What is Vitamin B12? Vitamin B12 plays a vital role in many biological processes within the human body. It's important in the production of red blood cells & essential for cell replication. It also assists in helping our body convert food to energy. B12 is also acknowledged for its benefits to the nervous system & the immune system. Being deficient in vitamin B12 can cause tiredness & fatigue, muscle weakness, memory & mood problems. Why take a Vitamin B12 supplement? If you feel that you are not getting enough of this very important nutrient then a supplement provides a quick & easy way to boost levels. Vegetarians & vegans may particularly benefit from supplementing with Vitamin B12 as the main food sources are meat, fish, dairy products & eggs. Older people may also benefit more so by supplementing due to the fact that the body's ability to absorb Vitamin B12 declines as we age. Vitamin B12, when combined with Folic Acid, helps process levels of an amino acid called homocys...