Nutrition Science and Everyday Application - beta v 0.1

PROTEIN IN FOODS AND DIETARY RECOMMENDATIONS 333
person excretes less nitrogen than what is taken in by the diet, such as during
pregnancy or growth in childhood. At these times the body requires more protein
to build new tissues, so more of what gets consumed gets used up and less
nitrogen is excreted. A person healing from a severe wound may also be in positive
nitrogen balance because protein is being used up to repair tissues.
Figure 6.16. People are in positive nitrogen balance when they excrete less nitrogen than they
consume, because they are using protein to actively build new tissue.
DIETARY SOURCES OF PROTEIN
Although meat is the typical food that comes to mind when thinking of protein, many other
foods are rich in protein as well, including dairy products, eggs, beans, whole grains, and
nuts. Table 6.3 lists the grams of protein in a standard serving for a variety of animal and
plant foods.