Eating less sugar and less processed foods, and adding more protein and omega-3 fatty acids can help shore up our mental faculties. Drinking filtered water can eliminate toxic chemicals found in our water.