There are a lot of vegetarians among us, some by circumstance and some by choice. Those who are vegetarians by choice can be divided into two general groups -- those who do not eat meat, poultry or fish, but do consume dairy products as - in theory - the animals are not harmed or killed by the gathering of those products. Vegans, however, use no animal products whatsoever. There are many health benefits to a planned vegetarian diet, as opposed to the unplanned vegetarian diets that result from poverty and a lack of food availability. However, there are also some special precautions that need to be taken to safeguard nutrition, as adequate amounts of some of the most important nutrients can be more difficult to obtain. This is especially true for those following the more restrictive vegan diet.

The body is a complex and delicate system, and the foundation of all of its functioning is chemical and electrical actions, interactions and reactions. The operation of this system rests firmly upon the balance of these chemicals. The majority of the chemicals in these essential physical processes come from the food that we eat, from the nutrients that come from its consumption. Thus, nutrition has a deep influence on the health of the body and the quality of its functioning.

Because the brain, like the body, functions on chemical reactions and electrical impulses, the processes of cognition, emotion and so on, are also affected by nutrition. In fact, deficiencies in certain vitamins and minerals can result in mental illness and retardation, as well as cognitive dysfunction and difficulties and emotional instability.