5 Common Causes of "Brain Fog"

Do you ever feel like your brain is wading through mud instead of racing on all cylinders? That frustrating sense of mental sluggishness, where focus is elusive, memory falters, and even simple tasks feel overwhelming, is commonly known as brain fog. 

While it’s a struggle many face, researchers have uncovered surprising triggers—from hormonal shifts to immune responses—and simple, actionable strategies that can help you regain mental clarity.

Curious about what might be clouding your mind and how to break free? Read on for answers.

Key Takeaways

• Women approaching menopause often experience brain fog due to challenges in working memory and sustained focus.

• Autoimmune diseases, chronic fatigue syndrome, and dietary triggers like gluten sensitivity can exacerbate brain fog.

• Omega-3 fatty acids, reduced sugar intake, and regular aerobic exercise can enhance brain function and counteract mental fog

What Does Brain Fog Feel Like?

Ever get one of those days where you feel like your brain isn’t on top of its game?

I do from time to time. And it’s awful.

On one of those days, it’s hard to stay focused on what you’re trying to accomplish. Distractions are impossible to ignore. Your mental powers and your thinking slow down.

The popular name for the condition is brain fog.

Though I think brain mud might be more appropriate.

So many people have complained about brain fog that researchers have been investigating how and why it occurs.

Here are five common causes, and a few solutions...

A University of Rochester study shows that women approaching menopause often suffer from brain fog.

The Rochester scientists examined 75 women ages 40 to 60 who were pre-menopausal or just beginning menopause. They gave the women tests that analyzed their learning abilities, their information retention, their ability to stay mentally focused, and how well they put new knowledge to use.

The researchers found that the most frequent memory problems – and complaints from the women – were linked to what is called "working memory." That’s the ability to process new information and draw a conclusion from it – such as being told what your restaurant bill is and then calculating how much you want to tip your server.

Another example could be getting bumped from one airline flight to another and then figuring out how this mishap affects your schedule in your destination city.

The next most frequently cited brain fog problem was maintaining focus on a mental task that takes hours – such as doing your taxes or finishing a difficult work report.

Five Causes of Brain Fog

This is not to say brain fog is a problem special to older women. Menopause just happened to be the focus of this one study. Other conditions and situations that can lead to brain fog include stress, poor sleep, and a variety of chronic illnesses, including:

• 1. Autoimmune diseases: Celiac, an autoimmune reaction to gluten, can cause brain fog. So can conditions like rheumatoid arthritis and multiple sclerosis.¹ At least for gluten sensitivity, the answer is obvious. You’d be amazed at how many people have cleared up brain fog by avoiding their "trigger foods."
• 2. Chronic Fatigue Syndrome (CFS): A study at Columbia University shows that immune system dysfunction in the central nervous system during CFS is linked to memory problems.² My problem with brain fog ten or fifteen years ago was linked to CFS – a problem I was able to solve.
• 3. Chemotherapy: Many chemotherapy drugs have been reported to cause memory gaps.³ It’s called “chemo brain.” Cancer is a big subject, but my two cents is that there are a lot of effective alternative treatments, and a great many cancer patients could avoid chemo, or manage with much lower doses.
• 4. Anyone who has suffered from allergies or colds can tell you they decimate your mental capacity. Some researchers believe that your immune response during an allergic reaction or a cold may hamper your ability to focus.⁴ Also be aware that the medications for these conditions are among the worst for your brain.
• 5. Hormone changes such as menopause-- which we already outlined above. Hormone changes are especially problematic for women going through menopause when estrogen levels dramatically decline. 

How to Maintain a Sharper Memory

The advice that experts offer for fighting back against brain fog includes better nutrition and mental strategies to help your memory work better. The Rochester researchers believe that working harder at retaining new information can help.

"When someone gives you a new piece of information, it might be helpful to repeat it out loud, or for you to say it back to the person to confirm it – it will help you hold onto that information longer," says researcher Miriam Weber. "Make sure you have established that memory solidly in the brain."

At the same time, researchers at Ohio State, who have investigated why chemotherapy fogs the brain, say that altering your diet may help you stay sharper.

Their advice: Take in more omega-3 fatty acids, the type of fats contained in fish oil, and cut back on your sugar consumption. Tests have shown that omega-3 oils reduce inflammation in the brain, lower oxidative stress, and help neurons stay healthier.⁵

This is good advice for anyone trying to keep their brain working better. Also, avoid processed foods that are filled with refined carbohydrates – these can increase inflammation which, in turn, can fog your mental functions.

Getting more exercise also helps. For me, a brisk daily walk clears my mind. And studies show that aerobic activity helps the brain build new neurons.⁶

Summary

Brain fog, a frustrating condition marked by difficulty focusing, memory lapses, and slowed mental processing, affects millions of people across all ages. Recent research has identified various causes, including menopause, autoimmune diseases, chronic fatigue syndrome, chemotherapy, allergies, and poor nutrition. The good news is that dietary changes, exercise, and mental strategies can alleviate symptoms. Omega-3 fatty acids, reduced sugar intake, and aerobic activity all play pivotal roles in combating brain fog, while mindfulness techniques can improve memory retention.

Frequently Asked Questions

What is brain fog?

Brain fog is a term for cognitive dysfunction marked by difficulty concentrating, memory lapses, and slowed mental processing. It’s a symptom, not a formal diagnosis.

Can menopause cause brain fog?

Yes, hormonal changes during menopause, particularly in working memory and focus, often lead to brain fog in women aged 40–60.

What lifestyle changes can help combat brain fog?

Improving sleep, adopting a diet rich in omega-3 fatty acids, reducing sugar intake, and engaging in regular exercise can significantly improve mental clarity.

Can brain fog be caused by allergies or medications?

Yes, immune responses during allergies or colds and certain medications can impair mental focus and clarity.

How does diet influence brain fog?

Diets high in refined sugars and processed foods can increase inflammation and oxidative stress, worsening brain fog, while omega-3 fats and nutrient-dense foods can improve cognition.