In this two-part series on Alzheimer disease, I would like to make my readers aware of the different risks that affect women and men. In part I, I’d like to talk primarily to my female readers about the hormonal and nutritional issues that put women at risk for Alzheimer as well as how the disease can progress differently in women.
Alzheimer’s – Women At a Distinct Disadvantage
When it comes to risks for disease in general, women (especially postmenopausal, elderly women) are at a disadvantage over men in developing Alzheimer disease. Although there are many possible causes of Alzheimer disease, one influence for this disadvantage, research suggests, is menopausal imbalance of types of estrogen. Let me explain why.
The brain is an important target organ for the hormone estrogen. Estrogen affects brain health and functioning by keeping its vascular system – veins, capillaries, arterioles – operating smoothly. When estrogen decreases, the vascular system can start to deteriorate, blood flow throughout the brain changes, making conditions ripe for dementia-like pathology to develop.
Adequate estrogen also boosts the female immune system which helps suppress inflammatory processes in the brain. When estrogen levels decrease, there’s no longer a checks/balance system in place and inflammation can gain a stronger footing. Inflammation is a pre-cursor condition that can lay the groundwork for many diseases – including Alzheimer’s.
In addition, without getting into too technical of an explanation, two different classes of estrogen greatly affect cognitive (learning) functions of the female brain – specifically the functioning of neurons and the neurotransmitter systems that figure importantly in memory processes.
In recent research, [Cognitive Changes After Menopause – Influence of Estrogen, Victor Henderson MD, MS et al, Clinical Obstetrics and Gynecology, September 2008], brain imaging studies had shown that estrogen levels in women modulates neural activity while performing cognitive (learning, memory) tasks. Around the time of menopause, many women report complaints in their ability to learn/recall new information that suggests a link to estrogen decline.
The study also reported that these cognitive complaints also occurred in younger, premenopausal women, who had had hysterectomies with ovaries removed. Sudden declines in estrogen can bring about many brain-function symptoms like depression, agitation, problems with concentration, language and attention span. These are also symptoms of Alzheimer’s disease. When estrogen levels were re-balanced, their symptoms improved. In other studies, women who had received hormone replacement at any age – especially 85 years and older – had much slower rates of cognitive decline. Still other studies didn’t report much improvement, so estrogen’s influence seemed inconclusive. Yet, reports out of the WHIMS (Women’s Health Initiative Memory Study) seemed to suggest that there is greater protective benefit against dementia when HRT is given at the onset of menopause, for several years, then stopped.
Women Deteriorate Faster – Estrogen or Nutritional?
Recent research out of England’s University of Hertfordshire [Women with Alzheimer’s deteriorate faster than men, Keith Laws, et al], has concluded that women with Alzheimer’s fare worse than men. In testing men and women in the 5 important skills areas, women did worse in verbal, visual spatial, and different types of memory. Researchers in this study concluded that possibly estrogen decline could be behind the faster deterioration but more evidence is needed.
Research also shows that there may be one critical, nutritional influence that may occur in women (and men) that can readily be addressed to immediately reduce risk of developing Alzheimer’s. That is the widespread prevalence of Vitamin B12 deficiency in women. Deficiencies can occur from pre/post menopausal blood loss (fibroids, cysts, etc) and the fact that women just don’t eat enough B12 rich foods, like red meat. Pernicious anemia from B12 deficiency also typically affects women – especially older women – more than men. Yet, both men and women over the age of 40 can become significantly deficient in Vitamin B12. Why? Just general slowing down of metabolism and the inability of the gut to completely absorb B12, (as well as other nutrients) from food.
Recent research out of Chicago’s Rush University Medical Center [Low Vitamin B12 May Lead to Brain Shrinkage and Cognitive Problems, Neurology, September 2011] has shown that deficiencies in vitamin B12 could be a culprit in both sexes developing brain atrophy and cognitive impairment. Using MRI’s to document, those with B12 deficiencies showed brain volume shrinkage as well as lower cognitive scores. The researchers concluded that B12 deficiency was a risk factor for brain atrophy and cognitive impairment.
In a similar study [Vitamin B12 may reduce risk of Alzheimer Disease, Neurology magazine, October 2010], it was shown that Vitamin B12 may protect against developing Alzheimer’s disease as it protected the brain’s neural pathways. The researchers concluded that greater research needed to be done on B12 deficiency as a risk factor in developing Alzheimer’s disease.
Aside from the estrogen association, I don’t think it’s coincidental that women may do worse with Alzheimer’s disease and that they are typically more deficient in Vitamin B12. Men typically eat more red meat and have higher B12 levels – at least until about their 80’s when adequate food intake can drop off in this age group of men.
Regardless, I always recommend my older patients to take 400 mcg of supplemental B12 a day. Sublingual or injection forms of B12 may be of more help to some people. See my prior newsletters on B12 deficiency. I am also an advocate of using bioidentical hormone replacement in menopausal women to treat troublesome physical or cognitive complaints and ward off Alzheimer’s. Talk to your doctor about your concerns and any symptoms you have.
Mark Rosenberg, M.D.
Cognitive Changes After Menopause: Influence of Estrogen, http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2637911/
Women with Alzheimer’s deteriorate faster than men, http://www.sciencedaily.com/releases/2012/08/120824082515.htm
Low Vitamin B12 levels may lead to brain shrinkage, http://www.sciencedaily.com/releases/2011/09/110926165852.htm
Vitamin B12 may reduce risk of Alzheimer disease, http://www.sciencedaily.com/releases/2010/10/101018162922.htm
HRT might ward off Alzheimer’s, http://news.bbc.co.uk/2/hi/health/7312252.stm