Fatty Acid Composition in Ergosteryl Esters and Triglycerides from the Fungus Ganoderma lucidum

Free and esterified ergosterols are detected almost solely in fungi and are often employed as a biomarker of living fungi. In this work, the fatty acid composition and δ¹³C values of major fatty acids in triglycerides and ergosteryl esters from the fungus Ganoderma lucidum were analyzed by gas chromatography–mass spectrometer and gas chromatography–isotopic ratio mass spectrometer, respectively. The results showed that the fatty acid profiles varied in triglycerides and ergosteryl esters. The percentage of saturated fatty acids in ergosteryl esters was remarkably higher than that in triglycerides, where C_18:1^Δ9c was the predominant fatty acid and constituted 61.26 % of the total fatty acids. In contrast, C_16:0 was the predominant fatty acid and constituted 71.88 % of the total fatty acids in ergosteryl esters. The study suggests that, after fungal death, free ergosterols in the cell membrane of the dead fungus were esterified with preferentially saturated fatty acids, mainly C_16:0, from triglycerides and then stored in lipid particles for a longer period while free ergosterol markedly decreased. The δ¹³C values of C_16:0, C_18:0, C_18:1 and C_18:2 in ergosteryl esters exhibit a pronounced depletion in ¹³C compared with that in triglycerides within the range of ?1.3 to ?0.9 ‰, supporting the above inference. It is again suggested that free ergosterol in the cell membrane should be used as an indicator of living fungi, and ergosteryl esters in the lipid particles should not be included in the measurement of living fungal biomass.     

Characterization and Authentication of Significant Chinese Edible Oilseed Oils by Stable Carbon Isotope Analysis

The ratios of stable carbon isotopes (δ¹³C) of 12 oils extracted from Chinese edible oilseed samples and their individual fatty acids were determined by elemental analysis-isotope ratio mass spectrometry (EA-IRMS) and gas chromatography-isotope ratio mass spectrometry (GC-IRMS). The results have demonstrated that the δ¹³C ratios of the oils from C3-plant seeds range from ?26.8 to ?30.7‰, while the δ¹³C ratios of C4-plant maize oil are in the interval of ?14.1 to ?16.2‰. Eighteen fatty acids were identified and their abundances were measured by gas chromatography–mass spectrometry (GC–MS) in these oils with C_16:0, C_18:0, C_18:1 and C_18:2 as the major constituents. From the data on fatty acids and stable carbon isotopes, several sensitive markers were developed to detect the adulteration of Chinese edible oilseed oils. Examples are provided with pre-blended samples to illustrate the discrimination procedures and corresponding sensitive markers with emphasis on camellia seed oil, flax seed oil and perilla seed oil.     

Bulk Sediment and Diatom Silica Carbon Isotope Composition from Coastal Marine Sediments off East Antarctica

Organic carbon occluded in diatom silica is assumed to be protected from degradation in the sediment. δ¹³C from diatom carbon (δ¹³C_(diatom)) therefore potentially provides a signal of conditions during diatom growth. However, there have been few studies based on δ¹³C_(diatom). Numerous variables can influence δ¹³C of organic matter in the marine environment (e.g., salinity, light, nutrient and CO₂ availability). Here we compare δ¹³C_(diatom) and δ¹³C_(TOC) from three sediment records from individual marine inlets (Rauer Group, East Antarctica) to (i) investigate deviations between δ¹³C_(diatom) and δ¹³C_(TOC), to (ii) identify biological and environmental controls on δ¹³C_(diatom) and δ¹³C_(TOC), and to (iii) discuss δ¹³C_(diatom) as a proxy for environmental and climate reconstructions. The records show individual δ¹³C_(diatom) and δ¹³C_(TOC) characteristics, which indicates that δ¹³C is not primarily controlled by regional climate or atmospheric CO₂ concentration. Since the inlets vary in water depths offsets in δ¹³C are probably related to differences in water column stratification and mixing, which influences redistribution of nutrients and carbon within each inlet. In our dataset changes in δ¹³C_(diatom) and δ¹³C_(TOC) could not unequivocally be ascribed to changes in diatom species composition, either because the variation in δ¹³C_(diatom) between the observed species is too small or because other environmental controls are more dominant. Records from the Southern Ocean show depleted δ¹³C_(diatom) values (1–4 ‰) during glacial times compared to the Holocene. Although climate variability throughout the Holocene is low compared to glacial/interglacial variability, we find variability in δ¹³C_(diatom), which is in the same order of magnitude. δ¹³C of organic matter produced in the costal marine environment seems to be much more sensitive to environmental changes than open ocean sites and δ¹³C is of strongly local nature.     

