The contribution of malabsorption to the reduction in net energy

absorption after long-limb Roux-en-Y gastric bypass

What is Roux-en-Y Gastric Bypass Surgery?

• Roux-en-Y Gastric Bypass (RYGB) combines both

• Restrictive and • Malabsorptive • Components

The contribution of malabsorption to the reduction in net energy absorption after long-limb Roux-en-Y gastric bypass

• Roux-en-Y gastric bypass (RYGB) restricts food intake, and

• when the Roux limb is elongated to 150 cm, the procedure is believed to induce malabsorption

• Objective measure reduction calories after RYGB

• Restriction of food intake 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. 4 704-713

The contribution of malabsorption to the reduction in net energy

absorption after long-limb Roux-en-Y gastric bypass

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 FordtranAm J Clin Nutr October 2010 vol. 92 no. 4 704-713

The contribution of malabsorption to the reduction in net energy absorption after long-limb Roux-en-Y gastric bypass

• No statistically significant effects of RYGB on

• Protein or

• Carbohydrate absorption coefficients

• 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

The contribution of malabsorption to the reduction in net energy absorption after long-limb Roux-en-Y gastric bypass

• 5 months after bypass, • Malabsorption reduced absorption of

combustible energy by 124 ± 57 kcal/d, whereas

• Restriction of food intake reduced energy absorption by 2062 ± 271 kcal/d

• In RNY 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

The contribution of malabsorption to the reduction in net energy absorption after long-limb Roux-en-Y gastric bypass

• 14 months after bypass, • Malabsorption reduced absorption of

combustible energy by 172 ± 60 kcal/d, whereas

• Restriction of food intake reduced energy absorption by 1418 ± 171 kcal/d

• Restriction 8 times as important as Restriction

• (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

The contribution of malabsorption to the reduction in net energy absorption after long-limb Roux-en-Y gastric bypass

• On average, malabsorption accounted for 6% and 11% of the total reduction in ccaloric intake at 5 and 14 mo, respectively, after 150 RNY gastric bypass

• RNY: Primarily a Restrictive Procedure

• NOTE: Early signs of 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

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

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

Correlation between the length of jejunum in the biliopancreatic (BP) limb and the reduction in coefficient of fat absorption at 5 (A) and 14 (B) mo after long-limb Roux-

en-Y gastric bypass (RYGB).

The contribution of malabsorption to the reduction in net energy absorption after long-limb Roux-en-Y gastric bypass

• RNY does not cause bile acid malabsorption

• Fecal bile acid excretion averaged • Before: 0.78 ± 0.08 g/d, • 5 mo: 0.50 ± 0.13 g/d, and • 14 mo: 0.68 ± 0.12 g/d • Decreased Bile Acids Rx Diabetes

Post Gastrectomy Steatorrhea

• Several authors have noted that • Fat malabsorption • More common and to a 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

Steatorrhoea following Gastric Operations:

• Rare after gastro-jejunostomy or vagotomy alone.

• Rare after Billroth I• Common after Polya gastrectomy. • The addition of vagotomy to gastrectomy or

gastrojejunostomy increased the fat• content of the stools.• (Butler, 1961)

Factors implicated as the cause of increased Body fat loss following gastrectomy & Billroth II

• Decreased caloric intake• Gastrointestinal motility

changes • Reservoir function are

responsible for the steatorrhea.

Factors implicated as the cause of increased fat loss following partial gastrectomy & Billroth II

• In a clinical study, Saxon and Ziese stated that

• Loss of the reservoir function of the stomach was of primary cause.

• Loss of body weight correlated significantly with the

• amount of stomach removed at operation and with no other factors.

Factors implicated as the cause of increased fat loss following partial gastrectomy & Billroth II

• Waddell and Wang Abnormal motility rather than lack of reservoir function was the basic physiologic disturbance involved.

• Glazebrook and Welbourn 6 indicted intestinal hypermotility as the cause

Fat absorption and the Billroth II Afferent loop

• An experiment was designed first, to determine whether progressive increase in the length of the afferent loop was predictably associated with increasing fat malabsorption

• Animals underwent a 50% distal gastrectomy with an antecolic

• Polya-type Billroth II anastomosis

Polya Type Gastro-Jejunostomy

Fat absorption and the Billroth II Afferent loop

• Animals underwent a 50% distal gastrectomy with an antecolic

• Polya-type Billroth II anastomosis

• Afferent loops of

• 30, 60, and 90 cm.

Fat absorption and the Billroth II Afferent loop

• Average fecal excretion on a 127 Gm. diet was 2.4% of the ingested fat.

• Similar to results both in dogs and in humans

• Animals with 30 cm. afferent loops

• Able to digest and absorb the fat diet without any apparent difficulty

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. loop fecal fat 2.4% (No Change)• 60 cm. loop fecal fat excretion 10.2%• 90 cm. loop 28.2%

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. loop fecal fat 2.4% (No Change)• 60 cm. loop fecal fat excretion 10.2%• 90 cm. loop 28.2%

Fat MAL-absorption and the Billroth II Afferent loop

• Afferent loop can be a most important factor in the cause of post gastrectomy steatorrhea, depending upon the LENGTH of its construction.

• Animals with short afferent loops did not demonstrate any significant steatorrhea.

• As the length of the afferent loop increased, a concomitant and dramatic rise in fecal fat excretion was noted.

Fat MAL-absorption and the Billroth II Afferent loop

• The malabsorption is probably not due to bypass of the upper jejunum

• Kremen’s demonstration in dogs that

• Over half the jejunum can be bypassed without producing steatorrhea.

• 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

Kremen, et al.

• Experimental studies in dogs reveal that animals also can, with reasonable assurance,

• be deprived of from 50 to 70 per cent of their small intestine and maintain a near normal nutritional status.

Experimental Evaluation of the Nutritional Importance of Proximal and Distal Small Intestine

• Study showed that after sacrifice of major lengths of the proximal small intestine,

• the animal's weight is satisfactorily maintained near preoperative levels, and

• no great interference with fat absorption is observed.

Experimental Evaluation of the Nutritional Importance of Proximal and Distal Small Intestine

• 50- 70% of the mesenteric small bowel bypassed

• The bypassed bowel had its blood supply preserved and

• proximal and distal ends were exteriorized as a cutaneous stoma.

• Intestinal continuity was re-established by end-to-end anastomosis

50% of Jejunum Bypassed

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!

70% Bowel Bypassed

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

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.

Transit Time & Fat Absorption

• 50-70% Bypass

• Made Little Difference in Transit Time

• Fat Absorption NOT affected

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

Absorption studies after gastrojejunostomy with and without vagotomy

• It is concluded that serious malabsorption does not follow either gastrojejunostomy or vagotomy

• but may occur quite often when these procedures are combined.

• It seems that the addition of vagotomy to the G-J is responsible for steatorrhea.

• Presumably vagotomy interferes with the gastric, intestine, or biliary response to food.