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Updated: Apr 6, 2026
Roux-en-Y Gastric Bypass Operation in Rats
Published on: June 11, 2012
A Systematic Review and Meta-analysis of the Effect of Gastric Bypass Surgery on Plasma Lipid Levels
Kirstin A Carswell1,2, Ajay P Belgaumkar3, Stephanie A Amiel4
1Department of General Surgery, King's College Hospital, Denmark Hill, London, UK, SE5 9RS. kirstincarswell@hotmail.com.
Insights
Roux-en-Y gastric bypass (RYGB) surgery significantly improves obesity-related dyslipidaemia. This bariatric procedure effectively lowers cholesterol and triglycerides while increasing HDL-cholesterol, supporting its use for high cardiovascular risk patients.
Area of Science:
- Metabolic Surgery
- Bariatric Procedures
- Cardiovascular Risk Management
Background:
- Obesity-related dyslipidaemia is characterized by abnormal cholesterol and triglyceride levels.
- Approximately 40% of morbidly obese surgical patients present with dyslipidaemia.
- Roux-en-Y gastric bypass (RYGB) offers metabolic benefits, but its precise impact on plasma lipids requires clarification.
Purpose of the Study:
- To systematically review and meta-analyze the effects of Roux-en-Y gastric bypass (RYGB) surgery on plasma lipid profiles in morbidly obese patients.
- To define the temporal changes in total cholesterol, LDL-C, HDL-C, triglycerides, and non-esterified fatty acids (NEFA) following RYGB.
Main Methods:
- A systematic review of electronic databases (1960-March 2012) identified 75 relevant studies with paired plasma lipid data around RYGB surgery.
- A meta-analysis was conducted using a random effects model to assess lipid changes up to 4 years post-surgery.
- Included studies involved morbidly obese patients (BMI 48 kg/m²) undergoing RYGB.
Main Results:
- RYGB surgery led to significant reductions in total cholesterol and LDL-C from 1 month to 4 years post-operation (p < 0.00001).
- HDL-C levels increased significantly from 1 year onwards (p < 0.00001), and triglyceride levels decreased from 3 months to 4 years (p < 0.00001).
- Non-esterified fatty acid (NEFA) levels transiently increased at 1 month but returned to baseline by 3 months post-RYGB.
Conclusions:
- Roux-en-Y gastric bypass surgery effectively reverses obesity-related dyslipidaemia.
- The findings support RYGB as a valuable intervention for managing lipid profiles associated with high cardiovascular risk 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.
Methods:
A systematic review of electronic databases (Ovid; Medline; PubMed; Embase) between 1960 and March 2012 was performed using search terms including the following: obesity surgery, bariatric surgery, gastric bypass, cholesterol, lipids, triglycerides and non-esterified fatty acids. A total of 2442 manuscripts were screened. Papers with paired plasma lipid levels around RYGB surgery were included. Exclusions included the following: editorials, dual publications, n < 10, resulting in 75 papers of relevance. A meta-analysis was performed of the effect of RYGB surgery upon plasma lipids at different time points up to 4 years following surgery, using a random effects model.
Results:
Paired data were available for 7815 subjects around RYGB surgery for morbid obesity with a baseline BMI 48 kg/m(2) (n = 2331). There was a reduction in plasma total cholesterol and LDL-C from 1 month up to 4 years post-RYGB (p < 0.00001, p < 0.00001). Following RYGB, HDL-C increased from 1 year onwards (p < 0.00001), and triglyceride levels were reduced postoperatively from 3 months up to 4 years (p < 0.00001). NEFA levels were increased at 1 month postoperatively (p = 0.003), but from 3 months onwards did not differ from preoperative levels (p = 0.07).
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.
