A medical update on Alzheimer’s

We tend to joke about Alzheimer’s a lot, possibly because forgetting, which signals we might be getting it, is so frightening. There’s a stage just before Alzheimer’s called mild cognitive impairment. One of the features of mild cognitive impairment is that you are forgetting more than your friends are, which is why when I’m coaxing myself through a daily jog that is supposed to be good for my brain, I’m frantically trying to recall the names of minor and major celebrities, just in case my friends want to engage me in a memory duel, that’ll prove my brain cells are more fritzed-out than theirs.

For those who can remember the last article I wrote about Alzheimer’s for this magazine, which was a few years ago, I indicated then that for those worried about their diminishing memories, there weren’t tests to tell them if they were heading into the firestorm that is Alzheimer’s. As it turns out these investigations have now arrived.

Testing Alzheimer’s

Radiological investigations, including MRI scans, which not only image the brain but can tell you how efficiently it is working, as well as scans such as positron emission tomography (PET), which focuses on the brain’s capacity to use glucose or sugar for energy, and single-photon emission tomography (SPECT), which tracks brain blood flow and therefore nerve cell activity, will let you know with a reasonable amount of confidence if you are stumbling towards Alzheimer’s. That is, if you want that sort of information.

If you are gun-shy about having these tests you can rest easy, as they aren’t freely available yet. Commercial radiology clinics have yet to invest in PET or SPECT scans, which may only be found in hospital-based specialised medical centres.

I also mentioned in the previous article that inflammation, a process characterised by overheating of the immune system, which is ultimately destructive, and excess accumulation of free radicals were some of the primary events that promoted the decimation of brain cells. Investigations that examine levels of the antioxidant co-enzyme Q10, which are besieged by free radicals, and another substance called 8-hydroxy-2’-deoxyguanosine, which reflects DNA damage, can give you some indication of how much your brain cells are being compromised by free radicals so you can intervene before these events get out of hand. Blood tests that measure a substance called HS-CRP, which identifies the presence of inflammation, will let you know to what extent this unruly molecule is sparking up to fry your brain cells. It’s also a process you can hose down before the conflagration becomes unmanageable.

But what has all this to do with depression, polycystic ovaries and a proposed miracle weight-loss cure?

The insulin link

As it turns out, inflammation and excess free radicals may also be the driving forces behind the development of depression and polycystic ovary syndrome. The link is insulin. What insulin does is facilitate glucose utilisation, ensuring our cells are provided with this essential substance so they can make energy. Another vital insulin function is to stimulate the function of mitochondria, the batteries of our cells. In addition, insulin ramps up the manufacture of new brain cells. This means the presence and effective functioning of insulin are critical, not only for brain function but also for the preservation of healthy brain activity and its revitalisation. Undermine all the good works insulin does and you’ll have a brain that’s significantly compromised.

Looking at depression, there is research showing that insulin resistance is connected to this disorder. Blood tests show that in a substantial number of those who suffer from depression, glucose levels are elevated, as this substance is not utilised effectively, while insulin production increases in a futile attempt to drive glucose into cells.

PET scans show that, in depression, areas of the brain connected to mood have reduced access to glucose. At the same time, the region that governs memory becomes increasingly ravaged. Images of the brain reveal that the structural and functional changes that predate Alzheimer’s also take place in the brains of those who have depression. Therefore it should come as no surprise that there is an association between depression and the development of Alzheimer’s disease. If insulin resistance is the underlying mechanism for the progression of depression to dementia, then identifying and treating this metabolic derangement might not only alleviate depression but also halt the evolution of a crippling disease into a harrowing mental catastrophe.

Although weight gain commonly leads to insulin resistance, this condition can be found in lean individuals. Another cause is the over-activity of a hormone called cortisol, normally harnessed by our bodies to get us out of bed in the morning and sustain our energy throughout the day, but when produced in excess during times of stress and constant late nights, it can put a noose over insulin, strangling its function.

There is scientific evidence that, in some cases, insulin resistance can lead to polycystic ovarian syndrome. High rates of depression have been found in women with polycystic ovarian syndrome. Treating insulin resistance has been shown to improve depressive symptoms in those who have this syndrome and it might also have the added benefit of preventing dementia.

One of the hormones that increase in the case of insulin resistance and polycystic ovarian syndrome is luteinising hormone (LH), a substance manufactured in the brain that primes hormone production in the ovaries. What LH does is bolster the presence of an inflammatory substance called tumour necrosis factor (TNF), which is associated with the development of Alzheimer’s. TNF also leads to insulin resistance. HCG is the pregnancy hormone that has been promoted as a weight-loss miracle. HCG’s chemical structure is similar to that of LH and in mice HCG has been shown to cause features similar to those of Alzheimer’s.

Connecting the dots, optimising insulin function might help those of us who are traumatised by our ailing memories and provide a biochemical lifeline for many who are staring down the barrel of imminent brain degeneration. All you need is a doctor who understands how to assess this.

Dr Michael Elstein is an anti-ageing physician and writer based in Sydney, Australia. He is the author of three books including his latest, The Wellness Guide to Preventing the Diseases of Ageing. He has also designed the app The Diet Guide to Ageing Prevention.