Dietary unsaturated fatty acids: interactions and possible needs in relation to eicosanoid synthesis

Integrated analysis of proteomics, epigenomics and metabolomics data revealed divergent pathway activation patterns in the recent versus chronic post-traumatic stress disorder

Metabolomics, proteomics and DNA methylome assays, when done in tandem from the same blood sample and analyzed together, offer an opportunity to evaluate the molecular basis of post-traumatic stress disorder (PTSD) course and pathogenesis. We performed separate metabolomics, proteomics, and DNA methylome assays on blood samples from two well-characterized cohorts of 159 active duty male participants with relatively recent onset PTSD (<1.5 years) and 300 male veterans with chronic PTSD (>7 years). Analyses of the multi-omics datasets from these two independent cohorts were used to identify convergent and distinct molecular profiles that might constitute potential signatures of severity and progression of PTSD and its comorbid conditions. Molecular signatures indicative of homeostatic processes such as signaling and metabolic pathways involved in cellular remodeling, neurogenesis, molecular safeguards against oxidative stress, metabolism of polyunsaturated fatty acids, regulation of normal immune response, post-transcriptional regulation, cellular maintenance and markers of longevity were significantly activated in the active duty participants with recent PTSD. In contrast, we observed significantly altered multimodal molecular signatures associated with chronic inflammation, neurodegeneration, cardiovascular and metabolic disorders, and cellular attritions in the veterans with chronic PTSD. Activation status of signaling and metabolic pathways at the early and late timepoints of PTSD demonstrated the differential molecular changes related to homeostatic processes at its recent and multi-system syndromes at its chronic phase. Molecular alterations in the recent PTSD seem to indicate some sort of recalibration or compensatory response, possibly directed in mitigating the pathological trajectory of the disorder.

Nutritional quality traits of raw and cooked Ark shell (Bivalvia: Arcidae): balancing the benefits and risks of seafood consumption

Biochemical composition and fatty acid profile of raw Ark shells (RA) were compared to Ark shells submitted to three different cooking methods (BA: baking in the oven; PF: pan-frying in butter and MW: cooking in a microwave). Moisture (%) was significantly higher in RA (79.66) with respect to PF (65.09), BA (48.63) and MW (47.02). Protein (mg/g of flesh) decreased significantly from 18.62 in RA to 15.40 in MW, 13.76 in PF and 13.33 in BA. However, lipids significantly increased in MW (43.32 mg/g of flesh) and PF (63.63 mg/g of flesh) with respect to RA (35.05 mg/g of flesh). Pan-frying affected considerably triacylglycerol (TAG) and the fatty acid composition (FA) of Ark shell flesh. The most changes occurred in saturated (SFA), monounsaturated (MUFA) and polyunsaturated (PUFA) fatty acid fractions after this process. The n-3 PUFA decreased significantly from RA (16.40 mg/g dry weight) to PF (10.02 mg/g DW). While, the opposite trend was observed for n-6 PUFA, revealing that this cooking method had considerable effects on the nutritional characteristics of this edible shellfish. The analysis of lipid peroxidation markers such as thiobarbituric acid reactive substances, free fatty acid and peroxide value confirmed that both heat treatment and time of cooking caused lipid degradation, which had been more accentuated during pan-frying treatment. For the populations who consume Ark shells occasionally or frequently, baking and microwave cooking could be then considered as wiser and healthier cooking methods since they conserve better the nutritional value of this marine product. The present study will be of practical value from a health perspective for Mediterranean populations.

Seasonal Changes in Free Amino Acid and Fatty Acid Compositions of Sardines, Sardina pilchardus (Walbaum, 1792): Implications for Nutrition

The aim of this study was to clarify the seasonal variation in the proximate composition of the free amino acid (AA) and fatty acid (FA) profiles of the European sardine (Sardina pilchardus) from the Adriatic Sea and to better understand the nutritive value needed to organize more effective industrial processing, aquaculture use and to ensure the health benefits for consumers through available bioactive compounds such as omega-3 FA and essential AA. The lipid content ranged from 1.18 to 10.58% during the year, being the highest from July to September. For the first time, this paper reports the monthly variation in AA content in sardines. The highest total AA content was measured during the winter period, from January (843 mg/100 g fillet) to March (953 mg/100 g) with histidine, arginine and threonine being the most dominant. The total content of essential free AA (histidine, threonine, valine, methionine, isoleucine, leucine, phenylalanine, tryptophan and lysine) ranged from 137 to 571 mg/100 g fillet (wet weight), recorded in May and March, respectively. The fatty acid profile analyses revealed the major saturated FA as palmitic (C16:0), followed by myristic (C14:0), and stearic (C18:0) acids, and the predominant monosaturated FA as oleic (C18:1n–9) and palmitoleic (C16:1n–7). The high concentrations of polyunsaturated FA in sardines were omega-3 FA, particularly eicosapentaenoic (EPA; 20:5n-3) and docosahexaenoic (DHA; 20:6n-3) FA. From July to September, their content was the highest (>3.5 g/100 g of sardine fillets), confirming that these species are excellent sources of bioactive lipids.

Topical application of omega-3-, omega-6-, and omega-9-rich oil emulsions for cutaneous wound healing in rats

Wound healing is a physiological event that generates reconstitution and restoration of granulation tissue that ends with scar formation. As omega fatty acids are part of membrane phospholipids and participate in the inflammatory response, we investigated the effects of omega-3, omega-6, and omega-9 fatty acids in the form of oils on wound healing. Linseed (LO), evening primrose (EPO), and olive oils (OO) rich in omega-3, omega-6, and omega-9 fatty acids were formulated into emulsions and were topically applied on rats with excision wounds. All omega-3-, omega-6-, and omega-9-rich oil formulations were found to accelerate wound closure compared to untreated, with significant improvement (p < 0.05) being observed at day 14. EPO induced early deposition of collagen as evaluated by Masson trichrome staining that correlated well with the hydroxyproline content assay, with the highest level at days 3 and 7. Vascular endothelial growth factor (VEGF) showed greater amount of new microvasculature formed in the EPO-treated group, while moderate improvement occurs in the LO and OO groups. EPO increased both the expression of proinflammatory cytokines and growth factors in the early stage of healing and declined at the later stage of healing. LO modulates the proinflammatory cytokines and chemokine but did not affect the growth factors. In contrast, OO induced the expression of growth factors rather than proinflammatory cytokines. These data suggest that LO, EPO, and OO emulsions promote wound healing but they accomplish this by different mechanisms.

