Howells L C, Livesey C T
BPP Department, Veterinary Laboratories Agency, Addlestone, Surrey, UK.
Food Addit Contam. 1998 Jan;15(1):10-8. doi: 10.1080/02652039809374595.
High oral doses of vitamin A have been shown to be teratogenic and accordingly the World Health Organization has recommended that the daily intake for pregnant women should not exceed 3.3 mg. Liver contains high concentrations of this vitamin and consequently it has become necessary to assess its level in the livers of food animals. A survey of fresh, frozen, imported and home-produced retail liver samples from calf (42), ox (121), lamb (228), pig (133) and chicken (125) was carried out between August 1992 and April 1993 using a modified version of the method of Ashoor and Knox (1987) to determine retinol and retinyl esters. Interlaboratory comparison showed no significant difference in results for this method and a method which employed hydrolysis of retinyl esters, and there were significant advantages in specificity, simplicity, cost and quality control. The mean +/- sd total vitamin A concentration calculated as retinol equivalents, for all species surveyed was 139 +/- 96 with a range of 3-1267 mg/kg liver. Mean values for individual species were: calf 188 +/- 125, ox 142 +/- 110, lamb 173 +/- 104, pig 174 +/- 118 and chicken 97 +/- 44 mg/kg liver. No change in the vitamin A concentrations in liver were observed compared with previous surveys in the UK, which suggests that the intake of vitamin A from dietary and supplementary sources by different species has not changed. The data from this survey confirm that liver cannot be recommended as a food for pregnant women.
高剂量口服维生素A已被证明具有致畸性，因此世界卫生组织建议孕妇每日摄入量不应超过3.3毫克。肝脏中含有高浓度的这种维生素，因此有必要评估食用动物肝脏中的维生素A水平。1992年8月至1993年4月期间，对来自小牛（42份）、牛（121份）、羔羊（228份）、猪（133份）和鸡（125份）的新鲜、冷冻、进口和国产零售肝脏样本进行了调查，采用了Ashoor和Knox（1987年）方法的改进版本来测定视黄醇和视黄酯。实验室间比较表明，该方法与采用视黄酯水解的方法在结果上无显著差异，且在特异性、简便性、成本和质量控制方面具有显著优势。以视黄醇当量计算，所有被调查物种肝脏中维生素A的平均浓度±标准差为139±96，范围为3 - 1267毫克/千克肝脏。各物种的平均值分别为：小牛188±125、牛142±110、羔羊173±104、猪174±118和鸡97±44毫克/千克肝脏。与英国之前的调查相比，未观察到肝脏中维生素A浓度的变化，这表明不同物种从饮食和补充剂来源摄入的维生素A没有变化。本次调查数据证实，不建议将肝脏作为孕妇的食物。
