Fish intake, erythrocyte n-3 fatty acid status and metabolic health in Danish adolescent girls and boys

Marinen-3 long-chain PUFA (n-3 LCPUFA) may have a beneficial effect on several aspects of the metabolic syndrome (dyslipidaemia, insulin resistance, hypertension and abdominal obesity). The metabolic syndrome is increasing in prevalence during adolescence, but only few studies have investigated the effects ofn-3 LCPUFA in adolescence. The present study examines associations between fish intake (assessed by a 7 d pre-coded food diary), erythrocyte (RBC) DHA status (analysed by GC) and metabolic syndrome measures (anthropometry, blood pressure and plasma lipids, insulin and glucose) in 109 17-year-old children from the Copenhagen Birth Cohort Study. Of the children, 8 % were overweight or obese and few showed signs of the metabolic syndrome, but all the metabolic syndrome variables were correlated. Median fish intake was 10·7 (interquartile range 3·6–21·2) g/d. Boys tended to have a higher fish intake (P = 0·052), but girls had significantly higher RBC levels of DHA (P = 0·001). Sex and fish intake explained 37 % of the variance in RBC-DHA (P &lt; 0·001). After adjusting for confounders, high DHA status was found to be significantly correlated with higher systolic blood pressure (P = 0·014) and increased fasting insulin (P = 0·018), but no adverse association was observed with the mean metabolic syndromez-score. Overall, the present study showed the expected association between fish intake and RBC-DHA, which in contrast to our expectations tended to be associated with a poorer metabolic profile. Whether these results reflect the physiological function ofn-3 LCPUFA, lifestyle factors associated with fish intake in Denmark, or mere chance remains to be investigated.</jats:p

Spatial and Temporal Structure of a Mesocarnivore Guild in Midwestern North America