Effect of chronic administration of arachidonic acid on the performance of learning and memory in aged rats

Background

Arachidonic acid (AA, C20:4, ω-6) is a ω-6 polyunsaturated fatty acid (PUFA) and plays diverse roles in cell signaling. Numerous reports on the effects of ω-3 PUFAs, such as docosahexaenoic acid (DHA, C22:6, ω-3) and eicosapentaenoic acid (EPA, C20:5, ω-3) on learning and memory impairments of rats are available, however, the role of AA on brain cognition is largely unknown.

Objective

In this study, our aim was to investigate the effect of oral administration of AA on spatial memory-related learning ability in aged (100 weeks) male rats.

Design

One group was per orally administered 240 mg/kg per day AA oil and the other group was administered the similar volume of control oil. Five weeks after the start of the administration, rats were tested with the partially baited eight-arm radial maze to evaluate two types of spatial memory-related learning ability displayed by reference memory errors (RMEs) and working memory errors (WMEs). Also, the time required to complete the task was recorded. The levels of lipid peroxide (LPO) and reactive oxygen species (ROS) were measured, as an indicator oxidative stress in the plasma and brain corticohippocampal brain tissues.

Results

The scores of RMEs and WMEs, which are analogous to long-term and short-term memory, respectively, were not affected, however, the trial time was shorter in the AA-administered rats than that of the controls. AA also significantly increased the degree of oxidative stress both in the plasma and corticohippocampal brain tissues.

Conclusions

Our results suggest that though AA deposition in the corticohippocampal tissues of senescent rats caused a faster performance activity, which is reminiscent to hyperactive behavior of animals, the spatial learning ability-related memory of the rats, however, was not improved.

Serum fatty acids are positively associated with changes in systemic blood pressure throughout pregnancy

OBJECTIVES

To assess whether serum concentrations of saturated (SFAs), polyunsaturated (PUFAs), and monounsaturated (MUFAs) fatty acids are associated with changes in blood pressure (BP) throughout pregnancy.

STUDY DESIGN

Prospective cohort.

MAIN OUTCOME MEASURES

Longitudinal measurements of systolic (SBP) and diastolic (DBP) BP.

METHODS

Two hundred twenty-three healthy pregnant women were recruited in a public health center in Rio de Janeiro, Brazil between 2009 and 2011. Fasting blood samples and BP measurements were obtained at the 1st (5th-13th weeks), 2nd (20^th-26th) and 3rd trimester (30th-36th). Crude and adjusted (maternal age, education, energy intake, gestational body weight change, leptin concentrations, early pre-pregnancy BMI, leisure time physical activity prior to pregnancy and linear and quadratic gestational weeks) longitudinal linear mixed-effects models were employed.

RESULTS

SBP and DBP decreased from the 1st to the 2nd trimester and slightly increased from the 2nd to the 3rd trimester (P < 0.001). In the adjusted model (ß and 95% CI), total SFAs [0.005 (0.001-0.008); P = 0.008], total MUFAs [0.005 (0.001-0.009); P = 0.019] and total n-6 PUFAs [0.005 (0.001-0.009); P = 0.025] were positively associated with SBP throughout pregnancy.

CONCLUSIONS

Maternal serum concentrations of total SFAs, MUFAs and n-6 PUFAs were positively associated with BP levels in normotensive pregnant women.

Direct analysis in real time coupled to high resolution mass spectrometry as a rapid tool to assess salmon (Salmo salar) freshness

Direct analysis in real time-high resolution mass spectrometry (DART-HRMS) was applied to the detection of lipid species in the lipid extracts of farmed salmon samples collected from a local retailer and analyzed right after the purchase and after storage for 4 and 6 days under refrigerated conditions. The recognition of type and composition of lipids detected in DART-HRMS spectra was performed by using the relevant accurate m/z data (accuracy better than 5 ppm) as input for a search on the LipidMaps database. As a result, several fatty acids (FA), either saturated or mono-/poly-unsaturated, and triacylglycerols (TAG) were recognized in the three types of samples from the corresponding negative and positive ion DART-HRMS spectra, respectively. Following, spectral intensities were exploited to monitor the evolution of selected FA and TAG during the refrigeration of salmon meat. In particular, after 4 days of refrigeration, a statistically significant increase was recorded for FA with side chain compositions 18:2, 18:1, 20:5, and 22:6 despite a significant decrease found for TAG with overall side chain compositions 50:4, 52:5, 52:4, and 52:3 after the same time. These evolutions were consistent with a general model already proposed for the effect of low temperature treatments on seafood, implying the action of endogenous lipases, with consequent increase of the free FA amount and decrease in glycerophospholipids and triglycerides contents. The described results indicate DART-HRMS as a promising MS-based rapid tool for the assessment of fish, or other seafood, freshness.

Long-chain ω-6 plasma phospholipid polyunsaturated fatty acids and association with colon adenomas in adult men: a cross-sectional study

Dietary lipid intake can be associated with an increased risk for colorectal cancer depending on its composition. Carcinogenesis alters lipid metabolism to facilitate cell growth and survival. For instance, metabolites of polyunsaturated fatty acids (PUFAs) are associated with increasing colon cell proliferation. Moreover, precancerous colon lesions (i.e. adenomas) increase the risk for colorectal cancer. In this study, we investigated associations between plasma PUFAs and the number of colon polyps and polyp type (i.e. hyperplastic and adenoma). Healthy male participants (n=126) of 48-65 years of age were recruited before a routine colonoscopy screening. Plasma phospholipid (PPL) PUFAs were isolated by means of solid phase extraction and methylated. Fatty acid methyl esters were analyzed using gas chromatography. Factor analysis was used to cluster PUFAs into groups, and then generated factors and individual PUFAs were analyzed using polytomous logistic regression. In our age-adjusted and smoking-adjusted polytomous logistic regression, for each unit increase in PPL docosatetraenoic acid (DTA), individuals were 1.43 (1.00-2.06) and 1.33 (0.99-1.80) times more likely to have hyperplastic polyps and adenomas rather than no polyps, respectively. In our factor analysis, high PPL ω-6 PUFA and trans-fatty acid loading scores were associated with increased odds of adenoma presence rather than no polyps. Increases in long-chain PPL ω-6 PUFAs are associated with an increased risk for adenomas. As relative levels of DTA increase in PPLs, individuals had increased odds of having hyperplastic polyps and adenomas. Elevated conversion of ω-6 PUFAs to longer-chain ω-6s such as DTA may indicate altered PUFA metabolism at the tissue level.

