Effects of dietary polyunsaturated fatty acid supplementation on fatty acid composition in muscle and subcutaneous adipose tissue of lambs

Lambs (n = 48) were used in a 2 × 2 factorial arrangement of treatments to evaluate effects of inclusion of oil containing PUFA in high-concentrate diets (with or without) and duration of oil supplementation (pre- vs. postweaning) on CLA concentration of muscle and adipose tissue. Lambs were fed preweaning creep diets (with or without oil) corresponding to the dietary lactation treatment diet (with or without oil) of the dam. Dams blocked by lambing date and rearing type were randomly assigned to 1 of 2 lactation dietary treatments with or without oil supplementation. Creep diets contained approximately 70% concentrate and 30% roughage and were provided to lambs for ad libitum intake. At weaning (58.7 ± 2.5 d of age), lambs (n = 48) were randomly assigned within preweaning treatment groups to 1 of 2 postweaning dietary treatments (with or without oil) and 16 pens in a randomized block design, blocked by sex and BW. Postweaning diets were formulated to contain approximately 80% concentrate and 20% roughage and were fed once daily for ad libitum intake. Soybean and linseed oil (2:1, respectively) replaced ground corn and provided 3% additional fat in pre- and postweaning diets. Lambs were slaughtered at 60.3 ± 4.2 kg of BW. A subcutaneous fat (SQ) sample was obtained within 1 h postmortem and a LM sample at the 12th rib was obtained 24 h postmortem, and both were analyzed for fatty acid profile. Feedlot performance and carcass measurements were not affected (P ≥ 0.26) by oil supplementation. Total CLA content of LM and SQ was not affected (P ≥ 0.08) by oil supplementation pre- or postweaning, but trans-10, cis-12 CLA was greater (P = 0.02) in SQ from lambs supplemented with oil postweaning. Total PUFA content in LM was greater (P = 0.02) in lambs supplemented with oil pre- or postweaning as a result of increased concentrations of 18:2cis-9, cis-12 and longer chain PUFA. Conversely, pre- and postweaning oil supplementation resulted in less (P = 0.04) MUFA content in LM. Only postweaning oil supplementation increased (P = 0.001) SQ PUFA content. Feeding oils containing PUFA to lambs pre- and postweaning did not increase CLA content of muscle, whereas postweaning oil supplementation minimally increased CLA concentration of SQ fat. Inclusion of soybean and linseed oil in pre- and postweaning diets increased total PUFA content of SQ fat and muscle tissue without adversely affecting growth performance or carcass characteristics.

Effect of linseed oil and fish oil alone or as an equal mixture of ruminal fatty acid metabolism in growing steers fed maize silage-based diets

