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Comparison of n-3 and n-6 PUFA composition of erythrocyte membrane and of plasma NEFA between pregnant and non-pregnant adolescents

Published online by Cambridge University Press:  28 January 2009

Flavia Meneses
Affiliation:
Laboratório de Bioquímica Nutricional e de Alimentos, Instituto de Química, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
Jacqueline G. Ney
Affiliation:
Laboratório de Bioquímica Nutricional e de Alimentos, Instituto de Química, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
Alexandre G. Torres
Affiliation:
Laboratório de Bioquímica Nutricional e de Alimentos, Instituto de Química, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
Nádia M. F. Trugo
Affiliation:
Laboratório de Bioquímica Nutricional e de Alimentos, Instituto de Química, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
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Abstract

Type
Abstract
Copyright
Copyright © The Authors 2009

When pregnancy occurs during adolescence the specific metabolic changes of gestation(Reference Herrera1) are superimposed on those characteristic of adolescence(Reference Mascarenhas, Zemel and Tershakovec2), and the combination of both periods might further affect adipose tissue(Reference Hediger, Scholl and Schall3), and possibly fatty acid metabolism. The objective of the present study was to evaluate the influence of pregnancy in adolescents on the composition of plasma NEFA, as a proxy for fatty acids mobilized from adipose tissue, and of erythrocyte membrane (EM) fatty acids, as a proxy for maternal status of essential fatty acids (EFA) and long-chain (LC) PUFA. Two groups of healthy adolescents (age 14–19 years), matched according to age, habitual diets and general socio-economic backgrounds, from Rio de Janeiro, Brazil were compared: non-pregnant (NP; n 20); pregnant (P; n 26; 32.7 (sd 3.9) weeks of gestation). Blood samples were collected after overnight fasting. Fatty acid composition of NEFA and EM were determined by GC. EM fatty acid composition was used to calculate indices of fatty acid status as follows: EFA status index ([Σ n–3+Σ n–6]/[Σ n–7+Σ n–9]; EFASTI); DHA status indices, 22:5n–6/22:4n–6 and 22:6n–3/22:5n–6). Dietary intake of n–3 PUFA was similar and below the current recommendations(4) in both groups, especially in group P. Total plasma NEFA was higher (P<0.001) in group P (1300 (sd 144) μmol/l) than in group NP (623 (sd 15) μmol/l), as a result of a higher mobilization of fatty acids from adipose tissue after fasting. Contents of NEFA 18:2n-6 and 20:4n-6 were higher in group P than in NP (Table). However, EM 20:4n-6, total n-6 and total PUFA were lower (P<0.05) in group P. NEFA and EM fatty acid compositions were not associated with BMI, age, age at menarche, period (years) post menarche and weeks of gestation. The EFA status and the DHA status for group P were similar to the values for group NP (Table) and of Brazilian pregnant adults(Reference Pontes, Torres and Trugo5), but DHA status was lower than that of pregnant adults from The Netherlands(Reference Vlaardingerbroek and Hornstra6).

Table. Plasma NEFA and EM composition (g/100 g) and status indices for groups P (n 26) and NP (n 20)

Values were significantly different from those for group NP (Student's t test):

* P<0.05.

These findings are consistent with the dietary pattern of Brazilian women, with a relatively high intake of n-6 PUFA and low intake of preformed n-3 LC PUFA, especially DHA.

Supported by: CNPq, CAPES, and FAPERJ (Brasil). F.M. and J.G.N. were recipients of studentships, and N.M.F.T. of a fellowship from CNPq.

References

1. Herrera, E (2000) Eur J Clin Nutr 54, S47S51.CrossRefGoogle Scholar
2. Mascarenhas, MR, Zemel, BS, Tershakovec, AM et al. (2001) In Present Knowledge in Nutrition, 8th ed. [BA Bowman and RM Russell, editors]. Washington, DC: ILSI Press.Google Scholar
3. Hediger, ML, Scholl, TO & Schall, JI (1997) Ann N Y Acad Sci 817, 281291.Google Scholar
4. Institute of Medicine (2002) Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. Washington, DC: The National Academies Press.Google Scholar
5. Pontes, PV, Torres, AG, Trugo, NMF et al. (2006) Prostaglandins Leukot Essent Fatty Acids 74, 117123.CrossRefGoogle Scholar
6. Vlaardingerbroek, H & Hornstra, G (2004) Prostaglandins Leukot Essent Fatty Acids 71, 363374.Google Scholar
Figure 0

Table. Plasma NEFA and EM composition (g/100 g) and status indices for groups P (n 26) and NP (n 20)