Omega-3 Polyunsaturated Fatty Acids in Youths with Attention Deficit Hyperactivity Disorder: a Systematic Review and Meta-Analysis of Clinical Trials and Biological Studies

The role of omega-3 polyunsaturated fatty acids (omega-3 or n-3 PUFAs) in the pathogenesis and treatment of children and adolescents with attention deficit hyperactivity disorder (ADHD) is unclear. A systematic review followed by meta-analysis was conducted on: (1) randomized controlled trials (RCTs) assessing the effects of n-3 PUFAs on clinical symptoms and cognition in children and adolescent with ADHD; and (2) case-control studies assessing the levels of n-3 PUFAs in blood and buccal tissues of children and adolescents with ADHD. In seven RCTs, totalling n=534 randomized youth with ADHD, n-3 PUFAs supplementation improves ADHD clinical symptom scores (g=0.38, p<0.0001); and in three RCTs, totalling n=214 randomized youth with ADHD, n-3 PUFAs supplementation improves cognitive measures associated with attention (g=1.09, p=0.001). Moreover, children and adolescents with ADHD have lower levels of DHA (seven studies, n=412, g=-0.76, p=0.0002), EPA (seven studies, n=468, g=-0.38, p=0.0008), and total n-3 PUFAs (six studies, n=396, g=-0.58, p=0.0001). In summary, there is evidence that n-3 PUFAs supplementation monotherapy improves clinical symptoms and cognitive performances in children and adolescents with ADHD, and that these youth have a deficiency in n-3 PUFAs levels. Our findings provide further support to the rationale for using n-3 PUFAs as a treatment option for ADHD.

Intravenous fish oil in critically ill and surgical patients - Historical remarks and critical appraisal

The purpose of this review is to explain the historical and clinical background for intravenous fish oil administration, to evaluate its results by using a product specific metaanalysis, and to stimulate further research in the immune-modulatory potential of fish oil. Concerning the immune-modulatory effects of fatty acids, a study revealed that ω-3 as well as ω-6 fatty acids would prolong transplant survival, and only a mixture with an ω-6:ω-3 ratio of 2.1:1 would give immune-neutral results. In 1998, the label of a newly registered fish oil emulsion also acknowledged this immune-neutral ratio in conjunction with ω-6 lipids. Also, two fish oil-supplemented fat emulsions, registered in 2004, used a similar ω-6:ω-3 ratio. Such an immune-neutral ω-6:ω-3 ratio denoted progress for most patients compared to pure ω-6 lipid emulsions. However, this immune-neutrality might on the other hand be responsible for the limited positive clinical results gained so far in critically ill and surgical patients where in most cases significance could only be shown for the pooled effect of numerous trials. Our product specific metaanalysis also did not reveal any differences, neither in infections rates nor in ICU or hospital length of stay. To evaluate the immune-modulatory effect of fish oil administered alone, new dose finding studies, reporting relevant clinical outcome parameters, are required. Precise mechanistic or physiological biomarkers for the indication of such a therapy should also be developed and validated.

Effect of breed on the deposition in beef muscle and adipose tissue of dietary n-3 polyunsaturated fatty acids

This study investigated the effects of dietary n-3 polyunsaturated fatty acids (PUFA) on muscle fatty acid composition and content in two cattle breeds; the Holstein-Friesian, a dairy breed, and the Welsh Black, a traditional beef breed. Animals were kept on ad libitum grass silage and one of three concentrates varying in the source of fat; Megalac (high in C16 : 0), formaldehyde treated whole linseed (high in C18 : 3 n-3) and a combination of formaldehyde treated whole linseed and fish oil (high in C20 : 5 n-3 and C22 : 6 n-3). The concentrates were offered at approximately 0·4 of total dry matter intake. Samples of m. longissimus thoracis from Holstein-Friesians contained higher total amounts of fatty acids (P < 0·05) than that of Welsh Blacks in neutral lipid, but the phospholipid fatty acid content was similar between the breeds. Over all treatments, the proportion of C18 : 3 n-3 was higher (P < 0·001) in muscle neutral lipid of Welsh Blacks and the proportions of C18 : 3 n-3 and C18 : 1 trans were higher (P < 0·05 and P < 0·001, respectively) in their subcutaneous adipose tissue. Feeding linseed increased the amounts of C18 : 3 n-3 and also C20 : 5 n-3 in muscle phospholipids suggesting chain elongation and desaturation of C18 : 3 n-3 had occurred. The concentration of C20 : 5 n-3 was significantly higher (P < 0·05) in muscle phospholipids of Welsh Blacks while no differences were found for C18 : 3 n-3 and C22 : 6 n–3. However, when expressed as a proportion of total fatty acids, both C20 : 5 n-3 and C18 : 3 n-3 were significantly higher (P < 0·001) in the Welsh Black phospholipids. These differences resulted in a significantly higher P : S ratio of the muscle total fat (P < 0·05) in the Welsh Black than in the Holstein-Friesian but P : S was not affected by diet. On the other hand, the n-6 : n-3 PUFA ratio was significantly lower in the Welsh Black, reflecting the higher n-3 PUFA content. This ratio was lower in the linseed and the mixed treatments for both breeds, reflecting higher delivery of n-3 PUFA from these diets. Fortification of the diet with sources of PUFA and exploiting breed differences offer the potential to develop systems to increase human intakes of n-3 PUFA in line with current nutritional recommendations.

