Vitamin B12 is probably the best known among the B complex vitamins because many people take B12 injections as a treatment for severe pernicious anemia. People who exhibit signs of weakness may be diagnosed with a B12 deficiency and a simple regimen of introducing Vitamin B12 in some other form may greatly help reduce the symptoms. If a true deficiency exists, the person may also have constipation and no appetite, often resulting in weight loss. In more extreme cases, tingling and confusion may be a manifestation of low B12 levels. Vitamin B12 deficiencies tend to be more common in older adults. The chronic weakness and tendency to sleep more hours than normal, though sometimes considered a normal sign of aging, may actually be attributed to a lack of sufficient B12 being absorbed and utilized by the body. One important point to remember about B12 is that you may be getting enough of this important vitamin in your daily diet, but your body may not absorb it properly. The release of Vitamin B12 is part of the function of stomach acids. Health issues that include gastric problems may mean the B12 is not being released as it should be. The result of this situation is that you still have a B12 deficiency, even though you’re eating all the right foods. There are a few foods that are simply rich in Vitamin B12, though those foods are likely not on the daily menu of most people. Mollusks, for example, provide more than 1,000 percent the daily recommended intake of this vitamin. Though many people don’t like liver, a single slice of beef liver will give you more than 700 percent of your body’s daily need for B12. Salmon, trout and tuna are also good sources of B12. This is one of the most important vitamins for infants, and babies with a B12 deficiency may simply fail to develop normally. There is some question about the amount of B12 an infant needs on a daily basis. If you are concerned, talk to you pediatrician. Many of the foods high in B12 content are meats, therefore are avoided by vegetarians. If you are a vegetarian (and especially if you are pregnant or nursing a baby), you should talk to your doctor about adding a B12 supplement to your daily routine. Since babies in the womb and nursing infants get only those vitamins their mothers have to offer, B12 could be an issue for babies if the mom is a strict vegetarian.