Our body does not make B12, so we rely on food groups for this essential vitamin. Vegan and Vegetarians may find that food groups high in B12 are excluded from their diet.
B12 contributes to the production of Red blood cells, which in turn increase the oxygen supply to your vital organs, if these do not get sufficient oxygen supply, you may experience fatigue and tiredness.
B12 is thought to aid with the digestion and absorption of macronutrients.

Fats, proteins and carbohydrates are all metabolised by B12 into energy. Without the right amount of B12 in your diet, vital nutrients will not pass through your body and not absorb into the blood. B12 contributes to the normal functioning of the nervous system, so may aid with the reduction in the effects of stress and anxiety on the body. Vitamin B-12 is crucial to the normal function of the brain and the nervous system. B12 is also involved in the formation of red blood cells and helps to create and regulate DNA.