Neurologists Point to Common Foods that May Increase Risks to Brain Health

When it comes to longevity and health, we often focus on our waistlines or our heart health. However, neurologists, the doctors who specialize in the intricate workings of the brain, are increasingly warning that what we eat is the primary tool for protecting our cognitive future.

While the brain represents only about 2% of our body weight, it consumes roughly 20% of our daily energy. This high demand makes it incredibly sensitive to what we put in our bodies. In a recent spotlight on brain health, several leading neurologists shared the specific foods they personally avoid to keep their neural pathways sharp.

The Science: How Food Talks to Your Brain

The relationship between your gut and your brain is governed by the gut-brain axis. This axis is a bidirectional communication network, meaning that the brain and our digestive tract (the “gut”) ‘talk’ to each other. When you eat, your body doesn’t just absorb calories; it absorbs molecules that can either protect or provoke your nervous system. 

In this relationship, there are two major scientific factors at play:

1. The Blood-Brain Barrier (BBB): This is a highly selective “security gate” that protects your brain from toxins. However, certain diets, particularly those high in processed sugars and trans fats, can weaken this barrier. This allows “leaky brain” conditions where harmful substances have better capacity to bypass the BBB and enter brain tissue.
2. Neuroinflammation: Unlike the visible swelling of a sprained ankle, neuroinflammation is invisible. It occurs when the brain’s immune cells (microglia) become chronically overactive due to poor nutrition, leading to the gradual “short-circuiting” of neurons and contributing to diseases like Alzheimer’s. 

6 Foods Neurologists Avoid (And Why)

Naturally, when thinking about the best foods to eat for brain health and those better left off of your plate, there is no one better to ask than a neurologist. These professionals have dedicated their lives to studying our brains and what affects brain health. The following foods are those neurologists recommend consuming with caution, if at all.

1. Protein Powder (The “Hidden Additive” Risk)

While protein is essential for brain function, many commercial powders are ultra-processed. Neurologists caution that some brands contain heavy metals like lead or mercury, or high amounts of artificial sweeteners. These can act as neurotoxins, interfering with neurotransmitter signaling. 

“It is those additives that really give me pause when it comes to protein powders because they wreak havoc on your gastrointestinal microbiome,” said neuroscientist Friederike Fabritius in an interview with HuffPost. “A healthy and robust internal microbiome is so important for great brain health because most of our neurotransmitters are produced in the gut.”

If you use protein powder, stick to brands with minimal, transparent ingredient lists. If you don’t understand something on the label, look it up. Knowledge is most definitely power in this case.

2. Soda (The Glucose Spike)

Both regular and diet sodas are on the “no” list. Regular soda causes a massive spike in blood glucose, which can lead to insulin resistance in the brain. When brain cells become resistant to insulin, they lose their ability to process energy, effectively “starving” your neurons. Diet sodas aren’t much better. Artificial sweeteners like aspartame can disrupt the gut microbiome, which produces the very chemicals your brain needs to regulate mood, like serotonin.

“Soda is one of the worst foods for brain health due to the high concentration of simple sugars, which damage the blood vessels supplying the brain,” said neurologist Dr. Shaheen Lakhan. “Over time, this starves the brain from the very fuels it needs to function, leading to premature dementia and strokes. Acutely, sugar also causes brain inflammation, irritability, poor mood and sleep disturbances.”

3. Alcohol (The “Brain-Shrinking” Solvent)

Alcohol is a neurotoxin that can cross the blood-brain barrier with ease. It directly interferes with neurogenesis, the process by which the brain creates new neurons. Chronic consumption is linked to a reduction in brain volume (shrinkage), particularly in the hippocampus, the area responsible for memory and learning.

“Alcohol is a neurotoxin that can injure both the central and peripheral nervous system, even if consumed in moderate amounts.” Said neurologist Dr. Byran Ho.

4. French Fries (The Acrylamide Factor)

Fried foods are a double-threat. First, they are high in trans fats, which stiffen the membranes of brain cells. Second, when starchy foods like potatoes are fried at high temperatures, they produce a chemical called acrylamide. Research suggests that acrylamide can induce oxidative stress, damaging the DNA within your nerve cells.

“A diet that incorporates fatty foods like French fries can damage blood vessels that supply the brain, causing cognitive impairment,” said Dr. Pedram Navab. “It reduces the blood-brain barrier (BBB) integrity and leads to neuronal damage of the hippocampus, a part of the brain that is instrumental for learning and memory.”

Surprisingly, many neurologists avoid certain types of decaf. To remove caffeine, many manufacturers use methylene chloride, a harsh solvent. While the FDA regulates the residue levels, many experts prefer to avoid even trace amounts of a chemical known to have carcinogenic and neurotoxic potential. 

“Solvents, the chemicals used to remove caffeine from coffee, are generally toxic to humans,” said neuroscientist Sean Callan. “Many are linked to increased risk of cancer or neurological harm, especially in large or repeated doses. Beyond that, solvents like methylene chloride (a solvent commonly used in the decaffeination process) are known to cross the placenta, meaning pregnant women risk exposing their unborn child to the solvent.”

If you go decaf, look for the “Swiss Water Process.” Which uses only water to extract caffeine.

6. Cannabis-Infused Foods (Edibles)

As legalization spreads, so do concerns about high-potency edibles. Neurologists warn that THC, the psychoactive component that produces the ‘high’, can impact the brain’s executive function. This is our ability to plan, focus, and multitask. Because edibles take longer to metabolize, users often consume higher doses than intended. This can lead to prolonged periods of cognitive fog and impaired memory formation.

“Besides the short-term cognitive impairing effects of cannabis, tetrahydrocannabinol (THC) appears to constrict arteries in the brain,” said neurologist Dr. Lester Leung. “This can be very dangerous when used in large amounts by people with migraines, a very common headache condition that, together with heavy cannabis use, can lead to stroke, even in young, otherwise healthy people.”

Read More: Post-Pandemic Spike in Gut-Brain Health Issues Raises Concerns

What Should You Eat?

While there are certainly many foods or types of food that we should be avoiding for our brain health, there are thankfully just as many foods (if not more) that support and improve brain health. To keep your brain healthy, neurologists recommend the MIND Diet. This is a hybrid of the Mediterranean and Dash diets. The science focuses on “neuro-protective” nutrients:

• Leafy greens: High in folate and Vitamin K, which help slow cognitive decline.
• Fatty Fish: These are rich in Omega-3 fatty acids, which are the building blocks of your brain’s cell membranes. Think salmon, mackerel, and sardines.
• Berries: Loaded with flavonoids, which act like “rust-protectors” for your neurons, preventing oxidative damage.
• Walnuts: It’s like Mother Nature shaped them like the brain for a reason. They are high in DHA, a type of Omega-3 that improves cognitive performance.

The Bottom Line

Your brain is the most expensive piece of “real estate” in your body. Protecting it doesn’t mean you can never enjoy a fry or a soda again, but it does mean being mindful of the chemical trade-offs. By choosing whole, anti-inflammatory foods, you aren’t just eating for today; you’re investing in a sharper, clearer version of yourself for decades to come.

Read More: Scientists Find High-Fat Diet Could Help Maintain Brain Health