The relief of troublesome symptoms at menopause such as hot flashes is the commonest reason to use estrogen. As well it protects against heart disease resulting in a 40-to 50 per cent reduction in symptoms of disease and even death. Estrogen slows the normal loss of bone and produces some bone growth so it protects against osteoporosis (fragile bones). Replacement with estrogen is often used in combination with its sister hormone progesterone to protect the lining of the uterus when estrogen is prescribed at menopause.
In many parts of the brain there are estrogen receptors. These include regions that play important roles in thinking, memory and mood. The receptors can influence the brain activity in a variety of ways. They affect the way chemicals carry nerve impulses from one nerve to another. They change the ability of a nerve to respond to an impulse and they alter the ability for a nerve to respond repeatedly. All of these effects suggest there may be a noticeable effect on the brain from the presence or absence of estrogen in the body.
The work of memory can be divided into short and long term. Memory also depends on how well we can see, hear, understand or pay attention to someone talking. How we process information on any given day depends on how many other things are demanding attention, how well we slept and many other factors. It is easy to realize that while major changes in our ability to remember and think are obvious, detection of more minor changes is difficult.
Despite the difficulties, researchers have tried to learn how estrogen affects these functions. This has been done through studying groups of women around the age of menopause who did or did not take estrogen. As well, one study focused on women at different times of the normal menstrual cycle. These studies showed some areas of the brain responded positively to the addition of estrogen, particularly short and long term verbal memory and abstract reasoning. These findings support the idea that memory occurs in different areas of the brain and that estrogen affects different areas of the brain differently.
Many other things affect our brain function and that could be confusing the results. These include poor sleep habits, mood disorders and our environment. More work needs to be done, but the early results are encouraging and suggest estrogen may improve memory and thinking.
Although there is a widespread belief that the rate of depression rises around the time of menopause, careful studies showed no relationship. If there is an association, it is likely because menopause often occurs at the same time as major life changes.
Depression is a very common disease in both men and women. Study of a large group of depressed women near the age of menopause suggests the use of estrogen improves mood. It can be used alone or in combination with anti-depressants.
In theory, there may be some connection between lack of estrogen and the development of Alzheimer's disease. The occurrence of this disease is very high in the elderly, rising to 50 per cent of all people who reach 90 years of age. That women have a higher rate of Alzheimer's is only partly explained by their greater average length of life; it may be partly attributed to lack of estrogen.
Current studies do not prove benefits for the brain from taking estrogen. However, there is strong evidence it may be valuable. Further work is needed to study its effects on healthy people. What is known so far is estrogen: