Chinese eat a lot animal meat, organs and seafood should not lack of B12 . They may need B6 to absorb B12 from those food instead. Be careful with vitamins. Even water soluble vitamin may hurt you if taken too much. If you were eating animal meat, organs and seafood frequently but still have sign of lacking B12 you could try to eat more potato as potato is typical B6 rich food. Body cannot absorb enough B12 without enough quantity of B6.