Incorporation of radioactive polyunsaturated fatty acids into liver and brain of developing rat

The incorporation of radioactivity from orally administered linoleic acid-1-¹⁴C, linolenic acid-1-¹⁴C, arachidonic acid-³Hg, and docosahexaenoic acid-¹⁴C into the liver and brain lipids of suckling rats was studied. In both tissues, 22 hr after dosing, 2 distinct levels of incorporation were observed: a low uptake (from 18∶2-1-¹⁴C and 18∶3-1-¹⁴C) and a high uptake (from 20∶4-³H₈ and 22∶6-¹⁴C). In adult rats, the incorporation of radioactivity into brain lipids from 18∶2-1-¹⁴C and 20∶4-³H was considerably lower than the incorporation into the brains of the young rats. In the livers of the suckling rats, the activity from the 18 carbon acids was associated mostly with the triglyceride fraction, whereas the activity from the 20∶4-³H₈ and 22∶6-¹⁴C was concentrated in the phospholipid fraction. In the brain lipids, the activity from the different fatty acids was associated predominantly with the phospholipids. In the liver and brain phospholipid fatty acids, some of the activity in the 18∶2-1-¹⁴C and 18∶3-1-¹⁴C experiments was associated with 20 and 22 carbon polyunsaturated fatty acids; however, radioactivity from orally administered 20∶4-³H₈ and 22∶6-¹⁴C was incorporated intact into the tissue phospholipid to a much greater extent compared with the incorporation of radioactivity into 20∶4 and 22∶6 in the experiments where 18∶2-1-¹⁴C and 18∶3-1-¹⁴C, respectively, were administered. Possible reasons for these differences are discussed. Rat milk contains a wide spectrum of polyunsaturated fatty acids, including linoleate, linolenate, arachidonate, and docosahexaenoate. During the suckling period in the rat, there is a rapid deposition of 20∶4 and 22∶6 in the brain. The results of the present experiments suggested that dietary 20∶4 and 22∶6 were important sources of brain 20∶4 and 22∶6 in the developing rat.     

Lipids of the pawpaw fruit: Asimina triloba

The fatty acid composition and structure of pawpaw fruit (Asimina triloba) triglycerides were examined and found to contain fatty acids ranging from C₆ to C₂₀. Octanoate represented 20% of the fatty acids while other medium-chain fatty acids were present in low amounts. Analysis of the intact triglycerides by high-temperature gas-liquid chromatography gave an unusual three-cycle carbon number distribution. Analysis of triglyceride fractions separated according to degree of unsaturation suggested that one octanoate was paired with diglyceride species containing long-chain fatty acids. Determination of the double-bond positions of monoene fatty acids revealed cis Δ9 and cis Δ11 hexadecenoate and cis Δ9, cis Δ11, and cis Δ13 octadecenoate isomers were present in significant quantities. Octanoate and positional monoene fatty acid isomers were found only in the fruit lipids and not in the seed lipids. Phenacyl esters of fatty acids were found to be useful derivatives for structure determination using multiple types of analyses.     

The metabolic fate of fatty acids derived from dietary triglycerides

The metabolic fates of dietary tricaprylin, trimyristin, tripalmitin, triolein, and trilinolein at the 15% level were followed with tracer doses of the corresponding C¹⁴-labeled acids. Distribution of the label in respiratory C¹⁴O₂ and in fatty acids of adipose tissue and liver lipids as well as the fatty acid composition of these unfractionated tissue lipids led to the following conclusions: Tissue fatty acid compositional homeostasis is limited mainly by the degrees to which dietary fatty acids can be converted to endogenous fatty acids. Other factors, such as their effects on lipogenesis and the relative degrees to which they are catabolized and stored, also play roles.     

