Hi Tash

- yes mental fogginess can be a symptom of B12 deficiency...
As it Vitamin B12 is an essential water-soluble vitamin (meaning it is quickly flushed out of the body) is commonly found in a variety of foods, such as fish, shellfish, meat, eggs, and dairy products.
Vitamin B12 is frequently used in combination with other B vitamins in a vitamin B complex formulation. Vitamin B12 plays an important role in supplying essential methyl groups for protein and DNA synthesis. Vitamin B12 is bound to the protein in food. Hydrochloric acid in the stomach releases B12 from protein during digestion. Once released, B12 combines with a substance called intrinsic factor (IF) before it is absorbed into the bloodstream.
The human body has the ability to store several years' worth of vitamin B12 in the liver (if the body is being provided with the foods that contain B12), however, deficiency can result from being unable to use vitamin B12.
Muscle weakness, fatigue and lack of energy, tingling in extremities, mental fogginess, memory problems, mood swings, feeling of apathy and lack of motivation may present as symptoms of B12 deficiencies. Often you may not be aware that you have a Vit B12 deficiency as these symptoms may only manifest after a number of years as mentioned it is very much influenced by diet and the bodies ability to absorb the vitamin.