RNY = Minimal Fat Malabsorption vs MGB = Major Fat Malabsorption

1. Malabsorption following the
Roux-en-Y gastric bypass

2. What is Roux-en-Y Gastric Bypass?
• Roux-en-Y Gastric
Bypass both (?)
• Restrictive
• Malabsorptive (?)
Components

3. Malabsorption vs. Restriction after
long-limb RNY gastric bypass
• Roux-en-Y gastric bypass (RNY)
restricts food intake
• when the Roux limb is elongated to
150 cm
• IS the RNY malabsorptive?
• Measure calorie reduction after RNY
• Restriction vs Malabsorption
• The contribution of malabsorption to the reduction in net energy absorption after long-limb Roux-en-Y gastric
bypass, Elizabeth A Odstrcil, et al. Am J Clin Nutr October 2010 vol. 92 no. 4 704-7

4. “The contribution of
malabsorption to the reduction in
net energy absorption after
long-limb
Roux-en-Y gastric bypass”
Elizabeth A Odstrcil, Juan G Martinez, Carol A Santa Ana,
Beiqi Xue, Reva E Schneider, Karen J Steffer, Jack L
Porter, John Asplin, Joseph A Kuhn, and John S Fordtran
Am J Clin Nutr October 2010 vol. 92 no. 4 704-713

5. The contribution of malabsorption to the reduction in net
energy absorption after long-limb Roux-en-Y gastric bypass
• Results:
• RNY:
• No significant effect on
• Protein or Carbohydrate
absorption
• “The contribution of malabsorption to the reduction in net energy
absorption after long-limb Roux-en-Y gastric bypass”, Elizabeth A
Odstrcil, et al. Am J Clin Nutr October 2010 vol. 92 no. 4 704-713

6. RNY Malabsorption vs. Restriction
• 5 months after bypass,
• Malabsorption reduced absorption by
124 kcal/d
• Restriction of food intake reduced energy
absorption by 2,062 kcal/d
• Restriction 16 times more important than
Malabsorption
• The contribution of malabsorption to the reduction in net energy absorption
after long-limb Roux-en-Y gastric bypass, Elizabeth A Odstrcil, et al. Am J
Clin Nutr October 2010 vol. 92 no. 4 704-713

7. RNY Malabsorption vs. Restriction
• 14 months after bypass,
• Malabsorption reduced absorption of
combustible energy by 172 kcal/d
• vs
• Restriction of food intake reduced energy
absorption by 1,418 kcal/d
• (Why: Restriction Beginning to Fail)
• The contribution of malabsorption to the reduction in net energy absorption after long-limb Roux-en-Y gastric bypass, Elizabeth A Odstrcil,
et al. Am J Clin Nutr October 2010 vol. 92 no. 4 704-713

8. Failure of RNY
Caloric Effect

9. RNY Malabsorption vs. Restriction
• Malabsorption ONLY
6%-11% reduction in calories
• RNY: Is Primarily a
“Restrictive Procedure”
• Study Shows: Early signs of
RNY caloric failure
• The contribution of malabsorption to the reduction in net energy absorption after long-
limb Roux-en-Y gastric bypass, Elizabeth A Odstrcil, et al. Am J Clin Nutr October
2010 vol. 92 no. 4 704-713

10. The contribution of malabsorption to the reduction in net
energy absorption after long-limb Roux-en-Y gastric bypass
• Dietary intake and net intestinal absorption of
fat, protein, and carbohydrate were measured
• Calculated the total reduction in fat, protein,
carbohydrate, and calories after RYGB
• Extent to which these reductions were due to
restriction or malabsorption
• The contribution of malabsorption to the reduction in net energy absorption after long-
limb Roux-en-Y gastric bypass, Elizabeth A Odstrcil, et al. Am J Clin Nutr October
2010 vol. 92 no. 4 704-713

11. The contribution of malabsorption to the reduction in net
energy absorption after long-limb Roux-en-Y gastric bypass
• Fat absorption and malabsorption
• Average fat intake was
• 156 g/d before bypass,
• 50 g/d 5 mo after bypass, and
• 82 g/d 14 mo after bypass.
• The contribution of malabsorption to the reduction in net energy absorption
after long-limb Roux-en-Y gastric bypass, Elizabeth A Odstrcil, et al. Am J
Clin Nutr October 2010 vol. 92 no. 4 704-713

13. Correlation between the length of jejunum in the
biliopancreatic (BP) limb and the reduction in fat absorption

14. Bile Acid Depletion:
Fat Malabsorption &
Treatment of Diabetes
Most Bariatric surgeons
DO NOT
Understand Bile/Bile Acids