Isolation and characterization of the monounsaturated long chain fatty acids ofMycobacterium tuberculosis

The positions of double bond in the monounsaturated C₁₅−C₃₂ fatty acids ofMycobacterium tuberculosis H37Ra were established by gas chromatography/mass spectrometry of the ozonized esters and their pyrrolidide derivatives. The monounsaturated C₁₅−C₂₁ fatty acids had the double bond primarily at the Δ⁹ position while the monounsaturated longer chain fatty acids (C₂₂−C₃₂) had the double bond in several positions. Many of the latter acids, especially the odd-numbered series, were very complex isomeric mixtures. Quantitation showed the most abundant even-numbered long chain fatty acid isomers to be as follow: C₂₂, Δ⁴; C₂₄, Δ⁵; C₂₆, Δ⁷ and Δ⁹; C₂₈, Δ⁹; C₃₀, Δ¹¹ and Δ¹³; C₃₂, Δ¹³ and Δ¹⁵.     

Markedly raised intake of saturated and monounsaturated fatty acids in rats on a high-fat ketogenic diet does not inhibit carbon recycling of13C-α-linolenate

Under various dietary and physiological conditions, carbon from α-linolenic acid (ALA) is extensively recycled into saturated and monounsaturated fatty acids. In this study we investigated whether carbon is still recycled from ALA when a dietary source of saturated and monounsaturated fatty acids is provided in excess.¹³C-labeled ALA was given to rats consuming a high-fat ketogenic diet and to rats consuming a low-fat control diet. In rats on the ketogenic diet,¹³C recycling from α-linolenate into several, but not all, saturated and monounsaturated fatty acids matched or exceeded that in the controls (P<0.05). We conclude that carbon recycling into saturated and monounsaturated fatty acids persists when the main end products of ALA recycling are provided in excess, using a ketogenic diet.     

Fatty acid-specific, regiospecific, and stereospecific hydroxylation by cytochrome P450 (CYP152B1) from Sphingomonas paucimobilis: Substrate structure required for α-hydroxylation

Fatty acid α-hydroxylase from Sphingomonas paucimobilis is an unusual cytochrome P450 enzyme that hydroxylates the α-carbon of fatty acids in the presence of H₂O₂. Herein, we describe our investigation concerning the utilization of various substrates and the optical configuration of the α-hydroxyl product using a recombinant form of this enzyme. This enzyme can metabolize saturated fatty acids with carbon chain lengths of more than 10. The K _m value for pentadecanoic acid (C₁₅) was the smallest among the saturated fatty acids tested (C₁₀–C₁₈) and that for myristic acid (C₁₄) showed similar enzyme kinetics to those seen for C₁₅. As shorter or longer carbon chain lengths were used, K _m values increased. The turnover numbers for fatty acids with carbon chain lengths of more than 11 were of the same order of magnitude (10³ min⁻¹), but the turnover number for undecanoic acid (C₁₁) was less. Dicarboxylic fatty acids and methyl myristate were not metabolized, but monomethyl hexadecanedioate and ω-hydroxypalmitic acid were metabolized, though with lower turnover values. Arachidonic acid was a good substrate, comparable to C₁₄ or C₁₅. The metabolite of arachidonic acid was only α-hydroxyarachidonic acid. Alkanes, fatty alcohols, and fatty aldehydes were not utilized as substrates. Analysis of the optical configurations of the α-hydroxylated products demonstrated that the products were S-enantiomers (more than 98% enantiomerically pure). These results suggested that this P450 enzyme is strictly responsible for fatty acids and catalyzes highly stereo- and regioselective hydroxylation, where structure of ω-carbon and carboxyl carbon as well as carbon chain length of fatty acids are important for substrate-enzyme interaction.     

Fatty acid biosynthesis in the developing endosperm ofCocos nucifera

Endosperm tissue of developing coconut endosperm incorporated [¹⁴C] acetate and [¹⁴C]-malonate into [¹⁴C]C₈-C₁₈ fatty acids. The distribution of [¹⁴C] label into the various fatty acids mimicked the distribution of endogenous fatty acids at early and middle stages of endosperm development. Although [¹⁴C] C₈-C₁₈ fatty acids were taken up rapidly by endosperm tissue slices, no elongation occurred; [¹⁴C] stearic acid was not desaturated to oleic. Cell free preparations have also been obtained from this tissue that readily incorporated [¹⁴C] malonyl-CoA into a range of [¹⁴C] fatty acids in the presence of ACP and NADH at pH 7.0. Employing this system, a number of experiments were designed to determine the mechanism of chain length termination. In contrast to intact tissue slice experiments, cell-free extracts yielded as principal products palmitic and stearic acid, although up to 20% were shorter chain acids. A number of possible mechanisms for chain length termination were proposed and tested. Supported in part by NSF Grant No. PCM76 01495.     

