A diet high in saturated fat and sugar doesn't only put us at risk of diabetes, but could also lead to dementia, according to new studies that link both conditions with insulin production.
Research on animals suggests the hormone insulin is a key factor in dementia development, which has caused some scientists to conclude Alzheimer's is another form of diabetes.
Type 2 diabetes, which is associated with a high intake of unhealthy foods, makes the body's cells resistant to insulin, which they need to convert sugar to energy.
Now it appears a similar thing could be happening with Alzheimer's, where a bad diet prevents the brain from responding to insulin properly.
The brain uses insulin to regulate chemicals that help memory and learning, plus strengthen brain cell connections and blood vessels that transport fresh blood to the brain.
Glenn Rees, CEO of Alzheimer's Australia, said the rising rate of diabetes is concerning.
"Every person who has a diagnosis of diabetes is at a greater risk of developing dementia," he said in a media release.
"In fact, the research suggests that they are 47 percent more likely to develop dementia during their lifetimes compared to other people at the same age."
In one study, researchers from Brown University in the US, gave rats a chemical to stop their brains using insulin.
When the researchers put them in a water maze –– a common memory exercise used to test rodents –– they splashed around aimlessly and were unable locate a submerged safety platform.
"They were demented –– they couldn't learn or remember," researcher Suzanne de la Monte said in a New Scientist report.
In another study, researchers fed healthy people sugary foods for a month and found their insulin levels rose.
"If they are right –– and a growing body of evidence suggests they might be –— the implications are deeply troubling," New Scientist wrote.
"Since calorific foods are known to impair our body's response to insulin, we may be unwittingly poisoning our brains every time we chow down on burgers and fries."
Suha Ali, dementia risk reduction manager at Alzheimer's Australia, told MSN NZ that further research is needed to create recommended guidelines around fat and sugar intake to prevent dementia.
For now, she said the best thing people can do to reduce their chance of diabetes and dementia is to eat healthy.
"We know we should be having a healthy balanced diet to help maintain brain health and functionality," she said.
"We recommend a balanced diet that includes higher intake of vegetables, fruit, nuts and legumes, and a lower intake of high saturated foods like you find in meat, high fat dairy products, fried food, sweets and junk foods. Eating good fats found in fish, olive oil and canola oil are good for us and can protect against dementia."