Increased α-linolenic acid intake increases tissue α-linolenic acid content and apparent oxidation with little effect on tissue docosahexaenoic acid in the guinea pig

The essential fatty acids do not have identical roles in nutrition. Linoleic acid (LA) accumulates throughout the body of most mammals, whereas α-linolenic acid (ALA) is rarely found in tissue lipids to the same extent as LA. It has been argued that this is the result of metabolism of ALA to docosahexaenoic acid (DHA) or that ALA is rapidly β-oxidized to acetyl CoA and CO₂. In this study, we consider the effect of high and low ALA levels on the tissue distribution of ALA and other n-3 polyunsaturated fatty acids (PUFA) in all tissues. Guinea pigs were fed one of two defined diets for 3 wk from wearning with both diets containing 1.8% (by weight) of LA and either 1.7% ALA or 0.03% ALA. The high ALA diet was associated with significantly increased ALA levels in all tissues except the brain and significantly increased levels of long-chain n-3 PUFA in all tissues except intestines, brain, carcass, and skin. The long-chain n-3 PUFA content of the whole body was less than 5% of that of the ALA content in both diet groups, and the major long-chain n-3 PUFA (>66% of total) in the body was 22∶5n−3. The brain was the only tissue where the DHA content exceeded that of 22∶5n−3. On the low ALA diet, there appeared to be conservation of ALA based on a comparison of the ratio of LA to ALA in the tissues compared with that in the diet. On the high ALA diet there was a loss of ALA relative to LA in the tissues compared with the diet. These studies suggest that the low levels of tissue ALA in the guinea pig are likely the result of β-oxidation or excretion via the skin and fur rather than metabolism to DHA.     

Effects of hydrocarbon structure on fatty acid,fatty alcohol,and β-hydroxy acid composition in the hydrocarbon-degrading bacterium <Emphasis Type="Italic">Marinobacter hydrocarbonoclasticus</Emphasis>

The lipids of the gram-negative bacterium Marinobacter hydrocarbonoclasticus grown in a synthetic seawater medium supplemented with various hydrocarbons as the sole carbon source were isolated, purified, and their structures determined. The hydrocarbons were normal, iso, anteiso, and mid-chain branched alkanes, phenylalkanes, cyclohexylalkanes, and a terminal olefin. According to the sequential procedure used for lipid extraction, three pools were isolated: unbound lipids extracted with organic solvents (corresponding to metabolic lipids and to the main part of membrane lipids), OH⁻ labile lipids [mainly ester-bound in the lipopolysaccharides (LPS)], and H⁺ labile lipids (mainly amide-bound in the LPS). Each pool contained FA, fatty alcohols, and β-hydroxy acids. The proportions of these lipids in the unbound lipid pools were 84–98%, 1.1–11.6%, and 0.1–3.6% (w/w), respectively. The chemical structures of the lipids were strongly correlated with those of the hydrocarbons fed; analytical data suggested a metabolism essentially through oxidation into primary alcohol, then into FA and degradation via the β-oxidation pathway. Subterminal oxidation of the hydrocarbon chains, α-oxidation of FA or double-bond oxidation in the case of the terminal olefin, were minor, although sometimes substantial, routes of hydrocarbon degradation. Cyclohexyldodecanedid not support growth, likely because of the toxicity of cyclohexylacetic acid formed in the oxidation of the alkyl side chain. In the OH⁻ and H⁺ labile lipid pools, β-hydroxy acids, the lipophilic moiety of LPS, generally dominated (28–72% and 64–98%, w/w, respectively). The most remarkable feature of these cultures on hydrocarbons was the incorporation in LPS of β-hydroxy acids with C_odd, ω-unsaturated, iso, or anteiso alkyl chains in addition to the specific β-hydroxy acid of M. hydrocarbonoclasticus, 3-OH-n-12∶0. These β-hydroxy acids were tolerated insofar as their geometry and steric hindrance were close to those of the 3-OH-n-12∶0 acid.     

Highly unsaturated fatty acid synthesis in vertebrates: New insights with the cloning and characterization of a Δ6 desaturase of Atlantic salmon

Fish are an important source of the n−3 highly unsaturated fatty acids (HUFA), eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids that are crucial to the health of higher vertebrates. The synthesis of HUFA involves enzyme-mediated desaturation, and a Δ5 fatty acyl desaturase cDNA has been cloned from Atlantic salmon (Salmo salar) and functionally characterization of a Δ6 fatty acyl desaturase of Atlantic salmon and describe its genomic structure, tissue expression, and nutritional regulation. A salmon genomic library was screened with a salmon Δ5 desaturase cDNA and positive recombinant phage isolated and subcloned. The full-length cDNA for the putative fatty acyl desaturase was shown to comprise 2106 bp containing an open reading frame of 1365 bp specifying a protein of 454 amino acids (GenBank accession no. AY458652). The protein sequence included three histidine boxes, two transmembrane regions, and an N-terminal cytochrome b₅ domain containing the heme-binding motif HPGG, all of which are characteristic of microsomal fatty acid desaturases. Functional expression showed that this gene possessed predominantly Δ6 desaturase activity. Screening and sequence analysis of the genomic DNA of a single fish revealed that the Δ6 desaturase gene constituted 13 exons in 7965 bp of genomic DNA. Quantitative real-time PCR assay of gene expression in Atlantic salmon showed that both Δ6 and Δ5 fatty acyl desaturase genes, and a fatty acyl elongase gene, were highly expressed in intestine, liver, and brain, and less so in kidney, heart, gill, adipose tissue, muscle, and spleen. Furthermore, expression of both Δ6 and Δ5 fatty acyl desaturase genes in intestine, liver, red muscle, and adipose tissue was higher in salmon fed a diet containing vegetable oil than in fish fed a diet containing fish oil.     

