Fish intake and mercury levels in young children's toenails
What it found
Three-year-old children who ate any fish had more than double the mercury in their toenails compared to those who ate none.
This was found in 700 children in the United States.
What they found
Studies in people
Any fish and mercury
Children who ate any fish had 108% higher mercury in their toenails than children who ate no fish. This means their levels were about twice as high.
Type of fish matters
Eating non-fried fish, including tuna, was linked to 120% higher toenail mercury. Eating fried fish or fish sticks was linked to a smaller rise of 23%.
How often children ate fish
About 70% of the children had eaten at least one fish meal in the past six months. Only 22.3% ate fish once a week or more on average.
Other elements measured
Children who ate fish had slightly lower copper and tin in their toenails. Those eating non-fried fish had somewhat higher aluminum. Mercury was by far the element most strongly tied to eating fish.
What the authors conclude
- They say that mercury levels in young children rose with fish consumption, even when children ate very little fish.
- The authors note the link was strongest for non-fried fish, including tuna.
- They call for more research to weigh the benefits of fish nutrients against mercury exposure in early childhood.
How it was done
Mercury from fish may affect children's developing brains, but few studies have looked at this in places where children do not eat much fish. Fish also provides nutrients needed for growth, so understanding both sides matters.
Researchers followed 700 three-year-old children in New Hampshire. Caregivers reported how often each child ate fish over the previous six months. The team then measured mercury and other elements in the children's toenail clippings.
What it can’t tell you
- This study measured what happened at one point in time, so it cannot prove that eating fish caused the higher mercury levels.
- Toenail mercury shows what built up in the body, but it does not show whether that amount affected the children's health or development.
- The food questionnaire grouped fish into broad types, so it cannot tell which specific fish species led to the highest mercury.
Who paid
- Funding
- Funded by NIH HHS; NIEHS NIH HHS; NCI NIH HHS; NIGMS NIH HHS (from the PubMed record).
- Conflicts
- Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Margaret R. Karagas reports financial support was provided by National Institutes of Health. Julia A. Bauer reports financial support was provided by National Institutes of Health. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
- Authors work at
- Geisel School of Medicine, USA; University of Illinois Chicago, USA; Trace Element Analysis Laboratory, USA
The paper
- Title
- Fish intake and mercury exposure in young children
- Type
- Study
- Evidence
- Studies in people
- Summarised from
- Full text
- Cite
- Notario Barandiaran L, Bauer JA, Jackson BP, Karagas MR (2024). Fish intake and mercury exposure in young children. Environmental research. doi:10.1016/j.envres.2024.119277Free full textPubMed 38821458DOI
Summary written 1 Oct 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error