Bariatric Surgeries and their Effect on Alcohol Metabolism
Inflated BAC/BrAC levels - NOT inflated BAC/BrAC readings
Counterpoint Volume 5: Issue 2 - Article 4 (April 2021)
An article for participants in the myCAMprogram
Jan Semenoff, BA, EMA
Forensic Criminalist
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2500 words (approximately 12-15 minutes); Video - 19 minutes.
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Important Note:
This information is intended for participants in Family Monitoring Programs where a small, legally allowable alcohol concentration is permitted. If you are under a zero-tolerance program, any alcohol use is a violation — regardless of your medical condition. ALWAYS follow your specific program rules.
This information is intended for participants in Family Monitoring Programs where a small, legally allowable alcohol concentration is permitted. If you are under a zero-tolerance program, any alcohol use is a violation — regardless of your medical condition. ALWAYS follow your specific program rules.
More than 250,000 bariatric surgeries were performed in the US alone in 2019. (Updated more than 270,000 in 2023). What effects do the various forms of gastric bypass surgeries have on the bariatric patient? Are there long-term implications with regards to alcohol consumption, and assessment of DUI occurrences? The studies would strongly indicate that bariatric surgery patients present with an abnormal medical condition that may inflate their BAC levels, sometimes four times what could be reasonably expected, given an insignificant and seemingly responsible consumption of alcohol. It appears that actual BAC levels are increased, not falsely inflated, as the result of the surgeries. Let’s examine the issue in greater depth in the article and accompanying video presentation.
Video
Video duration 18:57
Types of bariatric surgeries
There are currently three primary gastrointestinal weight loss (or bariatric) surgeries. They are Gastric Bypass, Gastric Banding, and Sleeve Gastrectomy. Each type of surgery has pros and cons, with none more ideal than the others.
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Gastric Bypass (also known as: Roux-en-Y Gastric Bypass) was the most common, having been performed for more than 20 years. The procedure involves bypassing the stomach so that food passes directly into the small intestine. It limits the portion size of food consumed before the person feels “full”, and also limits the absorption of food that would otherwise occur naturally in the stomach.
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Gastric Banding (also known as: Adjustable Gastric Banding, or Lap Band Surgery) has been available for about 10 years. It involves placing an adjustable silicone band around part of the stomach which is used to control the size of the stomach. It is the only one of the three procedures which is adjustable. By a simple office visit, the tightness of the band around the stomach can be adjusted.
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Sleeve Gastrectomy is the newest of the three procedures and is now the most frequently performed of the bariatric surgeries. It is a procedure where about 65 - 85% of the stomach is surgically removed, with the remainder of the stomach stapled together to form a narrow sleeve. This creates a condition where the patient is therefore limited in their food consumption.
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Regardless of the surgical procedure used, the net effect is to bypass or negate the initial processing of the food (and any alcohol) found in the stomach. It may be helpful to compare the procedures, taken from a retrospective study of more than 65,000 patients over a ten-year period:
Estimate of bariatric surgery numbers in the US, 2011-2019
The surgeries are very common, with more than 1.6+ million procedures performed in the last decade alone:
Issues with alcohol absorption
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Under ordinary circumstances, when alcohol enters the stomach, some of it is metabolized by the Alcohol Dehydrogenase Enzyme (ADH) found in the stomach in a process often referred to as First-Pass Metabolism. The length of time the alcohol stays in the stomach also helps regulate the BAC levels by controlling the rate of absorption. Although a small amount of the ethanol is absorbed in the stomach, the majority of absorption occurs once the alcohol moves into the small intestine.
Alcohol absorption is primarily regulated by the rate that the ethanol is delivered to the small intestine. The longer the ethanol stays in the stomach, the lower the overall BAC level, and the longer time it takes for Peak BAC to occur. However, after bariatric surgeries, up to 85% of the stomach is bypassed, negating the First Pass Metabolism of the stomach ADH and therefore substantially increasing the absorption rate and Peak BAC levels. Since the First Pass Metabolism is negligible, higher amounts of ethanol are then dumped directly into the small intestine where it is rapidly absorbed. The person’s BAC level will rise beyond what they’ve come to expect compared to their pre-surgery events.