Fatty acid metabolism in lambs fed citrus pulp

In the present study, we have hypothesized that replacing barley with high proportions of dried citrus pulp in a concentrate-based diet for lambs could increase the intake of unsaturated fatty acids and could reduce the rate of the ruminal biohydrogenation of PUFA, with a consequent improvement of the intramuscular fatty acid composition. To test this hypothesis, 26 Comisana lambs were divided into 3 groups and for 56 d were fed a barley-based concentrate diet (CON; 8 lambs) or 2 diets in which barley was replaced with 24% (CIT24; 9 lambs) or 35% (CIT35; 9 lambs) dried citrus pulp. An overall improvement of the fatty acid composition of LM from lambs fed citrus pulp-containing diets was found. The PUFA/SFA ratio was lower (P < 0.05) in the LM from lambs in the CON group compared with both the CIT24 and CIT35 groups. The thrombogenic index was lower (P < 0.05) in meat from lambs fed the CIT35 diet compared with those fed the CON diet. The CIT35 diet increased the proportion of C20:5 n-3 in the LM (P < 0.05), whereas the CIT24 diet enhanced that of C22:6 -3 (P < 0.05) compared with the CON diet. Some of these results might be explained considering that feeding the CIT24 and CIT35 diets increased the intake of total fatty acids (P < 0.05) and of C18:3 n-3 (P < 0.01) compared with feeding the CON treatment. On the other hand, phenolic compounds present in citrus pulp could have inhibited the ruminal biohydrogenation of PUFA. This is supported by the fact that regardless of the level of inclusion in the diet, citrus pulp increased the proportion of rumenic acid (P < 0.001) in LM compared with the CON diet. The plasma from lambs fed both CIT24 and CIT35 diets had a greater percentage of vaccenic acid (VA; < 0.001) compared with that from lambs fed the CON diet, and the CIT35 diet increased the proportion of rumenic acid in plasma compared with the CON treatment (P < 0.05). In the ruminal fluid, stearic acid (SA) tended to decrease, and the sum of CLA tended to increase (P = 0.09) with increasing level of citrus pulp in the diets. Furthermore, the SA/(SA + VA) ratio tended to be lower (P = 0.10) in the ruminal fluid from lambs fed the CIT35 diet compared with that of the CON group. In conclusion, our results support the hypothesis that replacing barley with citrus pulp in the diet of growing lambs improves intramuscular fatty acid composition and underline the need for specific studies to clarify the mechanisms by which feeding citrus pulp affects the fatty acid metabolism in ruminants.

Serum saturated fatty acid decreases plasma adiponectin and increases leptin throughout pregnancy independently of BMI

OBJECTIVE

The aim of this study was to investigate whether serum concentrations of total saturated fatty acids (SFAs), polyunsaturated fatty acids (PUFAs), and their fractions are associated with plasma adiponectin and leptin concentrations throughout pregnancy.

METHODS

A prospective cohort of 201 pregnant women was followed from gestational weeks 5 to 13, 20 to 26, and 30 to 36. Blood samples were collected at the three visits after 12 h of fasting. Fatty acid concentrations were determined using fast gas-liquid chromatography. Plasma adiponectin (μg/mL) and leptin (ng/dL) concentrations were evaluated using enzyme-linked immunosorbent assay kits. Statistical analyses included median adipokine concentrations according to the tertiles of fatty acid distribution and multiple linear mixed-effect models adjusted for body mass index, gestational age, total energy intake, alcohol consumption, and smoking.

RESULTS

Women classified in the third SFA concentration tertile had lower median values of adiponectin compared with those in the first tertile ([first trimester: first tertile = 5.36; third tertile = 5.00]; [second trimester: first tertile = 6.39; third tertile = 4.47]; [third trimester: first tertile = 6.46; third tertile = 4.60]). Similar trends were observed for the 14:0, 16:0 and 18:0 fractions. In the multiple longitudinal models, total SFA (β = -41.039; P = 0.008) and 16:0 were negatively associated with plasma adiponectin (16:0, β = -0.511; P = 0.001). Total PUFA ω-6 (β = 28.961; P = 0.002) and 18:2 ω-6 (β = 0.259, P = 0.006) were positively associated with the adiponectin. Total SFA (β = 0.110, P = 0.007), 14:0 (β = 0.072, P = 0.011), and 20:3 ω-6 (β = 0.039; P = 0.035) were positively associated with plasma leptin.

CONCLUSIONS

Total serum SFA and the 16:0 fraction were negatively associated with plasma adiponectin and positively associated with leptin concentrations. Total ω-6 PUFA was positively associated only with plasma adiponectin concentrations throughout pregnancy.

Modulation of Dietary Lipid Composition During Acute Respiratory Distress Syndrome: Systematic Review and Meta-Analysis

BACKGROUND

Pharmaconutrition including omega-3 and competitive analogs of omega-6 fatty acids has been used to modulate the inflammatory response during acute respiratory distress syndrome (ARDS). The clinical benefit of this approach when assessed in prospective randomized clinical trials has been inconsistent. We tried to assess the reasons for the conflicting results, including the possible influence of the composition of the control solution.

METHODS

We collected data from studies listed in PubMed, Ovid, the Cochrane Database of Systematic Reviews, Embase, the U.S. National Institute of Health database, and the ARDSnet database up to March 2013. We included all trials that evaluated effects of enteral pharmaconutrition vs a control solution on mortality, ventilator-free days, length of stay (LOS) in the intensive care unit (ICU), and ICU-free days. A sensitivity analysis was carried out to study the influence of the lipid content of the control solution.

RESULTS

We found 7 eligible studies (802 patients; 405 randomized to pharmaconutrition). The aggregated results showed no overall effect on mortality (risk ratio [RR] = 0.83 [0.55-1.25], P = .37), but there was a mortality benefit when only studies in which pharmaconutrition was compared to a lipid-rich control solution were considered (RR = 0.57 [0.41-0.78], P < .001). ICU LOS was shorter in patients randomized to pharmaconutrition (RR = 0.5 [0.85-0.16]).

CONCLUSION

Use of enteral pharmaconutrition in patients with ARDS was associated with decreased mortality only when the comparator solution contained a greater amount of lipid than is currently recommended. Hence, there is insufficient evidence to support the use of enteral pharmaconutrition in ARDS.

FemaleLeuciscus lepidusMay Be a New Alternative for Fish Oil Supplements

The proximate composition of male and femaleLeuciscus lepidusin Beyşehir Lake was investigated. The fatty acid profiles of total lipid, phospholipid, and triacylglycerol in muscle and liver of male and femaleL. lepiduswere evaluated by gas chromatography. Proximate analyses showed that meat of male and femaleL. lepidushad 15.13 ± 0.04 and 18.75 ± 0.11% fat, 20.42 ± 0.45 and 22.21 ± 0.56% protein, 65.47 ± 1.37 and 61.28 ± 1.03% moisture, and 1.51 ± 0.05 and 1.50 ± 0.03% ash, respectively. The percentage of total saturated fatty acids was higher in liver than in muscle, whereas the total polyunsaturated fatty acid (PUFA) content was the lowest in all fatty acid profiles. The phospholipids contained more PUFAs than triacylglycerol. Analysis of variance indicated significant differences (P<0.05) between male (47.51%) and female (49.98%) muscle PUFAs in total lipid. The proportion of omega 3 (ω3) to omega 6 (ω6) fatty acids of total lipid was 3.15 in male and 3.68 in female. The ratio is an important indicator for comparing the value of fish oil. Therefore, it was concluded thatL. lepiduswas considered to be a high quality product for healthy food choice. Additionally, femaleL. lepidusmay especially be used to produce fish oil supplements from freshwater fish combined with vegetable oils.

