Trying to boost your brain health with sudoku, sugar or even sex? Let’s take a look at the evidence

Trying to boost your brain health with sudoku, sugar or even sex? Let’s take a look at the evidence
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There are plenty of things people claim are good for your brain. But what does the evidence say?

Photo: ABC/Unsplash

Do you do cryptic crosswords in an attempt to boost your brain health?

Or have you heard that omega-3, a sugar boost, or even getting busy in the bedroom is good for your grey matter?

Let’s take a look at some of the things we often hear are good for our brain, review the evidence, and bust a few myths along the way.

Sudoku and crosswords

A newspaper open at the crossword sits on a coffee table with a plunger pot and mug, couch in background.
Doing puzzles helps your brain … be better at puzzles. But that’s about it.

It’s hard not to feel a little smug when we do a sudoku or a crossword puzzle.

After all, we’ve heard how good it is for our brains – just like exercise builds muscle, brain games make our brains stronger, right? Wrong.

Neuroplasticity is the term that describes how the pathways and connections in the brain change through experience.

When we practise something, the brain adapts, and we tend to become better at that skill.

When you do a sudoku puzzle every day and find you get faster … unfortunately this doesn’t mean you are getting any smarter.

Your brain is simply getting more efficient at doing sudoku — it doesn’t mean you’ll get better at finding your keys or writing essays.

If there’s a particular skill you want to improve, you’re probably better off practising that skill.

Verdict: Not really (the high quality evidence suggests it isn’t)


A generic image of a woman checking emails while at a table of work colleagues.
The effects of stress on the brain can come down to how you perceive the stress.

Stress is bad for you right? Well, not necessarily. The devil is in the dose, and how you perceive the stress.

A small burst of stress, such as the rush you get when you run a race, is really good for your body, helping you perform at your best.

The adrenaline kick from a stressful moment supercharges your focus, so you can attend to the task at hand and do it well. Evidence shows the way you perceive stress is important too.

A Harvard study showed that if you view the signs of stress – such as a pounding heart or sweating – as signs your body is preparing you to meet the challenge, not only will your performance improve significantly, but the impact that stress has on your body is lessened as well.

On the other hand, long-term stress, the kind that lasts for months to years – such as when you are a carer, or dealing with job insecurity – wreaks havoc on your body, and can change or even shrink your brain.

Neurons in the brain’s memory centre, known as the hippocampus, may become disconnected, making it harder to remember events. Stem cells start eating themselves, making the hippocampus shrink.

Chronic stress makes us adjust to a hypervigilant and reactive state.

The emotion centre of the brain, known as the amygdala, grows in size as it increases its connectivity with other neurons, making you more emotional and reactive than you otherwise would be.

And lastly, there is increasing disconnect with the prefrontal cortex, the decision-making part of your brain, making it harder to make clear judgements about a situation.

While the pressures of modern society may mean you are not always able to avoid stressful situations, you can reframe how you respond to them, as well as reduce the effects of stress on the brain with some of the following activities.

Verdict: A bit is good, a lot is bad

Meditation and mindfulness

A close-up of a woman's hand in a yoga position as she sits in lotus pose.
Meditation’s benefits used to be viewed with scepticism, but recent research shows it has measurable effects on the brain.

Ever wonder why monks have such a sense of joy and calm? Meditation and mindfulness may have a lot to do with it.

We used to think of meditation as being a bit of semi-spiritual pseudoscience.

Until recent years, little was known about how a few hours of quiet contemplation each week could affect us.

It has become clear that meditation has some potent effects on your body, and especially your brain.

Meditation and mindfulness doesn’t just reduce the levels of stress hormones (and therefore the impact stress has on your brain), but it also helps shrink your amygdala, therefore reducing your emotional reactivity.

As the amygdala reduces in size, the prefrontal cortex – the brain’s decision-making region – increases in thickness. This means you become less driven by your more primitive emotional reactions, and become much more decisively thoughtful.

Through its tangible effects on improving attention (and therefore an increased ability to choose which positive thoughts to focus on), meditation can bring a great feeling of joy and contentment.

This improved ability to focus attention even seems to influence how much pain you may feel.

The more mindfulness and meditation you do, the stronger these effects seem to be.

Perhaps 15 minutes of mindfulness a day might help us all be a bit more like the Tibetan Monk scientists claimed was the “happiest man in the world”.

Verdict: Good

Natural sugar

Liquid honey generic
It doesn’t matter if it’s “natural” or not — too much sugar is bad for your brain.

