Vahlquist A, Carlson K, Hallberg D, Rössner S
Int J Obes. 1982;6(5):491-7.
The plasma vitamin A and carotene transport in 45 obese patients was examined before and at various times after bypass surgery. The serum levels of lipoproteins, carotene, vitamin A and retinol-binding protein (RBP) were monitored and compared to those of healthy controls. LDL-cholesterol levels were decreased by 40 per cent (P less than 0.001) within the first year after surgery and remained low thereafter. The reduction of serum carotene (from a mean of 64 to 17 micrograms/dl) was rapid and constant. This change was observed already within 1-2 weeks post-surgery. The serum concentrations of carotene and LDL-cholesterol were highly correlated (r = 0.74). The concentrations of vitamin A and RBP were normal before the operation and remained so until 30 months after surgery, when slight reductions were observed compared to the control values [46 +/- 28 vs 66 +/- 11 micrograms/dl for vitamin A (P less than 0.01) and 32 +/- 8 vs 41 +/- 6 mg/l for RBP (P less than 0.01)]. No overt signs of vitamin A deficiency were observed. The mechanisms by which carotene (but not vitamin A) decreases so rapidly after bypass surgery cannot be explained by the decreased LDL levels.
对45名肥胖患者在旁路手术后的不同时间，于术前及术后各时间点检测其血浆维生素A和胡萝卜素转运情况。监测血清脂蛋白、胡萝卜素、维生素A及视黄醇结合蛋白（RBP）水平，并与健康对照者进行比较。术后第一年，低密度脂蛋白胆固醇（LDL - 胆固醇）水平下降40%（P < 0.001），此后一直维持在低水平。血清胡萝卜素（从平均64微克/分升降至17微克/分升）迅速且持续下降。术后1 - 2周内即观察到这一变化。血清胡萝卜素与LDL - 胆固醇浓度高度相关（r = 0.74）。术前维生素A和RBP浓度正常，术后直至30个月均保持正常，不过与对照值相比，此时出现了轻微下降[维生素A为46±28微克/分升对66±11微克/分升（P < 0.01），RBP为32±8毫克/升对41±6毫克/升（P < 0.01）]。未观察到明显的维生素A缺乏迹象。旁路手术后胡萝卜素（而非维生素A）迅速下降的机制无法用LDL水平降低来解释。
