A new study
highlights the metabolic changes that occur in the brains of menopausal and
perimenopausal women, suggesting that a loss of estrogen could make these women
vulnerable to developing Alzheimer's disease.
The study was carried out by researchers at Weill Cornell
Medicine - the biomedical research unit and medical school of Cornell
University - in New York City, NY, in collaboration with scientists at the
University of Arizona Health Sciences in Tucson.
Dr. Lisa Mosconi, from Weill Cornell Medicine, is the
lead author of the study. As Dr. Mosconi and her colleagues explain, after old
age, being female is the second most major risk factor for developing
Alzheimer's disease. In fact, two thirds of those with Alzheimer's disease in
the United States are women, according to 2017 estimates.
Although the mechanisms responsible for this increased
risk are not yet known, previous research has hinted at the transition to
menopause as a potential key.
As the authors explain, this transition also involves
neurological and metabolical changes. So, Dr. Mosconi and team decided to
investigate these transformations.
Low glucose brain
metabolism found
The team used positron emission tomography imaging
technology to examine how the brains of 43 women metabolize glucose, which is
the main source of energy for brain cells.
The earlier studies reveal that low levels of the sugar
precede and may even trigger the development of Alzheimer's disease. In the
current study, the women participating were aged between 40 and 60. Of them, 15
were premenopausal, 14 were perimenopausal - or transitioning to menopause -
and 14 were postmenopausal.
The study found that the perimenopausal and
postmenopausal women had significantly lower glucose metabolism levels than
those who were premenopausal.
In addition to this so-called hypometabolism, the
researchers found signs of mitochondrial dysfunction, which means that the
brain cells were not as efficient at processing energy.
A key metabolic enzyme called "mitochondrial
cytochrome oxidase" was found to be less abundant among menopausal and
perimenopausal women. These women also scored significantly lower in memory
tests.
The findings support previous research by the same team,
which showed how menopause is linked with an increase in the beta-amyloid
protein, a biomarker of Alzheimer's disease, in the brain.
The same study found a reduction in gray matter and white
matter in brain areas affected by the neurodegenerative condition.
Estrogen and
Alzheimer’s Disease
Estrogen and progesterone are steroid sex hormones that
not only contribute to female fertility but also play an important role in
brain functioning for both men and women. Estrogen is part of the brain’s
signaling system, and it helps direct blood to parts of the brain that are more
active.
Fluctuation of estrogen contributes to brain fog and mood
swings that come with menopause, and explains why women going through the
change are more focused and feel better on some days than others.
Estrogen is also key in the normal maintenance of brain
function in the nucleus basalis of Meynert (NBM). Degeneration of the NBM is
found in people with Alzheimer’s disease, and less estrogen in the brain can contribute
to this degeneration.
These fluctuating hormones also contribute to insomnia,
which not only impairs memory but also causes extra stress and inflammation in
the body because it’s not able to fully restore and repair itself at night.
Deep sleep is when the brain moves short-term memories into long-term storage.
Frequent interruptions in sleep are deadly to memory.
How loss of
estrogen may impact brain cells
Cognitive decline is known to be associated with
menopause, and the authors suggest that the estrogen deficiency that
characterizes menopause may also be responsible for the neurodegeneration that
occurs in Alzheimer's.
Brain cells have estrogen receptors, they explain, and a drop-in
estrogen levels may cause a "starvation reaction" in these cells.
Such a metabolic state can lead to brain cell dysfunction.
"Our findings show that the loss of estrogen in
menopause doesn't just diminish fertility. It also means the loss of a key
neuroprotective element in the female brain and a higher vulnerability to brain
aging and Alzheimer's disease." Reports Dr. Lisa Mosconi, "We
urgently need to address these problems because, currently, 850 million women
worldwide are entering or have entered menopause," she warns.
"Our studies demonstrate," Dr. Mosconi says,
"that women need medical attention in their 40s, well in advance of any
endocrine or neurological symptoms."
There may be a "critical window of opportunity when
women are in their 40s and 50s, to detect metabolic signs of higher Alzheimer's
risk and apply strategies to reduce that risk."
Beyond Estrogen:
Other Important Hormones
It’s not all about “female hormones.” Other hormones such
as insulin, leptin and amylin decrease as both men and women age, which means
your body has fewer natural antioxidant and anti-inflammatory agents. This
makes your body and brain more susceptible to the damaging effects of free radicals,
inflammation and excess cortisol.
Research shows these hormone decreases have a direct
effect on brain functioning and contribute to cognitive decline, dementia and
Alzheimer’s disease.
Another important hormone is gamma-aminobutyric acid
(GABA), a neurotransmitter that regulates communication between brain cells.
A study published in January 2017 in the journal
Biological Psychiatry: Cognitive Neuroscience and Neuroimaging found that older
adults who had lower levels of GABA in the frontal lobes of their brain (the
part that handles complex cognitive functioning) performed worse on cognitive
tests compared to those who had higher GABA levels.
However, all is not lost. There are things you can do to
boost production of GABA, estrogen and other important hormones to help keep
your brain healthy.
Challenges for
Early Diagnosis
Women show a lifelong advantage in verbal memory compared
to men. Interestingly, this advantage might make it more difficult for
clinicians to detect a memory problem in women who are in the early stages of
Alzheimer’s disease (AD).
Before developing AD, patients transition though a stage
called amnestic mild cognitive impairment, or aMCI. At this stage, memory
problems exceed what is expected for age but do not reach the level of severity
seen in AD. The female advantage in verbal memory persists in the aMCI stage.
Consequently, women perform better than men despite showing the same level of AD
disease on brain scans. Although this could be seen as an advantage, women may
be diagnosed with aMCI or AD at a later and more severe stage of the disease
than men. Researchers are now exploring whether it might be useful for
clinicians to use different cut-offs for memory tests in women and men, so that
AD can be detected earlier in women.
How to Manage Your
Hormones for Better Brain Health
Two important things you can do yourself to prevent
diminishing hormones, especially diminishing estrogen, are:
(1) Keep stress under control and
(2) Maintain a healthy diet.
Excess stress contributes to a flood of cortisol in your
body, which, if left untended, can essentially corrode your organs and
neurotransmitters, making you vulnerable to disease and dementia.
A healthy diet of whole foods and nutrients can actually
boost hormone production, increasing your body’s natural defenses. Foods said
to increase estrogen specifically include alfalfa, barley, baker’s yeast, beets,
cherries, chickpeas, carrots, celery, cucumbers, dates, fennel, oats, olives
and olive oil, papaya, peas, plums, pomegranates, potatoes, beans, rhubarb,
rice, tomatoes, wheat and yams.
A few things you can do to increase waning hormones in
your body, whether you’re a woman going through menopause or not, are:
* Move every day. Not
necessarily “exercise” but movement like walking or hiking outside in nature,
bike riding, etc. These activities reduce stress while increasing GABA
production.
* Take time for self-care. Rest,
take a hot bath, do yoga, read, take a nap… These things help you manage
stress, sleep better and reduce cortisol.
* Eat whole foods, healthy fats
and raw organic cacao. Cacao (dark chocolate) has been shown to boost hormones
and reduce cortisol.
* Practice mindfulness. Pay attention
to what you’re doing when you’re doing it. Don’t let yourself be so distracted
and stressed out that you can’t remember where you put your keys, whether or
not the stove was left on or what you came into the room for. Be aware of your
actions.
These are easy steps you can take daily to counteract the
natural decrease in hormones that happen as you age. While you can’t turn back
the clock, you can meet the future with a box of tools and a set of choices
that will keep you healthy longer.
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