15. Bile Acids: Not Just for Fat
Absorption
• Bile Acids Needed for Fat
absorption
(Decreased Bile Acids =>
Decreased Fat Absorption)
• Studies show that bile acids
also play a large role in
glucose homeostasis

16. Bile Acids: Not Just Detergents
Bile Acids as Hormones
• Bile acids as hormones act on several
Critical receptors:
• Farnesoid X receptor (FXR) and
• Pregnane X receptor (PXR),
• Constitutive androstane receptor (CAR),
• G-protein-coupled receptor TGR5.
• Bile acids AS HORMONES regulate
Cholesterol, Glucose, and
metabolism/energy homeostasis

17. What Most Bariatric Surgeons
Do Not Understand
• Bile Acids Critical to Fat and Glucose
Control in the Body
• Decreased Bile Acids =>
Decreased Fat absorption
Lowered Blood Glucose Levels
• MGB (Billroth II) =>
Decreased Bile Acids
• RNY does NOT Affect Bile Acid Pool

18. Study of long-limb Roux-en-Y gastric bypass
• Results: RNY does not cause bile
acid malabsorption
• Fecal bile acid excretion average
• Before: 0.8 g/d
• Post Op 5 mo: 0.5 g/d
• Post Op 14 mo: 0.7 g/d
• Decreased Bile Acids Rx Diabetes
• RNY Does Not Cause Loss of Bile

19. Bile Acid Sequestration Reduces Glucose
Levels by Increasing Metabolic Clearance
• Bile acid sequestrants (BAS) reduce
plasma glucose levels in type II
diabetics
• BAS induced plasma glucose
lowering by increasing metabolic
clearance rate of glucose in
peripheral tissues
• RNY Does Not Cause Loss of Bile
• MGB Does Cause Bile Acid Losses

20. Bariatric Surgeons Forget
History of GI Surgery
What have we learned from
100 years of GI Surgery?

21. Post Gastrectomy Steatorrhea
• For over 75 years authors have noted that
• Fat Malabsorption/Steatorrhea common
post gastrectomy syndrome in some
patients
• More common & Greater degree with
• Billroth II >> Billroth I
• EVERSON TC. Experimental comparison of protein and fat assimilation after Billroth II, Billroth I, and segmental
types of subtotal gastrectomy. Surgery. 1954 Sep;36(3):525-37
• MACLEAN LD, PERRY JF, KELLY WD, MOSSER DG, MANNICK A, WANGENSTEEN OH. Nutrition following
subtotal gastrectomy of four types (Billroth I and II, segmental, and tubular resections). Surgery. 1954
May;35(5):705-18
• WOLLAEGER EE, WAUGH JM, POWER MH. Fat-assimilating capacity of the gastrointestinal tract after partial
gastrectomy with gastroduodenostomy (Billroth I anastomosis). Gastroenterology. 1963 Jan;44:25-32
• …

22. 100 Years of GI Surgery: Steatorrhea
following Gastric Operations:
• What do we know:
• Rare after gastro-jejunostomy or vagotomy
alone.
• Rare after Billroth I
• Especially Common after Polya gastrectomy
with BII.
• (Butler, 1961)

23. Polya Type Gastro-Jejunostomy
NOTE:
Large
Wide Open
Gastro-
jejunostomy

24. Opinion Among BPD Surgeons
• Length of the Common Channel is
the Critical Factor for Fat
malabsorption & weight loss
• We review Animal studies and
MGB results that suggest this is
not the case
• Am J Surg. 2005 May;189(5):536-40, Common channel length predicts outcomes of
biliopancreatic diversion alone and with the duodenal switch surgery, McConnell DB, O'rourke
RW, Deveney CW

25. NUTRIENT ABSORPTION in the SMALL
INTESTINE: Remember the Basics
• Duodenum and Upper Jejunum:
most minerals
• Jejunum and Upper Ileum:
carbohydrates, amino acids,
water-soluble vitamins
• Jejunum: absorbs most of lipids
and fat-soluble vitamins
• Terminal Ileum: Bile,Vit B12

26. Fat absorption and the
Length of Billroth II Afferent Limb
• Experiment
• Question: Increase length of
afferent limb associated with
increased fat malabsorption
• Animals underwent a 50% distal
gastrectomy with an antecolic
• Polya-type Billroth II anastomosis

28. Fat absorption and the
Billroth II Afferent loop
• 50% distal
gastrectomy with
an antecolic
• Polya-type Billroth
II anastomosis
• Afferent limb of
• 30cm, 60cm, 90cm