Based on the potential benefits to human health there is interest in increasing 18:3n-3, 20:5n-3, 22:6n-6, and cis-9,trans-11 conjugated linoleic acid (CLA) in ruminant foods. Four Aberdeen Angus steers (406 ± 8.2 kg BW) fitted with rumen and duodenal cannulae were used in a 4 x 4 Latin square experiment with 21 d periods to examine the potential of fish oil (FO) and linseed oil (LO) in the diet to increase ruminal outflow of trans-11 18:1 and total n-3 polyunsaturated fatty acids (PUFA) in growing cattle. Treatments consisted of a control diet (60:40; forage:concentrate ratio, on a DM basis, respectively) based on maize silage, or the same basal ration containing 30 g/kg DM of FO, LO or a mixture (1:1, w/w) of FO and LO (LFO). Diets were offered as total mixed rations and fed at a rate of 85 g DM/kg BW0.75/d. Oils had no effect (P = 0.52) on DM intake. Linseed oil had no effect (P > 0.05) on ruminal pH or VFA concentrations, while FO shifted rumen fermentation towards propionate at the expense of acetate. Compared with the control, LO increased (P < 0.05) 18:0, cis 18:1 (Δ9, 12-15), trans 18:1 (Δ4-9, 11-16), trans 18:2, geometric isomers of ∆9,11, ∆11,13, and ∆13,15 CLA, trans-8,cis-10 CLA, trans-10,trans-12 CLA, trans-12,trans-14 CLA, and 18:3n-3 flow at the duodenum. Inclusion of FO in the diet resulted in higher (P < 0.05) flows of cis-9 16:1, trans 16:1 (Δ6-13), cis 18:1 (Δ9, 11, and 13), trans 18:1 (Δ6-15), trans 18:2, 20:5n-3, 22:5n-3, and 22:6n-3, and lowered (P < 0.001) 18:0 at the duodenum relative to the control. For most fatty acids at the duodenum responses to LFO were intermediate of FO and LO. However, LFO resulted in higher (P = 0.04) flows of total trans 18:1 than LO and increased (P < 0.01) trans-6 16:1 and trans-12 18:1 at the duodenum compared with FO or LO. Biohydrogenation of cis-9 18:1 and 18:2n-6 in the rumen was independent of treatment, but both FO and LO increased (P < 0.001) the extent of 18:3n-3 biohydrogenation compared with the control. Ruminal 18:3n-3 biohydrogenation was higher (P < 0.001) for LO and LFO than FO, while biohydrogenation of 20:5n-3 and 22:6n-3 in the rumen was marginally lower (P = 0.05) for LFO than FO. In conclusion, LO and FO at 30 g/kg DM altered the biohydrogenation of unsaturated fatty acids in the rumen causing an increase in the flow of specific intermediates at the duodenum, but the potential of these oils fed alone or as a mixture to increase n-3 PUFA at the duodenum in cattle appears limited.

Impact of income on nutrient intakes: implications for undernourishment and obesity

The relationship between income and nutrient intake is explored. Nonparametric, panel, and quantile regressions are used. Engle curves for calories, fat, and protein are approximately linear in logs with carbohydrate intakes exhibiting diminishing elasticities as incomes increase. Elasticities range from 0.10 to 0.25, with fat having the highest elasticities. Countries in higher quantiles have lower elasticities than those in lower quantiles. Results predict significant cumulative increases in calorie consumption which are increasingly composed of fats. Though policies aimed at poverty alleviation and economic growth may assuage hunger and malnutrition, they may also exacerbate problems associated with obesity.

Effect of food models and low-temperature storage on the adhesion of Lactobacillus rhamnosus GG to Caco-2 cells

This study evaluated the effects of fat and sugar levels on the surface properties of Lactobacillus rhamnosus GG during storage in food model systems, simulating yogurt and ice cream, and related them with the ability of the bacterial cells to adhere to Caco-2 cells. Freeze-dried L. rhamnosus GG cells were added to the model food systems and stored for 7 days. The bacterial cells were analyzed for cell viability, hydrophobicity, ζ potential, and their ability to adhere to Caco-2 cells. The results indicated that the food type and its composition affected the surface and adhesion properties of the bacterial cells during storage, with yogurt being a better delivery vehicle than ice cream in terms of bacterial adhesion to Caco-2 cells. The most important factor influencing bacterial adhesion was the storage time rather than the levels of fats and sugars, indicating that conformational changes were taking place on the surface of the bacterial cells during storage.

Frying of potato chips in a blend of canola oil and palm olein: changes in levels of individual fatty acids and tocols

The changes occurring in the levels of nutritionally relevant oil components were assessed during repeated frying of potato chips in a blend of palm olein and canola oil (1:1 w/w). The blend suffered minimal reductions in omega-3 and omega-6 polyunsaturated fatty acids. There was no significant difference between the fatty acid composition of the oil extracted from the product and that of the frying medium, in all three cases. The blend also contained a significant amount of tocols which add a nutritional value to the oil. The concentration of the tocols was satisfactorily retained over the period of oil usage, in contrast to the significant loses observed in the case of the individual oils. The blend also performed well when assessed by changes in total polar compounds, free fatty acids, p-anisidine value. When fried in used oil, the product oil content increased progressively with oil usage time. This study shows that blended frying oils can combine good stability and nutritional quality