Carnivore guilds play a vital role in ecological communities by cascading trophic effects, energy and nutrient transfer, and stabilizing or destabilizing food webs. Consequently, the structure of carnivore guilds can be critical to ecosystem patterns. Body size is a crucial influence on intraguild interactions, because it affects access to prey resources, effectiveness in scramble competition, and vulnerability to intraguild predation. Coyotes (Canis latrans), bobcats (Lynx rufus), gray foxes (Urocyon cinereoargenteus), raccoons (Procyon lotor), red foxes (Vulpes vulpes), and striped skunks (Mephitis mephitis) occur sympatrically throughout much of North America and overlap in resource use, indicating potential for interspecific interactions. Although much is known about the autecology of the individual species separately, little is known about factors that facilitate coexistence and how interactions within this guild influence distribution, habitat use, and temporal activity of the smaller carnivores. To assess how habitat autecology and interspecific interactions affect the structure of this widespread carnivore guild, we conducted a large-scale, non-invasive carnivore survey using an occupancy modeling framework. We deployed remote cameras during 3-week surveys to detect carnivores at 1,118 camera locations in 357 2.6-km2 sections (3–4 cameras/section composing a cluster) in the 16 southernmost counties of Illinois (16,058 km2) during January–April, 2008–2010. We characterized microhabitat at each camera location and landscape-level habitat features for each camera-cluster. In a multi-stage approach, we used information-theoretic methods to evaluate competing models for detection, species-specific habitat occupancy, multi-species co-occupancy, and multi-season (colonization and extinction) occupancy dynamics. We developed occupancy models for each species to represent hypothesized effects of anthropogenic features, prey availability, landscape complexity, and vegetative land cover. We quantified temporal activity patterns of each carnivore species based on their frequency of appearance in photographs. Further, we assessed whether smaller carnivores shifted their diel activity patterns in response to the presence of potential competitors. Of the 102,711 photographs of endothermic animals, we recorded photographs of bobcats (n = 412 photographs), coyotes (n = 1,397), gray foxes (n = 546), raccoons (n = 40,029), red foxes (n = 149), and striped skunks (n = 2,467). Bobcats were active primarily during crepuscular periods, and their activity was reduced with precipitation and higher temperatures. The probability of detecting bobcats decreased after a bobcat photograph was recorded, suggesting avoidance of remote cameras after the first encounter. Across southern Illinois, bobcat occupancy at the camera-location and camera-cluster scale (local = 0.24 ± 0.04, camera-cluster cluster = 0.75 ± 0.06) was negatively influenced by anthropogenic features and infrastructure. Bobcats had high rates of colonization (= 0.86) and low rates of extinction (= 0.07), suggesting an expanding population, but agricultural land was less likely to be colonized. Nearly all camera clusters were occupied by coyotes (cluster = 0.95 ± 0.03). At the local scale, coyote occupancy (local = 0.58 ± 0.03) was higher in hardwood forest stands with open understories than in other areas. Compared to coyotes, gray foxes occupied a smaller portion of the study area (local = 0.13 ± 0.01, cluster = 0.29 ± 0.03) at all scales. At the scale of the camera-cluster, gray fox occupancy was highest in fragmented areas with high proportions of forest, and positively related to anthropogenic features within 100% home-range buffers. Red foxes occupied a similar proportion of the study area as gray foxes (local = 0.12 ± 0.02, cluster = 0.26 ± 0.04) but were more closely associated with anthropogenic features. Only anthropogenic feature models made up the 90% confidence set at all scales of analysis for red foxes. Extinction probabilities at the scale of the camera-cluster were higher for both gray foxes (= 0.57) and red foxes (= 0.35) than their colonization rates (gray fox = 0.16, red fox = 0.06), suggesting both species may be declining in southern Illinois. Striped skunks occupied a large portion of the study area (local = 0.47 ± 0.01, cluster = 0.79 ± 0.03) and were associated primarily with anthropogenic features. Raccoons were essentially ubiquitous within the study area, being photographed in 99% of camera clusters. We observed little evidence for spatial partitioning based on interspecific interactions, with the exception of the gray fox-coyote pairs, and found that habitat preferences were more important in structuring the carnivore community. Habitat had a stronger influence on the occupancy of foxes than did the presence of bobcats. However, the level of red fox activity was negatively correlated with bobcat activity at a camera cluster. Gray fox occupancy and the number of detections within occupied sites were reduced in camera-clusters occupied by coyotes but not bobcat occupancy. Overall, gray fox occupancy was highest at camera locations with fewer hardwood and more conifer trees. However, gray foxes were more likely to occupy camera locations in hardwood stands than conifer stands if coyotes were also present indicating that hardwood stands may enhance gray fox-coyote coexistence. The 2 fox species appeared to co-occur with each other at the local scale more frequently than expected based on their individual selection of habitat. Similarly, occupancy of camera-location by red foxes was higher when coyotes were present. These positive spatial associations among canids may be a response to locally high prey abundance or unmeasured habitat variables. Activity levels of raccoons, bobcats, and coyotes were all positively correlated. Overall, our co-occurrence and activity models indicate competitor-driven adjustments in space use among members of a carnivore community might be the exception rather than the norm. Nevertheless, although our results indicate that gray foxes and red foxes currently coexist with bobcats and coyotes, their distribution appears to be contracting on our study area. Coexistence of foxes with larger carnivores may be enhanced by temporal partitioning of activity and by habitat features that reduce vulnerability of intraguild predation. For instance, hardwood stands may contain trees with structure that enhances tree-climbing by gray foxes, a behavior that probably facilitates coexistence with coyotes. Efforts to enhance gray fox populations in this region would likely benefit from increasing the amount of mature oak-hickory forest. Additionally, the varying results from different scales of analyses underscore the importance of considering multiple spatial scales in carnivore community studies

Plasma amino acid levels are elevated in young, healthy low birth weight men exposed to short-term high-fat overfeeding

