Fish intake, erythrocyten-3 fatty acid status and metabolic health in Danish adolescent girls and boys

Abstract

Marine n-3 long-chain PUFA (n-3 LCPUFA) may have a beneficial effect on several aspects of the metabolic syndrome (dyslipidaemia, insulin resistance, hypertension and abdominal obesity). The metabolic syndrome is increasing in prevalence during adolescence, but only few studies have investigated the effects of n-3 LCPUFA in adolescence. The present study examines associations between fish intake (assessed by a 7 d pre-coded food diary), erythrocyte (RBC) DHA status (analysed by GC) and metabolic syndrome measures (anthropometry, blood pressure and plasma lipids, insulin and glucose) in 109 17-year-old children from the Copenhagen Birth Cohort Study. Of the children, 8 % were overweight or obese and few showed signs of the metabolic syndrome, but all the metabolic syndrome variables were correlated. Median fish intake was 10·7 (interquartile range 3·6-21·2) g/d. Boys tended to have a higher fish intake (P¼ 0·052), but girls had significantly higher RBC levels of DHA (P¼ 0·001). Sex and fish intake explained 37 % of the variance in RBC-DHA (P,0·001). After adjusting for confounders, high DHA status was found to be significantly correlated with higher systolic blood pressure (P¼ 0·014) and increased fasting insulin (P¼ 0·018), but no adverse association was observed with the mean metabolic syndrome z-score. Overall, the present study showed the expected association between fish intake and RBC-DHA, which in contrast to our expectations tended to be associated with a poorer metabolic profile. Whether these results reflect the physiological function of n-3 LCPUFA, lifestyle factors associated with fish intake in Denmark, or mere chance remains to be investigated.

Usual dietary fatty acid intakes and red-blood-cell membrane fatty acid composition in Inuit children attending child-care centres in Nunavik, northern Québec, Canada

“…This is in agreement with the positive association observed between breast-feeding duration and RBC DHA and EPA levels in Danish adolescents (8) . When replacing breast-feeding status by breast-feeding duration, we observed a positive and significant association with RBC n-3 PUFA but not with RBC n-6 PUFA.…”

Associations of Whole Blood n-3 and n-6 Polyunsaturated Fatty Acids with Blood Pressure in Children and Adolescents – Results from the IDEFICS/I.Family Cohort

“…Beneficial effects of n-3 PUFA on BP have been shown in several intervention studies investigating the effect of supplemental FA intake [48–50] and in observational studies investigating dietary intake [8, 23, 51–53]. While observational studies investigating the association of n-3 PUFA blood levels and BP showed beneficial effects in adults [11, 42], results in children and adolescents were not consistent and indicated unfavorable effects [24, 25, 40]. In a Danish cross-sectional study including 8–11 year old children, whole-blood EPA was associated with a 2.7 mmHg higher DBP per weight% EPA in boys but not in girls [24].…”

“…In agreement with this, our data point to an inverse association of DHA with SBP in thin/normal weight children at baseline though the effect estimate did not reach statistical significance. In contrast, two smaller cross-sectional studies showed that whole-blood DHA was positively associated with DBP in 8–11 year old boys [40] and that erythrocyte DHA was positively related with SBP in 17 year old adolescents [25]. …”

“…Three studies reported positive associations between childhood n-3 LC PUFA and BP. In Danish children, cross-sectional data indicated whole blood EPA to be positively associated with DBP in boys but not in girls [24] while in Danish adolescents DHA was positively associated with SBP [25]. In a Finnish cohort, the sum of serum cholesterylester n-3 PUFA in childhood was positively associated with BP in adulthood after 27 years in males but not in females [26].…”

The Metabolic Syndrome and the Membrane Content of Polyunsaturated Fatty Acids in Hypertensive Patients

“…11 Nonetheless, studies that have investigated the effects of PUFA supplementation on cardiovascular risk factors and cardiovascular outcomes have yielded inconsistent results. [12][13][14] Because fatty acids are normal constituents of cell membranes, measurement of fatty acids composition and calculation of the ratio of polyunsaturated to saturated fatty acid components (PUFA/SFA) in red blood cell (RBC) membranes reflects the fatty acid content of the diet 15 and has been used as a reliable biomarker of fatty acid intake in epidemiological studies. 16 We have recently reported that the RBC membrane content of PUFA of the n-3 family (n-3 PUFA) affects the vascular response to vasodilators 17 and that a diet rich in PUFA that increases the n-3 PUFA content of RBC membrane decreases 24-hour blood pressure levels 18 and the carotid intima-media thickness in hypertensive patients.…”