Can tin from canned food during pregnancy cause birth defects?

What's actually in it

Tin is the metal that lines most food cans. While modern cans often have a plastic coating inside, tin still migrates into food, especially acidic foods like canned tomatoes, citrus juices, and pickled vegetables. The longer food sits in the can, and the more acidic it is, the more tin leaches out.

You won't taste it or see it. Tin dissolves into the liquid at levels that are hard to detect without lab equipment. Most people don't think twice about it because canned food is so common. But pregnant women eating canned tomato sauce, canned soups, or canned fruit several times a week are getting a steady dose.

What the research says

A 2026 study in Environmental Toxicology found that excessive tin exposure during pregnancy may cause neural tube defects (NTDs) in developing babies. NTDs are serious birth defects of the brain and spine, including spina bifida and anencephaly.

The researchers moved beyond just showing an association. They dug into the mechanism and found that tin interferes with the biological pathways the embryo needs to properly close the neural tube. This happens very early in pregnancy, often before a woman even knows she's pregnant.

Neural tube closure happens in the first 28 days after conception. That's why the timing of exposure matters so much. A woman eating a lot of canned food in early pregnancy could be exposing her embryo during the most vulnerable window.

Tin isn't as well-studied as lead or mercury, so it flies under the radar. But this research suggests it deserves more attention, especially for women who are pregnant or trying to conceive.

The fix is simple: choose foods in glass jars, cartons, or frozen packaging instead of metal cans. If you do use canned food, avoid storing leftovers in the open can. Transfer them to a glass container right away.