Introduction

You meet an acquaintance in the street and you just can’t remember their name.
You lose your train of thought mid-sentence.
You go upstairs, and at the top, you can’t remember what you went up for.

For many women over 50, this shift in thinking feels unfamiliar and unsettling.
Memory lapses, poor concentration and mental fatigue are very common during the menopause transition. Around half to two-thirds of women experience them, often without understanding the underlying causes of brain fog.

The causes of brain fog are rarely down to one single issue. They tend to build from a combination of hormonal changes, poor sleep, stress and shifts in metabolism.

Understanding the causes of brain fog is the first step to improving it.

What is brain fog?

Brain fog is not a medical diagnosis. It is a general term used to describe a group of cognitive symptoms that make everyday thinking feel harder.

It may include:

• difficulty concentrating
• memory lapses
• mental fatigue
• slower thinking
• trouble finding words

“Some days I feel sharp. Other days it’s like my brain is buffering.”

Common symptoms of brain fog

Difficulty concentrating
Tasks that once felt simple may now take more effort. You may get distracted more easily or struggle to stay focused.

Memory issues
Forgetting names, misplacing items, or struggling to recall familiar information becomes more noticeable.

Mental fatigue
This is a sense of your brain feeling drained, even after small tasks.

Slower decision-making
You may find yourself hesitating more or taking longer to make decisions.

Lack of mental clarity
Many describe this as a sense of “fuzziness” or not feeling mentally sharp.

“Many women report memory problems and difficulty concentrating during the menopause transition.” - Myra S. Hunter. Clinical & health psychologist.

Brain fog is not a sign your brain is failing. It’s a sign your body needs support. - Dawn

What are the main causes of brain fog?

Understanding the causes of brain fog in menopause is the first step to improving it.
In postmenopausal women, brain fog is usually multifactorial. Here are the most common root causes of brain fog.

Hormonal changes
One of the primary causes of brain fog in menopause is the decline in oestrogen. Oestrogen plays an important role in brain function. It helps your brain produce energy, maintain healthy blood flow and communicate efficiently. When levels fall, brain energy and connectivity can dip. That is often experienced as slower thinking, forgetfulness, or reduced clarity.

Poor sleep
Sleep disruption is one of the most common and overlooked causes of brain fog. Insomnia, night sweats and broken sleep reduce the brain’s ability to consolidate memory, clear waste products and restore mental energy.

Stress and anxiety
Chronic stress increases cortisol, which interferes with memory, focus and emotional control. Over time, this affects key brain areas involved in thinking clearly.

Blood sugar imbalance
Blood sugar swings are a major but often hidden cause of brain fog. Large, carbohydrate-heavy meals or insulin resistance can lead to energy dips, inflammation and poor concentration. This is often felt as the mid-afternoon slump or post-meal fatigue.

“Insulin resistance and metabolic dysfunction are increasingly recognised as contributors to cognitive decline.” - Suzanne Craft. Neurophysiologist

Nutritional deficiencies
Low levels of vitamin B12, iron and other B vitamins can contribute to fatigue and cognitive changes.

Gut-brain axis disruption
An imbalance in gut bacteria can increase inflammation, affect neurotransmitter production and influence mood and cognition.

Inflammation
Low-grade inflammation interferes with communication between brain cells, slowing thinking and reducing clarity.

Medications and underlying health conditions
Conditions such as an underactive thyroid, sleep apnoea or depression, as well as certain medications, can contribute to symptoms of brain fog.

The key systems to improve brain fog

Once you understand the causes of brain fog, you can begin to target the systems involved.

Hormones
Support balance across cortisol, insulin, thyroid and sex hormones including oestrogen, progesterone and testosterone.

Sleep
Restore sleep and support your body clock. Good sleep clears metabolic waste and helps form and maintain memories.

Blood sugar
Stabilise blood glucose to provide the brain with reliable, consistent fuel.

Stress response
Lower chronic stress to improve attention and memory.

Gut health
Support the gut microbiome to improve mood and cognition by reducing inflammation and supporting neurotransmitter production.

Circulation
Improve blood vessel health and brain blood flow through regular movement and a heart-healthy diet.

Inflammation
Reduce overall inflammation to protect nerve cells and their signalling.

If you’d like to go deeper into how these systems work together, I explain this in more detail in my 3-part blog series for healthy ageing, including the key pillars that support energy, metabolism and long-term health.

Best diets to support brain fog

Diet plays a central role in many of the causes of brain fog, particularly those linked to inflammation, blood sugar and brain energy.

Mediterranean and MIND-style eating patterns are among the most researched approaches for cognitive health.
They are linked with better memory and thinking, lower risk of cognitive decline and reduced inflammation.

Core features to focus on include:

• vegetables, fruit, legumes, nuts and whole grains
• healthy fats such as extra virgin olive oil, nuts and seeds
• oily fish rich in omega-3 fatty acids
• moderate protein from fish, beans and poultry
• minimal processed foods and added sugars

This way of eating also supports weight, insulin sensitivity and cardiovascular health, all of which are important in postmenopausal women.

Key nutrients for brain function and where to find them

Omega-3 fatty acids
Support brain cell structure, reduce inflammation and may support mood and cognitive performance.

Foods include salmon, mackerel, sardines, anchovies, trout, walnuts, chia seeds and flaxseeds.

Polyphenols and antioxidants
Support blood vessel health and help protect brain cells.

Foods include berries, green tea, dark chocolate, extra virgin olive oil and colourful vegetables such as spinach, kale, peppers and beetroot.

