1. PINEAPPLE
Calcium (Ca) Contributes to hardness of bones and teeth; ionized form (Ca2_) needed for blood clotting,
release of some hormones, contraction of muscle, and many other processes
Phosphorus (P) Component of nucleic acids and ATP; required for normal bone and tooth
Magnesium (Mg) Ionized form (Mg2_) needed for action of many enzymes, molecules that increase the
rate of chemical reactions in organisms.
Iron (Fe) Ionized forms (Fe2_ and Fe3_) are part of hemoglobin (oxygen-carrying protein in red blood
cells) and some enzymes (proteins that catalyze chemical reactions in living cells)
In humans and animals, carbohydrates function mainly as a source of chemical energy for generating ATP
needed to drive metabolic reactions.
Dietary fiber consists of indigestible plant carbohydrates—such as cellulose, lignin, and pectin—found in
fruits, vegetables, grains, and beans. Insoluble fiber, which does not dissolve in water, includes the woody
or structural parts of plants such as the skins of fruits and vegetables and the bran coating around wheat
and corn kernels. Insoluble fiber passes through the GI tract largely unchanged but speeds up the passage
of material through the tract. Soluble fiber, which does dissolve in water, forms a gel that slows the
passage of material through the tract. It is found in abundance in beans, oats, barley, broccoli, prunes,
apples, and citrus fruits.
People who choose a fiber-rich diet may reduce their risk of developing obesity, diabetes, atherosclerosis,
gallstones, hemorrhoids, diverticulitis, appendicitis, and colorectal cancer. Soluble fiber also may help
lower blood cholesterol. The liver normally converts cholesterol to bile salts, which are released into the
small intestine to help fat digestion. Having accomplished their task, the bile salts are reabsorbed by the
small intestine and recycled back to the liver. Since soluble fiber binds to bile salts to prevent their
reabsorption, the liver makes more bile salts to replace those lost in feces. Thus, the liver uses more
cholesterol to make more bile salts and blood cholesterol level is lowered.
Proteins are large molecules that contain carbon, hydrogen, oxygen, and nitrogen. Some proteins also
contain sulfur. A normal, lean adult body is 12–18% protein. Much more complex in structure than
carbohydrates or lipids, proteins have many roles in the body and are largely responsible for the structure
of body tissues. Enzymes are proteins that speed up most biochemical reactions. Other proteins work as
―motors‖ to drive muscle contraction. Antibodies are proteins that defend against invading microbes.
Some hormones that regulate homeostasis also are proteins. Table 2.8 describes several important
functions of proteins.