Some of the foods we consume daily may contain substances that harm the brain and accelerate dementia. Microplastics, heavy metals, and other toxins aren’t just found in seafood — they also lurk in common everyday foods, especially ultra-processed items and certain dietary supplements.
Microplastics accumulate the most in the brain
Microplastics are silently infiltrating our bodies through food, particularly targeting the brain. Dr Ming-Wei Zhao, a certified toxicologist with the American Board of Toxicology, stated: “Once microplastics accumulate excessively in the brain, the risk of dementia increases.”
A study published in February in Nature Medicine revealed that microplastics are present in the kidneys, livers, and brains of humans. The brain tissue of non-dementia patients contained far more microplastics than their liver or kidneys, and even higher levels were found in dementia patients. Other research shows that nano-sized plastics may accelerate the formation of beta-amyloid plaques, which are linked to neurodegenerative diseases like Alzheimer’s.
The human blood-brain barrier typically filters water — and fat-soluble substances. Since microplastics are not water-soluble, they can easily penetrate cell membranes and enter the brain. Recent research found that nanoplastics can breach the blood-brain barrier, causing cellular blockage, triggering brain thrombosis, and leading to abnormal neurological behaviour.
How to safely choose and eat seafood
According to Dr. Zhao, environmental pollution has led to an increase in the contamination of seafood. Coastal fish, shellfish, and crustaceans (such as crabs and shrimp) are especially prone to accumulating microplastics. In addition, larger fish tend to accumulate the most microplastics and heavy metals through the natural food chain as they consume smaller, already contaminated fish. Eating such polluted fish may lead to unintentional ingestion of toxic substances. He offers the following suggestions:
- Choose smaller fish species: Avoid large fish; palm-sized fish are generally a better option.
- Select seafood from clean sources: Avoid seafood from coastal areas or regions with high human activity, as they are more likely to be contaminated. Avoid fish caught near fishing ports, where boats may discharge pollutants into the water.
- Avoid consuming fish organs: Regardless of the seafood’s origin, try not to eat internal organs such as the liver, intestines, or marrow, since microplastics and heavy metals tend to concentrate in these tissues. Even fish bone broth is best avoided.
Microplastics found in supplements
Dr. Zhao also notes that supplements, particularly those in capsule form, are another potential source of microplastics. Many middle-aged and older adults take multiple supplements daily — vitamins A, C, D, calcium tablets, enzymes, probiotics, etc. If all of these come in capsule form, they may also simultaneously ingest many microplastics.
He stated that although the body may metabolize most microplastics, if small amounts continue to accumulate in the brain each day, by the age of 70, the risk of dementia could increase significantly, potentially leading to irreversible conditions.
Regarding how to take supplements more safely, Dr Zhao suggests the following:
- Avoid capsule-form supplements whenever possible: Opt for powdered or original-form supplements to minimize microplastic intake.
- Don’t take too many supplements at once: Taking multiple capsules simultaneously can result in excessive intake of microplastics or plasticizers, which can harm health.
- Select supplements from reputable biotech companies that hold government certification or have pharmaceutical backing. When confirming a product’s safety is difficult, look for official certification marks such as GMP or ISO.
Ultra-processed foods impair cognitive function.
A study published in JAMA Neurology found that consuming excessive amounts of ultra-processed foods accelerates cognitive decline. Dr. Zhao explains that many such foods have been so drastically altered that they no longer resemble their natural and original form, thus leaving people ignorant of what real ingredients they’re made from.
For instance, jam may appear to be made from strawberries or grapes, but it might actually be derived from corn. Similarly, trending plant-based meats may look and taste like real meat, but they aren’t made from animal flesh.
Ultra-processed foods undergo extensive artificial processing and refining, altering their original chemical structure to render them no longer natural or wholesome. This intricate processing may also generate harmful by-products, which can increase the risk of cardiovascular disease, dementia, and premature death.
Dr. Zhao believes that detecting ultra-processed foods by reading nutrition labels is difficult. The origins of many ingredients are so concealed that even the label may not reveal the raw materials or the degree of processing involved. For this reason, he advises avoiding ultra-processed foods and sticking to whole, unprocessed options instead.
A healthy diet and regular exercise aid in detoxifying the body
Can accumulated toxins be eliminated from the body? According to Dr. Zhao, that depends on the type of toxin being dealt with. If water-soluble toxins are accidentally consumed, drinking plenty of water can help flush them out. On the other hand, fat-soluble toxins are quickly absorbed by organs and the brain, making them much more challenging to eliminate.
He recommends eating plenty of fresh fruits and vegetables. A nutritious diet provides antioxidants that help boost immunity and neutralize toxins already in the body. Additionally, regular exercise enhances blood circulation, which supports the kidneys and circulatory system in removing harmful substances more effectively.
Translated by Cecilia and edited by Maria
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