Duodenal Switch Key to Bariatric Surgery's Efficacy


Staff member

Duodenal Switch Key to Bariatric Surgery's Efficacy

Murine data suggest switch is the key to long-term results.

by Salynn Boyles
Contributing Writer

Action Points

  • Note that this rat study demonstrated that biliopancreatic diversion with duodenal switch is particularly effective at inducing weight loss.
  • Be aware that this procedure is uncommonly performed in humans due to the complication rate, which is higher than the more-standard Roux-en-Y gastric bypass.
Research in rats has shown the duodenal switch component of biliopancreatic diversion with duodenal switch (BPD/DS) to be a key contributor to increased satiety and early resolution of type 2 diabetes following weight-loss surgery.

While BPD/DS, sleeve gastrectomy (SG) alone, or duodenal switch (DS) alone all resulted in a short-term reduction in food intake, only BPS/DS and DS alone led to persistent reductions in body weight and body fat and significant decreases in energy intake, Denis Richard, PhD, and colleagues wrote in the journal Endocrinology.

The researchers concluded that duodenal switch played a key role in metabolic changes in the high fat (HF) diet-fed rats.

"The DS component leads to a reduction in digestible energy intake while sustaining energy expenditure," the researchers wrote. "The intestinal diversion by DS also results in gut morphological changes, which are accompanied by elevation in satiating gut hormones such as (the satiating gut hormones) GLP-1 and PYY."

BPD/DS Not Widely Performed

In the bariatric procedure known as biliopancreatic diversion with duodenal switch, both the duodenum and the small intestine are divided and the portion of the small intestine is attached to a short duodenal section next to the stomach, which is left largely intact. The remaining section of the duodenum connected to the pancreas and gallbladder is attached to this limb close to the large intestine.

More than other bariatric surgery, biliopancreatic diversion with duodenal switch is associated with significant weight loss and metabolic improvements, such as normalization of plasma glucose, insulin triglycerides, and free fatty acids, Richard and colleagues noted.

But the demanding surgery also has a higher complication rate than other bariatric procedures, and is performed far less often.

Most studies in animals and humans exploring the mechanism driving the metabolic benefits of weight-loss surgery have involved Roux-en-Y intestinal bypass (RYGB) or sleeve gastrectomy, the researchers noted.

"The main objective of the present study was to delineate the contributions of SG and DS to the metabolic improvements produced by the BPD/DS in rats fed HF to induce obesity" they wrote.

Over a 9-week period following surgery, energy balance measurements were performed by Richard and colleagues in BPD/DS, DS, SG, and sham-operated male Wistar rats. Changes in plasma levels of gastrointestinal (GI) hormones were evaluated at the end of the 9 weeks.

Researchers estimated the thermogenic activity of interscapular brown adipose tissue (iBAT) using the positron emission tomography (PET) tracers 11C-acetate (oxidative activity) and 14-R,S-18F-fluoro-6-thiaheptadecanoic acid (18FTHA -- free fatty acid uptake). The expression of genes encoding proteins involved in BAT thermogenesis and fatty acid oxidation was also examined.

Energy Expenditure Not Related to Increased iBAT

Among the study findings:
  • BPD/DS and DS, but not SG, resulted in persistent reductions in body weight gain and body fat, which were accompanied by a significant decrease in digestible energy intake.
  • BPD/DS and DS also exhibited a reduction in energy expenditure, which was not totally accounted for by the reduction in body weight promoted by the surgeries; energy expenditure was slightly higher in BPD/DS rats than in sham high fat, pair weighted (Sham HF PW) animals.
  • BPD/DS and DS reduced iBAT oxidative activity (estimated from 11C-acetate) to the level seen in sham HF PW animals.
  • BPD/DS and DS led to significant elevations in GLP-1 and PYY levels.
These findings show the importance of the DS component of BPD/DS in creating a negative energy balance through reducing digestible energy intake, the researchers noted.

"The DS component is unique to the BPD/DS and likely behind the established efficacy of the procedure to treat obesity and resolve type 2 diabetes," they wrote.

The finding that BPD/DS rats ate more than sham HF PW rats to maintain the same body weight and fat mass showed the ability of BPD/DS to also stimulate energy expenditure, the researchers noted.

