"Heavy users of cinnamon should limit their intake," the agency said in a press release on Friday.
"The tolerable daily intake (TDI) of cinnamon is estimated at 1.4 ounces. This may have consequences for Bergen's 'skillingsboller' or Danish cinnamon rolls."
According to the FSA, cinnamon contains coumarin, an aromatic substance which can damage the liver if consumed in large quantities.
Children, with their taste for cinnamon buns, are particularly vulnerable, the FSA said.
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"It makes sense to be a little bit more careful about the cinnamon intake of young children," said Atle Wold, the head of the FSA's consumer section.
"They like to eat more porridge than others, and since their bodies are small, they also tolerate less than adults."