29. Fat absorption and the
Billroth II Afferent Limb: RESULTS
• PreOp: Fecal excretion on a 127 Gm. diet
2.4% of the ingested fat.
• Similar results in dogs and in humans
• Animals with BII + 30cm afferent limbs
• Able to digest and absorb the dietary fat
without any apparent difficulty

30. Fat absorption and the
Billroth II Afferent loop
• Average fecal excretion diet was
2.4% of the ingested fat.
• Longer Loops steatorrhea increased
• 30 cm. limb fecal fat 2.4% (No Change)
• 60 cm. limb fecal fat excretion 10.2%
• 90 cm. limb 28.2%

31. Fat Malabsorption
Billroth II (MGB) vs RNY
0
5
10
15
20
25
30
0 20 40 60 80 100
Bypass Limb Length
FatLost(%)
MGB
Billroth II
RNY

32. Fat absorption and the
Billroth II Afferent loop
• Average fecal excretion Pre Op
2.4% of ingested fat
• Longer Limb increased steatorrhea
• 30 cm. limb fecal fat 2.4% (No Change)
• 60 cm. limb fecal fat excretion 10.2%
• 90 cm. limb 28.2%

33. Fat MAL-absorption and the
Billroth II Afferent LIMB
• Afferent limb most important factor post
gastrectomy steatorrhea, “LENGTH”
• Animals with short afferent loops NO
significant steatorrhea.
• As the length of the afferent limb
increased, a concomitant and dramatic
rise in fecal fat excretion was noted.

34. Fat MAL-absorption and the
Billroth II Afferent loop
• Malabsorption is NOT due to
bypass of the upper jejunum
ALONE
• Kremen’s Study:
• Over half the jejunum can be
bypassed without producing
steatorrhea.

35. An Experimental Evaluation of the
Nutritional Importance of
Proximal and Distal Small
Intestine
• Arnold J. Kremen, et al.
Ann Surg. 1954 September; 140(3): 439–447

36. Kremen, et al.
• “Experimental studies in dogs
reveal that animals can bypass
• 50 to 70 per cent of their
small intestine
• and maintain a near normal
nutritional status”

37. Experimental Evaluation of the Nutritional
Importance of Proximal and Distal Small Intestine
• Study showed that
• Bypass of major lengths of the
proximal small intestine,
• Weight is well maintained
• No great interference with fat
absorption
• NOTE:
Contradiction with Prior Study

38. Experimental Evaluation of the Nutritional
Importance of Proximal and Distal Small Intestine
• 50 - 70% of the small bowel
bypassed
• Proximal and distal ends were
exteriorized as a cutaneous
stoma.
• Intestinal continuity was re-
established by end-to-end
anastomosis

41. 50% of Jejunum Bypassed:
No Weight Loss!

42. Massive bypass = No Effect
• The small intestine in adults is a
long and narrow tube about
7 meters (23 feet) long
• 50% Bypass = 11.5 ft (3.5 meters)
• Minimal Weight Loss!

43. 70% Bowel Bypassed
Minimal Weight Loss

44. Massive bypass = Little Effects!
• The small intestine in adults is
a long and narrow tube about
7 meters (23 feet) long
• 70% Bypass = 16 ft (5 meters)
• 5% weight loss

45. 70% Bypass = Little Effect
• Group IV animals, which were
similar to Group I except that 70%
instead of 50% of proximal small
bowel removed from intestinal
continuity,
• Lost about five per cent of their
preoperative weight and then
stabilized at this level.

46. Transit Time & Fat Absorption
• 50-70% Bypass
• Made Little Difference in
• Transit Time or
• Fat Absorption NOT affected

47. Experimental Evaluation of the Nutritional
Importance of Proximal and Distal Small Intestine
• CONCLUSIONS
• The proximal 50 to 70 per cent of the small
intestine can be removed with no apparent ill
effects.
• Weight is maintained, and protein and fat
absorption are not significantly altered.
• Arnold J. Kremen, John H. Linner, and Charles H. Nelson

48. Bypass of Jejunum; Experimental Results:
No Fat Malbsorption or Major Fat
Malabsorption
• 2 Studies; 2 Different Findings
• Massive Small Bowel Bypass
=> Minimal Effects
• Moderate Small Bowel Bypass
=>Major Effects
• What is the Difference?

49. It’s the Billroth II

50. Billroth II + Moderate Bypass
=
Fat Malabsorption and
Good Weight Loss

51. RNY
• Primarily Restrictive
• Minor fat malabsorption
• No Malabsorption of Protein or
Carbohydrate
• Restriction begins to fade early