The brain is hungry. It consumes about 20 per cent of your body’s energy at rest, despite only being 2 per cent of your body weight.

Your brain needs sugar, in the form of glucose, to function.

When you eat sugar or other more complex carbohydrates, your body converts this into glucose.

So what better sugar to feed your brain than natural sugar? Everything that’s natural is probably good for you, right? Think again.

While many things are OK in moderation, natural sugars, including those from honey and sugarcane, have been shown to be bad not just for your body but specifically your brain as well.

Evidence shows that a diet high in sugar stifles the growth of new neurons, and is associated with a smaller hippocampus and memory impairment.

And if you’re thinking of picking up that packet of lollies to make you feel better, a high-sugar diet is associated with a greater risk of anxiety and depression in the long term, and probably worsens your mood anyway.

If you have diabetes, you are twice as likely to develop neurodegenerative diseases like Alzheimer’s disease – in fact, some call Alzheimer’s disease “type 3 diabetes”.

The good news is, you may be able to train your brain to eat less sugar.

A very specific form of sugar has some surprising benefits though: Sugar pills when used as a placebo in experiments.

Placebo pills don’t contain any actual medicine, but they appear to relieve all sorts of maladies.

For example, sugar pills were shown to relieve pain as effectively as analgesic medication in 50 per cent of patients suffering from chronic pain.

How does this work? When you take a placebo pill, the sense of expectation makes your brain release its own endorphins, which improve mood and help relieve pain.

So no, it’s not the sugar in the placebo pills that’s making you feel better, just another trick our brains can play on you.

Verdict: Bad


Two feet in running shoes leap in the air
Physical exercise is one of the greatest gifts you can give your brain.

Exercise doesn’t just protect your heart, it also protects your brain.

In fact, it’s one of the most powerful things you can do to improve your brain health.

By increasing blood flow to the body, exercise delivers more oxygen and nutrients to your brain – which is particularly important, considering that brain blood flow decreases slightly as we age.

But this is not the most remarkable effect exercise has on the brain.

For a long time, it was thought that we had a set number of brain cells.

However, research has since shown that the brain contains stem cells – and stem cells have the ability to make new neurons in a process called neurogenesis.

Exercise also promotes the release of brain-derived neurotrophic factor, which is a bit like a fertiliser for the brain: It supports the growth of new neurons and increases neuroplasticity, making it easier for the brain to grow new connections between neurons.

Exercise can be a powerful antidepressant, because it helps counteract the decrease in neuroplasticity and neurogenesis observed in depression.

Exercise also makes your brain release endorphins, the feel-good hormones, and endocannabinoids, which activate your brain’s reward system and help relieve pain.

These brain chemicals are also responsible for the “runners high” or “second wind” experienced during endurance exercise.

So what is the optimal amount of exercise?

While varying types, intensities and lengths of exercise have been studied, 30 minutes of aerobic exercise (think heart-pumping, sweating), five times a week, is a great minimum level to work towards.

If you are over the age of 60, as little as 10 minutes of exercise can make a significant difference in your brain function.

Verdict: Amazing


Two pairs of feet stick out from under a doona.
Grab your partner and head to bed. It’s good for your noggin.

Sex doesn’t just make us feel good, it is good for us.

And because it often incorporates exercise, it may be doubly good.

Positive sexual activity has been shown to improve neurogenesis in rats, and we have no reason to believe humans are any different.

Intimacy releases bursts of oxytocin in the brain.

Oxytocin, fondly referred to as the love hormone, helps to cement feelings of trust and attraction, encouraging us to bond with our lover.

Oxytocin also has anti-inflammatory actions, reducing the levels of stress hormone cortisol in your blood and, therefore, reducing the toll of stress on your brain.

Orgasms release the hormone prolactin, which is responsible for that feeling of deep relaxation.

But if you’re wondering why masturbating doesn’t make you feel as chill, it’s because sexual intercourse releases about 400 per cent more prolactin.

So if you’re getting some, good for you – and your brain.

Verdict: Great

After we reach the age of 40, the brain shrinks by about 5 per cent each decade. This sounds troubling, but if you look after your brain health through exercise, sex, meditation and mindfulness, then you are setting yourself on the right track to live with a healthy brain, longer.

So sudoku fans, maybe you want to put the pencils away and pick up your joggers instead.

Dr Lila Landowski is a research fellow in neuroscience and brain plasticity at the School of Medicine, University of Tasmania. She is also one of the Top 5 scientists for 2019.

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