Conclusions RYGB surgery reverses the dyslipidaemia of obesity .
These findings support the use of RYGB in the management of high cardiovascular risk lipid profiles in morbid obesity
Background Obesity-related dyslipidaemia comprises hypercholesterolaemia , hypertriglyceridaemia , low HDL-cholesterol and normal to raised LDL-cholesterol levels .
40 % of morbidly obese surgical patients have dyslipidaemia .
Roux-en-Y gastric bypass ( RYGB ) surgery has many beneficial metabolic effects , but the full impact on plasma lipids has not been clearly defined .
Fat malabsorption and increased intestinal oxalate absorption are common after Roux-en-Y gastric bypass surgery.
BACKGROUND Hyperoxaluria and increased calcium oxalate stone formation occur after Roux-en-Y gastric bypass ( RYGB ) surgery for morbid obesity . The etiology of this hyperoxaluria is unknown . We hypothesized that after bariatric surgery , intestinal hyperabsorption of oxalate contributes to increases in plasma oxalate and urinary calcium oxalate supersaturation . METHODS We prospect ively examined oxalate metabolism in 11 morbidly obese subjects before and 6 and 12 months after RYGB ( n = 9 ) and biliopancreatic diversion-duodenal switch ( BPD-DS ) ( n = 2 ) . We measured 24-hour urinary supersaturations for calcium oxalate , apatite , brushite , uric acid , and sodium urate ; fasting plasma oxalate ; 72-hour fecal fat ; and increases in urine oxalate following an oral oxalate load . RESULTS Six and 12 months after RYGB , plasma oxalate and urine calcium oxalate supersaturation increased significantly compared with similar measurements obtained before surgery ( all P ≤ .02 ) . Fecal fat excretion at 6 and 12 months was increased ( P = .026 and .055 , 0 vs 6 and 12 months ) . An increase in urine oxalate excretion after an oral dose of oxalate was observed at 6 and 12 months ( all P ≤ .02 ) . Therefore , after bariatric surgery , increases in fecal fat excretion , urinary oxalate excretion after an oral oxalate load , plasma oxalate , and urinary calcium oxalate supersaturation values were observed . CONCLUSION Enteric hyperoxaluria is often present in patients after the operations  of RYGB and BPD-DS  that utilize an element of intestinal malabsorption as a mechanism for weight loss
Conclusions RYGB surgery reverses the dyslipidaemia of obesity .
These findings support the use of RYGB in the management of high cardiovascular risk lipid profiles in morbid obesity
Background Obesity-related dyslipidaemia comprises hypercholesterolaemia , hypertriglyceridaemia , low HDL-cholesterol and normal to raised LDL-cholesterol levels .
40 % of morbidly obese surgical patients have dyslipidaemia .
Roux-en-Y gastric bypass ( RYGB ) surgery has many beneficial metabolic effects , but the full impact on plasma lipids has not been clearly defined .