Transforming linoleic acid into a nanoemulsion for enhanced activity against methicillin susceptible and resistant Staphylococcus aureus

Schematic of formation of linoleic acid nanoemulsion.

Effects of chronic administration of arachidonic acid on lipid profiles and morphology in the skeletal muscles of aged rats

Arachidonic acid (20:4n-6, ARA) is a major component of the cell membrane, whereas ARA-derived eicosanoids are formed when cells are damaged. Aging is associated with an accretion of oxidative stress in skeletal muscles. In this study, we examined the effects of chronic administration (13 weeks) of ARA (240 mg/kg/day) on fatty acid composition, antioxidative status, and morphology of slow (soleus muscles) and fast (extensor digitorum longus muscles; EDL)-twitch muscles in aged rats (21 months old). The level of reactive oxygen species was higher in the EDL of ARA-administered rats than in that of control rats. ARA administration decreased the muscle cell volumes and increased the number of slow myosin heavy chain (MHC)-positive cells in the EDL. The relative content of MHC2X was increased whereas the relative content of MHC2B was decreased in the EDL of ARA-administered rats. These results suggest that ARA deposition in the fast-twitch muscle of aged rats reduced cell volume with an increase in oxidative stress.

Hypolipidemic and antioxidant effects of buckwheat leaf and flower mixture in hyperlipidemic rats

As a source of biologically active compounds, buckwheat has beneficial effects in nutrition due to its high content of flavonoids, particularly rutin. Aim of our study was to examine effects of buckwheat on plasma lipid status and phospholipids fatty acids composition, histological and parameters of oxidative stress in Wistar rats fed a high-fat diet. This study showed that buckwheat leaf and flower (BLF) mixture supplementation significantly reduce weight gain, plasma lipid concentrations and atherogenic index in rats fed a high-fat diet. Treatment of the high-fat group of animals with buckwheat significantly increased percentage of n-6 fatty acids as well as eicosapentaenoic acid (EPA) and decreased percentage of saturated fatty acids (SFA) and oleic acid. Buckwheat antioxidant effects diminished negative influence of high-fat diet in hyperlipidemic rats, while pathohistological analysis of liver confirmed changes after high-fat consumption. Our results showed hypolipidemic, antiatherogenic and antioxidative features of buckwheat leaf and flower mixture, and these parts of the plant with the highest rutin content could be beneficial in prevention and curing of hyperlipidemia.

Fatty acids as biocompounds: their role in human metabolism, health and disease: a review. part 2: fatty acid physiological roles and applications in human health and disease

BACKGROUND

This is the second of two review parts aiming at describing the major physiological roles of fatty acids, as well as their applications in specific conditions related to human health.

RESULTS

The review included the current literature published in Pubmed up to March 2011. In humans, fatty acids are a principle energy substrate and structural components of cell membranes (phospholipids) and second messengers. Fatty acids are also ligands of nuclear receptors affecting gene expression. Longer-chain (LC) polyunsaturated fatty acids (PUFA), including eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and arachidonic acid are precursors of lipid mediators such as eicosanoids (prostaglandins, leukotrienes, thromboxanes), resolvins and neuroprotectins. Lipid mediators produced by EPA and DHA (LC n-3 PUFA; mainly found in oily fish) are considered as inflammation-resolving, and thus, fish oil has been characterised as antiinflammatory. Recommendations for EPA plus DHA intake from oily fish vary between 250-450 mg/day. Dietary reference values for fat vary between nutrition bodies, but mainly agree on a low total and saturated fat intake. The existing literature supports the protective effects of LC n-3 PUFA (as opposed to n-6 PUFA and saturated fat) in maternal and offspring health, cardiovascular health, insulin sensitivity, the metabolic syndrome, cancer, critically ill patients, and immune system disorders.

CONCLUSION

Fatty acids are involved in multiple pathways and play a major role in health. Further investigation and a nutrigenomics approach to the effects of these biocompounds on health and disease development are imperative and highlight the importance of environmental modifications on disease outcome.

A double-blind randomized study comparing the efficacy and safety of a composite vs a conventional intravenous fat emulsion in postsurgical gastrointestinal tumor patients

BACKGROUND

Composite intravenous fat emulsion, a fat emulsion composed of soybean oil, medium-chain triglycerides (MCT), olive oil, and fish oil, was evaluated for metabolic efficacy, immune modulation, clinical efficacy, safety, and tolerance in surgical gastrointestinal (GI) tumor patients.

METHODS

In a prospective, randomized, double-blind study, 40 patients were randomized after elective digestive surgery to receive isonitrogenous, isoenergetic parenteral nutrition for 5 days postoperatively with either composite 20% IVFE (composed of soybean, MCT, olive, and fish oils) or a conventional long-chain triglyceride (LCT)/MCT 20% IVFE (LCT/MCT IVFE); IVFE was dosed at 1-2 g/kg body weight. Safety and efficacy parameters were assessed on operation day (day 0) and at the end of study (day 6). Adverse events were documented daily and clinical outcomes were recorded and compared between the groups.

RESULTS

Metabolic parameters, laboratory parameters, proinflammatory cytokine levels, adverse events, and clinical outcomes did not differ between the 2 groups, with the exception that postoperative low-density lipoprotein levels decreased significantly in the composite IVFE group (93.2 ± 24.3 vs 110.5 ± 26.4 mg/dL, P = .038).

CONCLUSIONS

composite IVFE was comparable with conventional LCT/MCT IVFE in efficacy, safety, tolerance, and clinical outcomes in surgical GI tumor patients.

