It’s a Saturday afternoon at a kids’ birthday party. Hordes of children are swarming between the spread of birthday treats and party games. Half-eaten cupcakes, biscuits and lollies litter the floor, and the kids seem to have gained superhuman speed and bounce-off-the-wall energy. But is sugar to blame?

The belief that eating sugary foods and drinks leads to hyperactivity has steadfastly persisted for decades. And parents have curtailed their children’s intake accordingly.

Balanced nutrition is critical during childhood. As a neuroscientist who has studied the negative effects of high sugar “junk food” diets on brain function, I can confidently say excessive sugar consumption does not have benefits to the young mind. In fact, neuroimaging studies show the brains of children who eat more processed snack foods are smaller in volume, particularly in the frontal cortices, than those of children who eat a more healthful diet.

But today’s scientific evidence does not support the claim sugar makes kids hyperactive.

The hyperactivity myth

Sugar is a rapid source of fuel for the body. The myth of sugar-induced hyperactivity can be traced to a handful of studies conducted in the 1970s and early 1980s. These were focused on the Feingold Diet as a treatment for what we now call Attention Deficit Hyperactivity Disorder (ADHD), a neurodivergent profile where problems with inattention and/or hyperactivity and impulsivity can negatively affect school, work or relationships.

Devised by American paediatric allergist Benjamin Feingold, the diet is extremely restrictive. Artificial colours, sweeteners (including sugar) and flavourings, salicylates including aspirin, and three preservatives (butylated hydroxyanisole, butylated hydroxytoluene, and tert-Butrylhdryquinone) are eliminated.

Salicylates occur naturally in many healthy foods, including apples, berries, tomatoes, broccoli, cucumbers, capsicums, nuts, seeds, spices and some grains. So, as well as eliminating processed foods containing artificial colours, flavours, preservatives and sweeteners, the Feingold diet eliminates many nutritious foods helpful for healthy development.

However, Feingold believed avoiding these ingredients improved focus and behaviour. He conducted some small studies, which he claimed showed a large proportion of hyperactive children responded favourably to his diet.

Flawed by design

The methods used in the studies were flawed, particularly with respect to adequate control groups (who did not restrict foods) and failed to establish a causal link between sugar consumption and hyperactive behaviour.

Subsequent studies suggested less than 2% responded to restrictions rather than Feingold’s claimed 75%. But the idea still took hold in the public consciousness and was perpetuated by anecdotal experiences.

Fast forward to the present day. The scientific landscape looks vastly different. Rigorous research conducted by experts has consistently failed to find a connection between sugar and hyperactivity. Numerous placebo-controlled studies have demonstrated sugar does not significantly impact children’s behaviour or attention span.

One landmark meta-analysis study, published almost 20 years ago, compared the effects of sugar versus a placebo on children’s behaviour across multiple studies. The results were clear: in the vast majority of studies, sugar consumption did not lead to increased hyperactivity or disruptive behaviour.

Subsequent research has reinforced these findings, providing further evidence sugar does not cause hyperactivity in children, even in those diagnosed with ADHD.

While Feingold’s original claims were overstated, a small proportion of children do experience allergies to artificial food flavourings and dyes.

Pre-school aged children may be more sensitive to food additives than older children. This is potentially due to their smaller body size, or their still-developing brain and body.

Hooked on dopamine?

Although the link between sugar and hyperactivity is murky at best, there is a proven link between the neurotransmitter dopamine and increased activity.

The brain releases dopamine when a reward is encountered – such as an unexpected sweet treat. A surge of dopamine also invigorates movement – we see this increased activity after taking psychostimulant drugs like amphetamine. The excited behaviour of children towards sugary foods may be attributed to a burst of dopamine released in expectation of a reward, although the level of dopamine release is much less than that of a psychostimulant drug.

Dopamine function is also critically linked to ADHD, which is thought to be due to diminished dopamine receptor function in the brain. Some ADHD treatments such as methylphenidate (labelled Ritalin or Concerta) and lisdexamfetamine (sold as Vyvanse) are also psychostimulants. But in the ADHD brain the increased dopamine from these drugs recalibrates brain function to aid focus and behavioural control.

Why does the myth persist?

The complex interplay between diet, behaviour and societal beliefs endures. Expecting sugar to change your child’s behaviour can influence how you interpret what you see. In a study where parents were told their child had either received a sugary drink, or a placebo drink (with a non-sugar sweetener), those parents who expected their child to be hyperactive after having sugar perceived this effect, even when they’d only had the sugar-free placebo.

The allure of a simple explanation – blaming sugar for hyperactivity – can also be appealing in a world filled with many choices and conflicting voices.

Healthy foods, healthy brains

Sugar itself may not make your child hyperactive, but it can affect your child’s mental and physical health. Rather than demonising sugar, we should encourage moderation and balanced nutrition, teaching children healthy eating habits and fostering a positive relationship with food.

In both children and adults, the World Health Organization (WHO) recommends limiting free sugar consumption to less than 10% of energy intake, and a reduction to 5% for further health benefits. Free sugars include sugars added to foods during manufacturing, and naturally present sugars in honey, syrups, fruit juices and fruit juice concentrates.

