Seafood
Raw freshwater fish and shellfish contain chemicals that destroy thiamine. Eating a lot of raw fish or shellfish can contribute to thiamine deficiency. But cooked fish and seafood are OK. They don't have any affect on thiamine, because cooking destroys the chemicals that harm thiamine. And it can also give high doses of vitamin B6, which over time can be toxic, and may result in nerve damage or numbness and tingling in the extremities that may eventually be irreversible. Too much B6 can also cause oversensitivity to sunlight, which can lead to skin rashes and numbness, as well as nausea, vomiting, abdominal pain, loss of appetite, and increased liver function test results.
