Class III Obesity and its Relationship with the Nutritional Status of Vitamin A in Pre- and Postoperative Gastric Bypass

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Epidemiological findings have shown the rise of the prevalence of obesity in several segments of the world population, and more recent evidences point to a possible association with vitamin A deficiency (VAD). The aim of this study was to investigate vitamin A nutritional status in individuals with class III obesity in the preoperative period and 30 and 180 days after Roux-en-Y gastric bypass, correlating these findings with lipid profile and body mass index (BMI).


The sample was composed of class III obese individuals, males and females, in the preoperative period (T1) and 30 (T2) and 180 days (T3) after bariatric surgery with 5,000 IU of supplementation of retinol acetate. Vitamin A nutritional status was assessed through biochemical indicators (retinol and β-carotene serum levels), which were quantified by high-performance liquid chromatography with an inadequacy cutoff of <1.05 μmol/L and ≥40 μg/dL, respectively.


Out of the 114 assessed patients, the mean age was 36.9 ± 11.6 years and BMI was ≥40 kg/m2. The prevalence of VAD was 14%, being 37.5% in T1, 50.8% and 67.8% in T2, and 52.9% and 67% in T3, according to retinol and serum β-carotene, respectively. A decrease of retinol and β-carotene serum levels was observed with BMI increase in T1. An increase of very-low-density lipoprotein cholesterol (VLDLc) and triglycerides was verified with the increase of retinol, being VLDLc in T3 and triglycerides in T1 and T2. In T1, high-dense lipoprotein cholesterol presented a positive and significant correlation with β-carotene and a negative and significant correlation in T3.


High prevalence of VAD in the preoperative period and in 30 and 180 postoperative days, even during supplementation, with higher inadequacy of β-carotene in all the three studied time periods, probably occurred because of its bioconversion to retinol due to the increased demand to which those individuals were exposed. It is suggested that the oral intake supplementation does not present the expected impact, and the need of assessing the nutritional status of vitamin A in the pre- and postoperative Roux-en-Y gastric bypass is emphasized. High prevalence of VAD in T1, with severity in T2 and T3, corroborates the utilization of the cutoff of <1.05 μmol/L as a VAD marker in the studied segment and reinforces its utilization as a tool in clinical practice to identify VAD in morbid obese patients who underwent bariatric surgery.

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