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Bariatric surgery & alcohol BAC related studies: The findings
Klockhoff, Naslund, & Jones, 2002
In a 2002 study, Klockhoff, Naslund, and Jones found that bariatric surgical patients had a significantly faster rate of alcohol absorption and higher Peak BAC compared to comparable persons in the non-surgical control group. The BAC levels of the gastric bypass patients were about 50% higher, and the time to Peak BAC was rapid - about ten minutes compared to 30 minutes for the non-surgical control group. They conclude that after bariatric surgery, even relatively small amounts of alcohol produced unexpectedly high BAC levels shortly after the end of consumption of alcohol.
The animated graph shows the blood alcohol profiles of the control group (in blue) with their high and low readings, and the median values indicated as a thick line. The graph in pink shows the BAC profiles of the participants who had experienced Gastric Bypass surgery, again with a range of readings indicated, plus the median value as a thick line. Finally, the two sets of median values (Blue control versus pink bariatric patients) are compared. The BAC peaks faster, and rises much higher, in the bariatric patient group. Note that when the control group had an average BAC level of about 0.02 g/dL, the bariatric patients exceeded 0.07 g/dL of blood. That is a significant difference.
Hagedorn, et al, 2007
In 2007, researchers from the Stanford School of Medicine compared a group of gastric bypass patients with a similar control group. After dosing the participants with a single 5-ounce glass of red wine they determined that the gastric bypass patients had a Peak BrAC of 0.08 grams compared to the control groups mean BrAC reading of 0.05 grams/210L. Further the gastric bypass patients needed on average, 108 minutes to reach a BrAC of zero, while the control group eliminated all their alcohol after only 72 minutes. More importantly, the gastric bypass patients did not experience more signs and symptoms of the effects of alcohol than did the control group.
Woodard, et al, 2011
In 2011, Stanford School of Medicine researchers matched pre- and post-operative gastric bypass patients. Three months before their surgery, and six months after, the same patients were given a single 5-ounce glass of red wine during each testing session. The Peak BAC was considerably higher in the post-operative patient group. Before surgery, the dose created an average BrAC reading of 0.024 grams/210L; Six months after surgery, the same glass of wine produced an average BrAC reading of 0.088 grams/210L.
Again, remember that they've received a single 5-ounce glass of wine. Before their operations, the Peak BAC was 0.03 grams/100mL blood. Three months after their bypass surgeries, that same glass of red wine produced a Peak BAC response of 0.06 g/dL; At six months - a single glass of wine given to the same group of people produced an average peak response of 0.088 g/dL. That is a three-fold increase in BAC levels from an equivalent dose, six months after surgery. Again, a significant difference.
Steffen, et al, 2013
In 2013, researchers in North Dakota found that within minutes of consuming a modest amount of alcohol, female bariatric surgery patients achieved disproportionately high BAC levels. In the five patients studied, all reached Peak BAC levels above 0.08 grams/210L within five minutes of consuming an amount of alcohol that should not have, under normal circumstances, generated readings of that magnitude. Since they only consumed 2-3 Standard Drinks each, their target BAC should be between 0.040 -0.070 g/dL. In fact, their measured blood draws showed their Peak BAC range was 0.098 – 0.170 g/dL (mean 0.138 +/- 0.028 g/dL).
This study doesn't compare a control group, or non-surgical patients, to those who have had bariatric surgery. It simply looks at the effect of a reasonable (responsible) dose of alcohol on the BAC response. The participants, all female bariatric patients, were dosed with 2-3 Standard Drinks, depending on their weight. None of the participants should have had a BAC that exceeded the legal limit. The red "target crosshairs" in the graph above estimates where the Peak BAC levels should have fallen. They should all have measured well below that - in the range of 0.04 - 0.07 g/dL. ALL measured above the legal limit, some significantly so at 0.098 - 0.170 g/dL. This is not a significant difference - it is an alarming one.
