Rock C L, Lovalvo J L, Emenhiser C, Ruffin M T, Flatt S W, Schwartz S J
Department of Family and Preventive Medicine, University of California, San Diego, La Jolla, CA 92093-0901, USA.
J Nutr. 1998 May;128(5):913-6. doi: 10.1093/jn/128.5.913.
Populations at risk of vitamin A deficiency usually rely on dietary provitamin A carotenoids to meet vitamin A needs, yet bioavailability of these compounds is influenced by several factors as follows: location in the plant source, the presence of other influencing dietary components, and type and extent of processing. The purpose of this study was to examine the plasma beta-carotene response to raw vs. processed carrots and spinach. Subjects were eight healthy females aged 23-36 y who consumed approximately 9.3 mg beta-carotene daily from either raw or thermally processed and pureed vegetables in two 4-wk treatment periods in a crossover study. Plasma concentrations of total, all-trans-, and cis-beta-carotene and alpha-carotene were measured at base line and the end of each treatment period by using HPLC assays. Total and all-trans (but not cis) plasma beta-carotene concentrations were significantly greater than base-line concentrations in the processed feeding period (P < 0. 04) and tended to be greater in the raw feeding period (P = 0.08). Daily consumption of processed carrots and spinach over a 4-wk period produced an increase in plasma beta-carotene concentration that averaged three times that associated with consumption of the same amount of beta-carotene from these vegetables in the raw form (P = 0.09). Increased cis isomers provided in the processed vegetables did not result in significantly greater plasma cis-beta-carotene isomer concentrations. These results suggest that isomerization of beta-carotene by heat treatment does not negate the enhanced beta-carotene uptake associated with consuming commercially processed vegetables compared with raw vegetables.
有维生素A缺乏风险的人群通常依靠膳食中的维生素A原类胡萝卜素来满足维生素A需求，然而这些化合物的生物利用度受以下几个因素影响：在植物来源中的位置、其他影响膳食成分的存在以及加工的类型和程度。本研究的目的是检测血浆β-胡萝卜素对生胡萝卜和菠菜与加工后的胡萝卜和菠菜的反应。研究对象为8名年龄在23至36岁之间的健康女性，她们在一项交叉研究的两个为期4周的治疗期内，每天从生的或经热处理并制成泥状的蔬菜中摄入约9.3毫克β-胡萝卜素。在基线期和每个治疗期结束时，使用高效液相色谱法测定血浆中总β-胡萝卜素、全反式β-胡萝卜素、顺式β-胡萝卜素和α-胡萝卜素的浓度。在加工喂养期，血浆总β-胡萝卜素和全反式（但不包括顺式）β-胡萝卜素浓度显著高于基线浓度（P < 0.04），在生喂养期也有升高的趋势（P = 0.08）。在4周内每日食用加工后的胡萝卜和菠菜使血浆β-胡萝卜素浓度升高，平均是食用相同量的生蔬菜中β-胡萝卜素所导致浓度升高的三倍（P = 0.09）。加工蔬菜中增加的顺式异构体并未导致血浆顺式β-胡萝卜素异构体浓度显著升高。这些结果表明，与生蔬菜相比，热处理使β-胡萝卜素异构化并不会抵消食用商业加工蔬菜所带来的β-胡萝卜素吸收增加的效果。
