Abstract
Background
The fatty acid (FA) composition of serum lipids is related to the quality of dietary fat intake.
Objective
To investigate the effects of a healthy Nordic diet (ND) on the FA composition of serum cholesterol esters (CE-FA) and assess the associations between changes in the serum CE-FA composition and blood lipoproteins during a controlled dietary intervention.
Design
The NORDIET trial was a 6-week randomised, controlled, parallel-group dietary intervention study that included 86 adults (53±8 years) with elevated low-density lipoprotein cholesterol (LDL-C). Serum CE-FA composition was measured using gas chromatography. Diet history interviews were conducted, and daily intake was assessed using checklists.
Results
Food and nutrient intake data indicated that there was a reduction in the intake of fat from dairy and meat products and an increase in the consumption of fatty fish with the ND. The levels of saturated fatty acids in cholesterol esters (CE-SFA) 14:0, 15:0, and 18:0, but not 16:0, showed a significant decrease after intake of ND compared to the control diet (p<0.01). Also, a significant increase in serum 22:6n – 3 was observed compared with the control diet (p<0.01). The changes in CE-SFA 14:0, 15:0, and 18:0 correlated positively with changes in LDL-C, HDL-C, LDL-C/HDL-C, ApoA1, and ApoB (p<0.01), respectively, whereas the changes in polyunsaturated fatty acids in cholesterol esters (CE-PUFA) 22:6n – 3 were negatively correlated with changes in the corresponding serum lipids.
Conclusions
The decreased intake of saturated fat and increased intake of n-3 PUFA in a healthy ND is partly reflected by changes in the serum CE-FA composition, which are associated with an improved serum lipoprotein pattern.
Authors' contributions
VA conceived the study and participated in the design, data acquisition, data analysis, and manuscript writing. BV conceived the study, participated in the design and data analysis, provided critical advice, and helped draft the manuscript. TC participated in the design, provided critical advice, and helped draft the manuscript. UR conceived the study, participated in the design and data analysis, provided critical advice, and helped draft the manuscript.
Acknowledgements
We thank Siv Tengblad for assessing the CE-FA composition and the Cerealia Foundation for funding the study.
Conflicts of interest and funding
The study was mainly financed by a research grant given to VA from the Cerealia Foundation. VA was employed by Lantmännen R&D at the time of data collection. The Lantmännen group is owned by Swedish farmers and operates within the food, energy, and agricultural industries. UR was funded by the Swedish Research Council and the Zetterling Foundation. UR, BV, and TC have no conflicts of interest. The sponsors had no role in the design and conduct of the study; the collection, management, analysis, and interpretation of the data; or the preparation, review, or approval of the manuscript.