Sabaté J, Fraser G E, Burke K, Knutsen S F, Bennett H, Lindsted K D
Center for Health Research, School of Public Health, Loma Linda University, CA 92350.
N Engl J Med. 1993 Mar 4;328(9):603-7. doi: 10.1056/NEJM199303043280902.
In a recent six-year follow-up study, we found that frequent consumption of nuts was associated with a reduced risk of ischemic heart disease. To explore possible explanations for this finding, we studied the effects of nut consumption on serum lipids and blood pressure.
We randomly placed 18 healthy men on two mixed natural diets, each diet to be followed for four weeks. Both diets conformed to the National Cholesterol Education Program Step 1 diet and contained identical foods and macronutrients, except that 20 percent of the calories of one diet (the walnut diet) were derived from walnuts (offset by lesser amounts of fatty foods, meat, and visible fat [oils, margarine, and butter]).
With the reference diet, the mean (+/- SD) serum values for total, low-density lipoprotein (LDL), and high-density lipoprotein (HDL) cholesterol were, respectively, 182 +/- 23, 112 +/- 16, and 47 +/- 11 mg per deciliter (4.71 +/- 0.59, 2.90 +/- 0.41, and 1.22 +/- 0.28 mmol per liter). With the walnut diet, the mean total cholesterol level was 22.4 mg per deciliter (0.58 mmol per liter) lower than the mean level with the reference diet (95 percent confidence interval, 28 to 17 mg per deciliter [0.72 to 0.44 mmol per liter]); the LDL and HDL cholesterol levels were, respectively, 18.2 mg per deciliter (0.47 mmol per liter) (P < 0.001) and 2.3 mg per deciliter (0.06 mmol per liter) (P = 0.01) lower. These lower values represented reductions of 12.4, 16.3, and 4.9 percent in the levels of total, LDL, and HDL cholesterol, respectively. The ratio of LDL cholesterol to HDL cholesterol was also lowered (P < 0.001) by the walnut diet. Mean blood-pressure values did not change during either dietary period.
Incorporating moderate quantities of walnuts into the recommended cholesterol-lowering diet while maintaining the intake of total dietary fat and calories decreases serum levels of total cholesterol and favorably modifies the lipoprotein profile in normal men. The long-term effects of walnut consumption and the extension of this finding to other population groups deserve further study.
在最近一项为期六年的随访研究中，我们发现经常食用坚果与缺血性心脏病风险降低有关。为探究这一发现的可能原因，我们研究了食用坚果对血脂和血压的影响。
我们将18名健康男性随机安排采用两种混合天然饮食，每种饮食持续四周。两种饮食均符合美国国家胆固醇教育计划第一步饮食标准，且包含相同的食物和常量营养素，只是其中一种饮食（核桃饮食）20%的热量来自核桃（由较少的脂肪类食物、肉类和可见脂肪[油、人造黄油和黄油]抵消）。
以参考饮食而言，总胆固醇、低密度脂蛋白（LDL）和高密度脂蛋白（HDL）胆固醇的平均（±标准差）血清值分别为每分升182±23、112±16和47±11毫克（每升4.71±0.59、2.90±0.41和1.22±0.28毫摩尔）。采用核桃饮食时，总胆固醇平均水平比参考饮食平均水平低22.4毫克每分升（0.58毫摩尔每升）（95%置信区间，28至17毫克每分升[0.72至0.44毫摩尔每升]）；LDL和HDL胆固醇水平分别低18.2毫克每分升（0.47毫摩尔每升）（P<0.001）和2.3毫克每分升（0.06毫摩尔每升）（P = 0.01）。这些较低的值分别代表总胆固醇、LDL和HDL胆固醇水平降低了12.4%、16.3%和4.9%。核桃饮食还降低了LDL胆固醇与HDL胆固醇的比值（P<0.001）。在两个饮食阶段，平均血压值均未改变。
在推荐的降胆固醇饮食中加入适量核桃，同时保持膳食总脂肪和热量的摄入量，可降低正常男性的血清总胆固醇水平，并有利于改善脂蛋白谱。食用核桃的长期影响以及将这一发现推广到其他人群值得进一步研究。