Low birth weight (LBW) individuals exhibit a disproportionately increased, incomplete fatty acid oxidation and a decreased glucose oxidation, compared with normal birth weight (NBW) individuals, and furthermore have an increased risk of developing insulin resistance and type 2 diabetes. We hypothesized that changes in amino acid metabolism may occur parallel to alterations in fatty acid and glucose oxidation, and could contribute to insulin resistance. Therefore, we measured fasting plasma levels of 15 individual or pools of amino acids in 18 LBW and 25 NBW men after an isocaloric control diet and after a 5‐day high‐fat, high‐calorie diet. We demonstrated that LBW and NBW men increased plasma alanine levels and decreased valine and leucine/isoleucine levels in response to overfeeding. Also, LBW men had higher alanine, proline, methionine, citrulline, and total amino acid levels after overfeeding compared with NBW men. Alanine and total amino acid levels tended to be negatively associated with the insulin‐stimulated glucose uptake after overfeeding. Therefore, the higher amino acid levels in LBW men could be a consequence of their reduction in skeletal muscle insulin sensitivity due to overfeeding with a possible increased skeletal muscle proteolysis and/or could potentially contribute to an impaired insulin sensitivity. Furthermore, the alanine level was negatively associated with the plasma acetylcarnitine level and positively associated with the hepatic glucose production after overfeeding. Thus, the higher alanine level in LBW men could be accompanied by an increased anaplerotic formation of oxaloacetate and thereby an enhanced tricarboxylic acid cycle activity and as well an increased gluconeogenesis

A study of associations between early DHA status and fatty acid desaturase (FADS) SNP and developmental outcomes in children of obese mothers

AbstractDHA from diet or endogenous synthesis has been proposed to affect infant development, however, results are inconclusive. In this study, we aim to verify previously observed fatty acid desaturase gene cluster (FADS) SNP-specific associations with erythrocyte DHA status in 9-month-old children and sex-specific association with developmental outcomes. The study was performed in 166 children (55 % boys) of obese mothers. Erythrocyte fatty acid composition was analysed in blood-samples obtained at 9 months of age, and developmental outcomes assessed by the Ages and Stages Questionnaire at 3 years. Erythrocyte DHA level ranged from 4·4 to 9·9 % of fatty acids, but did not show any association withFADSSNP or other potential determinants. Regression analysis showed associations between erythrocyte DHA and scores for personal–social skills (β1·8 (95 % CI 0·3, 3·3),P=0·019) and problem solving (β3·4 (95 % CI 1·2, 5·6),P=0·003). A tendency was observed for an association in opposite direction between minor alleles (G-variant) of rs1535 and rs174575 and personal–social skills (P=0·062 and 0·068, respectively), which became significant when the SNP were combined based on their previously observed effect on erythrocyte DHA at 9 months of age (β2·6 (95 % CI 0·01, 5·1),P=0·011). Sex–SNP interaction was indicated for rs174575 genotype on fine motor scores (P=0·016), due to higher scores among minor allele carrying girls (P=0·043), whereas no effect was seen among boys. In conclusion, DHA-increasingFADSSNP and erythrocyte DHA status were consistently associated with improved personal–social skills in this small cohort of children of obese mothers irrespective of sex, but the sample was too small to verify potential sex-specific effects.</jats:p

Plasma acylcarnitine profiling indicates increased fatty acid oxidation relative to tricarboxylic acid cycle capacity in young, healthy low birth weight men

We hypothesized that an increased, incomplete fatty acid beta‐oxidation in mitochondria could be part of the metabolic events leading to insulin resistance and thereby an increased type 2 diabetes risk in low birth weight (LBW) compared with normal birth weight (NBW) individuals. Therefore, we measured fasting plasma levels of 45 acylcarnitine species in 18 LBW and 25 NBW men after an isocaloric control diet and a 5‐day high‐fat, high‐calorie diet. We demonstrated that LBW men had higher C2 and C4‐OH levels after the control diet compared with NBW men, indicating an increased fatty acid beta‐oxidation relative to the tricarboxylic acid cycle flux. Also, they had higher C6‐DC, C10‐OH/C8‐DC, and total hydroxyl‐/dicarboxyl‐acylcarnitine levels, which may suggest an increased fatty acid omega‐oxidation in the liver. Furthermore, LBW and NBW men decreased several acylcarnitine levels in response to overfeeding, which is likely a result of an upregulation of fatty acid oxidation due to the dietary challenge. Moreover, C10‐OH/C8‐DC and total hydroxyl‐/dicarboxyl‐acylcarnitine levels tended to be negatively associated with the serum insulin level, and the total hydroxyl‐/dicarboxyl‐acylcarnitine level additionally tended to be negatively associated with the hepatic insulin resistance index. This indicates that an increased fatty acid omega‐oxidation could be a compensatory mechanism to prevent an accumulation of lipid species that impair insulin signaling