Pepino, et al, 2015
In 2015, Washington University School of Medicine researchers studied women who had received gastric bypass surgeries and compared their alcohol response to a control group of women awaiting their gastric bypass surgeries. Then, they compared the BAC response in the same women awaiting their bariatric surgeries to their response after they had undergone their procedures. They found that the time for the bariatric surgery patients to reach their Peak BAC level was more than twice as fast, and the Peak BAC level was twice as high, than the control group reached before their surgeries.
This data set is interesting. Note that the Pre-surgery group and the non-surgery control group have BAC profiles that are identical (shown in the animated graph as the black and blue lines, respectively). Now compare that alcohol response to the women who received their bariatric procedures (in pink and red in the graph). The difference in Peak BAC and time to Peak BAC is remarkable. An alcohol dosage that elicits an average 0.06 g/dL response in 35 minutes instead produces a 0.120 g/dL BAC reading, in 15 minutes. The surgery, they say, converted two drinks to four, in half the time. Again, twice the response in half the time is substantial.
Acevedo, et al, 2018
In a 2018 follow-up study, the same researchers from the Washington University School of Medicine found that Sleeve Gastrectomy patients reached two-fold higher BAC levels and significantly faster times to Peak BAC compared to their non-surgical control group. The level of increase was comparable to that of the previously studied Gastric Bypass patients. This is important in that it illustrates that it is not the type of surgery that is performed that creates the different BAC response, but rather, the consistency of the results regardless of the surgical methodology chosen.
The researchers also concluded that blood alcohol analysis was the only valid methodology of measuring BAC levels, as breath test devices were likely to be contaminated by recent consumption of alcohol (Acevedo, et al, 2018).
Acevedo, et al, 2020
Finally, in 2020, researchers from the Washington University School of Medicine again found that both Gastric Bypass and Sleeve Gastrectomy patients experienced both faster and two-fold higher Peak BAC levels in comparison to their non-surgical control group. Most of the bariatric patients reported experiencing enhanced effects of a relatively minor consumption of alcohol. More alarmingly, about 1/3 of the post-surgery women in the study felt no effects of the alcohol consumption whatsoever. In short, they had no self-correcting feedback indicating to them that the alcohol was creating an enhanced BAC reading. They could not identify if they had a high BAC or not...
An important distinction:
It is probably worth stressing that the data obtained regarding BAC levels was from actual blood draws. This data is not suggesting that any breath test results, or blood test results, are being falsely-elevated beyond the "true" BAC of the tested bariatric patient. Rather, the data is indicating that the actual BAC of the bariatric patient is enhanced due both to physical changes to the gastrointestinal system, and physical changes to the metabolism of the bariatric patient. But, given the lack of self identifying feedback that their BAC levels were higher than expected, how are they to know that the enhanced alcohol profile effect is occurring?
It is probably worth stressing that the data obtained regarding BAC levels was from actual blood draws. This data is not suggesting that any breath test results, or blood test results, are being falsely-elevated beyond the "true" BAC of the tested bariatric patient. Rather, the data is indicating that the actual BAC of the bariatric patient is enhanced due both to physical changes to the gastrointestinal system, and physical changes to the metabolism of the bariatric patient. But, given the lack of self identifying feedback that their BAC levels were higher than expected, how are they to know that the enhanced alcohol profile effect is occurring?
Issues with alcohol metabolism
In the non-bariatric surgery patient, alcohol is primarily metabolized in the liver by the ADH enzyme. In the bariatric surgery patient, the effects of fasting and low-calorie intake, and defects in liver function that occur with obesity, plus metabolic changes that occur with rapid and massive weight loss, all impair the effectiveness of the body to metabolize ethanol. Overall, this results in lower rates of metabolic clearance of the ethanol. As such, the bariatric patient will have a lower-than-normal elimination rate (Lieber, 2000).
In addition to the differences in Peak BAC reached, Woodard et al also reported significantly increased time to fully metabolize the single glass of wine they gave to their post-bariatric surgery patients. They concluded that alcohol metabolism was altered after gastric bypass surgery (Woodard, et al, 2011).