Composition of wax esters,triglycerides and diacyl glyceryl ethers in the jaw and blubber fats of the Amazon River dolphin (Inia geoffrensis)

The lower jaw fat of the Amazon River dolphinInia geoffrensis contains 52.8% wax ester, 44.7% triglyceride and 2.5% diacyl glyceryl ether, while its dorsal blubber fat is >98% triglyceride. Examination of the intact lipids, the derived fatty acids and the derived fatty alcohols by gas chromatography reveals that the blubber triglycerides show characteristics of freshwater fish fats, but the jaw fat lipids have several distinctive features. Jaw fat wax esters, triglycerides and diacyl glyceryl ethers are all rich in C₁₀, C₁₂ and C₁₄ fatty acids and contain no polyunsaturated acids. The fatty alcohols in the wax esters are over 90% saturated. The major carbon numbers in the jaw fat triglycerides (C₃₈–C₄₆) are considerably lower than those of the blubber triglycerides (C₄₈–C₅₄). The possible adaptation of the jaw lipids for use in the underwater echolocation process of this dolphin is discussed.     

Stable Carbon Isotope Composition of c9,t11-Conjugated Linoleic Acid in Cow’s Milk as Related to Dietary Fatty Acids

This study explores the potential use of stable carbon isotope ratios (δ¹³C) of single fatty acids (FA) as tracers for the transformation of FA from diet to milk, with focus on the metabolic origin of c9,t11-18:2. For this purpose, dairy cows were fed diets based exclusively on C₃ and C₄ plants. The FA in milk and feed were fractionated by silver-ion thin-layer chromatography and analyzed for their δ¹³C values. Mean δ¹³C values of FA from C₃ milk were lower compared to those from C₄ milk (−30.1‰ vs. −24.9‰, respectively). In both groups the most negative δ¹³C values of all FA analyzed were measured for c9,t11-18:2 (C₃ milk = −37.0 ± 2.7‰; C₄ milk −31.4 ± 1.4‰). Compared to the dietary precursors 18:2n-6 and 18:3n-3, no significant ¹³C-depletion was measured in t11-18:1. This suggests that the δ¹³C-change in c9,t11-18:2 did not originate from the microbial biohydrogenation in the rumen, but most probably from endogenous desaturation of t11-18:1. It appears that the natural δ¹³C differences in some dietary FA are at least partly preserved in milk FA. Therefore, carbon isotope analyses of individual FA could be useful for studying metabolic transformation processes in ruminants.     

In vivo 13C nuclear magnetic resonance: Applications and current limitations for noninvasive assessment of fatty acid status

As a noninvasive method,in vivo ¹³C nuclear magnetic resonance has potentially important applications in understanding the metabolism of long chain fatty acids in organs of living humans. At present, this methodology is most advanced for research on glucose utilization. However, the main¹³C signals visiblein vivo are from fatty acids in adipose tissue and the olefinic signals can be used to noninvasively estimate adipose tissue content and relative dietary intake of polyunsaturates and monounsaturates. The low natural abundance of¹³C improves the utility of this isotope for fatty acid tracer studies. Due to excessive signal broadening, uniform¹³C-labelling seems to have limited application inin vivo fatty acid studies. Tracer fatty acids with¹³C enrichment at a specific carbon position, i.e., [3-¹³C]_γ-linolenate, appear to be the most useful forin vivo tracer studies. Development of methods permitting resolution of¹³C enrichment in structural lipids of lean tissues will be an important breakthrough which may make human tracer studies feasible and worthwhile.     

The steryl ester and phospholipid fatty acids of the spongeAgelas conifera from the Colombian Caribbean

The steryl ester and phospholipid fractions of the marine spongeAgelas conifera were isolated and analyzed. The fatty acyl components of the steryl ester and phospholipid fractions as determined by gas chromatography and gas chromatography/mass spectrometry were very similar and consisted of 56.8 and 62.7% of C₁₄−C₂₀ acids (normal; branched, especiallyiso andanteiso; and monounsaturated, particularly Δ⁹ and Δ¹¹ acids) and of 43.1 and 35.5% of C₂₄−C₂₆ acids (Δ^5,9 diunsaturated acids), respectively. The major constituent fatty acids detected were 13-methyltetradecanoic,n-hexadecanoic, 10-methylhexadecanoic, 11-octadecenoic, 12-methyloctadecanoic, 5,9-pentacosadienoic and 5,9-hexacosadienoic acids. The phospholipids isolated were identified as phosphatidylcholine (37%), phosphatidylserine (34%), phosphatidylethanolamine (16%) and phosphatidylinositol (11%). The distribution of fatty acids within the phospholipid classes was also determined.     

