Garlic is well known for its ability to fight the common cold, however, Curtin researchers have also discovered that an odourless aged extract of the root vegetable may help reduce the risk of developing Alzheimer’s disease and even reverse its effects.
Memory loss, disorientation, emotional unpredictability, weakening motor skills, loss of speech. The symptoms of Alzheimer’s are well established, but despite the first case of the chronic neurodegenerative disease being documented more than 100 years ago, medical scientists have yet to determine what causes it, how to prevent it, or how to cure it.
With close to 50 million people worldwide living with Alzheimer’s and other types of dementia, a number expected to more than double by 2050, research into the disease has become increasingly important.
For the past ten years, Senior Research Fellow Associate Professor Ryu Takechi, from the Curtin Health Innovation Research Institute (CHIRI), and his team have been investigating the connection between cognitive impairment and subtypes of dementia, including Alzheimer’s.
Takechi has focused his team’s efforts around mounting evidence suggesting it is linked to breaches in the blood-brain barrier, a layer of tightly opposed cells lined with microscopic blood vessels called capillaries that regulates the transportation of molecules in and out of the brain.
When breaches occur, harmful molecules may enter the brain – including amyloid beta, a mysterious protein that causes the death of neurons and, in doing so, is believed to contribute to the development of Alzheimer’s disease.
“Our research identifies the factors that break down the brain’s capillaries and that can protect or restore the function of the blood-brain barrier integrity. Restoring and reversing a patient’s memory function is our ultimate goal,” Takechi says.
“In the last few years, we found the damage to the blood-brain barrier is induced by inflammation and oxidative stress[1].”
In 2010, the researchers published an important finding that diets enriched in saturated fatty acids, such as fast food, can increase dysfunction of the blood-brain barrier, and therefore potentially increase the risk of developing Alzheimer’s disease.
The researchers later found that aged garlic extract, an odourless product widely available in Australian pharmacies and even some convenience stores, can completely prevent the breakdown of blood-brain barrier.
The extract prevents dietary saturated fat-induced oxidative stress and protects the neurons in the brain that are central to memory function.
“The major strength of garlic is in its unique cocktail mixture of a number of strong anti-oxidant compounds that are both water soluble and insoluble, compared to other pharmacological drugs or nutraceutical agents that contain just a single beneficial compound,” Takechi says.
Since then, the team has established the Animal Behaviour Testing Unit within Curtin’s Life Science Facility to examine how the cognitive abilities of preclinical rodent test subjects are affected after they have been fed with garlic.
These studies are now close to completion, with new studies already well underway into whether certain classes of cardiovascular drugs may prevent inflammation in the brain and blood-brain barrier breakdown, and how metallic content, such as iron and copper, relate to the dysfunction of blood-brain barrier, ageing and Alzheimer’s disease onset.
Dr Virginie Lam, who has led the preclinical trials in the laboratory, says the vast output of findings wouldn’t be possible without strong collaboration between herself, Takechi, CHIRI Director Professor John Mamo, neuropsychologist Dr Matthew Albrecht and analytical chemist Dr Mark Hackett.
“It was great to have Dr Albrecht’s help, for example, in analysing how the memory and other cognitive functions of our preclinical models were affected after we conducted dietary interventions,” she says.
Since beginning their research, the diverse team has attracted substantial funding from the WA Department of Health, Dementia Australia Research Foundation, and the National Health and Medical Research Council.
Last year, Takechi was presented with a prestigious Boosting Dementia Research Leadership Fellowship worth $720,000 by Australian Minister for Health Greg Hunt, to begin work in associated research: investigating the connection between diabetes and dementia.
In the future, the team is planning to begin human clinical trials on the aged population or those afflicted with Alzheimer’s to see how their research can be translated into practice.
“We definitely want to see some public health outcomes with the increased adoption of aged garlic extract and nutraceuticals,” Lam says.
“We also want to conduct regular public seminars around Perth as part of CHIRI to help us disseminate our findings.”
[1] Oxidative stress is an imbalance caused by the body being unable to counteract the harmful effects of unstable oxygen atoms trying to ‘steal’ the electrons of nearby stable molecules.
