Comparison of Gastric Banding and Gastric Bypass Surgeries

	Gastric Banding	Gastric Bypass
Graphical Representation
Anatomy	A band made of adjustable silicon, has been inserted around the stomach as to form a small stomach pouch of approximately 15-20 ml.	The stomach is divided into two parts as to form a pouch of approximately 20-30 ml and this small stomach is connected to the intestine.
Weight Loss Mechanism	Food intake decreases due to restruction of the stomach volume and it can be well decreased by adjusting of the staple.	Food intake decreases due to restruction of the stomach volume and also digestion of the foods decreases because of the foods have taken directly pass down from small stomach to the intestine.
Weiht Loss Rates	50-60% of the excess weight is lost at 18-24 months period.	70-80% of the excess weight is lost at 18-24 months period.
Diet and Required Life Style Changes	High calorie diet (chocolate, icecream, desert etc) should be avoided. Regular exercises should be done in the forward periods.	High protein foods must be taken in the beginning, sugar foods should be avoided (dumping syndrome) and regular additional vitamins must be taken against to lack of vitamin and minerals. Regular exercises should be done in the forward periods.
Nutritional and Vitamin Requirements	Multivitamin, Calcium (rarely)	Multivitamin, Calcium, Vitamin B12, Iron
Surgery risks	Surgery risk rate of early and late period %0-8	Surgery risk rate of early and late period %0.2-10
Eating Adaptation	May be difficult, frequently nausea and vomittings may be experienced	There is usually more qualitied and easier eating adaptation.
Technical Difficulties	No	Yes (a difficult application, more training and surgery practises are required)
Prosthetics (Foreign) Material	Yes (there is silicon material but it’s adaptation is quite good, the reservoir sometimes may create problems)	No
Reversing of the surgery	Yes	Yes (but quite difficult)

Weight Loss Mechanism Following Gastric Bypass Surgery

It is a known fact that the patients fill more quickly and eat less after Gastric Bypass (GP) surgery due to decreasing of stomach volume. Two mechanism most mentioned as the cause of GP beeing successful are :

1. Malabsorbtion (decreasing of food absorption)

2. Dumping Syndrome

Malabsoption that clinically have importance and characterized with increased fat quantity at the feces, is not seen after the standart GB. Dumping syndrome (nausea, bulge, colic pain, diarrhea, dizziness, perspiration and flutter) is typically seen at some patients after high carbohydrate foods. Due to these effects this syndrome, creates a negative approach against the fattening foods like sugar at patients.

Impairing of the Ghrelin secretion that has developed after GB is indicated to be effective at the anorexia development. Ghrelin is an enteric peptide and it is the only known and participated to the circulatory appetizer. Endogenous levels increase before the meal and decrease after the meal. Ghlerin, is generally producted from the stomach and a small part from the duodenum. Both of these areas are bypassed after GB. Since the eaten food is main Ghrelin secretion trigger and this food is unable to contact the stomach and duodenum, this strengthens the accuracy about the hypothesis of this surgery impairs the Ghrelin secretion. In a study which Ghrelin levels have been investigated; 77% decreasing at the values of patients those have underwent GB 1.5 years ago compared with the thin patients and 72% less Ghrelin secretion compared with the obese control group have been seen.

Anti-Diabetic Effects of Gastric Bypass

Comorbidity related with obesity which has most dramatically showed recovery by GB is Type 2 Diabetes Mellitus (DM). 82-98 % diseases of patients with diabetes have been indicated to showed completely recovery. In a lasting approximately 5 years prospective study of the obese patients with impaired glucose tolerance, obesity surgeries have been shown to decreased the progress rate of diabetes more than 30 times. Thus, it has been seen that GB is largely effective on reversing the diabetes which has conventionally accepted as a progressive and deadly disease.

At the patients those have significantly lost weight after GB operation increasing of Adiponectin levels and muscle insulin receptor concentration and in addition decreasing of lipids and fatty acyl-coenzyme A molecules (cause to insulin resistance) have been shown. After weight loss induced by GB, insulin sensitivity measured with minimal modelling has been increased about 4-5 times. Decreasing of diabetes can be commented to weight loss which it’s impact on insulin sensitivity increasing is well known, thus glucose toxicity and lipotoxicity are decreased and cell function is improved.

After GB has adjusted the insulin secretion effect, positive changes occure at intestine hormones. Ghrelin is a hormone which has decreasing probability after the surgery, altough Ghlerin stimulation creates create induced hyperglycemia at humans, it supresses the insulin levels. Glucagon Like Peptide-1 (GLP-1) hormone and Glucose-Dependent Insulinotropic Polypeptide (GIP) are classical incretins which have stimulated the insulin secretion againts the enteral foods. After GB, the foods have gone down to stomach, more easily reach to the last intestine by skipping a part of upper bowel. Greater postprandial bolus of the foods after GB, raises the GLP-1 levels. Peptide YY (PYY) has been shown to decrease eating and body weight at humans. Since this is also a last intestine hormone, it’s levels increases after GB, particularly after the meal has been eaten and this is considered to help to the weight loss.

In brief; the mechanisms those can explain the weight loss and improved glucose tolerance after GB are :

1. Stomach volume decreasing that causes to early fillness, small meal porsions and negative conditioning

2. Impairing of the Ghrelin secretion due to mechanisms those can not be exactly defined and bypassing of the upper bowel that creates light malabsorption

3. Increasing of the PYY and GLP-1 and acceleration of the foods to reach to the lower bowel

4. Dumping syndrome formation due to intake of concentrated carbohydrates can contribute to the weight loss at some people.

Assoc. Prof. Halil Coskun M.D. www.halilcoskun.com

Gastric Bypass Surgery

This procedure is the most used method in the world for obesity treatment. First, stomach volume is reduced, therefore the food quantity have taken by the patient is decreased. Secondly, food absorption is decreased due to shortening of the covered way in intestine.

This operation should be more preferred particularly at the patients with sweet eating (nutrition with high calorie diet) habit. Because this group of patients are nourished with small quantities but high calorie foods. Achieving enough weight loss may be problem at the surgical operations those only have restricted the food intake. Beside the stomach volume has been decreased, gastric banding operation also provides discharge of the foods without being useful for the body by affecting the absortion of the foods have been eaten.
The patients loss 70-80% of their excess weights within average 1-2 years after the operation. This result is a close to excellent outcome. On the other side, easier adaptation period for new nutrition habit has been experienced after operation.

The most important problem for this operation is that some vitamin deficiencies may occur in the upcoming days due to malabsorption of the taken foods (like vit12, folic acid, iron deficiency). But it is not encountered with a problem for this condition by the vitamins suppliments from out. Experienced surgeons inform their patients on this issue and take the necessary precautions.
Gastric bypass is the most implemented procedur in the world, particularly in the USA. Because, the weight loss and the achieved success with this procedure is higher than the other methods. But reverse of this surgery is quite difficult. It is necessary to the patients will choice this surgery to know that this is a permenant operation.

In conclusion, Gastric Bypass Surgery is an operation that has very successful outcomes for long period. Also it should be more preferred at the patients those have been fed with high calorie foods compared to other methods.

Assoc. Prof. Halil Coskun M.D.