Among the potential disadvantages of vegetarianism are that a no flesh food product diet often makes it more difficult to balance our intake all of the necessary nutrients, particularly protein, vitamin B12, iron, and zinc. Calcium deficiency, in general a big concern, seems not to be as common in vegetarians as had been thought. Adequate protein can easily be obtained, as discussed later in this section. Vitamin B12, or cobalamin, is consistently a problem for vegetarians, especially for the pure vegetarian, or vegan, who eats no animal foods at all—not even milk products or eggs. Vitamin B12 is most plentiful in red meats, and some is found in other animal foods, but most plant proteins are fairly low in this "red" vitamin. Brewer’s yeast, tempeh (fermented soybeans), and some sprouts have small amounts of B12. Vitamin B12 deficiency leads to poor metabolism of protein, fats, and carbohydrate; problems in building the coverings of nerves; and a low red blood cell count, called pernicious anemia. Fortunately, though, B12 is stored in the tissues at levels high enough to last for several years of low intake. I believe that a vegetarian’s body, or the body of anyone who has a particularly low intake of a nutrient, will naturally develop better absorption of that nutrient. Very few long-term vegetarians whom I have evaluated have had low blood levels of vitamin B12. Extra B12 as a supplement (the sublingual tablets are currently the best source of oral B12) will usually prevent any deficiency unless there are problems with the stomach making "intrinsic factor" or with the liver’s ability to store this vitamin (see the discussion of Vitamin B12 in Chapter 5).

A vegetarian diet can also be an important part of a good therapeutic plan for many problems. It is more cleansing or detoxifying than the usual higher-fat and higher-protein diets, because it usually contains a greater percentage of dietary fiber and the watery fruits and vegetables. In terms of the body’s nutritional cycles of cleansing, building, and balancing, the vegetarian regime is very effective in cleansing, beneficial in balancing if it is well-planned and implemented, and generally less effective in its building powers. (For that reason, I do not recommend a vegan diet for children or teenagers or during pregnancy or lactation, where I feel more building and strengthening are needed. The lacto-ovo type of vegetarianism, though, should work fine.) It might be wise for all of us to eat a vegetarian diet every so often, such as a day or two a week, one week a month, or even more often during spring and summer. Variations of the vegetarian diet can be used for detoxification as discussed later in Chapter 18. A fast or cleansing diet may be a useful remedy for many types of congestive problems. With sickness, though, I usually suggest more complex carbohydrates in the diet, with higher intake of water and water-containing foods; this helps avoid dehydration and usually improves vitality.

Some choose vegetarianism for spiritual reasons, feeling that it elevates us to our higher vibrational levels and enhances sensitivity. Meats and animal foods pull us down into our earthly realms of sexual instincts, aggression, and desire for power. Often, someone eating a completely vegetarian diet will want to move away from the busy, active life of most cities where the hustle and bustle requires a more aggressive energy. When I lived for years in the country as a vegetarian, we used to describe going into San Francisco on business as a "meat loaf" day.