Elevated plasma homocysteine concentrations six months after gastroplasty in morbidly obese subjects

To investigate whether the increased homocysteine levels occur in the first 6 months postoperatively, when nutritional intake is the most inadequate and weight reduction is the most drastic.

Fasting glucose, insulin, lipoprotein, homocysteine, folic acid and vitamin B12 levels and oral glucose, tolerance test (OGTT) were determined in 12 morbidly obese subjects (3 men and 9 women with a mean age of 31+/-3 years, mean+/-SEM) before, 6 and 12 months after banded gastroplasty.

Gastroplasty resulted in significant weight loss, from 120+/-6 to 92+/-6 and 88+/-7 kgs, 6 and 12 months postoperatively (all p<0.001). Fasting plasma insulin and triglyceride concentrations, the ratio of total cholesterol to HDL cholesterol, glucose and insulin responses to OGTT, and the degree of insulin resistance as expressed by the Homeostasis model index decreased significantly (p<0.05-0.001) following gastroplasty. Fasting plasma homocysteine concentrations increased from 10.2+/-0.8 to 12.1+/-0.6 at 6 months (p=0.036) and 12.0+/-1.2 micromol/l at 12 months (p=0.040), respectively. Pooled plasma homocysteine levels were negatively correlated with serum folate concentrations (r=-0.42, p=0.013). However, serum folate and vitamin B12 levels did not change after gastroplasty, nor did the relation between the loss of body weight and increase in homocysteine levels.

We observed that elevated circulating homocysteine levels occurred as early as 6 months after gastroplasty despite improvement in carbohydrate and lipoprotein metabolism in morbidly obese Chinese subjects.