Bacterial Overgrowth
Another cause of vitamin B12 deficiency is the overgrowth of normal bacteria in your colon, which eventually takes up your gut and causes some digestive issues, such as nausea, weight loss, reflux, constipation, diarrhea, bloating, and gas. As a result, your body cannot absorb vitamin B12 as usual and lead to deficiency. Some of these bacteria would even use up this substance for their own purposes. Fortunately, this condition would be resolved easily with the help of your doctor. [9]
