| Objective: To explore the lipid-lowering effect of plant-derived n-3polyunsaturated fatty acid(n-3 PUFA)on marginal dyslipidemia subjects,and its effect on plasma and erythrocyte membrane fatty acid levels.Methods: This study is a double blind randomized controlled trial(RCT)with plant-derived n-3 PUFAs oil capsules as intervention.Marginal dyslipidemia and dyslipidemia subjects meet the criteria that serum total cholesterol(TC)≧ 5.2mmol/L(200 mg/dl)or serum triglyceride(TG)≧ 1.70 mmol/L(150 mg/dl)and other items could be included.Then the subjects would be assigned to the intervention group or the control group according to the community-stratified random number method.During the intervention period,neither the subjects nor the investigators would aware of the grouping situation,and two groups have same experimental procedures and capsules with consistent characteristics,to reduce confounding and ensure the objective and reliable experimental results.Subjects in both groups were given plant-derived oil capsules containing the same amount of Total fatty acids,the intervention group takes plant-derived n-3 PUFAs oil capsules with main active ingredients alpha-linolenic acid(ALA)and stearidonic acid(SDA),with n-3 PUFAs content of 41.20 %,the control group takes corn oil capsules with n-3 PUFAs content of 0.56 %.Subjects will take 4 g oil capsules per day for 12 weeks.Before the intervention and at the 6th week,the 12 th week of intervention,all subjects could received questionnaire survey,3 days 24 hours dietary recall,anthropometric indicators measurement,and blood samples collection to determine clinical biochemistry indicators,plasma and erythrocyte membrane fatty acid levels.The collected data would analyzed by two-factor(time×group)repeated-measures analysis of variance,and the changes before and after intervention would be compared between two groups,if significant,the within-group comparisons would be conducted.Results: In this study,a total of 1605 people wes screened for blood lipids and 255 of these met the inclusion criteria,75 subjects signed informed consent and enrolled into study.Before the intervention,there were no significant difference in height,weight,BMI,waist or hip circumference,blood pressure,smoking,drinking habits,blood lipid indicators,plasma erythrocyte cell membrane fatty acids component level and dietary total PUFAs intake between the 2 groups.During the intervention,12 patients in the intervention group and the control group discontinued,respectively.After intervention,26 subjects in intervention group and 25 subjects in control group who met the data requirements were included in the statistic analysis,the medication compliance of 2groups was high and the average medication rates of intervention group and control group were 83.8 % and 84.5 %,respectively.The results of 3 days 24 hours dietary recall showed that there was no significant difference in nutritional status between 2groups before and after intervention.In the plasma samples,there was a statistical significance of the EPA level(mole percentage)on the time × group interaction effect(P =0.02).At baseline,the 6th and 12 th week,the EPA levels of intervention group were0.58±0.39,0.72±0.44,and 0.77±0.43,respectively,with a total increase of 0.19±0.48,however,there was no significant difference between the changes of two groups and comparison within each group(P >0.05).The plasma DPA level of n-3 PUFAs intervention group was 0.44±0.15 at baseline,and significantly increased at the 6th week and 12 th week(P < 0.05),the level were 0.52±0.16,0.55±0.16,respectively,with a total increase of 0.12±0.16.While there was no significant change in control group,the total change during intervention in two groups of DPA levels had significant difference(P = 0.02).In the erythrocyte membrane samples,there was a statistical significance of the EPA level(mole percentage)on the time × group interaction effect(P =0.02),the EPA level of n-3 PUFAs intervention group was 0.31±0.15,and significantly increased at the 6th and 12 th week(P < 0.05),the level were 0.37±0.18,0.41±0.18,respectively,with a total increase of 0.10±0.13.While there was no significant change during intervention in control group,the total change of EPA levels during intervention in two groups had significant difference(P = 0.02).The results of repeated-measures analysis of variance showed that there were statistical significance in the interaction effect between time × group of TC and LDL-C(P values were 0.03 and0.05,respectively).The TC levels of n-3 PUFAs intervention group was 5.8±1.1mmol/L at baseline,and significantly reduced at the 6th week and 12 th week(P < 0.05),and the level were 5.5±1.0 mmol/L,5.4±0.9 mmol/L,respectively,with a total reduction of 0.4 ± 0.8 mmol/L.While there was no significant change during intervention in control group,the total change in two groups of TC levels during intervention has significant difference(P = 0.04).In addition,the LDL-C levels in the n-3 PUFAs intervention group were 3.5±0.7mmol/L,3.3±0.7mmol/L,and 3.3±0.7mmol/L at baseline,the 6th week and 12 th week,respectively,with a total reduction of 0.2 ± 0.6mmol /L.Among them,LDL-C levels at the 6th week were significantly lower than baseline(P <0.05),while LDL-C levels in the control group were not significantly changed during intervention.There was no significant change of TG,HDL-C and Apo A1,Apo B during intervention.Conclusions: plant-derived n-3 PUFA oil capsules with ALA and SDA as the main active components could reduce the levels of TC and LDL-C in patients of dyslipidemia,and increase the levels of long chain n-3 PUFAs in the circulation,especially EPA and DPA. |
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