The sustained energy expenditure did not appear to be accomplished through an increase in iBAT thermogenesis.

"BAT is a heat-producing tissue whose activity is mainly controlled by the sympathetic nervous system (SNS) and RYGB has been demonstrated to reduce SNS activity," the researchers wrote. "The mechanisms whereby BPD/DS stimulated energy expenditure while reducing BAT thermogenesis remain to be determined."

The researchers reported no funding source and they disclosed no relevant relationships with industry.

NOTE: I noticed that they are using the term DS as JUST the guts part of the surgery. Not as most of us use it to describe the whole thing, sleeve and guts!


Well-Known Member
This article comes from the Marceau and Biertho group in Quebec. They have done the DS for years and have studied the metabolism of morbid obesity and how the DS alters that metabolism in ways that no other operation does. We are learning more and more about the biology of obesity, and why any treatment, surgical or medical, that affects just one cause of obesity (appetite, portion size, whatever) doesn't work for the long term.


Active Member
I see this is a older post, but my question is this:
This article mentions BPD/DS differently from the DS. On these boards we always talk about the DS, but isn't it true that we are actually talking about the full procedure (BPD/DS)? Thanks!


Staff member
This article mentions BPD/DS differently from the DS. On these boards we always talk about the DS, but isn't it true that we are actually talking about the full procedure (BPD/DS)? Thanks!
Yes, we are...but using the term BPD/DS has been known to cause confusion with the older, BPD surgery aka the Scopinaro procedure. So many medical professionals stop listening when they hear BPD/DS at the BPD and think it is the older procedure.

Biliopancreatic Diversion (BPD)

Dr. Nicola Scopinaro introduced the Biliopancreatic Diversion in Italy during 1979.The procedure combines malabsorption with some gastric restriction. A large pouch between 250 and 400 ccs is created with the upper portion and the lower stomach is surgically removed (distal gastrectomy). The pyloric valve is circumvented so "dumping" often occurs. The duodenum (top part of the small intestine) is bypassed and the stomach pouch is connected to the lower 2-3 meters of the small intestine. Then, 4-metres of the small bowel (60%) is bypassed making the channel approximately 50 cm.

Stand-Alone Duodenal Switch

The Stand-Alone Duodenal Switch procedure (without the accompanying gastric bypass as used in weight-loss surgery) was developed by Dr. Tom R. DeMeester in the 1980's to treat bile-reflux gastritis, a condition in which the stomach and esophagus are irritated by bile that goes back through the pylorus to the stomach.

Biliopancreatic Diversion with Duodenal Switch (BPD-DS)

In 1986, Dr. Douglas Hess modified BPD and combined it with Duodenal Switch. This hybrid procedure is often referred to as the Biliopancreatic Diversion with Duodenal Switch, or GR-DS (Gastric Reduction- Duodenal Switch). Keep in mind; the BPD portion has been modified from the original procedure so the name can be misleading.

Duodenal Switch (DS)

DS surgeons and patients commonly refer to this procedure as the Duodenal Switch. Hess's Duodenal Switch has the advantages of the BPD, but without some of the associated problems like marginal ulcers, stoma closures and blockages, dumping syndrome, and serious protein-calorie malnutrition; all of which can occur after other gastric bypass procedures.


Yes, that is chocolate covered bacon
BPD/DS to me is the the proper name as it describes what the switch part is and actually it should be VSG/BPD/DS.....but on this board any most other places the term DS is accepted, synonomus and much easier to say and write.

I think the study summary is dead on and we all pretty much knew this to be true on the first place, hence we had the DS. I hadn't heard it expresses in terms of energy intake before, but that to me is THE reason the DS results in such great weight loss and maintenance. That part is simply math. Digest fewer calories and you lose weight.

The biological and chemical changes in the gut is not as simple but I am glad people smarter than me are researching that component because it is crucial in comorbidity, specifically diabetes, resolution. Hopefully in the future the research leads to non surgical interventions fir obesity and comorbidity resolution.

This is also the first study that I have seen that actually comes out and says the switch is why it works.

Great article. Thanks got posting it Liz.