Immune Enteral Nutrition Can Improve Outcomes in Medical-Surgical Patients with ARDS: A Prospective Randomized Controlled Trial

Objective

To determine if early continuous enteral feeding of a diet containing eicosapentaenoic acid (EPA), gamma-linolenic acid (GLA), docosahexaenoic acid, and antioxidants in surgical-medical patients with ARDS improves Lung Injury Score (LIS), gas exchange, Multiple Organ Dysfunction (MOD) Score, ICU length of stay, and days on mechanical ventilation.

Methods

Prospective randomized 2-center double-blind controlled trial of 17 ARDS patients whom continuously tube-fed the experimental diet (n=9) or an isonitrogenous, isocaloric standard diet (n=8) at a minimum caloric delivery of 90% of basal energy expenditure.

Results

In the experimental group, there was a decrease in lung injury score (p < 0.003) and lower ventilation variables (p < 0.001). Patients in the experimental group had a statistically significant decrease in 28-day MOD score (p < 0.05). The length of ICU stay was significantly decreased in the experimental group (12.8 vs. 17.5 days; p = 0.01). The study was underpowered to detect any survival benefits between the two groups.

Conclusion

An EPA and GLA supplemented diet contributes to improved gas exchange in addition to decrease LIS, MOD scores and length of ICU stay in patients with ARDS. An EPA+GLA-enriched enteral diet may be an effective tool in the medical management of ARDS.

Lipids for parenteral nutrition in neonates

PURPOSE OF REVIEW

In neonatal intensive care units, the interest and scope for research in the field of intravenous lipids has significantly widened in recent years. This brief review covers the advances in this field in the last 2 years.

RECENT FINDINGS

These include a significant amount of research in evaluating safety and efficacy of novel lipid emulsions that include olive oil or fish oil. Short-term studies involving novel lipid emulsions have documented safety and benefits in terms of reduced inflammation and lipid peroxidation. Fish oil-based lipid emulsions have also been used to prevent and treat parenteral nutrition-induced cholestasis. Other areas of progress include stability studies of all-in-one parenteral nutrition mixtures including lipid emulsions for neonates.

SUMMARY

Since the first soybean oil-based lipid emulsions were introduced 50 years ago, progress has been made in understanding the composition, dose and clinical effects of parenteral lipids in neonatal patients. However there is a paucity of data in terms of definitive head-to-head trials of different novel lipid emulsions evaluating short-term as well as long-term clinically important outcomes including neurodevelopment. Future research is required to determine long-term benefits of novel lipid emulsions for neurological outcome and effects on the immune system.

Dietary linoleic acid has no effect on arachidonic acid, but increases n-6 eicosadienoic acid, and lowers dihomo-gamma-linolenic and eicosapentaenoic acid in plasma of adult men

High intakes of linoleic acid (LA,18:2n-6) have raised concern due to possible increase in arachidonic acid (ARA, 20:4n-6) synthesis, and inhibition of alpha linolenic acid (ALA, 18:3n-3) desaturation to eicosapentaenoic (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3). In healthy men, 10.5% energy compared to 3.8% energy LA with 1% energy ALA increased plasma phospholipid LA and 20:2n-6, the elongation product of LA, and decreased EPA, with no change in ARA. However, LA was inversely related to ARA at both 10.5% energy and 3.8% energy LA, (r=-0.761, r=-0.817, p<0.001, respectively). A two-fold variability in ARA among individuals was not explained by the dietary LA, ARA, ALA, or fish intake. Our results confirm LA requirements for ARA synthesis is low, <3.8% energy, and they suggest current LA intakes saturate Delta-6 desaturation and adversely affect n-3 fatty acid metabolism. Factors other than n-6 fatty acid intake are important modifiers of plasma ARA.

Quantitation of alpha-linolenic acid elongation to eicosapentaenoic and docosahexaenoic acid as affected by the ratio of n6/n3 fatty acids

BACKGROUND

Conversion of linoleic acid (LA) and alpha-linolenic acid (ALA) to their higher chain homologues in humans depends on the ratio of ingested n6 and n3 fatty acids.

DESIGN AND METHODS

In order to determine the most effective ratio with regard to the conversion of ALA to eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), human hepatoma cells were incubated with varying ratios of [¹³C] labeled linoleic acid ([¹³C]LA)- and alpha-linolenic acid ([¹³C]ALA)-methylesters. Regulative cellular signal transduction pathways involved were studied by determinations of transcript levels of the genes encoding delta-5 desaturase (D5D) and delta-6 desaturase (D6D), peroxisome proliferator-activated receptor alpha (PPARα) and sterol regulatory element binding protein 1c (SREBP-1c). Mitogen-activated protein kinase kinase 1 (MEK1) and mitogen-activated protein kinase kinase kinase 1 (MEKK1) were also examined.

RESULTS

Maximum conversion was observed in cells incubated with the mixture of [¹³C]LA/[¹³C]ALA at a ratio of 1:1, where 0.7% and 17% of the recovered [¹³C]ALA was converted to DHA and EPA, respectively. Furthermore, differential regulation of enzymes involved in the conversion at the transcript level, dependent on the ratio of administered n6 to n3 fatty acids in human hepatocytes was demonstrated.

CONCLUSION

Formation of EPA and DHA was highest at an administered LA/ALA ratio of 1:1, although gene expression of PPARα, SREBP-1c and D5D involved in ALA elongation were higher in the presence of ALA solely. Also, our findings suggest that a diet-induced enhancement of the cell membrane content of highly unsaturated fatty acids is only possible up to a certain level.

Thiamine and fatty acid content of walleye tissue from three southern U.S. reservoirs

We determined the thiamine concentration in egg, muscle, and liver tissues of walleyes Sander vitreus and the fatty acid content of walleye eggs from three southern U.S. reservoirs. In two Tennessee reservoirs (Dale Hollow and Center Hill), in which there were alewives Alosa pseudoharengus in the forage base, natural recruitment of walleyes was not occurring; by contrast in Lake James Reservoir, North Carolina, where there were no alewives, the walleye population was sustained via natural recruitment. Female walleye tissues were collected and assayed for thiamine (vitamin B1) and fatty acid content. Thiamine pyrophosphate was found to be the predominant form of thiamine in walleye eggs. In 2000, mean total egg thiamine concentrations were similar among Center Hill, Dale Hollow, and Lake James reservoirs (2.13, 3.14, and 2.77 nmol thiamine/g, respectively). Egg thiamine concentration increased as maternal muscle (r2 = 0.73) and liver (r2 = 0.68) thiamine concentration increased. Walleye egg thiamine does not appear to be connected to poor natural reproduction in Tennessee walleyes. Threadfin shad Dorosoma petenense, which are found in all three reservoirs, had higher thiaminase activity than alewives. Six fatty acids differed among the walleye eggs for the three reservoirs. Two were physiologically important fatty acids, arachidonic acid (20:4[n-6]) and docosahexaenoic acid (22:6[n-3]), which are important eicosanoid precursors involved in the regulation of biological functions, such as immune response and reproduction.

