Good brain health is in our power

Over the past few years, The Lancet, a prestigious medical journal, has commissioned reports from experts about modifiable risk factors for dementia and cognitive decline. The most recent report came out in July this year. In total, 14 different factors have been identified – ones that may have an impact from childhood all the way through to later life.

Each time a report is written, more factors are determined and the percentage of cases of dementia that could potentially be prevented or delayed appears to increase. The 2024 report suggested that perhaps up to 45 per cent of cases would fall into this category.

One of the newly determined risk factors is high midlife LDL cholesterol.

It was suggested that up to seven per cent of cases of dementia worldwide could be delayed or avoided if LDL cholesterol is optimised at a patient and societal level.

Cholesterol, in fact, serves very necessary and helpful functions in the human body and brain. First of all, it is an integral part of the structure of the brain and, in particular, the cell membranes.

It is also part of myelin: an insulating coating around nerve fibres that helps them efficiently transmit messages. It influences the changeability (plasticity) of synapses, which are the gaps between nerve cells – again, a critical part of messages being transmitted throughout the brain. Cholesterol is a precursor to several hormones which play important roles in brain health.

Blood tests for cholesterol can differentiate between LDL-cholesterol (the so-called ‘bad cholesterol’) and HDL cholesterol (or ‘good cholesterol’). Ideally, you want to have low levels of LDL cholesterol and high levels of HDL cholesterol, and the reverse scenario is certainly not desirable. LDL cholesterol contributes to dementia risk in a number of ways, including by causing atherosclerotic disease (diseases of the blood vessels caused by build-up of cholesterol containing plaques on vessel walls) which impacts blood flow to the brain, and by inducing insulin resistance and chronic inflammation.

Some people have a genetic propensity to high LDL cholesterol, but it is also something amenable to lifestyle interventions and medication treatment. Chief among the former includes reducing your intake of saturated fat, found in  red meat, full fat dairy products and processed foods. Limiting these foods and replacing them with sources of healthy  fats (for example, olive oil, nuts and avocados) is advised.

Interestingly, the link between dietary cholesterol intake and LDL cholesterol levels is far less robust. Increasing fibre in your diet can also help, and there is some evidence that plant sterols (found, for instance, in certain margarines) may be beneficial. Exercising regularly may help lower LDL cholesterol levels as well with weight management. Alcohol and smoking can both elevate LDL cholesterol levels, and these should be addressed.

There is some controversy about medications for lowering cholesterol. The most popular drugs are the statins, and these medications perennially appear on the best-seller lists of drugs. Statins generally work by reducing cholesterol production in the liver. There is ample evidence that, in general, their use is associated with a reduced risk of dementia, though some users do report cognitive problems while on them (brain fog and poor memory) and there may be a subset of people who do not do well long term. This is perhaps in part because of a pathological reduction in brain cholesterol which we have seen to be a critical part of brain structure and function.

It does make me think, however, that the lifestyle interventions should be the primary treatment and statins only used when these are not working. Lowering LDL cholesterol is low-hanging fruit when it comes to reducing dementia risk and is worth discussing with your doctor.

 Kailas Roberts is a psychogeriatrician and author of Mind Your Brain: The Essential Australian Guide to Dementia, available at bookstores and online. Visit yourbraininmind.com or uqp.com.au