Welcome to the second article in our summer-long series about brain health. In this series, we walk through Dr. G’s 4 prong approach to protecting your brain as you age. Today, we discuss the top foods to avoid. For an overview of the 4 prongs, download our guide below.

In functional medicine, the first step in healing is always to remove irritants. If your goal is to support optimal concentration, memory, and brain health, eliminating neurotoxic foods from your diet is a top priority. Start cleaning up your diet by removing the top 3 neurotoxic foods listed here.


By now, you know gluten is bad. But why? We usually think that gluten upsets digestion, and research has even shown that gluten sensitivity is linked to leaky gut . But what many people don’t realize is that gluten can affect the brain and the nerves throughout the body.

Gluten free is not a fad. Since the 1960s, experts have studied the neurological aspect of celiac disease. The most common neurological effects of celiac disease are called gluten ataxia and peripheral neuropathy. Gluten ataxia causes loss of control over body movement, and peripheral neuropathy causes pain, tingling, or numbness in the fingers and toes. Recently, a neurologist in the United Kingdom reported that ataxia and neuropathy can also occur in non-celiac gluten sensitivity.

Aside from ataxia and neuropathy, gluten sensitivity has also been linked with a range of cognitive problems —including inattention, memory problems, Alzheimer’s disease, and other forms of dementia. One explanation for this may be that gluten and gliadin can turn into morphine-like substances, which act like opioids in the brain. Another reason may be that gluten increases inflammation in sensitive individuals.


Many additives and ingredients in processed foods can have neurotoxic effects. I recently wrote an article about the ravaging effects of MSG (monosodium glutamate) and aspartame . MSG is a source of glutamic acid, which excites brain cells to death. It is directly neurotoxic.

Although most of the studies related to the neurological effects of MSG have been done in rats, the results are extremely concerning. Studies are so clear that MSG causes memory problems that scientists now use MSG to induce memory impairments in animals in order to test treatment strategies.


Aspartame contains aspartic acid, which enters the brain and acts in the same way as glutamic acid does from MSG. Aspartame has been shown to impair memory and damage neurons in the brain of rats.

If you think that the amount of aspartame you consume in daily foods is not enough to cause brain damage, think again. A recent study of healthy adults found that those consuming more aspartame were more irritable, more depressed, and performed worse on spatial orientation tests. An important point of the study was that the participants consuming high amounts of aspartame were still consuming levels well below the “maximum acceptable daily intake level.”

Another concerning study related to aspartame was just released in 2017. The study monitored nearly 1500 adults over the age of 60 for dementia. Over a period of 7-10 years, those who consumed more artificially sweetened beverages were at a significantly increased risk for Alzheimer’s disease and other forms of dementia.

What if Aspartame and MSG aren’t Listed as Ingredients?

Avoiding MSG and aspartame can be tricky. These additives hide behind other names on food labels. We created a comprehensive guide to arm you with the knowledge you need to avoid them and protect your brain. Download our guide below to discover all names for MSG and aspartame. We encourage you to print this out and take it to the grocery store with you

Other Neurotoxic Foods

If you only focus on eliminating gluten, aspartame, and MSG from your diet … you’re on a great path. To take your preventative measures one step further, consider this: concerns have been raised about the neurotoxic effects of sucralose (Splenda), artificial food dyes, and artificial butter flavor. A good rule of thumb is to focus on whole, organic, fresh foods with minimal added ingredients. If you do this along with eliminating gluten, you may be surprised at how clear your mind will become.

Check out the next article in our brain health series: The Best Foods for Brain Health

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About The Care Group: We promote optimal wellness by providing an individualized, functional medicine approach to address root causes rather than simply treating symptoms. We help patients with a wide range of issues including autoimmune/ inflammatory disease, digestive disorders, hormone imbalances, and mood disorders. To learn more about our practice, click here.

About the Author: Dr. Gerard Guillory, MD is Board Certified in Internal Medicine and has published two books on Irritable Bowel Syndrome (IBS). In 1985, he opened The Care Group, PC. Today, his clinic is a Primary Care facility that is a hybrid of functional and traditional medicine treating patients with digestive disorders, autoimmune disease, and other conditions. You can learn more about Dr. Guillory here.