5 Neurotoxins Found in Popular Foods

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Last updated July 15, 2021.
Edited and medically reviewed by Patrick Alban, DC. Written by Deane Alban.

Neurotoxins are all around us, but are especially common in popular processed and prepared foods. Learn ways to avoid them and use healthy alternatives.

You’d like to think that our food supply is protected from neurotoxins — substances known to harm the central nervous system.

However, the US Food and Drug Administration allows 3,000 food additives to be used in our food supply.

And relatively few of them have been tested for safety. (1)

Of those food additives that have been tested, a handful are well-documented neurotoxins.

Some neurotoxins can be found in common foods and beverages, even those in relatively healthy diets.

In this article, you’ll find our “Top 5 Hit List” of neurotoxins found in foods.

These neurotoxins have been linked to everything from brain fog and headaches to anxiety, depression, and even Alzheimer’s.

We’ve included easy tips and substitutes to help you minimize your exposure.

Neurotoxin #1: Aspartame

Aspartame is a popular artificial sweetener found in diet sodas, processed foods labeled “sugar-free,” and those little blue packages that go by the brand names Equal or NutraSweet.

Aspartame is bad news for your brain, no matter what you call it.

There are over 90 documented symptoms of aspartame, including: (2, 3)

  • allergic symptoms (hives, itching, anaphylaxis)
  • anxiety
  • breathing difficulties
  • depression
  • headaches and migraines
  • joint pain
  • insomnia
  • loss of taste
  • memory loss
  • nausea
  • numbness
  • slurred speech
  • tinnitus
  • vertigo
  • weight gain


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It can trigger or worsen the symptoms of many disorders such as diabetes, fibromyalgia, Alzheimer’s disease, and multiple sclerosis.

Consumers have reported over 7,000 aspartame adverse side effects to the US Food and Drug Administration. (4)

You can also find lists of reported side effects on various reputable websites, including CDC.gov and Drugs.com.

" There are over 1,000 known neurotoxins, both man-made and naturally occurring.

One major study that followed over 250,000 soda drinkers found that drinking artificially sweetened soft drinks significantly increased the likelihood of depression. (5)

Aspartame’s long list of adverse effects is not surprising when you realize that it is composed of three brain-damaging chemicals — aspartic acid (40%), phenylalanine (50%), and methanol (10%). (6)

Each of these components is neurotoxic in its own right.

Aspartic Acid

Aspartic acid is the precursor of glutamate, the brain’s main excitatory neurotransmitter.

When present in excess, this brain chemical becomes an “excitotoxin,” meaning that it can literally excite, or stimulate, brain cells to death. (7)


Phenylalanine is an amino acid normally found in the brain.

In large amounts, it is considered a neurotoxin. (8)

It reduces serotonin levels by inhibiting the brain’s uptake and conversion of tryptophan. (9)


Methanol is wood alcohol, the kind of alcohol that is extremely poisonous.

In your body, it can turn into formaldehyde, another known neurotoxin. (10)

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A Safe Alternative to Artificial Sweeteners

There are many good reasons to avoid sugar-laden drinks, but artificial sweeteners are not a healthy alternative.

Ironically, artificial sweeteners don’t make you thinner.

In fact, they confuse your brain into increasing appetite and hunger. (11)

My favorite healthy sweetener is stevia (Stevia rebaudiana).

This naturally sweet herb can be used to sweeten foods and drinks with zero calories.

Stevia is 200 times sweeter than sugar and doesn’t increase blood sugar or promote tooth decay.

Read the product label carefully when buying stevia since some stevia products also contain sugar.

Two healthy all-stevia brands are SweetLeaf Stevia and Stevia in the Raw.

Neurotoxin #2: Diacetyl

Popcorn is a high-fiber, low-calorie snack that nearly everyone loves.

Every year, Americans munch down 17 billion quarts of it! (12)

But home-popped microwave popcorn often contains butter flavoring with the additive diacetyl.

It’s already established that this chemical causes a serious condition called “microwave popcorn lung.”

Diacetyl is able to cross the blood-brain barrier, a protective filter which prevents harmful substances from entering the brain.

Once in your brain, it causes beta-amyloid clumping which is a significant indicator of Alzheimer’s. (13)

You won’t see the word “diacetyl” on a microwave popcorn label, but if you see “artificial butter flavor” or “natural flavors,” assume that the product contains this neurotoxin.

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Healthy Popcorn Alternatives

I love popcorn and am as bummed about this as anyone.

But you can eat popcorn safely.

The best way to have healthy popcorn is to pop your own and add your own seasonings.

It’s fast, fun, and highly economical.

If you like the taste of butter, use the real thing.

Butter is a particularly good source of the fatty acid butyrate.

Butyrate reduces chronic inflammation and may help protect the brain against dementia. (14)

Neurotoxin #3: Monosodium Glutamate (MSG)

Glutamate naturally occurs in some foods and it’s also one of your brain’s most important neurotransmitters. (15)

Glutamate is essential for a healthy brain, but “the dose makes the poison.” (16)

In excess, glutamate becomes a potent excitotoxin that overstimulates brain cells, sometimes to death. (17)

There are two ways that glutamate occurs naturally in foods.

Glutamate can either be bound to other amino acids (bound glutamate) or not (free glutamate). (18)

Bound glutamate is absorbed slowly, whereas free glutamate is rapidly digested, leading to spikes in the bloodstream.

Since the flavor enhancer monosodium glutamate is pure, free glutamate, eating it acts like a glutamate bomb.


