Roux-en-Y gastric bypass surgery is the second most common weight loss operation performed in the United States. It is very successful, providing patients with significant postoperative weight loss. Patients can expect to lose about 70-74% of their excess body weight (EBW) because of the operation. Weight loss maintenance over time is quite durable, and patients usually maintain at least 50% of excess body weight loss over many years. Gastric bypass is the most studied weight loss surgical procedure; many experts consider it the “gold standard” against which all other weight loss operations are compared. The surgery is described as a “combination approach” to weight loss: a small gastric pouch restricts the amount of food that can be eaten, and the roux limb small intestinal reconstruction leads to malabsorption of nutrients. This combination results in weight loss from two separate mechanisms which are additive to effect greater weight loss.
There are, however, significant changes in absorption of food and nutrients from this operation. For example, patients must take multiple essential vitamins to avoid devastating complications associated with vitamin deficiencies. In a similar fashion, alcohol absorption is drastically altered because of the anatomic changes of gastric bypass.
After bypass, alcohol moves very quickly from the small stomach pouch into the small intestine. There is minimal-to-no food in the pouch because of the small size of the pouch and patients are trained to separate eating from drinking postoperatively. As a result, alcohol transits rapidly from the pouch to the small intestine and the bloodstream. The afore-described first 20% of absorption does not occur because of this rapid transit; full-strength alcohol hits the small bowel and enters the bloodstream. Consequently, gastric bypass surgery results in a higher peak BAC postoperatively compared to the equivalent amount of alcohol consumed preoperatively.
There is also literature to support that liver function is altered in the morbidly obese and, as a result, the processing of the alcohol by the liver is impaired. Nonalcoholic fatty liver disease (NAFLD) is very common amongst morbid obese individuals and is at the root of this dysfunction. Thus, the elimination of alcohol by morbidly obese people may also be defective compared with normal weight-people with no underlying liver disease.
An article in the 2002 British Journal of Clinical Pharmacology reported that gastric bypass patients have significantly higher rates of alcohol absorption and blood alcohol content than do age- and weight-matched controls. Blood alcohol levels of the bypass patients were 50% higher than their counterparts and required much less time to reach peak levels (10 v. 30 minutes). Other research has shown that with the same amount of alcohol consumption bypass patients attain unlawful blood alcohol content (i.e., concentration) (BAC) of 0.08 when the control group attain BAC of 0.052 – nearly a 40% difference for same amount of alcohol consumed. After one drink, gastric bypass patients reached the legal drinking limit; this is significantly faster than a person with normal intestinal anatomy with a smaller amount of alcohol consumed.
An elegant article by Woodard in the Journal of the American College of Surgeons in 2010 looked at BAC in the same patients before and after gastric bypass surgery; the patients were compared to themselves and acted as their own control group. The article reported that the patients’ peak BAC after drinking 5 oz of red wine was significantly different between preoperative and postoperative states: BAC was 0.024 preop, 0.059 at 3 months postop, and 0.088 at 6 months. Additionally, time-to-sober was 49 minutes preop v. 61 minutes 3 months postop, and 88 minutes 6 month postop. Gender, age, and weight loss did not alter the findings.