Patients with chronic illnesses, especially those with chronic infections, often suffer from vitamin B 12 deficiency

From Georgia Lyme Disease Association: "Fantastic Discovery: Vitamin B 12 is needed for iron uptake and utilization and it is crucial to the normal functioning of the brain and nervous system. Patients with chronic illnesses, especially those with chronic infections, often suffer from vitamin B 12 deficiency. Now, a "scientific breakthrough by researchers at the University of Kent has revealed how vitamin B12/antipernicious anaemia factor is made – a challenge often referred to as ‘the Mount Everest of biosynthetic problems."

"The team hopes that this newly acquired information can be used to help persuade bacteria to make the vitamin in larger quantities, thereby contributing to its use in medication for people suffering with the blood disorder pernicious anaemia, amongst other things."

http://www.kent.ac.uk/news/stories/VitaminB12/2013