Bioavailability of vitamin C from kiwifruit in non-smoking males: determination of 'healthy' and 'optimal' intakes.
Bioavailability of vitamin C from kiwifruit in non-smoking males: determination of 'healthy' and 'optimal' intakes.
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DOI：
10.1017/jns.2012.15
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发表时间：
2012
影响因子：
2.5
通讯作者：
Vissers, Margreet C M
中科院分区：
文献类型：
--
作者：
Carr, Anitra C;Pullar, Juliet M;Moran, Stephanie;Vissers, Margreet C M
维生素C是人体必需的营养素，必须通过饮食获得。本研究的目的是确定健康志愿者食用猕猴桃（猕猴桃变种）后维生素C的吸收。Hort.16A），并确定将血浆维生素C提高到“健康”（即>50 µmol/l）和“最佳”或饱和水平（即>70 µmol/l）所需的水果量。还测定了白细胞和尿维生素C水平。共有15名血浆维生素C水平低于平均水平的男性大学生被选入这项研究。在4周的导入期内获得每周空腹血液样品，并在每天依次补充半个、一个、两个和三个黄金猕猴桃后，每个持续4-6周，然后是最后的4周洗脱期。结果表明，每天只添加半个猕猴桃就能显著增加血浆维生素C。然而，每天需要一个猕猴桃才能达到被认为是健康的水平。将猕猴桃的剂量增加到每天两个导致血浆维生素C水平进一步增加，以及维生素的尿排出量增加，表明血浆水平在此剂量下饱和。根据基线血浆和白细胞维生素C水平将参与者分为高维生素C组和低维生素C组，这表明获得低初始维生素水平的研究人群以确定补充剂的一致效果至关重要。
Vitamin C is an essential nutrient in humans and must be obtained through the diet. The aim of this study was to determine vitamin C uptake in healthy volunteers after consuming kiwifruit (Actinidia chinensis var. Hort. 16A), and to determine the amount of fruit required to raise plasma vitamin C to ‘healthy’ (i.e. >50 µmol/l) and ‘optimal’ or saturating levels (i.e. >70 µmol/l). Leucocyte and urinary vitamin C levels were also determined. A total of fifteen male university students with below average levels of plasma vitamin C were selected for the study. Weekly fasting blood samples were obtained for a 4-week lead-in period and following supplementation with, sequentially, half, one, two and three Gold kiwifruit per d for 4–6 weeks each, followed by a final 4-week washout period. The results showed that addition of as little as half a kiwifruit per d resulted in a significant increase in plasma vitamin C. However, one kiwifruit per d was required to reach what is considered healthy levels. Increasing the dose of kiwifruit to two per d resulted in further increases in plasma vitamin C levels as well as increased urinary output of the vitamin, indicating that plasma levels were saturating at this dosage. Dividing the participants into high and low vitamin C groups based on their baseline plasma and leucocyte vitamin C levels demonstrated that it is critical to obtain a study population with low initial levels of the vitamin in order to ascertain a consistent effect of supplementation.