Anderson Richard A
Nutrient Requirements and Functions Laboratory, Beltsville Human Nutrition Research Center, US Department of Agriculture, ARS, Building 307, Room 224 BARC-East, Beltsville, MD 20705-2350, USA.
Nutr Res Rev. 2003 Dec;16(2):267-75. doi: 10.1079/NRR200366.
Insulin resistance leads to the inability of insulin to control the utilization and storage of glucose. It is associated initially with elevated levels of circulating insulin followed by glucose intolerance which may progress to type 2 diabetes, hyperlipidaemia, hypertension, obesity and cardiovascular diseases. While the causes of these diseases are multifactorial, one nutrient that is associated with all of these abnormalities is Cr. In the presence of Cr, in a biologically active form, much lower levels of insulin are required. Modern diets, which are often high in refined carbohydrates, are not only low in Cr, but lead to enhanced Cr losses. In response to the consumption of refined carbohydrates, there is a rapid rise in blood sugar leading to elevations in insulin that cause a mobilization of Cr. Once mobilized, Cr is not reabsorbed but lost via the urine leading to decreased Cr stores. Several studies involving both human subjects and experimental animals have reported improvements in insulin sensitivity, blood glucose, insulin, lipids, haemoglobin A1c, lean body mass and related variables in response to improved Cr nutrition. However, not all studies have reported beneficial effects associated with improved Cr nutrition. Well-controlled human studies are needed to document an unequivocal effect of Cr on insulin sensitivity in human subjects. Studies need to involve a significant number of subjects with insulin resistance, glucose intolerance or early stages of diabetes, who have not been taking supplements containing Cr for at least 4 months, and involve at least 400 to 600 microg supplemental Cr daily or more. Studies should be at least 4 months to document sustained effects of supplemental Cr on insulin resistance and related variables. Cr is a nutrient and not a therapeutic agent and therefore will only be of benefit to those whose problems are due to suboptimal intake of Cr.
胰岛素抵抗导致胰岛素无法控制葡萄糖的利用和储存。它最初与循环胰岛素水平升高相关，随后出现葡萄糖不耐受，进而可能发展为2型糖尿病、高脂血症、高血压、肥胖症和心血管疾病。虽然这些疾病的病因是多因素的，但与所有这些异常相关的一种营养素是铬。在有生物活性形式的铬存在时，所需的胰岛素水平要低得多。现代饮食通常富含精制碳水化合物，不仅铬含量低，还会导致铬流失增加。食用精制碳水化合物后，血糖会迅速升高，导致胰岛素升高，从而引起铬的动员。一旦被动员，铬不会被重新吸收，而是通过尿液流失，导致铬储存减少。几项涉及人类受试者和实验动物的研究报告称，改善铬营养后，胰岛素敏感性、血糖水平、胰岛素、血脂、糖化血红蛋白、瘦体重及相关变量都有所改善。然而，并非所有研究都报告了铬营养改善带来的有益效果。需要进行严格对照的人体研究，以证明铬对人类受试者胰岛素敏感性的明确作用。研究需要纳入大量患有胰岛素抵抗、葡萄糖不耐受或糖尿病早期阶段的受试者，他们至少4个月未服用含铬补充剂，且每天摄入至少400至600微克或更多的补充铬。研究应至少持续4个月，以证明补充铬对胰岛素抵抗及相关变量的持续影响。铬是一种营养素而非治疗剂，因此仅对那些因铬摄入不足而出现问题的人有益。
