Vitamin B12 is found naturally in animal foods such as meat, poultry, fish, eggs and dairy products. It is not present in plant foods with the exception of some algae. Because of this, vegetarians who do not eat any animal products are at risk of developing a vitamin B12 deficiency unless they supplement their diet or consume fortified foods. Vitamin B12 is essential for the proper function of the brain and nervous system as well as the formation of red blood cells. Symptoms of vitamin B12 deficiency include fatigue, weakness, constipation, loss of appetite and weight loss. In severe cases it can lead to anemia and neurological problems such as memory loss and depression.
The best way to get enough vitamin B12 on a vegetarian diet is to take a supplement or eat fortified foods such as breakfast cereals or soy milk that have been enriched with this nutrient. Some types of cheese are also good sources of vitamin B12 but check labels carefully because not all brands are equally high in this nutrient. If you choose to take a supplement be sure to select one that provides at least 10 micrograms (mcg) per day since this is the minimum amount needed to prevent deficiency symptoms from developing over time (1).