[3-13C] γ-linolenic acid: A new probe for 13C nuclear magnetic resonance studies of arachidonic acid synthesis in the suckling rat

Our objective was to develop a suitable probe to study metabolism of polyunsaturated fatty acids by ¹³C nuclear magnetic resonance (NMR) in the suckling rat pup. [3-¹³C] γ-Linolenic acid was chemically synthesized, and a 20 mg (Experiment 1) or 5 mg (Experiment 2) dose was injected into the stomachs of 6–10-day-old suckling rat pups that were then killed over a 192 h (8 d) time course. ¹³C NMR showed that ¹³C in γ-linolenate peaked in liver total lipids by 12-h post-dosing and that [5-¹³C]-arachidonic acid peaked in both brain and liver total lipids 48–96 h post-dosing. ¹³C enrichment in brain γ-linolenic acid was not detected by NMR, but gas chromatography-combustion-isotope ratio mass spectrometry showed that its mass enrichment in brain phospholipids at 48–96 h post-dosing was 1–2% of that in brain arachidonic acid. ¹³C was present in liver and brain cholesterol and in perchloric acid-extractable water-soluble metabolites in the brain, liver and carcass. We conclude that low but measurable amounts of exogenous γ-linolenic acid do access the suckling rat brain in vivo. The slow time course of [5-¹³C] arachidonic acid appearance in the brain suggests most of it was probably transported there after synthesis elsewhere, probably in the liver. Some carbon from γ-linolenic acid is also incorporated into lipid products other than n−6 long-chain polyunsaturated fatty acids.     

Natural abundance stable carbon isotope evidence for the routing and <Emphasis Type="Italic">de novo</Emphasis> synthesis of bone FA and cholesterol

This research reported in this paper investigated the relationship between diet and bone FA and cholesterol in rats raised on a variety of isotopically controlled diets comprising 20% C₃ or C₄ protein (casein) and C₃ and/or C₄ nonprotein or energy (sucrose, starch, and oil) macronutrients. Compoundspecific stable carbon isotope analysis (δ¹³C) was performed on the FA (16∶0, 18∶0, 18∶1, and 18∶2) and cholesterol isolated from the diet (n=4) and bone (n=8) of these animals. The dietary signals reflected by the bone lipids were investigated using linear regression analysis. δ¹³C values of bone cholesterol and stearic (18∶0) acid were shown to reflect whole-diet δ¹³C values. whereas the δ¹³C values of bone palmitic (16∶0), oleic (18∶1), and linoleic (18∶2) acids reflected dietary FA δ¹³C values. Dietary signal differences are a result of the balance between direct incorporation (or routing) and de novo synthesis of each of these bone lipids. Estimates of the degree of routing of these bone lipids gleaned from correlations between Δ¹³C _dlipid-wdiet (δ¹³C_{diet lipid}-δ¹³C_{whole diet}) spacings and Δ¹³C _blipid-wdiet (δ¹³C_{bone lipid}-δ¹³C_{whole diet} fractionations demonstrated that the extent of routing, where 18∶2>16∶0>18∶1>18∶0>cholesterol, reflected the relative abundances of these lipids in the diet. These findings provide the basis for more accurate insights into diet when the δ¹³C analysis of bone fatty FA or cholesterol is employed.     

Monoenoic fatty acids in human brain lipids: Isomer identification and distribution

The carbon chain length distribution and the double bond positional isomer composition of the monoenoic fatty acids of the lipids of total human brain tissue have been determined using gas chromatography and gas chromatography/mass spectrometry of the fatty acid methyl and picolinyl esters. The even chain length monoenoic C₁₆ to C₂₈ fatty acids contain predominantly two positional isomer series, the n−7 and n−9cis homologues, whose relative proportion varies significantly with chain length. The odd chain length long-chain fatty acids consist of n−8 and n−10 isomers, whereas the odd chain length very long-chain (more than 22 carbon) fatty acids are n−7 and n−9 isomers.     

