Dietary lipids: more than just a source of calories

The Dioscorea Genus (Yam)-An Appraisal of Nutritional and Therapeutic Potentials

The quest for a food secure and safe world has led to continuous effort toward improvements of global food and health systems. While the developed countries seem to have these systems stabilized, some parts of the world still face enormous challenges. Yam (Dioscorea species) is an orphan crop, widely distributed globally; and has contributed enormously to food security especially in sub-Saharan Africa because of its role in providing nutritional benefits and income. Additionally, yam has non-nutritional components called bioactive compounds, which offer numerous health benefits ranging from prevention to treatment of degenerative diseases. Pharmaceutical application of diosgenin and dioscorin, among other compounds isolated from yam, has shown more prospects recently. Despite the benefits embedded in yam, reports on the nutritional and therapeutic potentials of yam have been fragmented and the diversity within the genus has led to much confusion. An overview of the nutritional and health importance of yam will harness the crop to meet its potential towards combating hunger and malnutrition, while improving global health. This review makes a conscious attempt to provide an overview regarding the nutritional, bioactive compositions and therapeutic potentials of yam diversity. Insights on how to increase its utilization for a greater impact are elucidated.

Clinical Nutrition in Critical Care Medicine - Guideline of the German Society for Nutritional Medicine (DGEM)

PURPOSE

Enteral and parenteral nutrition of adult critically ill patients varies in terms of the route of nutrient delivery, the amount and composition of macro- and micronutrients, and the choice of specific, immune-modulating substrates. Variations of clinical nutrition may affect clinical outcomes. The present guideline provides clinicians with updated consensus-based recommendations for clinical nutrition in adult critically ill patients who suffer from at least one acute organ dysfunction requiring specific drug therapy and/or a mechanical support device (e.g., mechanical ventilation) to maintain organ function.

METHODS

The former guidelines of the German Society for Nutritional Medicine (DGEM) were updated according to the current instructions of the Association of the Scientific Medical Societies in Germany (AWMF) valid for a S2k-guideline. According to the S2k-guideline classification, no systematic review of the available evidence was required to make recommendations, which, therefore, do not state evidence- or recommendation grades. Nevertheless, we considered and commented the evidence from randomized-controlled trials, meta-analyses and observational studies with adequate sample size and high methodological quality (until May 2018) as well as from currently valid guidelines of other societies. The liability of each recommendation was described linguistically. Each recommendation was finally validated and consented through a Delphi process.

RESULTS

In the introduction the guideline describes a) the pathophysiological consequences of critical illness possibly affecting metabolism and nutrition of critically ill patients, b) potential definitions for different disease phases during the course of illness, and c) methodological shortcomings of clinical trials on nutrition. Then, we make 69 consented recommendations for essential, practice-relevant elements of clinical nutrition in critically ill patients. Among others, recommendations include the assessment of nutrition status, the indication for clinical nutrition, the timing and route of nutrient delivery, and the amount and composition of substrates (macro- and micronutrients); furthermore, we discuss distinctive aspects of nutrition therapy in obese critically ill patients and those treated with extracorporeal support devices.

CONCLUSION

The current guideline provides clinicians with up-to-date recommendations for enteral and parenteral nutrition of adult critically ill patients who suffer from at least one acute organ dysfunction requiring specific drug therapy and/or a mechanical support device (e.g., mechanical ventilation) to maintain organ function. The period of validity of the guideline is approximately fixed at five years (2018-2023).

Fish oil after abdominal aorta aneurysm surgery

OBJECTIVE

Fish oil (FO) may attenuate the inflammatory response after major surgery such as abdominal aortic aneurysm (AAA) surgery. We aimed at evaluating the clinical impact and safety aspects of a FO containing parenteral nutrition (PN) after AAA surgery.

METHODS

Intervention consisted in 4 days of either standard (STD: Lipofundin medium-chain triglyceride (MCT): long-chain triglyceride (LCT)50%-MCT50%) or FO containing PN (FO: Lipoplus: LCT40%-MCT50%-FO10%). Energy target were set at 1.3 times the preoperative resting energy expenditure by indirect calorimetry. Blood sampling on days 0, 2, 3 and 4. Glucose turnover by the (2)H(2)-glucose method. Muscle microdialysis.

CLINICAL DATA

maximal daily T degrees, intensive care unit (ICU) and hospital stay.

RESULTS

Both solutions were clinically well tolerated, without any differences in laboratory safety parameters, inflammatory, metabolic data, or in organ failures. Plasma tocopherol increased similarly; with FO, docosahexaenoic and eicosapentaenoic acid increased significantly by day 4 versus baseline or STD. To increased postoperatively, with a trend to lower values in FO group (P=0.09). After FO, a trend toward shorter ICU stay (1.6+/-0.4 versus 2.3+/-0.4), and hospital stay (9.9+/-2.4 versus 11.3+/-2.7 days: P=0.19) was observed.

CONCLUSIONS

Both lipid emulsions were well tolerated. FO-PN enhanced the plasma n-3 polyunsaturated fatty acid content, and was associated with trends to lower body temperature and shorter length of stay.

