Riboflavin intakes and status of morbidly obese females during the first postoperative year following gastroplasty

Obesity surgery: a model of programmed undernutrition

Surgical treatment of obesity (bariatric surgery) is the only effective long term solution for many patients. The procedures are designed to produce reduced intake, various degrees of malabsorption of nutrients, or both. Micronutrient deficiencies, especially those involved in erythropoiesis and bone metabolism, are common to nearly all bariatric surgery. They are inconsistently responsive to supplementation. The pattern of deficiency associated with gastrointestinal bypass procedures suggests that absorption of micronutrients is more dependent upon the functioning of the gut as a whole than the capacity of any single segment.

Surgery for obesity

The medical risks of obesity increase exponentially as weight increases, and these risks are reduced by sustained weight loss. Behavior modification and dieting provide an approximately 6% loss of body weight at 1 year. Fenfluramine provides an approximately 8% weight loss at 1 year, which can be doubled to 16% when a drug such as phentermine, which works through a different biochemical mechanism, is added to it. This amount of weight loss is insufficient for many severely obese individuals. It was with these facts in mind that the National Institutes of Health Consensus Conference in 1992 recommended that obesity surgery is an appropriate treatment for patients with a body mass index greater than 40 kg/m2 who had failed in attempts at medical treatment and for patients with a body mass index greater than 35 kg/m2 with severe complications of obesity. Vertically banded gastroplasty and Roux-en-Y gastric bypass are the two operations presently recommended because of their relative safety and effectiveness. This article reviews previous procedures that have provided insight into the mechanisms by which these surgeries cause weight loss. The presently used surgeries and their results also are reviewed because until medical therapy improves substantially, surgery remains the most reasonable treatment option for most morbidly obese patients.

Thiamin and vitamin B6 intakes and erythrocyte transketolase and aminotransferase activities in morbidly obese females before and after gastroplasty

To assess the need for postoperative vitamin supplements, intakes and nutritional status of thiamin (B1) and vitamin B6 were studied in 18 female gastroplasty patients who received a placebo or different levels of supplemental vitamins. Postoperative erythrocyte transketolase basal (BA) and thiamin pyrophosphate-stimulated (SA) activities and activity coefficients (AC) correlated significantly with B1 intake. Despite a decrease in apotransketolase, low thiamin intakes were associated with increased AC values during the first 3 months. With return to low B1 intakes following repletion during month 4, the AC values remained normal with low total activities. Both alanine (EALT) and aspartate (EAST) aminotransferase apoenzyme levels declined and AC values increased significantly during the first 3 months. Although the EALT-indices were more sensitive to changes in B6 intake than the EAST-indices, the EASTBA and SA correlated most consistently with the intake. Postoperative dietary intakes of both vitamins were inadequate for maintenance of normal activities of these erythrocyte enzymes. Although B1 intake of greater than or equal to 1.0 mg/day was adequate for maintenance of normal thiamin status in most subjects of this study, supplementation with greater than or equal to 1.5 mg/day is prudent even though it may not prevent the early postoperative loss of apotransketolase. Vitamin B6 intake at the current recommended dietary allowance (1.6 mg) was not adequate to maintain coenzyme saturation of the erythrocyte aminotransferases. Marginal intake of other nutrients may have affected the utilization of both thiamin and vitamin B6.