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and less than 10 percent of fat have been digested. Very little absorption occurs in the
stomach. In the small intestine, most digestion takes place in the duodenum. Fats do not
usually mix with water, but this process is facilitated by bile once it is released from the
gallbladder into the duodenum. Nutrients absorbed through the intestinal lining pass into
the interior of the villi. Each villus contains blood vessels and a lacteal. Most minerals,
with the exception of potassium, sodium, and chloride, are absorbed in the small intestine.
Undigested material and some liquid move on to the large intestine, where water and
electrolytes are absorbed, leaving waste material to be excreted as feces.
Nutrition and GI Disorders
A diet low in fiber and water and high in fat is the most common cause of constipation. As
people age, the colon develops small pouches that bulge outward through weak spots. This
condition is known as diverticulosis. Eating a diet high in fiber can help prevent this
condition. GERD occurs when the lower esophageal sphincter relaxes inappropriately.
The esophagus has no protective mucous lining, so acid can quickly damage it. Doctors
recommend avoiding foods that can weaken this sphincter, such as peppermint. The cause
of IBS remains a mystery. Some foods that are often offenders are beans and chocolate.
Without treatment, IBS will not progress to a more serious illness. It is likely that a number
of physical and psychosocial factors combine to trigger this disorder. After lung cancer,
colon cancer is the most common form of cancer in the United States. Research to date
shows that diets high in vegetables and regular physical activity are the most significant
factors in reducing risk of this type of cancer. Flatus composition depends largely on
carbohydrate intake and the activity of the colon’s bacterial population. The major cause
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