Can sugar cause ADHD?

We know sugar isn’t good for our health and can make us fat - but new research has indicated it can also affect children’s brains adversely.

A recent study from Queensland University of Technology has indicated that children who consume too much sugar could be at greater risk of becoming hyperactive, and cognitively impaired as well as obese.

Lead author, Professor Selena Bartlett commented on the study, which used mice and recreated the sugary diet of children: ‘Our data suggest that sugar-induced obesity may participate to the developing pathogenesis of ADHD-like symptoms in western countries. In children, high sugar consumption correlates with hyperactivity and in adults, with inattention and impulsivity.

‘What has been unclear though, is whether chronic overconsumption of sucrose -- starting from childhood -- would have the same negative impact on our nervous system, emotions or cognition throughout adulthood as other addictive drugs.

‘This study on mice goes a long way to resolving that question. Our results show for the first time that long-term consumption of sucrose leads to significant weight gain and produces persistent hyperactivity and learning impairments.’

Sugar its self is unlikely to be a sole cause of attention deficit hyperactivity disorder (ADHD), which is believed to be partly genetic. Those diagnosed often have differences in brain structure. However, this research may point the way to improve symptoms.

Hidden sugars part of the problem

Health experts are already aware that high sugar consumption leads to serious health problems, such as diabetes. Ready-meals and processed foods – even the ‘healthy’ low fat varieties – are often laden with sugars. And they’re sneaky sugars you probably won’t even recognise, often listed in ingredients as fructose, dextrose, or maltodextrin.

These ‘hidden’ sugars explain why we keep getting fatter, despite the fact that we are eating fewer calories. 

An analysis of 68 studies commissioned by the World Health Organisation (WHO), indicated that sugar is a principle cause of the obesity epidemic. When people eat more of it, they gain weight; when they eat less of it they lose weight. 

As well as ADHD-type symptoms, eating a lot of sugar has also been linked with:

  • Type 2 diabetes 
  • High blood pressure
  • Heightened cholesterol
  • High triglyceride levels
  • Cardiovascular disease
  • Cancer 
  • Dementia

Why is sugar bad for us?

Sugar is half glucose, half fructose, and fructose encourages the body to store fat. It’s very easy to get fat from eating sugar because unless you have just done exercise, any sugar (fructose) you eat will be converted to fat. 

The problem with sugar is that it acts on the same hormonal pathways in the brain that drugs do - eating it feels like a reward.

Robert Lustig, an American professor of paediatrics, says that sugar is as addictive as nicotine, alcohol and cocaine. Some people are more genetically more susceptible to sugar addiction, which means they need to eat more and more to get the same pleasure. 

Sugar doesn’t satisfy hunger because it doesn’t trigger a hormone called leptin, which tells your brain you’re full. Neither does it reduce the hunger hormone called ghrelin. If you’re healthy, slim and active you’ll probably burn off the odd sugary snack through exercise but even so, the less you eat, the healthier you’ll be.

How much sugar is safe to eat? 

Even a small amount of sugar affects your health. One study from Imperial College, London, found drinking just one sugary drink a day increases the risk of type 2 diabetes by 22%.

You should get no more than 10% of your daily calories from added sugars, which equates to about 50g for the average person consuming 2000 calories a day – remember to check ingredients lists. Just one can of coke contains 35g of sugar while a Kit Kat contains 23g. 

Is fruit sugar as bad as processed sugar?

Sugars in fruit and vegetables are locked into the structure of the foods, and much less concentrated, which means your body absorbs the sugar slowly  so you don’t get that sharp rise in blood sugar and insulin, and lower insulin levels means less fat storage. Also, these foods are very difficult to overeat. 

How to cut down on sugar

  • Avoid soft drinks as much as possible, as they are saturated with sugar – 35g in a 300ml can.
  • Drink less fruit juice as they contain the same amount of sugar as soft drinks
  • Say no to sweets as they provide sugar and nothing else
  • Ditch the biscuits and cakes as these too are high in sugar and refined carbohydrates
  • Watch out for low-fat or reduced-fat foods such as desserts, ready-meals etc because while they may be low in fat they are often very high in sugar
  • Drink water instead of soft drinks and fruit juice, and eat fresh fruit to satisfy your sweet tooth. 

Tips on cutting down on sugar

  • Check labels for sugars - sucrose, glucose syrup, invert sugar, fructose, dextrose, maltodextrin, fruit syrup, raw sugar, cane sugar and glucose.
  • If a packaged food contains sugar in the first 3 ingredients, avoid it
  • If a packaged food contains more than one type of sugar, avoid it
  • Remember -  agave nectar, honey, organic cane sugar and maple syrup are sugars too and will count in your daily allowance
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A fluid that transports oxygen and other substances through the body, made up of blood cells suspended in a liquid. Full medical glossary
A group of compounds that are an important energy source, including sugars and starch. Full medical glossary
A substance present in many tissues and an important constituent of cell membranes although high concentrations of a certain type of cholesterol in the blood are unhealthy. Full medical glossary
A disease of long duration generally involving slow changes. Full medical glossary
A narcotic drug extracted from coca leaves. Full medical glossary
A disorder caused by insufficient or absent production of the hormone insulin by the pancreas, or because the tissues are resistant to the effects. Full medical glossary
A sudden outbreak of infection that affects a large proportion of a population. Full medical glossary
One of the three main food constituents (with carbohydrate and protein), and the main form in which energy is stored in the body. Full medical glossary
The basic unit of genetic material carried on chromosomes. Full medical glossary
Relating to the genes, the basic units of genetic material. Full medical glossary
A simple sugar that is an important source of energy in the body. Full medical glossary
A substance produced by a gland in one part of the body and carried by the blood to the organs or tissues where it has an effect. Full medical glossary
A hormone produced by the beta cells of the pancreas that acts to lower blood glucose levels. Full medical glossary
The system that gathers and stores information and is in overall control of the body. The brain and spinal cord form the central nervous system. Full medical glossary
An addictive substance found in tobacco and nicotine replacement therapies. Full medical glossary
Excess accumulation of fat in the body. Full medical glossary

  A bacterium, virus, or other microorganism that can cause disease.

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A tube placed inside a tubular structure in the body, to keep it patent, that is, open. Full medical glossary
A type of fat in the bloodstream, formed from the digestion of fat in the diet. Full medical glossary
Relating to blood vessels. Full medical glossary