Hormones are known to play a protective role in brain health so here we examine whether HRT can help prevent diseases to keep your brain healthy
• Hormones can protect and support brain function
• Some studies have shown that women who take natural, body identical HRT can reduce their risk of dementia
• More research is needed into the role HRT may play in dementia reduction
Many people worry about dementia, particularly if there is someone in your family who has been affected. As there isn’t a known cure for dementia, doctors and scientists focus on prevention, by taking steps to improve heart health and reducing known risk factors, which include high blood pressure, diabetes, obesity and smoking. There’s also some evidence that regular exercise, an active social life, and stimulating hobbies such as learning a new language, playing a musical instrument, or tackling puzzles like crosswords and sudoku can help reduce the risk of dementia and cognitive decline.
In recent years, there has been a great deal of research into dementia, with some researchers suggesting that HRT could potentially reduce the risk of dementia [1, 2, 3], specifically Alzheimer’s, along with other neurodegenerative diseases, including Parkinson’s.
Am I at risk of dementia?
According to the Alzheimer’s Society, worldwide, women with dementia outnumber men 2:1 [4]. It’s not yet fully understood why this is the case, and it isn’t entirely explained by the fact that women live longer than men. It is important to note that even though the risk of dementia increases with age, dementia is caused by diseases in the brain and not by age alone.
There is limited knowledge about women’s brains and risk of dementia, partly due to the fact that women have only been included in clinical trials since 1993. However, brain scans indicate that the rate at which brain cells die is faster in women than in men, and some researchers believe that this could be linked to declining levels of hormones during perimenopause and menopause. Some studies have shown that hormones can have a protective effect on brain cells, which is why researchers are working hard to assess whether taking HRT could reduce the risk of dementia [5, 6].
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How do hormones affect your brain?
The hormones oestradiol (oestrogen), progesterone and testosterone are produced not just in your ovaries but in your brain too. These hormones are chemical messengers, and every single cell in your body (including your brain) has receptors that, when the hormone locks on to the receptor, triggers a cascade of reactions. These hormones play numerous vital roles in your brain’s health, growth and function.
Dr Lisa Mosconi, a neuroscientist, author of The Menopause Brain and Director of the Weill Cornell Women’s Brain Initiative, has been studying the effects of hormones on women’s brains. She believes that menopause can be a turning point for brain health and cognitive function.
Dr Mosconi explains: “Oestrogen stimulates your brain, keeps the neurons firing, supports the growth of new cells and helps existing cells to form new connections. When oestrogen levels fall during the menopause transition, your entire body – including your brain – goes into a deprivation state. We have found that there is an overall reduction of brain energy levels during menopause, which might be one reason why you can suffer hot flushes, night sweats, anxiety, depression, brain fog, and even memory loss.”
She adds: “Testosterone has similar functions but, in men, it declines very gradually over time. In many cases, men are fertile into old age. But oestrogen really goes away during menopause – suddenly your most potent oestrogen is gone. For some women, it can happen almost overnight if you have surgery, and sometimes due to cancer treatment, and that’s a shock. A lot of people see menopause as a natural process we go through, which is absolutely correct. But they don’t see it as a process that puts you at an increased risk of future conditions – including dementia – and this is what’s really key.”
Progesterone is anti-inflammatory, it helps brain cells to communicate better, which improves mood, memory and brain health. It also helps nerve function. There is increasing evidence that progesterone has potent and direct neuroprotective and neuroregenerative effects in the brain [7]. It has also been shown that progesterone, given in acute stage of injury, could improve function after a brain trauma [8].
Glucose metabolism in the brain of Alzheimer’s patients is reduced but progesterone has been shown to significantly improve the glucose metabolism of neurons, suggesting progesterone could be a new target in delaying the progression of Alzheimer’s [9].
Like oestradiol and progesterone, testosterone is anti-inflammatory and has neuroprotective effects [10]. Testosterone improves concentration, memory, verbal learning and spatial abilities. A study by Newson Health on the effect of testosterone replacement for four months in perimenopausal and menopausal women already taking HRT found 39% reported an improvement in cognition [11].
RELATED: Hormones and brain health
Can HRT protect against dementia?
As hormones support brain function, there’s increasing evidence to suggest that taking HRT could also play a key role in reducing the risk of dementia. For instance, one review found women in midlife who used oestrogen-only HRT had a 32% lower dementia risk compared to those not taking HRT, while those taking combined oestrogen and progesterone HRT had a 23% lower risk [12].
Another study, carried out at the University of Arizona Center for Innovation in Brain Science, found that women who took HRT went on to have a 58% lower risk of Alzheimer’s, and that taking HRT for more than one year gave greater protection from Alzheimer’s, dementia and Parkinson’s disease than short-term treatment, where HRT was taken for less than one year [13].
Dr Roberta Diaz Brinton, senior author on the paper, said: “The key is that hormone therapy is not a treatment, but it’s keeping the brain and this whole system functioning, leading to prevention. It’s not reversing disease; it’s preventing disease by keeping the brain healthy.”
There have been conflicting results from studies into the effect of HRT on dementia risk – for example, a Danish study indicated that women who use HRT are at higher risk of dementia than those who do not and that longer periods of use are associated with higher increase of risk [14]. However, most women in this study who took combined HRT used oral formulations - synthetic hormones rather than the body identical, natural hormones more commonly prescribed today.
Dr Lisa, and other researchers, has been looking at the gap between the findings of randomised controlled trials and observational studies on the effect of HRT on dementia risk.
In studies where there was a negative effect on dementia risk with taking oestrogen and progesterone, the women were taking a synthetic form of progesterone (known as progestogen). These older, synthetic progestogens are not now commonly prescribed. Dr Lisa believes that it is possible that synthetic progestogen accounts for increased dementia risk and that transdermal oestradiol, with cyclic micronised progesterone, is the more beneficial option [1].
Dr Lisa also says that taking HRT when menopausal symptoms begin is the optimum time to protect your brain from dementia.
RELATED: The role of hormones in our brain and nervous system
Can I reduce my risk of dementia?
Some people are at a greater risk of developing dementia due to a family history, predisposing condition or other risk factors. This is why it’s vital to have individualised advice and to look at lifestyle factors that support brain health to help minimise your risk of dementia. This includes eating a healthy diet that’s rich in polyunsaturated fatty acids, which are found in fish and legumes, taking regular exercise, prioritising relaxation and reducing your stress levels, and getting enough sleep.
It can be a challenge to make these lifestyle changes, especially if you’re not feeling your best. Insomnia, aches and pains, and fatigue are all common symptoms of perimenopause and menopause – but they can be relieved with the correct dose and type of HRT, giving you the energy and focus you need to prioritise your health and wellbeing.
We already know that improving heart health can help reduce the risk of dementia [15] and this can be done by exercising regularly, staying a healthy weight and not smoking or drinking excessively. As an added bonus, taking HRT through the skin, via a patch, a gel or a spray, can help to keep cholesterol down and lower your blood pressure.
