November being Alzheimer’s Disease Awareness Month, we bring you some recent research, strategies and treatments to help you preserve your memory and brain health as you age.
Strengthen your mind, this Alzheimer’s Disease Awareness Month
Alzheimer’s Disease (AD) affects millions across the world, and there is currently no cure. However, neurologist Sam Gandy, MD, PhD, director of Mount Sinai’s Centre for Cognitive health and NFL Cognitive Care, says that there are some hopeful developments in AD research – along with potentially promising data you may have seen reported in the news that needs further investigation before its clinical significance can be clarified. Here, Dr Gandy offers his verdict on some recent studies.
Downward Trend in Dementia
A large study published in ‘JAMA Internal Medicine’, suggests that between 2000 and 2012, the prevalence of dementia decreased by about 25% in people aged 65 and older, even though the population has continued to age. Those with the most years of education had the lowest chances of developing dementia.
Doctor’s verdict Cardiovascular risk factors such as high blood pressure, cholesterol, and blood sugar may play a role in AD. During the last decade, progress has been made in addressing these risk factors, and more people are taking medications to treat them. These data reflect that progress.
Cholesterol Fluctuations a Factor?
The connection between heart and brain health is underlined by a study associating greater fluctuations in LDL (‘bad’ cholesterol) levels with worse cognitive function in seniors. The study in ‘Circulation’ included 4,428 older adults who underwent standard memory tests. Compared to people with the lowest variability in LDL, those with the highest LDL variability took 2.7 seconds longer, on average, to name the real colours of colour names written in different ink (for example, the world blue written in red ink). Greater LDL fluctuations also were associated with lower brain blood flow, and a greater number of white matter hyperintensities (tiny lesions that have been associated with a greater risk for AD).
Doctor’s verdict High cholesterol is associated with a
build-up of an abnormal protein called beta-amyloid in the brain. It is believed that beta-amyloid deposits contribute to AD by destroying the brain cells’ ability to communicate with each other. In mouse studies, lowering cholesterol works like magic: Beta-amyloid melts away – but no human trial has come close to achieving the same result. Further studies are needed to examine whether these data could be useful in clinical practice, but right now they support expert advice to follow healthy lifestyle measures that can help maintain normal cholesterol levels.
The Role of Tau
Of the two abnormal proteins that characterize AD, beta amyloid has been more thoroughly studied than tau, which builds up and forms tangles in the brains of people with AD. This is largely due to the development of new brain scanning techniques that allow researchers to visualize beta-amyloid – and similar techniques can now visualize tau. A recent small study (‘Science Translational Medicine’) included 10 people with mild AD and 36 healthy older adults. Participants underwent imaging scans for beta-amyloid and tau, and completed standard tests of memory and cognition. People with AD had an accumulation of beta-amyloid and tau tangles. The location in the brain of the tau tangles correlated to the specific problems with memory and thinking experienced by the participants with AD, but this was less true for beta-amyloid. Doctor’s verdict These findings suggest that tau tangles more closely track the symptoms of AD. The failure of drugs that are designed to target betaamyloid means scientists are now investigating tau-lowering therapies. The first tau drugs are in trials. However, the key will still be early intervention, before the damage caused by AD has been set in motion.
Vitamin D Connection
In addition to its essential role in building healthy bones, vitamin D has effects on other organs in the body, including the brain. Studies suggest that people with AD have low vitamin D levels. For a 15-year study published in the ‘Journal of Alzheimer’s Disease’, researchers measured vitamin D levels in more than 3,400 people aged 60 and older. Those with a vitamin D deficiency performed worse on tests of cognitive function, and also tended to have a smaller hippocampus. This brain structure, which is involved in short term memory, is one of the first affected by AD.
Doctor’s verdict There is lots of new research into vitamin D, which appears to activate the immune system’s ‘garbage disposal’ cells in the brain. These cells may help clear betaamyloid. Vitamin D should be checked routinely and treated if low, but it is important to keep in mind that there currently is no evidence that