Dont take any sort of vitamin suppliments... use only whole foods. Now I am of the belief that the body should be making this vitamin on its own, but I think that the body of a person with candida/leakygut often cant do itbecause of the environment in the bowels. I also am not sure why, but people in the western world have more instances of b12 deficiencies than 3rd world countries. It could be water treatment, it could be coffee... it could be the amount of food we eat that causes this. I dont know... but if you want b12, eat some easily digestible eggs or meat every now and again. Something like fish... maybe even some chicken, trust your instincts. Unless your a vegan, then there is a yeast you can eat.