Effects of dietaryn-3 polyunsaturated fatty acids from plant and marine origin on platelet aggregation in healthy elderly subjects

In the present intervention study we compared the effects of α-linolenic acid with those of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) on platelet aggregationin vitroandex vivoin healthy non-institutionalized elderly subjects. We also compared the effects of α-linolenic acid on platelet aggregation in elderly subjects with those in younger volunteers. During a run-in period of 3 weeks all subjects (thirty-eight elderly (> 60 years) and twelve younger volunteers (< 35 years)) received a diet rich in oleic acid. For the next 6 weeks the elderly subjects received a diet rich in oleic acid (n11), α-linolenic acid (n14) (6·8 g/d) or EPA/DHA (n13) (1·05 g EPA plus 0·55 g DHA). The younger subjects were given a diet rich in α-linolenic acid. The diets did not affect ADP- or collagen-induced platelet aggregationin vitroin either platelet-rich plasma or whole blood. Theex vivoplatelet aggregation as measured with filtragometry was significantly decreased in the elderly group that received EPA/DHA compared with the α-linolenic acid (P= 0·006) and the oleic acid (P= 0·005) diet groups. Effects of α-linolenic acid were not age-dependent. Our results suggest that α-linolenic acid and EPA/DHA do not changein vitroplatelet aggregation. Compared with oleic acid, EPA/DHA, but not α-linolenic acid, favourably affectsex vivoplatelet aggregation in healthy elderly subjects.

Effects of hempseed and flaxseed oils on the profile of serum lipids, serum total and lipoprotein lipid concentrations and haemostatic factors

BACKGROUND

Both hempseed oil (HO) and flaxseed oil (FO) contain high amounts of essential fatty acids (FAs); i.e. linoleic acid (LA, 18:2n-6) and alpha-linolenic acid (ALA, 18:3n-3), but almost in opposite ratios. An excessive intake of one essential FA over the other may interfere with the metabolism of the other while the metabolisms of LA and ALA compete for the same enzymes. It is not known whether there is a difference between n-3 and n-6 FA of plant origin in the effects on serum lipid profile.

AIM OF THE STUDY

To compare the effects of HO and FO on the profile of serum lipids and fasting concentrations of serum total and lipoprotein lipids, plasma glucose and insulin, and haemostatic factors in healthy humans.

METHODS

Fourteen healthy volunteers participated in the study. A randomised, double-blind crossover design was used. The volunteers consumed HO and FO (30 ml/day) for 4 weeks each. The periods were separated by a 4-week washout period.

RESULTS

The HO period resulted in higher proportions of both LA and gamma-linolenic acid in serum cholesteryl esters (CE) and triglycerides (TG) as compared with the FO period (P < 0.001), whereas the FO period resulted in a higher proportion of ALA in both serum CE and TG as compared with the HO period (P < 0.001). The proportion of arachidonic acid in CE was lower after the FO period than after the HO period (P < 0.05). The HO period resulted in a lower total-to-HDL cholesterol ratio compared with the FO period (P = 0.065). No significant differences were found between the periods in measured values of fasting serum total or lipoprotein lipids, plasma glucose, insulin or hemostatic factors.

CONCLUSIONS

The effects of HO and FO on the profile of serum lipids differed significantly, with only minor effects on concentrations of fasting serum total or lipoprotein lipids, and no significant changes in concentrations of plasma glucose or insulin or in haemostatic factors.

Fatty acids as modulators of the immune response

Research describing fatty acids as modulators of inflammation and immune responses abounds. Many of these studies have focused on one particular group of fatty acids, omega-3. The data from animal studies have shown that these fatty acids can have powerful anti-inflammatory and immunomodulatory activities in a wide array of diseases (e.g., autoimmunity, arthritis, and infection). However, the evidence from human trials is more equivocal. In this review, a historical framework for understanding how and why fatty acids may affect the immune system is provided. Second, highlights of two recent landmark reports from the Agency for Healthcare Research and Quality are presented. These reports critically evaluate the evidence from human clinical trials of omega-3 fatty acids and rheumatoid arthritis, asthma, and a few other immune-mediated diseases. Third, the data from human clinical trials investigating the impact of various bioactive fatty acids on ex vivo and in vivo immune response are reviewed. Limitations in experimental design and immune assays commonly used are discussed. The discordance between expectation and evidence in this field has been a disappointment. Recommendations for improving both animal-based and human studies are provided.

Ácidos graxos como marcadores biológicos da ingestão de gorduras

Os ácidos graxos da dieta têm sido associados ao desenvolvimento de doenças crônicas. Os inquéritos alimentares, utilizados em estudos clínicos e epidemiológicos para estimativa da ingestão de nutrientes, apresentam limitações na coleta de informações. Nesse sentido, a utilização da composição de ácidos graxos do plasma e do tecido adiposo como marcadores do tipo de gordura alimentar pode fornecer uma medida mais acurada da ingestão de gorduras. Esta pesquisa tem como objetivo evidenciar aspectos metabólicos de alguns ácidos graxos e o papel como marcadores da ingestão de gorduras, e apresentar as técnicas analíticas empregadas na sua determinação. A biópsia do tecido adiposo, com determinação da composição de ácidos graxos, fornece uma informação a longo prazo da ingestão de gorduras, enquanto que a avaliação da composição das frações lipídicas séricas representa a ingestão a curto e médio prazos. Os ácidos graxos essenciais, os ácidos graxos saturados com número ímpar de carbonos (15:0 e 17:0) e os ácidos graxos trans, por não apresentarem síntese endógena, são utilizados como marcadores biológicos da ingestão de gorduras ou de sua própria ingestão. As principais técnicas utilizadas para a determinação de ácidos graxos são a cromatografia gasosa e a cromatografia líquida de alta precisão. No presente momento, o uso de marcadores biológicos para a ingestão de gorduras, associados aos inquéritos alimentares, representa a forma mais completa de avaliação da ingestão de gorduras.

