The modern Western diet has evolved to prioritize the tasty over the healthy, which has brought about ultra-processed foods loaded with artificial sweeteners and food additives with little consideration for their health impacts. One of the ways these foods can harm our health is excitotoxicity; some components of processed foods, known as excitotoxins, overstimulate neurons, leading to their dysfunction and death, which manifests as unexplained headaches, inattention, and difficulties with concentration, and is linked to numerous neurological, mental, and systemic illnesses.

What is excitotoxicity?

When an excitatory neurotransmitter (chemicals naturally found in our bodies that neurons use to communicate), like glutamate, binds to its receptor on the surface of a neuron, it starts a process that changes the chemical composition of these neurons and increases calcium inside them. When this process happens in a controlled manner, it activates neurons without causing any damage. Some food additives and synthetic chemicals in ultra-processed foods mimic the effect of excitatory neurotransmitters, and when present in large amounts, they overstimulate neurons, leading to the accumulation of calcium inside these cells. The high calcium level is toxic to neurons as it inappropriately activates enzymes, causes oxidative stress, and damages proteins and DNA. Another way excitotoxins cause diseases is by inducing inflammation in organs like the kidneys and the gut through activation of immune cells in these organs.

Some examples of excitotoxins

Excitotoxins are chemicals added to processed fast foods and food additives; they either mimic the effect of glutamate and other excitatory neurotransmitters or contain high amounts of glutamate, resulting in neuron overstimulation and excitotoxicity. Among these excitotoxins are:

  • Monosodium glutamate (MSG), a food additive used to enhance flavor, is usually found in savory snacks, instant noodles, canned soups, and salad dressings. MSG is a well-established excitotoxin that induces neuron overstimulation, oxidative stress, and inflammation.
  • Aspartame, an artificial sweetener added to diet sodas, sugar-free beverages, gum, low-calorie desserts, and protein bars. It is a precursor to glutamate, and, similar to MSG, it causes hyperexcitability of neurons. Additionally, aspartate is linked to brain tumors.
  • Hydrolyzed vegetable proteins, found in processed meats (e.g., sausages, hot dogs, deli meats) and vegetarian meat substitutes. This food additive is high in glutamate and impairs brain function through excitotoxicity.
  • Soy protein concentrates, commonly used in “healthy” meat alternatives like veggie burgers, plant-based sausages and hot dogs, meatless chicken nuggets or patties. They cause DNA damage in the gut lining and were shown to be a carcinogen, causing intestinal tumors.
  • Some artificial colors like tartrazine are associated with excitotoxicity and hyperactivity in children.

Other excitotoxins like autolyzed yeast, whey protein isolates, and sodium or calcium caseinates aren’t found only in fast foods; they can also be found in foods marketed as “healthy” like vegan meat alternatives, protein bars and shakes, and low-calorie foods.

Some natural foods like tomatoes, cheese, and soy sauce are not excitotoxins, but their glutamate content is very high and, in sensitive individuals, can cause some symptoms of excitotoxicity.

The health impact of excitotoxins

Besides the symptoms that affect everyday life, like headaches, cognitive impairment, memory problems, and brain fog, excitotoxicity causes multiple neurological conditions, mental illnesses, and systemic diseases by inducing nerve cell death or inflammation. For example:

  • Alzheimer’s disease: The neuronal cell death that results from glutamate excitotoxicity is a major contributor to the origin of Alzheimer’s disease; moreover, exposure to MSG in childhood causes Alzheimer’s-like cognitive and memory impairment.
  • Parkinson’s disease: Exposure to excitotoxins was found to accelerate the degeneration of dopamine-secreting neurons in susceptible individuals, leading to earlier onset and a more severe course of parkinsonism.
  • Amyotrophic lateral sclerosis (ALS): The same effect observed in Parkinson’s is seen in ALS with motor neuron degeneration.
  • Attention deficit hyperactivity disorder (ADHD): Studies found that exposure to excitotoxins in childhood, especially MSG, was linked to the development of ADHD symptoms and their persistence into adulthood.
  • Kidney disease and inflammatory bowel disease: Excitotoxins activate immune cells and promote inflammation, causing gut and kidney diseases.
  • Cancer: The relationship between excitotoxins and cancer is reciprocal; excitotoxins are involved in the pathogenesis of many types of cancer, and tumors can produce excitotoxins.

How to identify and avoid excitotoxins?

  1. Look for these terms in the ingredients list on labels:
  • Monosodium glutamate (MSG)
  • Hydrolyzed vegetable protein (HVP)
  • Autolyzed yeast extract
  • Glutamic acid
  • Sodium caseinate
  • Aspartame

And avoid products that have one or more of them.

  1. Choose whole, unprocessed foods.
  2. Cook at home to control ingredients.
  3. Supplement your diet with antioxidants (vitamins C and E), magnesium (a natural glutamate receptor blocker), and omega-3 fatty acids.

Excitotoxins are very popular in the processed and fast food industries, and many people consume them regularly, which is contributing to the increasing burden of disease and disability. More radical measures need to be taken on a societal level, but until that happens, please be careful about what you eat.

References