Competitive adsorption among sesame oil components in a concentrated miscella system

Competitive adsorption of free fatty acids and carotenoids adsorption from sesame oil miscellas on vegetable carbon was studied by regression analysis. The equations obtained indicated that unsaturated carbonyls, free fatty acids (FFA₀), and carotenoids interacted to determine fatty acid and carotenoid adsorption. The driving force for carotenoid adsorption, the carotenoid concentration (C₀), was affected by a quadratic function of free fatty acid concentration [i.e., (FFA₀/C₀)²]. As FFA₀/C₀ increased, carotenoid adsorption efficiency was reduced, possibly because the accessible adsorption sites for carotenoids were occupied by fatty acids. Unsaturated carbonyls promoted free fatty acid adsorption, probably in the pores that were readily accessible for fatty acids. However, when the carbonyl concentration increased in the oil miscella, carbonyls were adsorbed instead of fatty acids. The results indicated how different oil molecules interact and affect adsorption (i.e., free fatty acids and carotenoids). Therefore, the adsorption process of vegetable oils (i.e., bleaching) has to be considered a multicomponent adsorption system.     

Influence of medium-chain triglycerides on lipid metabolism in the chick

The effect of corn oil, coconut oil, and medium-chain triglyceride (MCT, a glyceride mixture consisting almost exclusively of fatty acids of 8 and 10 carbons in length) ingestion on lipid metabolism was studied in chicks. In chicks fed cholesterol-free diets, MCT ingestion elevated plasma total lipids and cholesterol and depressed liver total lipids and cholesterol when compared to chicks receiving the corn oil diet. As a consequence of the opposite effects of MCT ingestion on plasma and liver cholesterol and total lipids, the plasma-liver cholesterol pool was not altered. When cholesterol was included in the diets, dietary MCT depressed liver and plasma total lipids and cholesterol as compared with corn oil, consequently also lowered the plasmaliver cholesterol pool. The in vitro cholesterol and fatty acid synthesis from acetate-1-¹⁴C was higher in liver slices from chicks fed MCT than in those from chicks fed corn oil. The percentage of radioactivity from acetate-1-¹⁴C incorporated into the carboxyl carbon of fatty acids by liver slices was not altered by MCT feeding, indicating that the increased acetate incorporation represented de novo fatty acid synthesis. The conversion of palmitate-1-¹⁴C to C₁₈ acids was increased in liver of chicks fed MCT, implying that fatty acid chain elongating activity was also increased. Studies on the conversion of stearate-2-¹⁴C to mono- and di-unsaturated C₁₈ acids showed that hepatic fatty acid desaturation activity was enhanced by MCT feeding. Data are presented on the plasma and liver fatty acid composition of chicks fed MCT-, corn oil-, or coconut oil-supplemented diets. The principles of laboratory animal care, as promulgated by the National Society for Medical Research, were observed.     

Higher Increase in Plasma DHA in Females Compared to Males Following EPA Supplementation May Be Influenced by a Polymorphism in ELOVL2: An Exploratory Study

Young adult females have higher blood docosahexaenoic acid (DHA), 22:6n-3 levels than males, and this is believed to be due to higher DHA synthesis rates, although DHA may also accumulate due to a longer half-life or a combination of both. However, sex differences in blood fatty acid responses to eicosapentaenoic acid (EPA), 20:5n-3 or DHA supplementation have not been fully investigated. In this exploratory analysis, females and males (n = 14–15 per group) were supplemented with 3 g/day EPA, 3 g/day DHA, or olive oil control for 12 weeks. Plasma was analyzed for sex effects at baseline and changes following 12 weeks' supplementation for fatty acid levels and carbon-13 signature (δ¹³C). Following EPA supplementation, the increase in plasma DHA in females (+23.8 ± 11.8, nmol/mL ± SEM) was higher than males (−13.8 ± 9.2, p < 0.01). The increase in plasma δ¹³C-DHA of females (+2.79 ± 0.31, milliUrey (mUr ± SEM) compared with males (+1.88 ± 0.44) did not reach statistical significance (p = 0.10). The sex effect appears driven largely by increased plasma DHA in the AA genotype of females (+58.8 ± 11.5, nmol/mL ± SEM, n = 5) compared to GA + GG in females (+4.34 ± 13.5, n = 9) and AA in males (−29.1 ± 17.2, n = 6) for rs953413 in the ELOVL2 gene (p < 0.001). In conclusion, EPA supplementation increases plasma DHA levels in females compared to males, which may be dependent on the AA genotype for rs953413 in ELOVL2.