Vitamin B1 Interactions

Some early studies suggested coffee contains compounds with antithiamine activity, but follow-up work showed chlorogenic and caffeic acids are not active antithiamine agents under physiological conditions. Heavy coffee or tea intake on a marginal thiamine diet can still modestly worsen thiamine status.

Magnesium is the required cofactor that converts thiamine (vitamin B1) into its active coenzyme form, thiamine pyrophosphate (TPP). Without adequate magnesium, thiamine cannot activate properly, so supplementing thiamine in a magnesium-deficient person produces little benefit until magnesium is restored.