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You're Probably Eating One Of The Five Foods That Cause Brain Fog

Gary Kaplan, D.O.
Doctor of Osteopathic Medicine
By Gary Kaplan, D.O.
Doctor of Osteopathic Medicine
Gary Kaplan, D.O. is the founder and medical director of the Kaplan Center for Integrative Medicine in Washington D.C. and a founder of the Foundation for Total Recovery.

Feeling unproductive? Fatigued? Having trouble concentrating? These are just some of the complaints associated with brain fog.

Brain fog is characterized by cognitive impairments to memory, attention, executive function, and the speed of cognitive processing. It is not a medical condition itself but rather symptomatic of an underlying condition that can range from poor nutrition or illness to undiagnosed food sensitivities or sleep deprivation.

If you haven’t already spoken to your physician about how you feel, make that priority number one in determining what may be causing your brain fog. In the meantime, there are things you can do right away to "clear up" your brain for optimal functioning. Environmental factors, particularly nutrition, can worsen or improve your symptoms; here are five types of foods and drinks that may be contributing to your brain fog:


Salad dressings & precooked meals.

If your lunch salads get a good dose of dressing, it may be one of the causes of your brain fog. The food additive monosodium glutamate (MSG), used as a taste enhancer and flavoring agent, is hidden in almost all processed foods, ranging from bottled salad dressings, soups, and canned goods to many restaurant meals. People can experience physical symptoms when eating foods that contain MSG that last from a few hours to days, and the most common of these is brain fog. Here’s how it works:

  • Free glutamic acid is the active component in MSG and is converted to glutamate in the body.
  • Glutamate is a neurotransmitter, or simply a chemical messenger, that transmits signals between neurons in the brain. However, too much glutamate is toxic to the brain as it triggers an excitotoxic state that leads to cell death.
  • In addition, glutamate overload depletes glutathione1 and other powerful antioxidants that are needed to scavenge free radicals (toxic cellular waste) in the body.

Identifying foods with MSG can be tricky, however, because it goes by many names. How can you make a difference? Focus on eating a variety of whole and unprocessed foods, for one, and eating food products with as few ingredients as possible. Supplementation may also help; a 2016 research study found that curcumin, the active component in turmeric, decreases the glutamate toxicity in the brain2.


Artificial sweeteners.

Aspartame is one of the most widely used artificial sweeteners worldwide and also one of the most controversial. The public health crisis of rising obesity drove us to embrace the idea of sweetness without the calories. But study after study has shown that artificial sweeteners, such as aspartame, can do more harm than good3.

When aspartame is ingested, it breaks down into three different compounds: aspartic acid, phenylalanine, and methanol. When consumed in isolated and large amounts, as in aspartame, they then are able to cross the blood-brain barrier, excite the brain cells, and trigger their death. Even worse, methanol further breaks down to formaldehydes, which are neurotoxic and carcinogenic.

Common symptoms of aspartame toxicity are headaches, mental confusion, problems with balance, and numbness.



Sodium nitrite, sodium nitrate, and sodium/potassium benzoate are salts added to processed foods, particularly meats, to preserve freshness. The food industry relies on these additives as taste enhancers and as a way to preserve bright colors that will catch the eye of the consumer.

Although the use of these additives is approved by the Food & Drug Administration in regulated amounts, these chemicals are classified "Group 1 Carcinogen" by World Health Organization (WHO) experts. A large number of health complaints have been reported by consumers: among them skin issues, respiratory problems, headaches, dizziness, and brain fog.

The best way to avoid these additives, commonly found in bacon, jerky, hot dogs, pepperoni, and sausages, is to read the labels and choose to eat unprocessed foods.



Various components in alcohols can cause sensitivity, and the severity of the allergic reactions depend on the person’s genetic profile, one major symptom being brain fog.

Here is a list of the ingredients in wine, beer, liquor, and spirits that may be worsening your brain fog:

  • Sulfite additives are used to sterilize barrels and tanks before fermentation takes place.
  • Histamines are suggested to play a major role in allergic-like reactions to wine.
  • Ethanol is found to play a role in inducing allergic reactions—especially in Asians and certain other populations—due to their lack of the enzyme that metabolizes ethanol.
  • Most beers contain gluten. People who are sensitive to gluten report an improvement in brain fog when gluten is cut out of their diets.

Cheese & Dairy.

Milk and dairy products, such as cheese, yogurt, and whey protein (found in bodybuilding and energy drinks) are just one of the food categories that the FDA has also recognized as a major allergen, potentially causing allergic reactions in some people that can range from mild to severe, and in some cases can be fatal.

Other foods considered major allergens are gluten, soy, egg, shellfish (two kinds: crustacean and mollusk), tree nuts (such as walnuts, almonds, and cashews), peanuts (in the legume family), certain types of finned fish, and sesame. For people with sensitivities or allergies to these foods, the body sees the proteins as a threat and produces antibodies to chase them out.

If you experience symptoms of brain fog, headache, or digestive discomfort when you eat a specific type of food, you may have a sensitivity but not necessarily an allergy. With either situation it is best to avoid those foods altogether, and be careful when reading labels, as there may be hidden ingredients, especially milk and eggs.

To help get rid of brain fog, you may want to check out these herbalist-approved herbs; plus, the six best foods for getting you clearheaded, stat.

Gary Kaplan, D.O. author page.
Gary Kaplan, D.O.
Doctor of Osteopathic Medicine

Gary Kaplan, D.O. is the founder and medical director of the Kaplan Center for Integrative Medicine and a founder of the Foundation for Total Recovery. He also authored the book Total Recovery. He graduated from the College of Osteopathic Medicine and Surgery in Des Moines, Iowa and completed his residency training at Georgetown University/Providence Hospital’s Family Practice Residency Program. A pioneer and leader in the field of integrative medicine, Dr. Kaplan is one of only 19 physicians in the country to be board-certified in both family medicine and pain medicine. He created the Kaplan Center to offer patients suffering with chronic pain and illness a more effective model of medical care.