Addicted to sugar? Here’s how your sweet tooth may change your brain chemistry

Sugar in the morning, sugar in your afternoon snack, sugar at supper time – we know it’s hard to escape sugar in our diets. South Africans consume between 12 and 24 teaspoons of sugar per day, compared to the World Health Organization's suggested limit of six teaspoons per day.

Sugar is highly addictive, study after study has shown. But a more recent study, involving researchers from Aarhus University, took a closer look and examined what happens in the brains of pigs when they drink sugar water.

They found that sugar influences their brain reward circuitry in ways very similar to when addictive drugs are consumed.

Although one of the main authors of the work, Michael Winterdahl, Associate Professor at the Department of Clinical Medicine at Aarhus University, was aware of the number of physiological effects sugar has on the human body, he admitted to being in doubt about the effects it has on the human brain and behaviour.

“I had hoped to be able to kill a myth," he said.

‘Major changes in the brain’s dopamine and opioid systems’

The experiment, published in Scientific Reports, was done using seven pigs who received two litres of sugar water daily over a 12-day period. The researchers then mapped the consequences of their sugar intake by imaging the brains of the pigs. The imaging was done at the beginning of the experiment, again on the first day, and finally, after the 12th day.

"After just 12 days of sugar intake, we could see major changes in the brain's dopamine and opioid systems,” said Winterdahl, adding that the opioid system, which is the part of the brain's chemistry associated with well-being and pleasure, was already activated after the first intake.

Craving and reward: sugar as an artificial stimulant

The craving-and-reward outcome you get when you consume sugar is very similar to that of addictive drugs. Winterdahl explains that our brains reward us with a sense of happiness and enjoyment when we experience something meaningful.

This happens as a result of either natural stimuli, such as sex or socialising, and artificial stimuli, such as drugs. These stimuli activate the brain’s reward system, causing neurotransmitters like dopamine and opioids to be released.

"If sugar can change the brain's reward system after only twelve days, as we saw in the case of the pigs, you can imagine that natural stimuli such as learning or social interaction are pushed into the background and replaced by sugar and/or other 'artificial' stimuli,” said Winterdahl.

“We're all looking for the rush from dopamine, and if something gives us a better or bigger kick, then that's what we choose.”

Sugar addiction

In most studies that look at substances and their level of addiction on the brain, the effects are typically examined using rodents. Winterdahl explains that it would be better if the studies could be done on humans. This, however, presents challenges.

For example, humans are harder to control, and dopamine levels can be altered by a number of factors, like entering a new romantic relationship during a trial, which would affect the outcome.

Studying these effects on pigs is therefore a better alternative, the researcher explains, as their brains are more complex than those of rodents and large enough for imaging deep brain structures.

Should you adopt a sugar-free diet?

Some foods with naturally occurring sugars, like in dairy and fruit, contain essential nutrients like B vitamins, fibre and antioxidants. Pure sugar doesn’t contain these nutrients, which can have a negative effect on your health.

Reducing your sugar intake will help lower your risk of developing type 2 diabetes and cardiovascular disease, as well as improve your immunity and gut health. Your body will thank you in the long run.

The sugars to especially avoid are refined, processed sugars that have little nutritional value. The biggest culprits are table sugar (sucrose), sweeteners such as honey and maple syrup, condiments, soft drinks and sweets.

But you don’t have to go cold-turkey and adopt a completely sugar-free diet. Instead, treat yourself in moderation. Here are a few tips to make the transition easier:

• Cut back on sugar-sweetened beverages: this includes energy and sports drinks – they’re all laden with sugar. 
• Avoid processed foods: swap out cookies and cakes for unsalted, raw nuts.
• Avoid flavoured yoghurt: try low-fat, plain yoghurt instead.
• Check food labels: choose items with the lowest amount of added sugar.

^{Image credit: iStock}