Garry P J, Vanderjagt D J, Hunt W C
Ann N Y Acad Sci. 1987;498:90-9. doi: 10.1111/j.1749-6632.1987.tb23753.x.
The data presented show that elderly men have significantly lower plasma ascorbic acid concentrations than elderly women at similar intakes of ascorbic acid. We hypothesize that this difference is due to lower renal tubular reabsorption of ascorbic acid in elderly men. The finding that more than half of the healthy elderly men had plasma ascorbic acid levels less than 0.3 mg/dl with daily intakes of ascorbic acid in the range of 40 to 50 mg raises concern about the rationale of lowering the RDA for vitamin C from the current value of 60 mg to 40 mg for men and 30 mg for women. This recommendation is inconsistent with efforts to improve the health status of elderly Americans by assuring adequate intakes of all essential nutrients. Our data do not allow us to determine an optimal intake of ascorbic acid for the elderly. The possibility of increased health benefits associated with intakes that exceed the current RDA of 60 mg needs to be examined. We believe, however, that a prudent approach to both of these questions would be to recommend that elderly receive a daily ascorbic acid intake that would allow plasma concentration to be maintained at or near 1.0 mg/dl. The daily level of intake required to maintain this level would be approximately 125 mg and 75 mg in healthy elderly men and women respectively. These intakes would assure adequate body reserves of ascorbic acid.
所呈现的数据表明，在抗坏血酸摄入量相似的情况下，老年男性的血浆抗坏血酸浓度显著低于老年女性。我们推测这种差异是由于老年男性肾小管对抗坏血酸的重吸收较低所致。超过一半的健康老年男性，其抗坏血酸日摄入量在40至50毫克范围内，但血浆抗坏血酸水平却低于0.3毫克/分升，这一发现引发了人们对于将男性维生素C的推荐膳食摄入量（RDA）从当前的60毫克降至40毫克、女性从30毫克降低的合理性的担忧。这一建议与通过确保所有必需营养素的充足摄入来改善美国老年人健康状况的努力不一致。我们的数据无法让我们确定老年人抗坏血酸的最佳摄入量。需要研究摄入量超过当前60毫克RDA可能带来的更多健康益处。然而，我们认为，对于这两个问题采取谨慎的做法是建议老年人每日摄入抗坏血酸，以使血浆浓度维持在或接近1.0毫克/分升。健康老年男性和女性维持该水平所需的每日摄入量分别约为125毫克和75毫克。这些摄入量将确保体内有足够的抗坏血酸储备。
