Short‐term biological reproducibility of serum fatty acid composition in children

Abstract

To assess the biological day-to-day reproducibility of the fatty acid composition in serum lipid fractions in children on their habitual diets, fasting serum specimens were collected from healthy 8- to 9-year-old boys at 2-day (n = 21) or 7-day (n = 19) intervals. Percentage compositions of fatty acids in serum cholesteryl esters (CE), triglycerides (TG), free fatty acids (FFA) and phospholipids (PL) were analyzed by gas chromatography. The reproducibility was estimated by calculating linear correlation coefficients between the values obtained at the two time-points. Generally the correlations were higher in CE and PL than in TG and FFA. In CE the 7-day correlations of major fatty acids were only slightly lower than the 2-day ones. In PL the impairment of correlations was somewhat greater than in CE, but in TG and FFA there was a marked drop in reproducibility from 2- to 7-day intervals. The 2-day correlation coefficients of the percentages of linoleate, dihomo-gamma-linolenate, arachidonate and eicosapentaenoate in CE were 0.95, 0.84, 0.91 and 0.92, respectively. In PL, the respective values were 0.86, 0.82, 0.95 and 0.90. The present results indicate high short-term biological reproducibility of fatty acid composition in serum CE and PL and clearly lower in those of TG and FFA.

Serum fatty acids and risk of advanced β-cell autoimmunity: a nested case–control study among children with HLA-conferred susceptibility to type I diabetes

“…The daily intra-individual variation is more marked in the fatty acid profile of triglycerides and free fatty acids than in the fatty acid profile of cholesterol esters and phospholipids (Moilanen, 1987). The lipid fractions in serum differ in their fatty acid composition (Nikkari et al, 1983;Moilanen, 1987) and changes in relative proportions of lipid fractions also affect the percentages of fatty acids in serum. For this reason we applied a separate statistical model, which was adjusted for serum cholesterol concentration.…”

“…Most likely, the discrepancy in results is caused by different methods used for the assessment of fatty acid status. The fatty acid composition of erythrocyte membranes describes the intake of n-3 fatty acids over a period of 4-6 weeks (Baur et al, 2000), whereas our method reflects the intake during the preceding 1 to 2 weeks (Moilanen, 1987;Katan et al, 1997;Arab, 2003). An important source of n-3 fatty acids in the diet is fatty fish, which is consumed rather rarely by young children (Ylönen et al, 1996).…”

Plasma essential fatty acids, cigarette smoking, and dietary antioxidants in peripheral arterial disease. A population-based case-control study.

“…24 In this study, fatty acid levels were measured in three plasma fractions: the triglyceride fraction, which primarily reflects recent dietary intake, plus the phospholipid and cholesteryl ester fractions, which are more independent of recent intake and are probably better indicators of the longer-term composition of dietary fats. 25 Several epidemiological studies have concentrated on measuring adipose tissue fatty acids, but this method provides information mostly about long-term nutritional supply of linoleic acid and provides little information with respect to subsequent metabolism, as levels of metabolites are very low in adipose tissue. 26 In this study, there were few differences in the levels of n-6 fatty acids between case and control subjects.…”

Effect of low-saturated fat, low-cholesterol dietary intervention on fatty acid compositions in serum lipid fractions in 5-year-old children. The STRIP project

“…Changes in the fatty acid composition of TG take place rapidly in response to changes in the diet, that is, signi®cant changes can be detected within one to two days, whereas changes in CE and PL fatty acids occur more slowly, that is, within one to two weeks Vessby et al, 1980). Consequently, it is easy to understand that the long-term reproducibility of TG fatty acid composition is poorer than that of CE or PL (Moilanen, 1987). This was also demonstrated in the STRIP children as the correlation of dietary fatty acids with the fatty acids in TG was signi®-cantly better when blood samples were drawn for determination of TG fatty acid compositions immediately after the four-day food records than when there was an interval of 5 to 15 days between food records and drawing of the blood sample (Lagstro Èm et al, 1998).…”

“…Adipose tissue is regarded a reliable marker of long-term fat intake representing mean fat intake of 2 ± 3 y duration whereas the others re¯ect intake of fat during the preceding few weeks (CE, PL, cell membrane lipids Glatz et al, 1989)) or days (TG (Moilanen, 1987)). …”