| Summary: | 碩士 === 臺北醫學大學 === 保健營養學系 === 91 === 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.
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