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Reported side effects of MSG include: (19, 20)

  • asthma
  • back pain
  • burning or tingling
  • chest pain
  • convulsions
  • diarrhea
  • flushing
  • fuzzy thinking
  • headache
  • heart palpitations
  • migraines
  • mood swings
  • muscle weakness
  • nausea
  • numbness
  • sweating

Glutamate system dysfunction has been linked to numerous psychological disorders and neurodegenerative diseases. (21, 22, 23)

If you’ve ever felt strange after eating at an Asian restaurant, you may have experienced MSG symptom complex. (24)

The US National Library of Medicine lists symptoms of MSG symptom complex as ranging from mild to life-threatening. (25)

Avoiding MSG: List of Top MSG Sources

If you want to avoid MSG, you need to be aware of common MSG sources.

Generally, the saltier the food, the more MSG it’s likely to contain.

The worst offenders include foods like canned soups, salty snacks, ramen noodles, and refined soy products.

Here are some label-listed ingredients that always contain MSG: (26)

  • autolyzed yeast
  • calcium caseinate
  • hydrolyzed protein
  • plant protein extract
  • sodium caseinate
  • textured protein
  • yeast extract


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These ingredients may contain MSG:

  • beef or chicken flavoring
  • bouillon
  • broth
  • flavoring
  • malt flavoring
  • natural flavoring
  • seasoning
  • spices
  • stock

Supplements to Offset MSG Ingestion

If you accidentally ingest MSG, you don’t have to wait out the symptoms.

There are several supplements that protect the brain from MSG-induced toxicity, including taurine, vitamin C, ginger, and coenzyme Q10. (27, 28, 29, 30)

Vitamin C acts as a powerful detoxifier that also removes heavy metal neurotoxins like lead, mercury, and aluminum. (31, 32)

Neurotoxin #4: Mercury

When it comes to eating fish, there’s a quandary.

We’re told to eat fish often because it’s good for your brain due to its high omega-3 essential fatty acid content.

But fish is also a top source of the neurotoxin mercury.

Unlike the first three neurotoxins we’ve discussed, mercury is not intentionally added to our food supply, but gets into our waterways where it accumulates in fish and seafood.

Some mercury naturally occurs (volcanic eruptions being the top source), but much of it is a side effect of modern-day pollution.

The neurotoxic effects of mercury are well-documented.

Mercury has the ability to cross the blood-brain barrier and accumulate in the brain.

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Chronic mercury poisoning happens slowly over time.

The first signs of mercury toxicity include memory loss, depression, anxiety, mood swings, numbness, and tremors. (33)

Fish That Are Low in Mercury

While there are legitimate concerns about mercury, it’s widely agreed that the benefits of moderate fish consumption still outweigh the risks. (34)

Harvard Medical School recommends eating 12 ounces of fish per week but sticking to those low in mercury. (35)

We recommend eating fish that is both high in brain-healthy omega-3s and low in mercury.

Fortunately, there are a handful of fish that meet both these criteria — wild-caught Alaskan salmon, herring, mackerel, and sardines. (36)

fish high in omega-3 fatty acids and low in mercury

Fish to Avoid

It’s recommended that you avoid predatory or long-lived fish, since they accumulate the most mercury. (37)

These include swordfish, shark, orange roughy, and tuna. (38)

If you eat canned tuna, the most widely consumed fish of all, it’s recommended that you eat no more than 4 servings per month. (39)

Neurotoxin #5: Aluminum

Aluminum is the most abundant metal in the earth’s crust.

It’s used as an additive in baking powder and anti-caking agents.

You may also be exposed to it from your drinking water, antacids, or deodorant, and from aluminum cans, foil, and cookware.

By using mass spectrometry and reviewing autopsy results, researchers have found that considerable amounts of aluminum accumulate in the brains of Alzheimer’s patients. (40)

A review of studies that covered over 10,000 participants found that regular exposure to aluminum increased the risk of Alzheimer’s by 71%. (41)

One large study that followed thousands of seniors for 15 years concluded that drinking water that contained aluminum doubled the risk of dementia and tripled the risk for Alzheimer’s. (42)

It’s been over 50 years since the aluminum-Alzheimer’s correlation was first made, yet there is still much skepticism about it in the medical community. (43)

How to Minimize Aluminum Exposure

You can wait for the scientific community to reach a consensus, or you can take measures to minimize aluminum exposure now.

Start by using only aluminum-free versions of baking powder, deodorant, and antacids.

You can minimize your use of aluminum cookware.

This soft metal leaches into food especially when you cook acidic foods like tomato, lemon, or vinegar.

Stainless steel cookware is a better choice.

It is more durable, scratch-resistant, and less reactive than aluminum.

You can cook on parchment paper instead of aluminum foil too.

Other Neurotoxins You’re Likely to Encounter

Of the many thousands of man-made chemicals that have been introduced into the environment, over 1,000 are known to be neurotoxins. (44, 45)

Hundreds of these, both synthetic and naturally occurring, are commonly encountered in daily life.

Neurotoxins can be found in the water you drink and the air you breathe.

They can be found in toiletries, cosmetics, and household products you use every day.

They can even be found in drugs you take, both prescription and recreational.

Some experts believe we are facing a “silent pandemic” of developmental brain damage caused by neurotoxins.

The image below shows the “dirty dozen” neurotoxins suspected of contributing to attention disorders, autism, and a significant drop in IQ.

chart showing the 12 worst neurotoxins
The “dirty dozen” neurotoxins. (Image courtesy of TheAtlantic.com)

Neurotoxins in Food: Take the Next Step

Neurotoxins are chemicals known to be harmful to the brain.

Unfortunately, some lurk in our favorite foods, such as soda, microwave popcorn, canned tuna, and salty snacks of all kinds.

There are healthy alternatives, so you can reduce your intake of these ubiquitous neurotoxins with some simple adjustments to the way you eat and cook.

Reducing your exposure to these “big 5” neurotoxins is a sensible way to help keep your brain and nervous system healthy.