Meksawan Kulwara, Pendergast David R, Leddy John J, Mason Melanie, Horvath Peter J, Awad Atif B
Department of Exercise and Nutrition Sciences, School of Public Health and Health Professions and School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York 14214, USA.
J Am Coll Nutr. 2004 Apr;23(2):131-40. doi: 10.1080/07315724.2004.10719353.
The desired level of dietary fat intake is controversial. The effect of decreasing fat intake to 19% and increasing it to 50% from a control diet of 30% on nutritional status and cardiovascular risk factors in healthy individuals was studied.
Eleven healthy subjects (5 men and 6 women) were randomized to consume diets with 19% and 50% calories from fat. Each diet lasted 3 weeks, with a one-week washout. The habitual and washout diets were determined to be 30% fat. At the beginning and the end of each diet, fasting blood was collected to determine plasma lipoproteins, and physiological factors were measured.
Total caloric expenditure was similarly balanced to intake on the 30% and 50% fat diets, but intake was significantly lower on the 19% fat diet and led to a loss of 0.6 kg body weight. Consumptions of essential fatty acids, vitamin E and zinc were improved with increased fat intake, but folate intake was compromised on the 30% and 50% fat diets. Compared with the 50% fat diet, subjects consuming the 19% fat diet had significantly lower HDL cholesterol (HDL-C) (54 +/- 3 vs. 63 +/- 3 mg. dL(-1), p < 0.05) and apolipoprotein A1 (ApoA1) (118 +/- 4 vs. 127 +/- 3 mg/dL, p < 0.05). Changing the levels of fat intake did not affect % body fat, heart rate, blood pressure, blood triglycerides, total cholesterol (TC), LDL cholesterol, apolipoprotein B (ApoB), TC/HDL-C and ApoA1/ApoB ratios.
A low fat diet (19%) may not provide sufficient calories, essential fatty acids, and some micronutrients (especially vitamin E and zinc) for healthy untrained individuals, and it also lowered ApoA1 and HDL-C. Increasing fat intake to 50% of calories improved nutritional status, and did not negatively affect certain cardiovascular risk factors.
膳食脂肪摄入的理想水平存在争议。本研究探讨了将健康个体的脂肪摄入量从对照饮食的30%降至19%以及增至50%对营养状况和心血管危险因素的影响。
11名健康受试者（5名男性和6名女性）被随机分配食用脂肪供能占19%和50%的饮食。每种饮食持续3周，中间有1周的洗脱期。习惯性饮食和洗脱期饮食的脂肪含量均为30%。在每种饮食开始和结束时，采集空腹血样以测定血浆脂蛋白，并测量生理指标。
在脂肪供能占30%和50%的饮食中，总热量消耗与摄入量相似，但脂肪供能占19%的饮食摄入量显著较低，导致体重减轻0.6千克。随着脂肪摄入量增加，必需脂肪酸、维生素E和锌的摄入量有所改善，但在脂肪供能占30%和50%的饮食中叶酸摄入量受到影响。与脂肪供能占50%的饮食相比，食用脂肪供能占19%饮食的受试者高密度脂蛋白胆固醇（HDL-C）显著降低（54±3对63±3毫克/分升，p<0.05），载脂蛋白A1（ApoA1）也显著降低（118±4对127±3毫克/分升，p<0.05）。改变脂肪摄入水平对体脂百分比、心率、血压、血甘油三酯、总胆固醇（TC）、低密度脂蛋白胆固醇、载脂蛋白B（ApoB）、TC/HDL-C和ApoA1/ApoB比值无影响。
低脂饮食（19%）可能无法为健康的未受过训练的个体提供足够的热量、必需脂肪酸和一些微量营养素（尤其是维生素E和锌），并且还会降低ApoA1和HDL-C。将脂肪摄入量增至热量的50%可改善营养状况，且不会对某些心血管危险因素产生负面影响。
