Gastric Bypass Procedure

Before making the decision to undergo a gastric bypass procedure, it may help to understand the role of the stomach and small intestine. When you eat something it enters your esophagus and travels into your stomach. When food leaves the stomach it enters the small intestine, which is composed of three distinct parts.

The first part of the small intestine is the duodenum, followed by the jejunum and the ileum. Each section has a specific role. In the stomach, iron and vitamin B12 are absorbed. The three parts of the small intestine are the powerhouses in terms of calorie and nutrient absorption. In addition, most of the absorption of vitamin D and calcium occurs in the duodenum and first portion of the jejunum.

There are two types of gastric bypass procedure - restrictive and malabsorptive. In a restrictive gastric bypass procedure, the size of the stomach is dramatically reduced. This type of surgery makes a person very full, very fast. Overeating results in a very unpleasant feeling and sometimes vomiting. After a restrictive gastric bypass procedure, weight loss is the result of not being able to consume calories.

In a malabsorptive gastric bypass procedure, a large portion of the small intestine is bypassed making the food you eat pass through only a part of the small intestine. Weight loss following this type of procedure is the result of an inability to absorb calories because food does not come in contact with the bypassed portion of the small intestine. The most popular gastric bypass procedure is called Roux-en-Y and is both restrictive and malabsorptive.

There are four major gastric bypass procedures. These include vertical-band gastroplasty, gastric banding, biliopancreatic diversion with duodenal switch, and the most commonly used Roux-en-Y gastric bypass procedure. These procedures either make the stomach very small through restrictive procedures; bypass much of the small intestine through malabsorptive procedures, or both.

Vertical banded gastroplasty and gastric banding are purely restrictive gastric bypass procedures. In vertical-banded gastroplasty, the stomach is stapled fairly close to where the esophagus meets the stomach. The staples are placed in a vertical fashion and a polypropylene band is placed near the bottom of the staple line.

In the stomach food comes in contact with gastric acid. Iron found in foods such as spinach, raisins, and red meat requires contact with gastric acid to convert it from the ferrous form, which is not readily absorbed, to the ferric form, which is. If iron is not absorbed adequately, anemia can result.