Dietary fatty acid composition in pregnancy alters neurite membrane fatty acids and dopamine in newborn rat brain.

The importance of maternal dietary fatty acids on arachidonic acid [AA; 20:4(n-6)] and docosahexaenoic acid [DHA; 22:6(n-3)] in fetal brain nerve growth cone membranes and monoaminergic neurotransmitters was investigated. Rats were fed purified diets containing 20 g/100 g safflower oil with 74.3% 18:2(n-6), 0.2% 18:3(n-3), soybean oil with 55.4% 18:2(n-6), 7.7% 18:3(n-3) or high fish oil with 24.6% 22:6(n-3) through gestation. Tissue for rats within a litter were pooled at birth, brain growth cone membranes prepared and phosphatidylcholine (PC), phosphatidylserine (PS), phosphatidylethanolamine (PE) and phosphatidylinositol (PI) fatty acids quantified by gas-liquid chromatography. Dopamine, serotonin, and the metabolites 3,4-dihydroxyphenylacetic acid and homovanillic acid, and 5-hydroxyindolacetic acid were quantified by HPLC. Growth cone membranes from offspring of rats fed safflower oil had significantly lower, and offspring of rats fed high 22:6(n-3) fish oil had significantly higher 22:6(n-3) in PE, PS and PI than the soybean oil group. The growth cone membrane PC, PE and PS 20:4(n-6) was significantly lower in the fish oil than in the soybean or safflower oil groups. Serotonin concentration was significantly higher in brain of offspring in the safflower oil compared with the soybean oil group. The newborn brain dopamine was inversely related to PE DHA and PS DHA (P < 0.001), but positively related to PC AA (P < 0.05). These studies show that maternal dietary fatty acids may alter fetal brain growth cone (n-6) and (n-3) fatty acids, and neurotransmitters involved in neurite extension, target finding and synaptogenesis. The functional importance, however, is not known at this time.

Diverse, region-specific effects of addition of arachidonic and docosahexanoic acids to formula with low or adequate linoleic and alpha-linolenic acids on piglet brain monoaminergic neurotransmitters.

Differences in visual, auditory, and learning tasks have been reported for infants and animals given diets varying in omega-3 fatty acids, but the neurobiochemical basis for these changes is unclear. This study investigated the effect of feeding formula with 0.8% energy C18:2omega-6 + 0.05% C18:3omega-3 (low), or 8.3% C18:2omega-6 + 0.8% C18:3omega-3 (adequate), with and without 0.2% energy arachidonic acid (C20:4omega-6) and 0.16% docosahexanoic acid (C22:6omega-3), on monoaminergic neurotransmitters in different brain regions of piglets fed formula from birth to 18 d. The amount of C18:2omega-6 + C18:3omega-3 fed in formula had a significant effect on frontal cortex dopamine, 3,4-dihydroxyphenylacetic acid, homovanillic acid, serotonin, and 5-hydroxyindolacetic acid; striatum serotonin and inferior colliculus serotonin, resulting in lower concentrations in piglets fed the low compared with adequate C18:2omega-6 + C18:3omega-3 formula. Inclusion of arachidonic acid and docosahexanoic acid in the low, but not in the adequate, C18:2omega-6 + C18:3omega-3 formula resulted in increased concentrations of all monoamines in the frontal cortex, and in striatum and inferior colliculus serotonin. Feeding arachidonic acid and docosahexanoic acid in the formulas increased dopamine and 5-hydroxyindolacetic acid in superior and inferior colliculus, areas related to processing and integration of visual and auditory information. Higher dopamine and 5-hydroxyindolacetic acid were found in these regions even when arachidonic acid and docosahexanoic acid were added to the C18:2omega-6 + C18:3omega-3 adequate formula. This study suggests that functional changes among animals and infants fed diets varying in omega-6 and omega-3 fatty acids may involve altered neurotransmitter metabolism.

Docosahexaenoic and arachidonic acid prevent a decrease in dopaminergic and serotoninergic neurotransmitters in frontal cortex caused by a linoleic and alpha-linolenic acid deficient diet in formula-fed piglets.

This study examined the effects of diets deficient (D) in linoleic [18:2(n-6)] and linolenic acid [18:3(n-3)] at 0.8 and 0.05% energy, respectively, or adequate (C) in 18:2(n-6) and 18:3(n-3) at 8.3 and 0.8% energy, respectively, without (-) or with (+) 0.2% energy arachidonic [20:4(n-6)] and 0.16% energy docosahexaenoic [22:6(n-3)] acid in piglets fed from birth to 18 d. Frontal cortex dopaminergic and serotoninergic neurotransmitters and phospholipid fatty acids were measured. Piglets fed the D- diet had significantly lower frontal cortex dopamine, 3,4-dihydroxyphenylacetic (DOPAC), homovanillic acid (HVA), serotonin and 5-hydroxyindoleacetic acid (5-HIAA) concentrations than did piglets fed the C- diets. Frontal cortex dopamine, norepinephrine, DOPAC, HVA, serotonin and 5-HIAA were higher in piglets fed the D+ compared to those fed the D- diet (P < 0.05) and not different between piglets fed the D+ and those fed the C- diets or the C- and C+ diets. Piglets fed the D- diet had lower frontal cortex phosphatidylcholine (PC) and phosphatidylinositol (PI) 20:4(n-6) and PC and phosphatidylethanolamine (PE) 22:6(n-3) than did piglets fed the C- diet (P < 0.05). Piglets fed the D+ diet had higher frontal cortex PC and PI 20:4(n-6) and PC, PE, PS and PI 22:6(n-3) than did piglets fed the D- diet. These studies show that dietary essential fatty acid deficiency fed for 18 d from birth affects frontal cortex neurotransmitters in rapidly growing piglets and that these changes are specifically due to 20:4(n-6) and/or 22:6(n-3).

