降低飲食脂質攝取對年輕人血脂質與血漿脂肪酸組成的影響
Effects of low fat diet on lipids and fatty acid composition of plasma
in young adults
中文摘要 第三次國民營養調查指出，年輕人有飲食脂質過量的問題，本研究為 4 週的飲食 介入實驗，調整年輕人飲食為適當熱量、降低飲食脂質佔熱量比例，探討對血脂 質及血漿脂肪酸組成的影響。18 位女性、16 位男性共 34 位 20~30 歲的健康受試 者，攝取由營養師設計符合男性 2200 大卡、女性 1800 大卡，與碳水化合物、蛋 白質、脂質佔熱量分別為 58~68%、10~14%、20~30%原則之午餐及晚餐共 4 週(假 日不供餐)。自飲食介入前一週起，每日填寫飲食記錄，並於介入前、介入第 1、 4 週，空腹收集靜脈血。飲食介入對男女體重均無顯著影響。在飲食攝取方面， 介入前男女受試者飲食脂質佔熱量比例分別為 35.0%、37.9%，飲食介入後顯著 減少為 29.5~27.8% (平均值 28.7%)、35.1~30.3% (平均值 32.3%)。女性多元不飽 和脂肪酸、單元不飽和脂肪酸、飽和脂肪酸之比由介入前的 1.11 /1.07 /1 改變為 1.56 /1.12 /1，男性則由 1.28 /1.04 /1 變為 1.59 /1.12 /1。飲食介入亦顯著增加了男 女受試者各週的纖維攝取量。血脂質方面，介入 1 週及 4 週後，顯著降低女性血 清總膽固醇、低密度脂蛋白膽固醇，對三酸甘油酯無顯著影響，而男性除了在介 入 1 週後總膽固醇顯著降低之外，飲食介入對男性血脂質無顯著影響。血漿脂肪 酸組成方面，在介入 4 週後，女性顯著增加 14:0、18:3 n-3 脂肪酸含量，顯著降 低 20:4 含量、18:2/18:1 比例，而男性較介入前 16:0 含量顯著增加，總 n-6 多元 不飽和脂肪酸、18:2 含量顯著降低，其餘脂肪酸與介入前無顯著差異。降低年輕 人飲食脂質佔熱量比例約 5~7%，改變了飲食中飽和脂肪酸、單元不飽和脂肪酸、 飽和脂肪酸之比，4 週後使女性血脂質濃度顯著降低，並對男女之血漿脂肪酸組 成有不同的顯著改變。 英文摘要The third Nutrition Survey in Taiwan reported that young adults have a problem with excessive fat intake. The aim of this study was to investigate the effect of reducing the amount of dietary total fat as serum lipids and plasma fatty acid composition in 34 healthy young adults. This was a 4-wk interventional study using experimental meals. Sixteen male and 18 female subjects (age 20-30 yr) were given experimental meals including lunch and dinner for a 4-wk period, but on weekends and holidays, no meals were provided. The experimental meals were designed to provide 2200 kcal/day for each male subject and 1800 kcal/day for each female subject, including 20%~30% of energy from fat, 58%-68% of energy from carbohydrates, and 10%~14% of energy from protein. All subjects kept diet are records. At weeks 0, 1, and 4, blood samples were collected from fasting subjects. Intervention using experimental meals did not
affect the body weight of subjects. After the experimental-meals intervention, the energy intake had increased in male subjects, and the energy intake of dietary fat had significantly decreased from 35.0% to 28.7% in males and from 37.9% to 32.3% in females. The polyunsaturated/ monounsaturated/saturated fatty acids (P/M/S) ratios were 1.11/1.07/1 in females and 1.28/1.04/1 in males at week 0. After the 4 wk intervention, the P/M/S ratios were 1.56/1.12/1 in females and 1.59/1.12/1 in males. All subjects had significant higher intake of fiber after the experimental-meals intervention. In female subjects compared with week 0, serum total cholesterol and LDL cholesterol concentration had significantly decreased at weeks 1 and 4, serum HDL cholesterol concentration had significantly decreased only at week 4, and there was no significant difference in serum triglyceride concentrations after the
experimental-meals intervention. In male subjects, only serum total cholesterol concentration had significantly decreased at week 1. The experimental-meals intervention was associated with significantly greater 14:0 and 18:3 n-3 levels as percentages of total plasma fatty acids and with a significantly lower 20:4 level and 18:2/18:1 ratio as percentages of total plasma fatty acids in females. In male subjects, the 16:0 level of total plasma fatty acids had significantly increased, and the 18:2 and total n-6 polyunsaturated fatty acids levels as percentages of total plasma fatty acids had significantly decreased compared with week 0. Therefore, the benefits of
lowering dietary fat intake to 5%-7% of energy may favor changes in serum lipids in females and in plasma fatty acid composition in both males and females.