Treating sugary foods as rewards can result in them becoming highly valued by children. Non-sugar rewards also have this effect, so it’s a good idea to use stickers, toys or a fun activity as incentives for positive behaviour instead.

While sugar may provide a temporary energy boost, it does not turn children into hyperactive whirlwinds.

Amy Reichelt, Senior Lecturer (Adjunct), Nutritional neuroscientist, University of Adelaide

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Sweating is our body’s way of cooling down, a bit like an internal air conditioner.

When our core temperature rises (because it’s hot outside, or you’re exercising), sweat glands all over our skin release a watery fluid. As that fluid evaporates, it takes heat with it, keeping us from overheating.

But sweating can vary from person to person. Some people might just get a little dewy under the arms, others feel like they could fill a swimming pool (maybe not that dramatic, but you get the idea).

So what’s a normal amount of sweat? And what’s too much?

Why do some people sweat more than others?

How much you sweat depends on a number of factors including:

• your age (young kids generally sweat less than adults)
• your sex (men tend to sweat more than women)
• how active you are.

The average person sweats at the rate of 300 millilitres per hour (at 30°C and about 40% humidity). But as you can’t go around measuring the volume of your own sweat (or weighing it), doctors use another measure to gauge the impact of sweating.

They ask whether sweating interferes with your daily life. Maybe you stop wearing certain clothes because of the sweat stains, or feel embarrassed so don’t go to social events or work.

If so, this is a medical condition called hyperhidrosis, which affects millions of people worldwide.

People with this condition most commonly report problematic armpit sweating, as you’d expect. But sweaty hands, feet, scalp and groin can also be an issue.

Hyperhidrosis can be a symptom of another medical condition, such as an overactive thyroid, fever or menopause.

But hyperhidrosis can have no obvious cause, and the reasons behind this so-called primary hyperhidrosis are a bit of a mystery. People have normal numbers of sweat glands but researchers think they simply over-produce sweat after triggers such as stress, heat, exercise, tobacco, alcohol and hot spices. There may also be a genetic link.

OK, I sweat a lot. What can I do?

1. Antiperspirants

Antiperspirants, particularly ones with aluminium, are your first line of defence and are formulated to reduce sweating. Deodorants only stop body odour.

Aluminum chloride hexahydrate, aluminium chloride or the weaker aluminum zirconium tetrachlorohydrex glycinate react with proteins in the sweat glands, forming a plug. This plug temporarily blocks the sweat ducts, reducing the amount of sweat reaching the skin’s surface.

These products can contain up to 25% aluminium. The higher the percentage the better these products work, but the more they irritate the skin.

2. Beat the heat

This might seem obvious, but staying cool can make a big difference. That’s because you have less heat to lose, so the body makes less sweat.

Avoid super-hot, long showers (you will have more heat to loose), wear loose-fitting clothes made from breathable fabrics such as cotton (this allows any sweat you do produce to evaporate more readily), and carry a little hand fan to help your sweat evaporate.

When exercising try ice bandanas (ice wrapped in a scarf or cloth, then applied to the body) or wet towels. You can wear these around the neck, head, or wrists to reduce your body temperature.

Try also to modify the time or place you exercise; try to find cool shade or air-conditioned areas when possible.

If you have tried these first two steps and your sweating is still affecting your life, talk to your doctor. They can help you figure out the best way to manage it.

3. Medication

Some medications can help regulate your sweating. Unfortunately some can also give you side effects such as a dry mouth, blurred vision, stomach pain or constipation. So talk to your doctor about what’s best for you.

Your GP may also refer you to a dermatologist – a doctor like myself who specialises in skin conditions – who might recommend different treatments, including some of the following.

4. Botulinum toxin injections

Botulinum toxin injections are not just used for cosmetic reasons. They have many applications in medicine, including blocking the nerves that control the sweat glands. They do this for many months.

A dermatologist usually gives the injections. But they’re only subsidised by Medicare in Australia for the armpits and if you have primary hyperhidrosis that hasn’t been controlled by the strongest antiperspirants. These injections are given up to three times a year. It is not subsidised for other conditions, such as an overactive thyroid or for other areas such as the face or hands.

If you don’t qualify, you can have these injections privately, but it will cost you hundreds of dollars per treatment, which can last up to six months.

5. Iontophoresis

This involves using a device that passes a weak electrical current through water to the skin to reducing sweating in the hands, feet or armpits. Scientists aren’t sure exactly how it works.

But this is the only way to control sweating of the hands and feet that does not require drugs, surgery or botulinum toxin injections.

This treatment is not subsidised by Medicare and not all dermatologists provide it. However, you can buy and use your own device, which tends to be cheaper than accessing it privately. You can ask your dermatologist if this is the right option for you.

6. Surgery

There is a procedure to cut certain nerves to the hands that stop them sweating. This is highly effective but can cause sweating to occur elsewhere.

There are also other surgical options, which you can discuss with your doctor.

7. Microwave therapy

This is a newer treatment that zaps your sweat glands to destroy them so they can’t work any more. It’s not super common yet, and it is quite painful. It’s available privately in a few centres.

Michael Freeman, Associate Professor of Dermatology, Bond University

This article is republished from The Conversation under a Creative Commons license. Read the original article.