We know sugar is not very good for our waistline, but new research out of the US has found the negative impacts of sugar may extend even further: to your brainpower.
And don't think that because you don't add sugar to your coffee you're immune, because you're probably consuming more than you think.
An American study on lab rats, which appeared in the Journal of Physiology, found that a diet with consistent amount of high-fructose corn syrup effectively ruined their memories.
Researchers from the University of California in Los Angeles (UCLA) fed two groups of rats a solution with the syrup as drinking water for six weeks.
Corn syrup is produced using enzymes and acids sometimes used to break down corn starch into fructose, glucose and simple sugars.
The chemical composition of corn syrup closely resembles table sugar, sucrose.
It is made up of half glucose and half fructose.
High fructose corn syrup commercially used comes in two rations, 45 percent glucose to 55 percent fructose used in soft drinks, 58 percent glucose to 42 percent fructose used in sweetening ice cream, desserts and baked goods.
They have the same number of kilojoules.
High-fructose corn syrup is a common ingredient in processed foods, particularly soft drinks, condiments, baby foods and other snacks, and has gained interest over recent years as doctors and dieticians warn against consuming too much of the additive.
Earlier this year, a US study found that a tax on high-sugar drinks could save 26 000 American lives per year.
It is estimated that the average American consumes 45 gallons of sweetened drinks each year, while the US Department of Agriculture estimates they that more than 18 kilograms of just high-fructose corn syrup each year.
While both groups of rats were fed the high-fructose corn syrup, only one also consumed flaxseed oil, an omega-3 fatty acid, which has been shown to improve brain balance and function, and docosahexaenoic acid (DHA).
Prior to consuming the corn syrup, and for one group the flaxseed oil and DHA, the rats were given a five-day training session in a complicated maze.
After six weeks of consuming the additives, they were placed back in the maze to see if their abilities to manoeuvre it was the same, with some frightening results.
“The DHA-deprived animals were slower, and their brains showed a decline in synaptic activity," Fernando Gomez-Pinilla, professor of neurosurgery at the David Geffen School of Medicine at UCLA.said.
"Their brain cells had trouble signalling each other, disrupting the rats' ability to think clearly and recall the route they'd learned six weeks earlier."
Of even more concern, further examination found that those rats who were not fed the DHA supplements appeared to have developed a resistant to insulin.
Insulin is a hormone that controls blood sugar and regulates brain function, which Type 1 diabetics lack, while those with Type 2 diabetes produce insulin but is less efficient at moving sugar out of the bloodstream than healthy people.
Many years ago, Type 2 diabetes was often referred to as “sugar diabetes,” as it was known to be caused by lifestyle factors including obesity, high consumption of sugar and fat and low levels of exercise.
"Because insulin can penetrate the blood-brain barrier, the hormone may signal neurons to trigger reactions that disrupt learning and cause memory loss," Gomez-Pinilla said.
And it’s not just memory that feels the effect of the sugar, with thoughts and emotions also impacted as the fructose interferes with insulin’s ability to regulate cells.
"Insulin is important in the body for controlling blood sugar, but it may play a different role in the brain, where insulin appears to disturb memory and learning," Gomez-Pinilla said.
"Our study shows that a high-fructose diet harms the brain as well as the body.
“This is something new."
While it is not clear what the equivalent amount of high-fructose corn syrup a human would have to consume to suffer the same consequences in the brain, the study does raise questions and concerns over the amount of the additive we are consuming without knowing it.
"Our findings illustrate that what you eat affects how you think," Gomez-Pinilla said.
"Eating a high-fructose diet over the long term alters your brain's ability to learn and remember information.
“But adding omega-3 fatty acids to your meals can help minimise the damage."
Do you think Australians need more education about high-fructose corn syrup? Do we need better labelling around this additive?
Image: High-fructose corn syrup