n-3 Docosapentaenoic Acid Intake and Relationship with Plasma Long-Chain n-3 Fatty Acid Concentrations in the United States: NHANES 2003–2014

The long-chain n-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), play a crucial role in health, but previous National Health and Nutrition Examination Survey (NHANES) analyses have shown that EPA and DHA intake in the United States is far below recommendations (~250–500 mg/day EPA + DHA). Less is known about docosapentaenoic acid (DPA), the metabolic intermediate of EPA and DHA; however, evidence suggests DPA may be an important contributor to long-chain n-3 fatty acid intake and impart unique benefits. We used NHANES 2003–2014 data (n = 45,347) to assess DPA intake and plasma concentrations, as well as the relationship between intake and plasma concentrations of EPA, DPA, and DHA. Mean DPA intake was 22.3 ± 0.8 mg/day from 2013 to 2014, and increased significantly over time (p < 0.001), with the lowest values from 2003 to 2004 (16.2 ± 1.2 mg/day). DPA intake was higher in adults (20–55 years) and seniors (55+ years) compared to younger individuals. In regression analyses, DPA intake was a significant predictor of plasma EPA (β = 138.5; p < 0.001) and DHA (β = 318.9; p < 0.001). Plasma DPA was predicted by EPA and DHA intake (β = 13.15; p = 0.001 and β = 7.4; p = 0.002), but not dietary DPA (p = 0.3). This indicates that DPA intake is not a good marker of plasma DPA status (or vice versa), and further research is needed to understand the factors that affect the interconversion of EPA and DPA. These findings have implications for future long-chain n-3 fatty acids dietary recommendations.     

Factors associated with infants’ and young children’s (6–23 months) dietary diversity in Pakistan: evidence from the demographic and health survey 2012–13

Background

Optimum nutrition and good feeding practices amongst infants and young children are the key determinants of growth for a healthy life. Dietary diversity is considered to be a reliable and easy-to-measure proxy variable to assess young children’s feeding practices for dietary adequacy and nutritional intake. This research aims to examine the current practices of dietary diversity amongst infants and young children aged 6–23 months in Pakistan and the various associated factors at child, maternal, household and community levels.

Methods

Secondary data analysis was performed for this research using the nationally representative dataset of the Pakistan Demographic and Health Survey 2012–13. Data on the last-born infants and young children aged 6–23 months (n?=?1102) was taken from their mothers’ interviews, who reported on their child’s consumption of 7 food groups during the 24 h immediately preceding the survey. Data was analysed, using IBM® SPSS® Complex Sample to measure the association between children’s dietary diversity and various factors at child, maternal, household and community levels through multiple linear regressions.

Results

Our research uncovered positive associations between children’s dietary diversity and other sociodemographic variables. Overall, a variation was observed in consumption of 7 food groups across the youngest, middle and oldest age-groups of children. Multivariate analysis revealed that the children’s Dietary Diversity Score (scale from 0 to 7) increases to 0.56 (95% CI: 0.18–0.94) amongst children in the middle age-group (12–17 months). Furthermore, the children who were still breastfeeding, with mothers who had a primary level of schooling and whose mothers also received information/services from lady health workers (LHWs) on maternal and child health were found to be a statistically significant predictor of infants’ and young children’s dietary diversity. Nevertheless, amongst them, the DDS had a negative association with the children’s status of still breastfeeding and mothers’ primary level of schooling, whereas it had a positive association with children being in the middle age-group and with mothers who received information/services from LHWs.

Conclusion

The dietary diversity of infants and young children aged 6–23 months has a modest, nevertheless statistically significant, relationship with sociodemographic characteristics in Pakistan. There is a need for practical efforts to change the behaviour of communities to encourage more diverse foods to promote the healthy growth of children.

     

Maternal fruit and vegetable or vitamin C consumption during pregnancy is associated with fetal growth and infant growth up to 6 months: results from the Korean Mothers and Children’s Environmental Health (MOCEH) cohort study

Background

Based on data obtained from pregnant women who participated in the Mothers and Children’s Environmental Health (MOCEH) study in South Korea, we aimed to determine whether maternal intake of fruits and vegetables or vitamin C is associated with fetal and infant growth.

Methods

A total of 1138 Korean pregnant women at 12–28 weeks gestation with their infants were recruited as study participants for the MOCEH. Intake of fruits and vegetables or vitamin C during pregnancy was assessed by a 1-day 24-h recall method. Fetal biometry was determined by ultrasonography at late pregnancy. Infant weight and length were measured at birth and 6 months.

Results

A multiple regression analysis after adjusting for covariates showed that maternal intake of fruits and vegetables was positively associated with the biparietal diameter of the fetus and infant’s weight from birth to 6 months. Also, maternal vitamin C intake was positively associated with the abdominal circumference of the fetus and infant birth length. In addition, there was a significant inverse relationship between consumption of fruits and vegetables (below the median compared to above the median of ≥519 g/d) and the risk of low growth (<25th percentile) of biparietal diameter (odds ratio (OR): 2.220; 95% confidence interval (CI): 1.153–4.274) and birth weight (OR: 1.434; 95% CI: 1.001–2.056). A significant inverse relationship also existed between vitamin C consumption (below vs above the estimated average requirement (EAR) of ≥85 mg/d) and the risk of low growth (<25th percentile) of birth weight (OR: 1.470; 95% CI: 1.011–2.139), weight from birth to 6 months (OR: 1.520; 95% CI: 1.066–2.165), and length at birth (OR: 1.579; 95% CI: 1.104–2.258).

Conclusions

An increased intake of fruits and vegetables or vitamin C at mid-pregnancy is associated with increased fetal growth and infant growth up to 6 months of age.