Dietary linoleic acid influences desaturation and acylation of deuterium-labeled linoleic and linolenic acids in young adult males

Emken, E. A.; Adlof, R. O.; Gulley, R. M.

doi:10.1016/0005-2760(94)00054-9

Cited by 426 publications

(293 citation statements)

References 40 publications

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“…However, we hardly found any 13 C enrichment in plasma of these latter two fatty acids. This is in agreement with results of Emken et al, (1994Emken et al, ( , 1998. These ®ndings may be due to the preferential b-oxidation of C22X4n-6 rather than esteri®cation, and the preferential esteri®cation of C20X4n-6 rather than b-oxidation (Verdino et al, 1964;Sprecher, 1967;Sprecher et al, 1995).…”

Section: Discussionsupporting

confidence: 91%

“…Furthermore, a small percentage was detected as its longer chain metabolites in plasma. Since Emken et al have demonstrated that on average 92% of the linoleic acid may be absorbed (Emken et al, 1994), a large part of the tracer is still missing. Parts of the tracer may be incorporated into membranes or stored in adipose tissue reserves.…”

Section: Discussionmentioning

confidence: 99%

“…In 1967, Nichaman et al reported the in vivo oxidation and conversion of 14 C labelled linoleic acid into arachidonic acid in normo-and hyperlipidemic males (Nichaman et al, 1967). More recently, the conversion of deuterated linoleic acid has been demonstrated in three human studies (Emken et al, 1994(Emken et al, , 1998(Emken et al, , 1999. In these studies, however, large doses of deuterated linoleic acid were administered, which may have decreased the dietary n-3 to n-6 fatty acid ratio considerably.…”

Section: Introductionmentioning

confidence: 99%

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The metabolism of linoleic acid in healthy subjects after intake of a single dose of 13C-linoleic acid

et al. 2001

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Objective: To investigate the in vivo oxidation of 13 C18X2n-6 and its conversion into longer-chain polyunsaturates (LCPs) in healthy subjects. Design: Blood samples were collected from six subjects before (fasted) and 7, 11 (non-fasted), 24, 48, 72, 168 and 336 h (fasted) after ingestion of a single bolus of 45 mg uniformly labeled 13 C18X2n-6 dissolved in 8 g olive oil. In three subjects, breath was also sampled and CO 2 production measured every hour during the ®rst 12 h. Subjects consumed their habitual diets. Plasma 13 C-enrichments were measured by GC-C-IRMS and fatty acid compositions by GCaFID. Setting: Maastricht University, Department of Human Biology. Subjects: Three men and three women, recruited by local advertisement. Results: The traceratracee ratio (TTR) of C18X2n-6 in plasma total lipids was already increased 5 h after tracer intake. The mean peak amount (AE s.e.m) of 13 C18X2n-6 (3.4AE 0.8 mg; 7.6% of dose) was found after about 17 h, 13 C18X3n-6 (0.018 AE 0.008 mg; 0.04% of dose) after 7 ± 48 h, and 13 C20X3n-6 (0.028 AE 0.011 mg; 0.06% of dose) after 48 ± 336 h. Time to peak TTRs of C20X4n-6 varied between subjects and were on average 0.022 AE 0.006 mg (0.05% of dose). The proportion of 13 C18X2n-6 recovered in breath after 12 h ranged between 16.8 and 25.1%. Conclusions: These ®ndings suggest that a single bolus of 45 mg U-13 C18X2n-6 can be used to study the oxidation of 13 C18X2n-6. However, because of the low TTRs for C20X4n-6, a higher dose is recommended for studying the conversion of 13 C18X2n-6 into LCPs. In addition, since only about 35% of the tracer was found in plasma total lipids and as 13 CO 2 in breath, it might be necessary to study other accessible lipid fractions as well to study the overall conversion of linoleic acid.

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Section: Discussionsupporting

confidence: 91%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The metabolism of linoleic acid in healthy subjects after intake of a single dose of 13C-linoleic acid

et al. 2001

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“…In vitro, with the exception of one study (Maniongui et al, 1993) desaturation of fatty acids by the liver was found to decrease at advanced ages in rat (Peluffo & Brenner, 1974;Bordini et al, 1988;Choi et al, 1989;Biagi et al, 1991) and in Latent polyunsaturated fatty acid de®ciency in non-institutionalised elderly women F Babin et al mouse (Bourre et al, 1990). Furthermore, data obtained in vivo in humans using stable isotope labelling have clearly shown that even in healthy adults, the n-6 biosynthesis pathway is very limited, i.e., 1 ± 2% of total conversion (Emken et al, 1994), especially the D5 desaturase step (El Boustani et al, 1989). No direct information can be obtained from the present data.…”

Section: Discussionmentioning

confidence: 96%

Differences between polyunsaturated fatty acid status of non-institutionalised elderly women and younger controls: a bioconversion defect can be suspected

