Fatigue
Fatigue and weakness would also happen in people with vitamin B12 deficiency. They happen as your body does not have sufficient vitamin B12 to produce red blood cells, which help transport nutrients and oxygen to other parts of the body. Thus, you cannot transport oxygen efficiently to other cells, making you feel weak and tired. This condition is often caused by pernicious anemia in older adults. These patients do not produce enough intrinsic factor, which is important in the absorption of vitamin B12. [4]
