What Is Brain Fog?

Sabina Brennan just couldn’t find the words — literally. She was in the middle of writing a book when she started experiencing brain fog in October 2021.

“It felt like there was just nothing in my brain,” Brennan said. “I was struggling to read and write. Coherent sentences just seemed out of my grasp. I felt as if my life was a game of charades, and not a fun game of charades. I just couldn’t say what I wanted to say.”

Brennan, a neuroscientist and author of “Beating Brain Fog,” knew that her symptoms were related to brain fog after a bout with Covid-19. But even for her, “The experience was really quite frightening,” she said.

What is brain fog?

Brain fog is an umbrella term for a collection of symptoms that may include having a lack of concentration, memory loss, heightened clumsiness or the inability to recall words, process information quickly or multitask. Uma Naidoo, M.D., a Harvard-trained nutritional psychiatrist, calls it “mental fuzziness.”

You might forget what you just did earlier in the day, or something important that a loved one told you. If you’re normally quick-witted, you might find yourself processing information so slowly that you’re unable to respond in a conversation with friends or during a presentation at work. Or you might suddenly feel ill-equipped to do tasks at which you’re normally an expert.

Brennan compares dealing with brain fog to being in a constant state of jet lag. “It’s not a disease. It’s not a disorder in and of itself, but rather, it is a signal that something is amiss, like your brain is malfunctioning,” she explained. “But just because it’s not a disease or a disorder doesn’t mean that it doesn’t exist. It is very real.”

While everyone has moments when a word escapes them or they forget where they put their keys, brain fog will have a noticeable negative impact on your life.

“When you have brain fog … the symptoms are persistent, they occur regularly, and they actually interfere with the quality of your life, with your relationships and with your ability to carry out your job,” Brennan said. “If it’s interfering with your life, you need to take it seriously and seek medical care to determine the underlying health condition.”

Causes of brain fog

Unfortunately, Brennan said, many of these underlying health conditions affect women.

Hormonal changes can lead to brain fog during pregnancy (hence the term “pregnancy brain”), perimenopause and menopause, and diseases like hypothyroidism and diabetes can also cause hormonal changes, which in turn can affect cognitive ability.

“You tend to hear about neurotransmitters like serotonin and dopamine, but your brain also communicates via hormones, including estrogen,” Brennan said. “You have estrogen receptors in your hippocampus, which is involved in learning in memory, but also in your cerebral cortex, which is involved in thinking, language and various other functions. So when your estrogen levels drop, they’re going to impact those functions.”

Autoimmune inflammatory diseases like lupus and multiple sclerosis, which affect women at nine and four times the rate they affect men, respectively, as well as fibromyalgia and Crohn’s disease, can all cause brain fog. The Covid-19 pandemic has also shone a spotlight on brain fog, a common lingering effect of the virus. A recent study published in Frontiers in Aging Neuroscience found that large numbers of people experiencing Covid symptoms reported difficulty concentrating (78%), brain fog (69%), forgetfulness (68%), tip-of-the-tongue (ToT) word finding problems (60%), and saying or typing the wrong words when communicating (44%).

Depression, cancer or viral or bacterial infections can also lead to brain fog.

To make the problem even worse, medications used to treat many of these illnesses can also cause brain fog as a side effect.

“Any medication that acts on the central nervous system has the capacity to disrupt your cognitive functioning, your mental processes,” Brennan said.

What can you do about brain fog?

Brennan recommends keeping a journal of your symptoms, so you can understand whether you’re just having an off day, or if your brain fog is a sign of something more serious.This will also help you advocate for yourself when you talk to your healthcare provider (HCP) about treatment.

If you’re on medication, it’s important to talk to your HCP about whether the medicine may be the cause, and if a change in dosage might help.

Additionally, you can ask for a blood test to evaluate your vitamin B12, vitamin D and iron levels, as deficiencies in these can lead to brain fog.

While you’re working to find the cause and appropriate treatment with your medical provider, there are also lifestyle changes you can make to help your body beat brain fog.

Getting enough sleep is Brennan’s number one recommendation. “Sleep is absolutely critical for brain health and optimal cognitive functioning,” she said. “Your brain is a really high-energy organ. It produces a lot of waste, and it can’t clear that waste during the day when you’re awake. It needs you to go through REM sleep.”

How does food affect brain fog?

As more research is done on the brain-gut connection, scientists are finding more evidence that what you eat can affect your mood and your cognitive function.

“Diet may just be our secret weapon in fending off brain fog,” said Naidoo, author of “This is Your Brain on Food.” “Nutrition has the tremendous power to help us reduce mental cloudiness and maximize focus, productivity and brain power in the workplace.”

Here are four dietary changes she recommends to help fight brain fog:

1. Fill up your plate with colorful fruits and veggies that help fight inflammation: “Fiber-rich, plant-based foods are packed with antioxidants, polyphenols, flavonols, vitamins and minerals that help reduce inflammation in the brain and resist the effects of oxidative stress (the kind that damages cells, and even leads to premature aging,” Naidoo explained. [They] can help improve focus, reduce fatigue and enhance cognition for optimal performance.”

2. Eat fewer simple carbs, like sugary pastries, cookies and white bread. These foods can cause a sugar imbalance, Naidoo said. Instead, choose foods rich in healthy

fats and fiber to reduce sugar cravings, and opt for low-glycemic fruits like berries.

3. Stay hydrated. “Many symptoms of poor mental health and cognitive function are tied to dehydration. Sip on water throughout the day and include hydrating fruits and vegetables in the diet, such as cucumber and leafy green lettuces,” Naidoo advised.

You may think that caffeine will give your brain a boost, but instead, it can affect your sleep and cause you to crash, keeping you in a vicious cycle. Instead, choose foods that are truly energizing, such as roasted nuts with 80%+ natural dark chocolate, Naidoo recommended.

“I don’t want people to take on an entire diet reset, as it becomes too overwhelming and then unsustainable,” she said. “My recommendations are always for slow, steady

small habit changes [such as] changing out a food that you are eating, such as daily ice cream or a candy bar that may be worsening your brain fog.”