Babin¹,

Abderrazik

Favier

et al. 1999

Eur J Clin Nutr

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Objective: To evaluate the polyunsaturated fatty acid (PUFA) status in non-institutionalised elderly women and to detect a possible essential fatty acid bioconversion defect. Design and subjects: The fatty acid composition of total plasma lipids, plasma triglycerides (TG), cholesterol esters (CE), phospholipids (PL), and erythrocytes was determined by capillary column gas-liquid chromatography in a sample of 200 non-institutionalised healthy elderly women over 75 years of age. The data were compared with those of a control group of 50 young female volunteers aged 20 ± 48 y. Results: In elderly women, the n-6 series precursor, linoleic acid (18:2 n-6), was lower in TG and CE (P 0.029 and 0.014, respectively). In CE, this fatty acid was highly correlated with vegetable and vegetal fat intakes (P`0.0001), suggesting a lower dietary supply than in controls. Higher percentages of 16:1 n-7 were found in all the plasma lipid fractions in elderly women, especially in CE (P`0.0001). The ratios 20:4 n-6a20:3 n-6 and 22:6 n-3a20:5 n-3 were signi®cantly lower in PL from elderly women (P`0.005 and P`0.002, respectively), raising the question of the ef®ciency of the terminal steps of 20:4 n-6 and 22:6 n-3 biosynthesis. Dietary investigations in elderly women indicated that a high dietary protein intake via meat probably contributed to the supply of 20:4 n-6 and thus maintained the status of this fatty acid, despite the suspected altered biosynthesis. Conclusion: The PUFA status in the elderly women group could be more fragile and dependent on exogenous supply of long-chain PUFAs than previously suspected. Descriptors: non-institutionalised elderly women; polyunsaturated fatty acid; D5 desaturase; peroxisomal b oxidation; de®ciency; plasma lipid fractions; erythrocyte; capillary gas-chromatography

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“…Furthermore it is now apparent that, in the brain, ALA is substantially and preferentially used more for cholesterol as compared to DHA synthesis (Cunnane et al, 1994). If LA and ALA are not converted in suf®cient amounts and proportion to meet the requirements (Emken et al, 1994) expressed by the tight AAaDHA relationship, one needs to ask what price is being paid in cell membrane formation.…”

Section: Discussionmentioning

confidence: 99%

Arachidonic and docosahexaenoic acids are strongly associated in maternal and neonatal blood

et al. 2000

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Background: The red cell membrane fatty acid composition has frequently been used as an index of essential fatty acid (EFA) nutrition. After birth there is a decline in plasma arachidonic acid (AA) and docosahexaenoic (DHA) acids in babies fed on conventional formula which contains only the parent linoleic and a-linolenic acids. In human studies, the red cell phosphoglyceride composition appears to be more constant than that of plasma. In infants fed ®sh oil without AA, the AA proportions fall in the plasma but much less so in the red cells. This result might be considered to mean that there is no need for preformed AA. On the other hand, in a study where the levels of AA fell there was reduction of infant growth. Indeed, where cell membrane composition does change there is often an associated alteration in physiological functions of membranes. We therefore felt it worth investigating the balance between AA and DHA in a physiological situation where plasma levels are known to change, namely in pregnancy. Purpose: The aim of the study was to investigate a relationship between blood phosphoglyceride AA and DHA in pregnant women and neonates. Subjects: Health pregnant women from London, England (n 193) and their term babies n 45 ; healthy pregnant women from Seoul, South Korea n 40 and their term babies n 40); and preterm neonates n 72 from London. Method: Blood samples were taken from British and Korean pregnant women during the third trimester, and from term and preterm babies at birth. These samples were taken for routine monitoring purposes in Korea and were a part of a study on pregnancy outcome for which ethical permission was granted from the East London and The City Health Authority and Lambeth, Southwark and Lewisham Health Authority. Approval was also obtained from the Ethical Committee of the Asan Medical Centre, Seoul, South Korea. Results: AA and DHA correlated in plasma choline phosphoglycerides (CPG) of the British mothers (r 0.52 P`0.0001). The correlation coef®cients and signi®cance were much stronger in the red cell CPG and even more so in the term and preterm infant red cell CPGs (r 0.75, 0.80 and 0.88, respectively). Similarly, AA and DHA correlated in red cell CPGs of the Korean women and their term babies. There was also a signi®cant relationship between the two fatty acids in red cell ethanolamine phosphoglycerides in the mothers and their babies. Both linoleic (LA) and -linolenic acids (ALA) were inversely associated with AA and DHA in some of the phosphoglyceride fractions of the mothers and babies. Conclusions: Although AA and DHA have different primary dietary origins, there were signi®cant relationships between AA and DHA in the phosphoglycerides of the red cell membrane. This ®nding seems surprising if the red cell composition is determined by diet. These results suggest a physiological mechanism which attempts to maintain an appropriate balance between AA and DHA. It is plausible that there is an optimum balance between AA and DHA for membrane stability, deformability, enzyme and recep...

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Dietary linoleic acid influences desaturation and acylation of deuterium-labeled linoleic and linolenic acids in young adult males

Cited by 426 publications

References 40 publications

The metabolism of linoleic acid in healthy subjects after intake of a single dose of 13C-linoleic acid

The metabolism of linoleic acid in healthy subjects after intake of a single dose of 13C-linoleic acid

Differences between polyunsaturated fatty acid status of non-institutionalised elderly women and younger controls: a bioconversion defect can be suspected

Arachidonic and docosahexaenoic acids are strongly associated in maternal and neonatal blood

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