There can be a number of reasons you’re not firing on all cylinders. But you can do something about them


Tweaking your diet can have a huge impact on your brain © iStock

We all know that feeling – as though your brain is in a cloud, waiting for the sun to break through.

Names and other words elude you, you lose your train of thought, or you stride purposefully into a room then can’t remember why.

‘You may put it down to ageing – but, however old you are, there’s often a reversible reason for this kind of brain fog,’ says nutritional therapist Dr Marilyn Glenville.

‘Tweaking your diet, drinking more water and cutting out sugar can make a big difference – though it’s also important to know when you need to see a doctor or other health practitioner.’

You’re drinking too much tea

Keep reading about all the health benefits of your lovely cuppa? Well, there’s a downside – the tannins in tea fight with iron, so too much can prevent you from absorbing iron properly.

And that can lead to anaemia, warns nutritionist Judy Watson ( ‘When you’re anaemic, you have too little oxygen travelling around your body – and one result can be a lack of clarity in your brain.’

Try… eating more protein – meat, fish and eggs – for iron. ‘Watercress is good too. Serve it with lemon juice, for vitamin C to help the iron absorption,’ says Judy.

You need more water

You can’t get away from it – drinking enough water is essential for good health, and provides the means for nutrients to travel to organs and for toxins to be removed, says Dr Glenville.

‘Allowing yourself to become dehydrated can lead to a number of symptoms, including brain fog and reduced concentration.’

Try… to aim for six to eight glasses a day, including herbal teas – but you can get away with less if you have a diet packed with fruit and vegetables (they are typically 90% water).

You’re full of yeast

Gut flora that gets way out of balance creates the perfect breeding ground for the yeast Candida albicans, says Judy.

‘You’re especially prone to problems with this if you’ve been on a course of antibiotics as they wipe out all the friendly flora that would normally keep the yeast infection in check. One sign that your foggy brain is caused by candida is if you feel drunk or hung-over – that’s because the yeast produces the same chemical, acetaldehyde, that‘s created when alcohol is broken down by your liver.’

Try… shifting your diet away from sugars and carbs and in favour of more proteins. ‘You don’t have to give up all bread and toast, but have less of it,’ says Judy. The ‘friendly’ yeast supplement S. boulardii is also very helpful (try OptiBac, £6.49 for 10 capsules, from health stores).

Is it your hormones?

Around menopause, hormonal changes make a lot of women fear they’re going mad, says Dr Glenville. ‘In my clinic, women say they go upstairs, but can’t remember what they went up for. They read a page in a book, but can’t remember a word of it. Or they may struggle to find the right word in the middle of a sentence.

This kind of muzzy mind is thought to be due to the decline in oestrogen at menopause – but research shows that memory does return to premenopausal levels once a woman is post-menopausal.

Try… altering your diet if you’re impatient to get your brain back. Add flaxseeds, soya, chickpeas and lentils. ‘They have a balancing effect on your hormones, lessening the impact of the changes,’ says Dr Glenville.

You could have a parasite

The parasite Giardia lamblia, caught from people who haven’t washed their hands properly before handling food, affects an estimated 3,500 of us each year in the UK, says Sue Koten, a medical herbalist who specialises in its treatment at

‘It lives in the small intestine, causing IBS-like symptoms such as bloating and tummy upsets. But it also devours B12, so you’re prevented from absorbing what you need from your diet.’

Try… talking to your GP, who can test for Giardia in your stools. The conventional treatment is with antibiotics – the disadvantage of these is that they can cause side effects of their own, including candida – and foggy brain!

For a more natural solution, see a registered medical herbalist, who can prescribe specific remedies, such as wormwood, to eradicate it.

You need a B-boost

Most of us know a lot less about B vitamins than we do about vitamin C and, these days, vitamin D. But a foggy brain is a classic symptom of a B12 deficiency, says Martyn Hooper, author of What You Need To Know About Pernicious Anaemia & Vitamin B12 Deficiency (£14.99, Hammersmith Books).

‘Many people have been misdiagnosed with dementia or depression when really they need more B12,’ he says. You get it very easily from all animal products but some of us cannot absorb this for various reasons, including the inherited glitch called pernicious anaemia, which usually kicks in later in life, even though it’s been present since birth.

Try… talking to your GP. Even if your B12 level appears to be ‘normal’ in a blood test, they should want to try you on B12 supplements to see if your health improves.

If your problem is to do with diet (if you’re vegan, for example), you can take oral supplements. Otherwise you may need injections.

Your thyroid is on a go-slow

Your thyroid controls your metabolism, and when it slows down virtually every body function slows down too – including your thought processes. ‘You may be trying to say one thing but find that something else comes out instead,’ says Judy. ‘Though you’ll usually have other symptoms too, such as weight gain and fatigue.’

Try… talking to your GP about getting your thyroid tested. Your doctor can prescribe a synthetic version of the hormone thyroxine to get you back up to speed. ‘Selenium, zinc and iodine can also encourage a healthy thyroid,’ says Judy.

Fear of fat

If your low-fat diet means you’re eschewing healthy fats from fish, nuts, avocados, etc, it’s bound to affect your ability to think clearly, says Dr Glenville.

‘Your brain is 70% fat and research has shown that the omega-3 fats (in particular, docosahexaenoic acid or DHA) boost brain health and can even prevent the characteristic Alzheimer’s plaque from forming. Other research has shown that the hippocampus, the part of your brain which is important for memory and cognitive function, is smaller in those people with the lowest omega-3 levels.’

Try… to eat oily fish and eggs (the yolks contain omega-3) at least
two or three times a week. If you can’t manage that, try an omega-3 supplement of at least 510mg DHA daily.

You’re just too sweet

Brain fog can also result from too much sugar in your diet, says Dr Glenville. ‘Sugary foods cause a sudden surge in your blood- sugar level – but the higher it rises, the lower it will fall afterwards; and a very low level (hypoglycaemia) can trigger a foggy brain.’

Try… cutting back on sugary foods with Dr Marilyn Glenville’s new book, Natural Alternatives To Sugar (£9.97, from

You need a tummy bug!

Well, the right kind, obviously. ‘It’s the friendly flora, or bugs, in your gut that help to produce serotonin, the brain chemical that keeps your mood upbeat,’ says. ‘Avoid too many processed, sugary foods, as these create more of the bad bacteria that crowd out the probiotics that you need to feed your brain chemicals,’ says Judy Watson.

Try… taking a really powerful probiotic such as Bio-Kult (£9.49 for 30 capsules), to allow serotonin to flourish.