Addition of triglycerides with arachidonic acid or docosahexaenoic acid to infant formula has tissue- and lipid class-specific effects on fatty acids and hepatic desaturase activities in formula-fed piglets.

The effects of including triglycerides with arachidonic [20:4(n-6)] or docosahexaenoic acid [22:6(n-3)] in formula on plasma chylomicron, LDL and HDL, liver, heart, kidney and brain (n-6) and (n-3) fatty acids were investigated in formula-fed piglets. Piglets were fed formula with (in % total fatty acids) 20% 18:2(n-6) and 2% 18:3(n-3) without or with 0.8% 20:4(n-6) or 0.3% 22:6(n-3) from birth to 18 d. The effects of adding 20:4(n-6) or 22:6(n-3) to the formula differed among different tissues and lipids, with the brain showing resistance to change. Piglets fed formula with 20:4(n-6) had significantly higher plasma, heart and kidney phospholipid and triglyceride, and liver triglyceride 20:4(n-6), but lower plasma and tissue phospholipid 18:2(n-6) than piglets fed formula without 20:4(n-6). Supplementation with 22:6(n-3), in contrast, had no effect on plasma or tissue 18:2(n-6). Higher 22:6(n-3) in liver phospholipid (30-92% greater) and triglyceride (200% greater) in piglets fed formula with 22:6(n-3) rather than without 22:6(n-3) was accompanied by lower 20:4(n-6) in liver phosphatidylethanolamine (mean +/- SEM, 8.6 +/- 0.4 and 10.5 +/- 0.4% fatty acids, respectively), but higher 20:4(n-6) in triglyceride (5.2 +/- 0.4 and 11.5 +/- 0.5%, respectively), and higher liver, heart and kidney phospholipid 20:5(n-3). These results indicate competitive interaction between dietary 20:4(n-6) and tissue 18:2(n-6), and between dietary 20:4(n-6) and tissue 20:5(n-3), rather than 22:6(n-3). The results also show that even at low intakes, dietary 22:6(n-3) or 20:4(n-6) supplementation alters the tissue phospholipid 20:4(n-6) to 20:5(n-3) balance. Studies on the physiologic effects of dietary 20:4(n-6) and 22:6(n-3) supplementation should consider the different sensitivity among tissues to dietary fatty acids.

Fatty acid composition of human milk in Spain.

The fatty acid composition of mature human milk obtained from 40 Spanish women was analyzed by capillary gas chromatography. The women were from two regions in Spain, Navarre and Catalonia. Milk samples were collected between 20 and 30 days postpartum. The fatty acid composition was expressed as weight percentage (% wt/wt of all fatty acids detected with a C8 to C22 chain length). Monounsaturated fatty acids represent 41.97%, mostly 18:1 n-9/n-7 (38.39%). The second major fraction was formed by saturated fatty acids, 41.09%. Polyunsaturated fatty acid fraction (15.23%), included seven long chain polyunsaturated fatty acids (LCPs; 2.21%). Among LCPs, 1.6% accounted for the n-6 series and 0.64% for the n-3 series. LCPn-6/LCPn-3 ratio was 2.51. Mothers reporting a high fish consumption showed higher (p < 0.05) 22:6 n-3 and 20:5 n-3 content. The use of olive oil as the preferential fat source showed higher 18:1 n-9/n-7 and lower 18:2 n-6 content (p < 0.0001), while the use of sunflower oil instead of olive oil significantly (p < 0.0001) increased 18:2 n-6 and decreased 18:1 n-9/n-7. Regional differences (p < 0.05) were detected only for the n-6 LCP and the total LCP content. The higher n-6 LCP and total LCP content was found in Navarre. This could have been due to different diet habits, like higher egg consumption.

Determination of sterol content in different food samples by capillary gas chromatography.

An accurate method for the determination of sterols by capillary gas chromatography was developed and applied to the analysis of food. The procedure includes the following steps: dichloromethane-methanol (2:1, v/v) lipid extraction, saponification at 80 degrees C and separation of the unsaponifiable matter with cyclohexane, derivatization to form trimethylsilyl ethers and gas chromatography using 5 alpha-cholestane as the internal standard. The method shows good accuracy, precision and sensitivity and is suitable for the determination of sterols in food.