17 Check your hormones
Your hormone levels are crucial to your brain’s ability to function well as many of them support the making and maintenance of the brain’s synapses. However, as we age, levels of the sex hormones oestrogen, progesterone and testosterone tend to drop, while thyroid hormones can often get out of kilter.
Optimal thyroid function, says Dr Bredesen, is crucial to cognitive health. Your thyroid function sets your metabolism, your heart rate and your mental sharpness. It can also affect your sleep and whether you become depressed. Low thyroid function is commonly found in those with Alzheimer’s.
There’s an easy way to test it — take your basal body temperature with a thermometer under your armpit for 10 minutes before you get up in the morning. It should read between 97.8F and 98.2F; any lower and you may have low thyroid function. If so, Dr Bredesen recommends asking your GP to test your complete thyroid panel of TSH (thyroid stimulating hormone), T3, T4 and reverse T3.
He also suggests supporting your thyroid if your TSH levels are more than 2.0microlU/ml (a level a good deal lower than that considered in the normal range of 4.25microlU/ml in Ireland).
When it comes to oestrogen, Dr Bredesen acknowledges that hormone replacement therapy is controversial. “There are side effects [to supplementing hormones] and so you have to be very judicious with your use of hormones,” he says.
However, he cites studies from the Mayo Clinic that show that women who have had their ovaries removed by the age of 40 and don’t have HRT may face double the risk of Alzheimer’s.
Secondly, the ratio of oestradiol (a form of oestrogen) to progesterone is important. Too high and you will experience ‘brain fog’ and poor memory. Symptoms many menopausal women will identify with. “There are multiple studies that show that optimising your oestradiol is helpful for your cognition.”
Before you approach your GP about boosting your hormones, Dr Bredesen suggests trying lifestyle approaches first. “You may not need to take hormones. You may improve your own production just by improving your metabolism and improving your levels of inflammation (see page 5). As long as you have systemic, ongoing inflammation, you’re going to damage your ability to make your own hormones.” If lifestyle interventions fail, and you wish to try hormone support, Dr Bredesen stresses that it is crucial to work with a practitioner expert in hormone therapy and cognitive function who can help you weigh up the risks and benefits of hormonal support.