The content and composition of lipids in the digital cushion of the bovine claw with respect to age and location – A preliminary report

The pads of the bovine digital cushion, which serves as a shock absorber, have specific anatomical structures to cope with the substantial forces acting within the claw. To gain more information on the lipid composition and content of the pads, horn shoes from 12 slaughtered heifers and cows were removed and different samples of the pads excised with a scalpel. Pad lipids were extracted and the fatty acid composition determined by gas chromatography. Fat from perirenal and subcutaneous adipose tissues served as a comparison. Overall, this fat contained a higher quantity of extracted lipids than that of the claw pads and did not differ between heifers and cows. In contrast, lipid content in the pads was significantly higher in the cows than in the heifers. In both groups, the lipid content of the middle and abaxial pads, which are situated directly under the distal phalanx, was lower than in the pads of the other locations. The lipids in all pads contained >77% monounsaturated fatty acids (MUFA), differing sharply from the adipose tissue with values <51%. Among the polyunsaturated fatty acids (PUFA) a significantly higher proportion of arachidonic acid (AA) was found in the heifer pads than in those of the cows, whereas the proportion of AA was similar in the adipose tissue of all animals. The proportion of AA in the pad lipids also varied between the defined locations with the highest proportion found in locations that showed the lowest lipid content and was related to the age of the animal.

Safety and Efficacy of a New Parenteral Lipid Emulsion (SMOFlipid) in Surgical Patients: A Randomized, Double-Blind, Multicenter Study

BACKGROUND/AIMS

A new lipid emulsion based on soybean oil, medium chain triglycerides, olive oil and fish oil (SMOFlipid) was tested for safety, tolerance, metabolic and clinical efficacy in surgical patients.

METHODS

In a prospective, double-blind European multicenter study, postoperative patients (elective abdominal or thoracic surgery) were randomized to receive isonitrogenous, isoenergetic (30-35 kcal/kg) total parenteral nutrition over 5 postoperative days including either SMOFlipid 20% or standard soybean oil emulsion (Lipovenoes 20%) as lipid source (1.5 g kg(-1) day(-1)). Metabolic efficacy measurements included serum levels of triglycerides (AUC), phospholipids, and total cholesterol. Safety/tolerance parameters were: hematology; clinical chemistry; coagulation profile; clinical course (arterial blood pressure, heart rate, body temperature), and documentation of adverse events. Clinical efficacy was monitored by length of hospital stay and mortality.

RESULTS

The 2 groups (per-protocol population: SMOFlipid n = 99, and Lipovenoes n = 100) were similar with respect to demographic characteristics and types of surgical intervention. Concentrations of serum triglycerides, phospholipids, and total cholesterol were comparable in both groups and within the expected ranges. Laboratory and clinical parameters were not different. A trend towards a reduced length of hospital stay was observed with SMOFlipid (15.7 +/- 6.3 vs. 17.8 +/- 13.2 days).

CONCLUSIONS

SMOFlipid is clinically safe and well tolerated in postoperative patients. There are indications that SMOFlipid may be associated with a better liver tolerance and a shorter length of hospitalization.

A front-end desaturase from Chlamydomonas reinhardtii produces pinolenic and coniferonic acids by omega13 desaturation in methylotrophic yeast and tobacco

Pinolenic acid (PA; 18:3Delta(5,9,12)) and coniferonic acid (CA; 18:4Delta(5,9,12,15)) are Delta(5)-unsaturated bis-methylene-interrupted fatty acids (Delta(5)-UBIFAs) commonly found in pine seed oil. They are assumed to be synthesized from linoleic acid (LA; 18:2Delta(9,12)) and alpha-linolenic acid (ALA; 18:3Delta(9,12,15)), respectively, by Delta(5)-desaturation. A unicellular green microalga Chlamydomonas reinhardtii also accumulates PA and CA in a betain lipid. The expressed sequence tag (EST) resource of C. reinhardtii led to the isolation of a cDNA clone that encoded a putative fatty acid desaturase named as CrDES containing a cytochrome b5 domain at the N-terminus. When the coding sequence was expressed heterologously in the methylotrophic yeast Pichia pastoris, PA and CA were newly detected and comparable amounts of LA and ALA were reduced, demonstrating that CrDES has Delta(5)-desaturase activity for both LA and ALA. CrDES expressed in the yeast showed Delta(5)-desaturase activity on 18:1Delta(9) but not 18:1Delta(11). Unexpectedly, CrDES also showed Delta(7)-desaturase activity on 20:2Delta(11,14) and 20:3Delta(11,14,17) to produce 20:3Delta(7,11,14) and 20:4Delta(7,11,14,17), respectively. Since both the Delta(5) bond in C18 and the Delta(7) bond in C20 fatty acids are 'omega13' double bonds, these results indicate that CrDES has omega13 desaturase activity for omega9 unsaturated C18/C20 fatty acids, in contrast to the previously reported front-end desaturases. In order to evaluate the activity of CrDES in higher plants, transgenic tobacco plants expressing CrDES were created. PA and CA accumulated in the leaves of transgenic plants. The highest combined yield of PA and CA was 44.7% of total fatty acids, suggesting that PA and CA can be produced in higher plants on a large scale.

POLYUNSATURATED FATTY ACID REGULATION OF GENES OF LIPID METABOLISM

Apart from being an important macronutrient, dietary fat has recently gained much prominence for its role in regulating gene expression. Polyunsaturated fatty acids (PUFAs) affect gene expression through various mechanisms including, but not limited to, changes in membrane composition, intracellular calcium levels, and eicosanoid production. Furthermore, PUFAs and their various metabolites can act at the level of the nucleus, in conjunction with nuclear receptors and transcription factors, to affect the transcription of a variety of genes. Several of these transcription mediators have been identified and include the nuclear receptors peroxisome proliferator-activated receptor (PPAR), hepatocyte nuclear factor (HNF)-4alpha, and liver X receptor (LXR) and the transcription factors sterol-regulatory element binding protein (SREBP) and nuclear factor-kappaB (NFkappaB). Their interaction with PUFAs has been shown to be critical to the regulation of several key genes of lipid metabolism. Working out the mechanisms by which these interactions and consequent effects occur is proving to be complicated but is invaluable to our understanding of the role that dietary fat can play in disease management and prevention.