B vitamins play crucial roles in converting food to energy, supporting nervous system function, and maintaining healthy red blood cells
Science 336 , 12681273 (2012)
This is a theoretical concern raised by the biology, not a demonstrated harm in humans for either compound, and it should be described as exactly that an unresolved question that the absence of long-term human data leaves open, not a proven risk and not a reason for false reassurance either
Conversely, some studies show that a deficiency in vitamin B12 may cause appetite loss, potentially leading to weight loss if left untreated ( If youre low or deficient in B12, your healthcare provider will likely recommend oral vitamin B12 supplements or injections to increase your blood levels ( summary Low levels of vitamin B12 can cause megaloblastic anemia, which is characterized by shortness of breath, headaches, and fatigue