Most of the microplastic in our diet is not from seafood

Ask most people where dietary microplastics come from and they will say fish and shellfish. That is where most of the research has been done, which is not the same thing. A review in the Journal of Hazardous Materials by Maria Hayder, Maud Laan, and Annemarie van Wezel of the University of Amsterdam pooled every study it could find and asked which foods actually dominate intake.

What they did

The authors collected 193 papers that reported microplastic particle counts in food and 12 that reported plastic mass, covering 13 categories: grains, vegetables, fruit, meat, shellfish, tap and bottled water, beer, milk, salt, sugar, honey, and others. They combined the concentrations with how much of each food people typically eat to estimate daily intake, and they compared results across the analytical methods the studies used.

What they found

• Vegetables, grains, and meat are important dietary sources, and in the intake estimate they outweigh seafood, mostly because people eat far more of them.
• Shellfish still carry high concentrations per serving. Microplastics appeared in nearly every category, including salt, sugar, honey, and beer.
• Bottled water had somewhat higher concentrations than tap water, but tap water contributed more overall because of volume.
• The polymers found roughly track global production: polyethylene, PET, and polypropylene are most common.
• The choice of analytical protocol changed the results, and not in a predictable direction. The effect was strongest for fruit and vegetables and for tap and bottled water.

What it cannot show

The intake estimates span many orders of magnitude between studies, which is a warning about the data rather than a description of real diets. Studies differ in the smallest particle they can see, in how they guard against lab contamination, and in how they confirm that a particle is plastic. A ranking of foods built from such studies is a ranking of what has been measured with current tools. It says nothing about health effects, which the review does not address.

Why it matters here

This is one reason the consumption calculator on this site refuses to blend studies together and instead shows the single published coefficient behind each food category. It is also a reminder that soil is a long-term sink: plastic mulch, sewage sludge used as fertilizer, and contaminated irrigation water put particles where plants grow.

Read the review (open access) · Hayder, Laan & van Wezel, Journal of Hazardous Materials, 2026