Bariatric surgery and GERD
GERD (Gastroesophageal Reflux Disease) is a common comorbid condition in bariatric patients. There is also an interplay between bariatric surgery and GERD. Studies have shown the relationship between increasing body weight and its role in creating incompetence of the Lower Esophageal Valve leading to incidences of gastric reflux. Often, bariatric surgery and its resulting weight loss will alleviate the GERD symptoms. However, it is now being recognized that the gastric banding surgeries can lead to increased GERD symptoms, and more frequent bouts of refluxation (Hadi, et al; 2014).
Conclusions
The results of these studies are noteworthy and consistent:
- In all cases, the bariatric surgery patient had a two-to-four-fold increase in their Peak BACs from the same dose of alcohol in pre-surgery conditions or comparably matched non-surgical control groups. The dose of alcohol, often very minor, unexpectedly created exaggerated BAC effects beyond the legal limit.
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- The time to reach Peak BAC was quite a bit quicker, typically twice as fast, in the post-surgery groups.
- The alcohol lingered in the person’s system for longer (alcohol metabolism was decreased and the elimination time was increased).
- Plus, the patients did not identify the increased BAC levels or time to Peak BAC in about 30% of those studied. They exhibited no outward signs and symptoms of intoxication, In short, they could not self-identify their level of impairment or intoxication.
- GERD, and its effect on a breath alcohol test result could be a contributing factor in forensic breath analysis, leading to false-positive reported BrAC readings.
Bariatric surgery patients present with an abnormal medical condition that may inflate their BAC readings, sometimes four times what could be reasonably expected, given an insignificant and seemingly responsible consumption of alcohol. However, this appears to be an actual increase in BAC levels, not an inflated false-positive reading due to the surgery. GERD may also play a contributing role. They reached substantially higher Peak BAC levels more rapidly and retained alcohol in their systems for longer than non-surgery control groups. But problematically, the post-surgery patients could not identify the increased BAC level about 1/3 of the time. With no feedback to self-correct the situation, the likelihood of experiencing a DUI-related incident is enhanced.
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Comments
For further study:
- Acevedo, M., Eagon, C., et al, Sleeve Gastrectomy Surgery: When Two Alcoholic Drinks are Converted to Four, Surgery for Obesity and Related Diseases, 2018; 14(3): 277-283.
- Acevedo, M., Teran-Garcia, M., et al., Alcohol Sensitivity in Women after Undergoing Bariatric Surgery: A Cross-Sectional Study, Surgery for Obesity and Related Diseases, 2020; 16(4): 536-544.
- Arterburn, D., Wellman, R, et al., Comparative Effectiveness and Safety of Bariatric Procedures for Weight Loss, Annals of Internal Medicine, December 2018.
- El-Hadi, M., Birch, D., et al., The Effect of Bariatric Surgery on Gastroesophageal Reflux Disease, Canadian Journal of Surgery, Vol. 57, No. 2, April 2014: 139-144.
- Jones, A.W., Jonsson, K.A., Neri A., Peak Blood-Ethanol Concentration and the Time of its Occurrence After Rapid Drinking on an Empty Stomach, Journal of Forensic Sciences, 1991; 36: 376–85.
- Klockhoff, H., Naslund, I., Jones A.W., Faster Absorption of Ethanol and Higher Peak Concentration in Women After Gastric Bypass Surgery, British Journal of Clinical Pharmacology, 2002;54:587–91.
- Lieber, C.S. Alcohol and the Liver: Metabolism of Alcohol and Its Role in Hepatic and Extrahepatic Disease, Mount Sinai Journal of Medicine, 2000; 67: 84–94.
- Pepino, M., Okunade, A., et al., Effect of Roux-en-Y Gastric Bypass Surgery Converting 2 Alcoholic Drinks to 4, JAMA Surgery, November 2015.
- Steffen, K., Engel, S., et al., Blood Alcohol Concentrations Rise Rapidly and Dramatically Following Roux-en-Y Gastric Bypass, Surgery for Obesity and Related Diseases, 2013; 9(3): 470-473.
- Woodward, G., Downey, J., et al., Impaired Alcohol Metabolism after Gastric Bypass Surgery: A Case-Crossover Trial, Journal of the American College of Surgeons, 2011; 212 (2).