B vitamins and choline
Support energy production and neurotransmitter function.

Foods include eggs, leafy greens, legumes, whole grains, poultry, fish and liver.

Iron
Supports oxygen delivery to the brain.

Foods include red meat in moderation, lentils, beans, spinach and pumpkin seeds. Pair plant sources with vitamin C foods to improve absorption.

Phytoestrogens
May provide mild oestrogen-like effects in some women.

Foods include flaxseeds, tofu, tempeh and edamame.

Gut-supportive foods
Support the microbiome and gut-brain connection.

Foods include yoghurt, kefir, sauerkraut, kimchi, onions, garlic, leeks, oats and apples.

Lifestyle factors that improve brain fog

Lifestyle habits directly affect many of the causes of brain fog, particularly sleep, stress, metabolism and inflammation.

Exercise
Aerobic exercise improves blood flow to the brain, supports insulin sensitivity and improves mood. It is consistently linked with better cognitive performance and reduced risk of decline.
Resistance training supports muscle mass and metabolic health and may improve executive function and memory in midlife and older adults.

Sleep
Menopause-related insomnia and night sweats are common contributors to brain fog. Poor sleep affects attention, working memory and emotional regulation.
Helpful strategies include maintaining a consistent wake time, getting morning light exposure, keeping the bedroom cool, reducing caffeine and alcohol, and creating a simple evening wind-down routine.

For a great DIY sleep course you can follow at home, follow this link to my Sleep Soundly Course.

Stress regulation
Chronic stress and elevated cortisol can affect key brain areas such as the hippocampus and prefrontal cortex.
Helpful approaches include breathwork with slow exhale breathing, mindfulness or meditation, yoga or tai chi, and time in nature or walking. These approaches can also support sleep and digestive health.

Cognitive and social engagement
Keeping your mind active and staying socially connected support both cognitive function and emotional wellbeing.
Activities such as learning a new skill, reading, puzzles or taking a class can strengthen attention and memory. Regular social interaction helps reduce stress and supports communication and problem-solving skills.

These lifestyle factors directly influence many of the underlying causes of brain fog, including:

• blood sugar balance
• inflammation
• hormone regulation
• brain blood flow
• nervous system function

This is why small, consistent changes in daily habits can often lead to noticeable improvements in clarity and focus.

Conclusion

Brain fog during menopause is common and often temporary. The key is understanding that the causes of brain fog are usually modifiable.
The key is understanding that the causes of brain fog are usually modifiable.

Many women find that brain fog is just one piece of a bigger picture. Exploring sleep, metabolism and gut health together often gives the best results, rather than trying to fix one symptom in isolation.
Small, consistent changes can begin to improve how your brain feels.

Start simple. Balance one meal, go for a short walk, or improve your sleep routine. These small steps often build into noticeable improvements in clarity and confidence over time.

Your next step

If you recognise yourself in this, you are not alone.
I share practical, step-by-step strategies to improve energy, metabolism and brain health inside my free community.

Or, if you want a more personalised approach, you can book a free discovery call to explore what may be driving your symptoms and what to do next.

References

Conde, D.M. et al., 2021. Menopause and cognitive impairment: A narrative review of current knowledge. World Journal of Psychiatry, 11(8), pp.412–428.

Gurvich, C., Spector, A. & Hickey, M., 2026. Advances in understanding of cognitive symptoms during menopause. The Lancet: Obstetrics, Gynaecology & Women’s Health, 2(4), e335–e345.

Naysmith, L.F. et al., 2026. Cognition and the menopause transition: cross-sectional evidence from a large community cohort. npj Women’s Health, 4, Article 14.

Barnes, L.L. et al., 2023. Trial of the MIND Diet for Prevention of Cognitive Decline in Older Persons. New England Journal of Medicine, 389, pp.602–611.

Valls-Pedret, C. et al., 2015. Mediterranean Diet and Age-Related Cognitive Decline: A Randomized Clinical Trial. JAMA Internal Medicine, 175(7).

Altınsoy, C. et al., 2026. Nutritional Approaches to Managing Brain Fog: Insights Into Neuroinflammation, the Gut-brain Axis, and Sleep. Current Nutrition Reports, 15, article 33.

Shieu, M.M. et al., 2023. The Interplay Among Natural Menopause, Insomnia, and Cognitive Health: A Population-Based Study. Nature and Science of Sleep, 15, pp.39–48.

Tooley, K.L., 2020. Effects of the Human Gut Microbiota on Cognitive Performance, Brain Structure and Function: A Narrative Review. Nutrients, 12(10), 3009.

Loh, J.S. et al., 2024. Microbiota–gut–brain axis and its therapeutic applications in neurodegenerative diseases. Signal Transduction and Targeted Therapy, 9, Article 37.

Shahinfar, H. et al., 2025. A systematic review and dose-response meta-analysis of Omega-3 supplementation on cognitive function. Scientific Reports, 15, Article 30610.

Welty, F.K., 2022. Omega-3 Fatty Acids and Cognitive Function. Current Opinion in Lipidology, 34(1), pp.12–21.

Arcila Castaño, L.A. et al., 2022. Resistance Training Combined With Cognitive Training Increases Brain Derived Neurotrophic Factor and Improves Cognitive Function in Healthy Older Adults. Frontiers in Psychology, 13:870561.

Herold, F. et al., 2019. Functional and/or structural brain changes in response to resistance exercises and resistance training lead to cognitive improvements. European Review of Aging and Physical Activity, 16:10.