Comparison of the structures of triacylglycerols from native and transgenic medium-chain fatty acid-enriched rape seed oil by liquid chromatography--atmospheric pressure chemical ionization ion-trap mass spectrometry (LC-APCI-ITMS)

The sn position of fatty acids in seed oil lipids affects physiological function in pharmaceutical and dietary applications. In this study the composition of acyl-chain substituents in the sn positions of glycerol backbones in triacylglycerols (TAG) have been compared. TAG from native and transgenic medium-chain fatty acid-enriched rape seed oil were analyzed by reversed-phase high performance liquid chromatography coupled with online atmospheric-pressure chemical ionization ion-trap mass spectrometry. The transformation of summer rape with thioesterase and 3-ketoacyl-[ACP]-synthase genes of Cuphea lanceolata led to increased expression of 1.5% (w/w) caprylic acid (8:0), 6.7% (w/w) capric acid (10:0), 0.9% (w/w) lauric acid (12:0), and 0.2% (w/w) myristic acid (14:0). In contrast, linoleic (18:2n6) and alpha-linolenic acid (18:3n3) levels decreased compared with the original seed oil. The TAG sn position distribution of fatty acids was also modified. The original oil included eleven unique TAG species whereas the transgenic oil contained sixty. Twenty species were common to both oils. The transgenic oil included trioctadecenoyl-glycerol (18:1/18:1/18:1) and trioctadecatrienoyl-glycerol (18:3/18:3/18:3) whereas the native oil included only the latter. The transgenic TAG were dominated by combinations of caprylic, capric, lauric, myrisitic, palmitic (16:0), stearic (18:0), oleic (18:1n9), linoleic, arachidic (20:0), behenic (22:0), and lignoceric acids (24:0), which accounted for 52% of the total fat. In the original TAG palmitic, stearic, oleic, and linoleic acids accounted for 50% of the total fat. Medium-chain triacylglycerols with capric and lauric acids combined with stearic, oleic, linoleic, alpha-linolenic, arachidic, and gondoic acids (20:1n9) accounted for 25% of the transgenic oil. The medium-chain fatty acids were mainly integrated into the sn-1/3 position combined with the essential linoleic and alpha-linolenic acids at the sn-2 position. Eight species contained caprylic, capric, and lauric acids in the sn-2 position. The appearance of new TAG in the transgenic oil illustrates the extensive effect of genetic modification on fat metabolism by transformed plants and offers interesting possibilities for improved enteral applications.

Effects of fish oil on the neuro-endocrine responses to an endotoxin challenge in healthy volunteers

BACKGROUND & AIMS

Fish oil (FO) has been shown to modulate the acute and chronic inflammatory responses. Endotoxin (LPS) has been shown to mimic several aspects of sepsis. The study aimed at testing the effects of oral FO supplements in healthy subjects submitted to intravenous LPS on systemic and endocrine response.

SUBJECTS AND METHODS

Fifteen healthy men (aged 26.0+/-3.1 years, BMI 23.8+/-1.9 kg/m2), were enrolled. Subjects were randomised to 3-4 weeks of oral FO supplementation (7.2 g/day, providing 1.1 g/day of 20:5 (n-3) and 0.7 g/day of 22:6 (n-3) fatty acids) or no supplementation and then submitted to endotoxin challenge: 2 ng/kg of LPS. All subjects were studied twice (placebo and LPS).

MEASUREMENTS

vital signs, energy expenditure (EE), glucose and lipid metabolism ((2)H2-glucose), plasma cytokines and stress hormones for 6 h after LPS or placebo.

RESULTS

LPS caused cytokine release, fever, increases in heart rate, resting EE and substrate oxidation, plasma glucagon and glucose concentrations; the neuro-endocrine response was characterised by increased plasma stress hormones. FO significantly blunted fever, ACTH and cortisol plasma levels (no effect on cytokine release). FO blunted the peak norepinephrine after LPS.

CONCLUSION

FO supplements blunted the endocrine stress response and the increase in body temperature, but had no impact on cytokine production after LPS. These findings conflict with the postulated anti-inflammatory effects of FO on arachidonic acid metabolism and cytokine release. These results suggest that FO may exert beneficial effects in sepsis though non-inflammatory which require further investigations.

sn-Position determination of phospholipid-linked fatty acids derived from erythrocytes by liquid chromatography electrospray ionization ion-trap mass spectrometry

The sn-position of FA in membrane lipids has an influence on the physiological function of cells, is predictive for diseases, and therefore is useful for diagnostics. The current study compares the compositions of acyl chain substituents in the sn-1 and sn-2 positions of the glycerol backbones of phospholipids derived from human erythrocytes by using RP-HPLC coupled with on-line electrospray ionization ion trap MS. Preferential loss of the acyl group in the sn-1 position was used to determine the degree of regiospecific preference exhibited by the phospholipid molecules. The identities of the molecular species and the positions of the acyl substituents were identified using product-ion spectra of major precursor ions selected from the mass spectra averaged across peaks in the total ion chromatogram. Saturated FA were found to be located mainly in the sn-1 position of the glycerol backbones of erythrocyte phospholipids, whereas PUFA were found primarily in the sn-2 position. All measured phospholipids revealed palmitic acid (16:0) at the sn-1 position. Linoleic acid (18:2n-6) and arachidonic acid (20:4n-6) were found to be attached exclusively to the sn-2 position of the backbone, whereas eicosadienoic (20:2n-6) and eicosatrienoic acid (20:3n-9) occurred in both positions of the backbone of PC. Oleic (18:1n-9), linoleic (18:2n-6), and octadecatrienoic (18:3) acids of PE and PS were linked to both positions. Lignoceric acid (24:1 n-9) was found to be strictly localized at the sn-2 position, whereas nervonic (24:1n-9) acid of PS was associated with both positions of the backbone. A detailed analysis of the blood cell membrane lipids by MS might be helpful to characterize postprandial kinetics of pharmacological or dietary lipid applications, as well as environmental influences on cell membranes.