Brain Fog

What is brain fog?  & Why does it happen?

Brain fog is one of the most common, and frustrating symptoms I hear about from women over 40.

It can come at a time of life when there may be a lot going on… when women are often juggling a lot. This could include having parents who are getting older and may need more time and care, managing teenagers, jobs and careers, and even new businesses.

And then there is brain fog on top of all this…

What is brain fog?

The term brain fog is not a scientific term but it is a very real symptom of perimenopause.

It’s used to describe symptoms such as difficulty focusing, reduced memory or forgetfulness, difficulty making your mind up and making decisions, even small ones. Or perhaps it shows up as no longer being able to multi-task and having to concentrate on just one thing or going upstairs to get something and forgetting what it was by the time you get there or forgetting where you put your phone or your glasses…

What causes brain fog?

There is no single cause of brain fog, but there could be a few key factors

One of these is fluctuating and declining levels of the hormone oestrogen during perimenopause.

Lisa Misconi is a leading neuroscientist. Her specialist area is women’s brain health and she has a great TED talk on the topic.

She believes that oestrogen is key for producing energy in the brain and that estrogen helps the brain neurons to burn glucose for energy. So, if your oestrogen levels are high, brain energy is high. But when your oestrogen declines, your brain starts slowing down too.

This happens independently of age, you could be 45 or 55 but what matters is that you are going through peri/menopause.

Studies have also shown that an area in the brain responsible for memory called the hippocampus is affected by changing levels of oestrogen. This area has a lot of oestrogen receptors and when there is limited oestrogen to attach itself to the receptors, this could result in memory lapses.

There are also a lot of oestrogen receptors in the part of our brain that deals with planning and complex thinking. If oestrogen is not available to attach to the receptors, you may feel foggy and have less focus. You may find that you are no longer able to multi-task and can only concentrate on one thing at a time.

Gut health

The gut and the brain are connected. The health of your gut and imbalances in beneficial bacteria in the gut could contribute to brain fog.

This can happen due to gases and chemicals produced by a fermentation process the presence of certain bacteria. It can be determined by the types of bacteria you have and the types of foods you eat i.e in the presence of some bacteria a high carb diet can produce gas and bloating and contribute to brain fog

Nutrient deficiencies

The brain requires certain nutrients to be able to function optimally. These include some which are commonly deficient such as vitamin D, zinc, magnesium, some B vitamins, and omega 3 fatty acids.

The brain is made up of proteins and fats, so you need to ensure that you eating enough of these to get the best out of your brain.


There is a correlation between oestrogen levels and levels of our stress hormone cortisol. When one cortisol goes up often oestrogen comes down. This means that less oestrogen is available to attach itself to receptors in the brain.

Adrenalin is also released at times of stress and this hormone diverts energy away from other functions in the body including energy to the brain.


Lack of sleep or poor quality sleep can also affect brain health. I’m sure that you have experienced at some time or other the effects of this, being so tired that you can’t think straight.

It is also during sleep at night that toxins and debris (old cells) are cleared from the brain so sleep helps us to protect our brains.

What you can do?


One of the most important things you can do to support brain health making sure that you are eating a varied and colourful diet to protect against nutrient deficiencies.

You should aim for your diet to include whole foods and avoiding processed and sugary foods and support balanced blood sugar levels by eating protein with each meal.

Lisa Lisconi suggests a Mediterranean style diet as it is abundant in fresh colourful vegetables, healthy fats oily fish like sardines, mackerel, salmon, olives and olive oil.

Plant-based compounds called polyphenols from all the vegetables feed beneficial bacterial in the gut. Phytoestrogens found in foods such as flax seeds, sesame seeds, beans and legumes may be beneficial by mimicking oestrogens in your body and attaching to oestrogen receptors.


Getting enough sleep might be one of the most important things you can do for your gut and your brain. Go back to my post on sleep to find out more about how sleep hygiene can help

Manage Stress

Another very important and sometimes neglected area… Managing your stress levels is essential to good health, including brain health

Block off some time each day even if it’s for just a few minutes to do something that helps you to relax and dampen down stress responses

You could try 5 minutes of deep breathing, journaling, yoga, reading, meditation, a walk etc whatever works for you.

This allows you time to decompress and clear your head. All of which can go a long way towards lifting brain fog. You can find more advice on stress management here.


Our circulation slows down as we age. Less oxygen reaching our brain cells can mean that it isn’t as sharp. Exercise can help by increasing oxygen levels. It can also improve other menopausal symptoms and help to lower stress

Taking time to move every day, even if it’s just a quick walk, 15 minutes of HIIT or strength training or half an hour of yoga or pilates.

Don’t despair

Symptoms can improve over time as the brain adjusts to new hormone levels.

But there are lots you can do to help yourself concerning the “brain fog” associated with menopause

Eat well, get good sleep, exercise, and keep your mind active to support brain health.

Certain medications and thyroid disorders can also be linked to brain fog.

If your “brain fog” gets worse, make an appointment with your doctor to rule out other health issues or to ask about hormone treatments for menopause. HRT may help some women but not all – speak to your GP or health care provider

For more tips and advice on peri/menopause join a growing community of like-minded women here