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

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

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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。

Effects of low fat diet on lipids and fatty acid composition of plasma in young adults

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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 lipid s 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 inc luding lunch and dinner for a 4-wk period, but on weekends and holidays, no meals were provided. The ex perimental 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 su bjects. 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 3 2.3% 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 experi

mental-meals intervention. In female subjects compared with week 0, serum total cholesterol and LDL chol

esterol concentration had significantly decreased at weeks 1 and 4, serum HDL cholesterol concentration h

ad significantly decreased only at week 4, and there was no significant difference in serum triglyceride con

centrations after the experimental-meals intervention. In male subjects, only serum total cholesterol concen

tration had significantly decreased at week 1. The experimental-meals intervention was associated with sig

nificantly greater 14:0 and 18:3 n-3 levels as percentages of total plasma fatty acids and with a significantl

y lower 20:4 level and 18:2/18:1 ratio as percentages of total plasma fatty acids in females. In male subject

s, the 16:0 level of total plasma fatty acids had significantly increased, and the 18:2 and total n-6 polyunsat

urated fatty acids levels as percentages of total plasma fatty acids had significantly decreased compared wit

h week 0. Therefore, the benefits of lowering dietary fat intake to 5%-7% of energy may favor changes in s

erum lipids in females and in plasma fatty acid composition in both males and females.