Effect of dairy fat on plasma phytanic acid in healthy volunteers - a randomized controlled study

BACKGROUND: Phytanic acid produced in ruminants from chlorophyll may have preventive effects on the metabolic syndrome, partly due to its reported RXR and PPAR- α agonist activity. Milk from cows fed increased levels of green plant material, contains increased phytanic acid concentrations, but it is unknown to what extent minor increases in phytanic acid content in dairy fat leads to higher circulating levels of phytanic acid in plasma of the consumers. OBJECTIVE: To investigate if cow feeding regimes affects concentration of plasma phytanic acid and risk markers of the metabolic syndrome in human. DESIGN: In a double-blind, randomized, 4 wk, parallel intervention study 14 healthy young subjects were given 45 g milk fat/d from test butter and cheese with 0.24 wt% phytanic acid or a control diet with 0.13 wt% phytanic acid. Difference in phytanic acid was obtained by feeding roughage with low or high content of chlorophyll. RESULTS: There tended to be a difference in plasma phytanic acid (P = 0.0730) concentration after the dietary intervention. Plasma phytanic acid increased significantly within both groups with the highest increase in control group (24%) compared to phytanic acid group (15%). There were no significant effects of phytanic acid on risk markers for the metabolic syndrome. CONCLUSIONS: The results indicate that increased intake of dairy fat modify the plasma phytanic acid concentration, regardless of cows feeding regime and the minor difference in dietary phytanic acid. Whether the phytanic acid has potential to affects the risk markers of the metabolic syndrome in human still remain to be elucidated

Fish oil supplementation from 9 to 18 months of age affects the insulin-like growth factor axis in a sex-specific manner in Danish infants

AbstractSeveral studies have investigated the effects of fish oil (FO) on infant growth, but little is known about the effects of FO and sex on insulin-like growth factor-1 (IGF-1), the main regulator of growth in childhood. We explored whether FOv. sunflower oil (SO) supplementation from 9 to 18 months of age affected IGF-1 and its binding protein-3 (IGFBP-3) and whether the potential effects were sex specific. Danish infants (n115) were randomly allocated to 5 ml/d FO (1·2 g/dn-3 long-chain PUFA (n-3 LCPUFA)) or SO. We measured growth, IGF-1, IGFBP-3 and erythrocyte EPA, a biomarker ofn-3 LCPUFA intake and status, at 9 and 18 months. Erythrocyte EPA increased strongly with FO compared with SO (P&lt;0·001). There were no effects of FO compared with SO on IGF-1 in the total population, but a sex×group interaction (P=0·02). Baseline-adjusted IGF-1 at 18 months was 11·1 µg/l (95 % CI 0·4, 21·8;P=0·04) higher after FO compared with SO supplementation among boys only. The sex×group interaction was borderline significant in the model of IGFBP-3 (P=0·09), with lower IGFBP-3 with FO compared with SO among girls only (P=0·03). The results were supported by sex-specific dose–response associations between changes in erythrocyte EPA and changes in IGF-1 and IGFBP-3 (bothP&lt;0·03). Moreover, IGF-1 was sex specifically associated with BMI and length. In conclusion, FO compared with SO resulted in higher IGF-1 among boys and lower IGFBP-3 among girls. The potential long-term implications for growth and body composition should be investigated further.</jats:p