Does sugar make you stupid Study suggests it sabotages learning and memoryFructose is commonly added to processed foods such as soft drinksIt was found to hamper memory and slow brain activity
09:34 GMT, 16 May 2012
Stay off the sweet stuff: Fizzy drinks contain high amounts of fructose which slows the brain
Anyone with an important presentation coming up or an exam looming should stay off the fizzy drinks, say scientists.
A study from UCLA has revealed that binging on such treats for as few as six weeks could make you stupid.
The researchers found consuming a diet consistently high in fructose slows the brain, hampering memory and learning.
However, the good news is that eating fish like salmons and nuts can counteract this disruption.
'Our findings illustrate that what you eat affects how you think,' said Professor Fernando Gomez-Pinilla.
'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.'
While earlier research has revealed how fructose harms the body through its role in diabetes, obesity and fatty liver, this study is the first to uncover how the sweetener influences the brain.
The researchers were studying the impact of high-fructose corn syrup on rats, who have similar brain chemistry to humans.
The inexpensive liquid is six times sweeter than cane sugar and is commonly added to processed foods such as soft drinks.
'We're not talking about naturally occurring fructose in fruits, which also contain important antioxidants,' said Prof Gomez-Pinilla.
'We're concerned about high-fructose corn syrup that is added to manufactured food products as a sweetener and preservative.'
Prof Gomez-Pinilla and co-author Rahul Agrawal studied two groups of rats that each consumed a fructose solution as drinking water for six weeks.
The second group also received omega-3 fatty acids in the form of flaxseed oil and docosahexaenoic acid (DHA). We need DHA for healthy brain function.
Professor Gomez-Pinilla recommends yoghurt with fruit rather than processed desserts
The animals were trained on a maze twice daily for five days before starting the experimental diet. The UCLA team tested how well the rats were able to navigate the maze, which contained numerous holes but only one exit. The scientists placed visual landmarks in the maze to help the rats learn and remember the way.
Six weeks later, the researchers tested the rats' ability to recall the route and escape the maze.
The group of rats who received the fatty acids navigated the maze much faster than those given the fructose. What is more the animals not given the omega-3 saw a decline in synaptic activity in their brains.
Prof Gomez-Pinilla said: 'Their brain cells had trouble signaling each other, disrupting the rats' ability to think clearly and recall the route they'd learned six weeks earlier.'
A closer look at the rats' brain tissue suggested that insulin had lost much of its power to influence the brain cells.
The authors suspect that eating too much fructose could block insulin's ability to regulate how cells use and store sugar for the energy required for processing thoughts and emotions.
However, their study also suggests that eating foods rich in omega-3 regularly could protect the brain from the effects of fructose.
Prof Gomez-Pinilla said: 'It's like saving money in the bank. You want to build a reserve for your brain to tap when it requires extra fuel to fight off future diseases.'