How diet can help with brain fog
Feeling like you're lacking focus or suffering mental fatigue? A neurologist and gut health expert explain how what you eat can affect your brain
Brain fog is a recurring problem for 39 per cent of Brits, manifesting as a range of symptoms including forgetfulness, slower thinking and a clouded mental state.
In many cases, it’s difficult to cure the root causes of brain fog, or even to identify them. But it’s well known that the food we eat affects our brains. The right ingredients might even boost your brainpower or improve your memory.
So how can diet help with brain fog specifically? Which foods should you eat to improve brain fog symptoms? We spoke to a neurologist specialising in brain fog and a gut health expert to bring some much-needed clarity.
What is brain fog?
…wait, what was the question?
If you’re having memory problems, or if you’ve become more prone to confusion or ‘fuzzy thoughts’, then you might be experiencing brain fog.
The NHS defines brain fog as a range of symptoms, rather than a specific medical condition.
“Brain fog is a general term that refers to a collection of symptoms that affect attention, memory, learning, processing speed, language, spatial navigation and executive function leading to a loss of mental clarity and mental fatigue,” says Dr Sabrina Brennan, a neuroscientist and author of the book, Beating Brain Fog.
Some of these symptoms are familiar experiences – forgetting words, struggling to concentrate, bumping into things, and so on. If you only experience them from time to time, there’s probably no cause for concern.
“Brain fog is different to these short-term disruptions, because it is persistent, occurs regularly and can interfere with the quality of your life, your relationships, and your work,” says Dr Brennan.
Despite its association with COVID-19, clouded consciousness is nothing new. According to the OED, there’s evidence that ‘brain fog’ has been discussed since as early as 1853.
What are the main causes of brain fog?
There are many reported causes of brain fog, including:
- Minor head injury
- Illnesses such as COVID-19
- Auto-immune conditions
- Menopause
- Anxiety
- Depression
- Stress
- Nutritional deficiency
- Medication side-effect
- Gluten consumption (among those with coeliac disease)
“Brain fog is not a disease, disorder or diagnosis; rather, it is a sign or a symptom of an underlying cause,” says Dr Brennan.
“I see brain fog as a sign that something is amiss. It’s a signal to take action.”
Does your diet impact brain fog?
One action you can take to alleviate brain fog symptoms is tweaking your diet.
Certain nutrients influence brain function by acting on molecular systems and cellular processes within our grey matter. Some foods can also manage conditions associated with brain fog – as seems to be the case with omega 3-rich walnuts and depression.
Given their effects on the brain and underlying health conditions, eating the right ingredients could alleviate brain fog symptoms in some cases. And on the flipside, eating too little of certain nutrients could cause or aggravate brain fog.
Eating for better gut health may also have a role to play in combating brain fog. Your gut is filled with nerves, and unlike smaller sensory organs that sense the outside world, such as the eyes, ears and skin, the gut’s nervous system senses your inner state, from nutritional intake and gut bacteria to your immune system and hormones.
Your gut sends signals to the brain via the vagus nerve. While many of these messages are about everyday things like the food you eat, some relate to potential problems such as overgrowth of bacteria in the small intestine (SIBO) or food intolerance, both of which are associated with brain fog. Why these gut conditions cause brain fog is up for debate, but it’s clear that brain and gut are closely linked in function and health.
In short, reducing or increasing intake of certain foods can improve brain fog symptoms by managing their causes, or through improving gut or brain health.
Which foods or nutrients can make brain fog worse?
Ultra-processed foods
According to Dr Megan Rossi, a research fellow at King’s College London and founder of The Gut Health Doctor, people whose diet is high in ultra-processed foods (UPFs) are running the risk of experiencing brain fog issues.
“UPFs are often low in essential nutrients like magnesium, omega-3 fatty acids and iron, all of which are crucial for brain function and mental clarity,” she says.
“Relying on UPFs increases the risk of nutrient deficiencies which can lead to sluggish cognitive performance, whereas prioritising a whole food, nutrient-rich diet packed with vegetables, whole grains, lean proteins and healthy fats will help to ensure your brain gets the fuel it needs.”
Plant-only diet
A plant-only diet might be packed with nutrients that help with good brain health, but one key vitamin – B12 – is often lacking.
“B12 is essential for optimal brain and central nervous system function, meaning a deficiency can lead to brain fog, memory issues, and fatigue,” says Dr Rossi.
“Since B12 is primarily found in animal-based foods, vegans are particularly at risk of this deficiency. So, if you follow a plant-only diet, I recommend including B12-fortified foods or taking a supplement to ensure you meet your needs,” she adds.
Which foods or nutrients can improve brain fog symptoms?
Blueberries
“Blueberries are rich in polyphenols, particularly anthocyanins, which have been shown to improve memory and cognitive function in clinical trials,” says Dr Rossi.
“They enhance blood circulation in the brain, which is vital for mental clarity and focus. Including a handful of blueberries into your daily diet, whether as a snack or as part of your breakfast, could give your brain the support it needs.”
Try our blueberry baked oats recipe
Dark chocolate
Good news! Dr Rossi also recommends dark chocolate (with a cocoa content of 75 per cent or higher) as a helpful ingredient for brain fog sufferers.
“It contains flavanols, another group of polyphenols, which have been shown to improve cognitive performance,” she says.
“The caffeine in dark chocolate can also provide an additional alertness boost, making it a great option for staying focused during a busy day.”
Water
Are you drinking enough? The Eatwell Guide recommends we drink six to eight glasses or cups of fluids a day – or more if we’re pregnant, breastfeeding, unwell, highly physically active or in a hot place.
“The brain is 73 per cent water, and it needs to be kept hydrated in order to function properly, especially in how it transports oxygen, nutrients and waste,” says Dr Brennan.
“Severe dehydration can cause cognitive deficits in short-term memory and can disturb mood.”
How can hormones influence brain fog?
As we all know, hormones can affect our mental state – so it should come as no surprise that some of these chemical messengers are linked to brain fog symptoms.
“Many people notice brain fog during times of hormonal change, such as menopause,” says Dr Rossi.
“The main hormone involved in the menopause process, oestrogen, plays a vital role in brain health. Most organs, including the brain, have oestrogen receptors, so changes in oestrogen levels (like those that occur during menopause) can impact cognitive function. This is thought to explain why symptoms like forgetfulness and difficulty concentrating are common during this phase of life.”
While the links between menopause and brain fog are not well understood, there’s some evidence that turmeric (curcumin) and ginkgo biloba supplements may help with cognitive function during and after menopause.
Another hormone that can affect brain fog symptoms is cortisol, the body’s primary stress hormone.
“Cortisol affects how the brain functions through the gut-brain connection,” says Dr Rossi.
“Elevated cortisol levels have been shown to impair memory retrieval, which highlights how important stress management is for maintaining mental clarity.’’
How to eat for better brain health
Whether or not your brain fog symptoms are dissipated, eating for good brain health will likely have a positive impact.
“Studies have not identified individual nutrients as outstanding soloist performers in brain health, so it is better to tap to the beat of an orchestra of nutrients from a medley of food types obtained from a balanced diet,” says Dr Brennan.
“Instead of going to the shop with a list of all the macro- and micro-nutrients that your brain requires you could take a big-picture approach and keep your brain and heart in good shape by adopting a Mediterranean-style diet.”
For some people, such as those who are vitamin B12 deficient, diet could be the root cause of brain fog, so making appropriate dietary adjustments could resolve the issue. For others with long-term brain fog, the solution may lie in addressing the underlying cause – although tweaking your nutrition could alleviate some symptoms in the meantime.
