Koutsari C, Malkova D, Hardman A E
Human Muscle Metabolism Research Group, Loughborough University, Leicestershire, UK.
Metabolism. 2000 Sep;49(9):1150-5. doi: 10.1053/meta.2000.8612.
Replacement of dietary fat with carbohydrate may not reduce the overall risk of coronary heart disease (CHD), because this elevates plasma triacylglycerol (TAG) concentrations. The lipoproteinemic effects of a high-carbohydrate diet are likely to be more marked shortly after the initiation of such a diet than after longer periods of intervention during which adaptive processes may counteract the initial effects. Therefore, we studied the postprandial responses to a standard meal after 3-day dietary intervention periods. An additional objective was to establish a model for future study of the mechanisms involved. Nine normolipidemic men consumed the meal (1.2 g fat, 1.1 g carbohydrate, and 0.2 g protein per 1 kg body mass) after 3 days on a high-carbohydrate diet (68% +/- 3% energy from carbohydrate, mean +/- SD) and also after 3 days on an isoenergetic high-fat diet (66% +/- 5% energy). Venous blood samples were obtained from fasted subjects and for 6 hours after the meal. In the fasted state, TAG was higher after the high-carbohydrate diet (1.18 +/- 0.18 v0.62 +/- 0.09 mmol/L, mean +/- SEM, P = .02) and high-density lipoprotein (HDL) cholesterol was lower (1.01 +/- 0.08 v 1.10 +/- 0.09 mmol/L, P = .002). The area under the plasma TAG concentration versus time curve was 42% +/- 7% higher after the high-carbohydrate diet (P = .003). After the high-carbohydrate diet, the postprandial insulin response did not differ between trials, but glucose and 3-hydroxybutyrate responses were lower (P = .009 and P = .02, respectively) and the lactate response was higher (P = .001). Plasma nonesterified fatty acids (NEFAs) were lower after the high-carbohydrate diet in the fasted state and for 4 hours postprandially, but were higher thereafter (interaction of time x trial, P = .001). These results indicate that compared with a high-fat diet, the plasma TAG response to a standard high-fat meal is markedly higher after a few days on a high-carbohydrate diet, with major differences in the associated metabolic milieu. The magnitude of these changes and the rapidity with which they developed suggest that this model may be attractive for future studies of the underlying mechanisms.
用碳水化合物替代膳食脂肪可能不会降低冠心病（CHD）的总体风险，因为这会升高血浆三酰甘油（TAG）浓度。高碳水化合物饮食对血脂的影响在开始这种饮食后不久可能比在较长时间的干预后更为明显，在较长时间的干预过程中，适应性过程可能会抵消初始影响。因此，我们研究了3天饮食干预期后对标准餐的餐后反应。另一个目标是建立一个模型，以便将来研究其中涉及的机制。9名血脂正常的男性在高碳水化合物饮食（碳水化合物提供68%±3%的能量，均值±标准差）3天后以及等能量高脂肪饮食（66%±5%的能量）3天后食用了该餐（每1千克体重含1.2克脂肪、1.1克碳水化合物和0.2克蛋白质）。从空腹受试者身上采集静脉血样，并在餐后6小时内采集。在空腹状态下，高碳水化合物饮食后的TAG更高（1.18±0.18对0.62±0.09毫摩尔/升，均值±标准误，P = 0.02），高密度脂蛋白（HDL）胆固醇更低（1.01±0.08对1.10±0.09毫摩尔/升，P = 0.002）。高碳水化合物饮食后血浆TAG浓度随时间变化曲线下的面积高出42%±7%（P = 0.003）。高碳水化合物饮食后，餐后胰岛素反应在各试验之间没有差异，但葡萄糖和3 - 羟基丁酸反应更低（分别为P = 0.009和P = 0.02），乳酸反应更高（P = 0.001）。高碳水化合物饮食后，空腹状态下以及餐后4小时内血浆非酯化脂肪酸（NEFAs）更低，但此后更高（时间×试验的交互作用，P = 0.001）。这些结果表明，与高脂肪饮食相比，在高碳水化合物饮食几天后，血浆TAG对标准高脂肪餐的反应明显更高，且相关代谢环境存在重大差异。这些变化的幅度及其发展速度表明，该模型可能对未来潜在机制的研究具有吸引力。