The combined action of carvacrol and high hydrostatic pressure on Listeria monocytogenes Scott A

Aims: The aim of the study was to investigate the combined antimicrobial action of the plantderived volatile carvacrol and high hydrostatic pressure (HHP). Methods and Results: Combined treatments of carvacrol and HHP have been studied at different temperatures, using exponentially growing cells of Listeria monocytogenes, and showed a synergistic action. The antimicrobial effects were higher at 1°C than at 8 or 20°C. Furthermore, addition of carvacrol to cells exposed to sublethal HHP treatment caused similar reductions in viable numbers as simultaneous treatment with carvacrol and HHP. Synergism was also observed between carvacrol and HHP in semi-skimmed milk that was artifcially contaminated with L. monocytogenes. Conclusions: Carvacrol and HHP act synergistically and the antimicrobial effects of the combined treatment are greater at lower temperatures. Significance and Impact of the Study: The study demonstrates the synergistic antimicrobial effect of essential oils in combination with HHP and indicates the potential of these combined treatments in food processing.

Olive leaf phenolics and cardiovascular risk reduction: Physiological effects and mechanisms of action

Olive oil, an important component of the Mediterranean diet, is rich in polyphenols and is known to possess positive health effects relative to other dietary fats. In addition, the leaves of the olive plant (Olea europaea) contain similar phenolics (oleuropein, luteolin-7-glucoside, apigenin-7-glucoside, verbascoside and hydroxytyrosol) to those of olives and olive oil, although at higher concentrations. For example, the most abundant is the secoiridoid, oleuropein, representing 1–14% of olive leaf weight vs. 0.005–0.12% in olive oil. Although currently considered a waste product of the olive oil industry, recent research has suggested beneficial effects of phenolic-rich olive leaf extracts (OLE) in modifying cardiovascular risk biomarkers such as blood pressure, hyperglycaemia, oxidative stress and inflammation, as well as improving vascular function and lipid profiles. Despite this, data regarding the biological actions of OLE has mostly derived from animal, in vitro and ex vivo studies, with limited evidence deriving from human trials. Although the absorption and metabolism of olive oil phenolics has been investigated, less is known about the bioavailability of phenolics from OLE, limiting the interpretation of existing in vitro and ex vivo data. The current review will begin by describing the phenolic composition of olive leaves in comparison with that of the better studied olive oil. It will then review the effects of OLE on cardiovascular risk factors, covering both animal and human studies and will end by considering potential mechanisms of action

Fish oil fatty acids and vascular reactivity

Endothelial dysfunction and an associated increase in vascular tone are risk factors for cardiovascular disease and highly predictive of future cardiovascular events. A part of the benefits associated with increased intake of the long chain (LC) n-3 polyunsaturated fatty acids (PUFA), eicosapentaenoic acid and docosahexaenoic acid, found in fish oils is a positive impact on cardiovascular health. Here, the recent evidence from human observational and intervention trials are reviewed, and an insight into potential mechanisms underlying the impact of LC n-3 PUFA on vascular reactivity is provided.

Lifestyle-induced metabolic inflexibility and accelerated ageing syndrome: insulin resistance, friend or foe?

The metabolic syndrome may have its origins in thriftiness, insulin resistance and one of the most ancient of all signalling systems, redox. Thriftiness results from an evolutionarily-driven propensity to minimise energy expenditure. This has to be balanced with the need to resist the oxidative stress from cellular signalling and pathogen resistance, giving rise to something we call 'redox-thriftiness'. This is based on the notion that mitochondria may be able to both amplify membrane-derived redox growth signals as well as negatively regulate them, resulting in an increased ATP/ROS ratio. We suggest that 'redox-thriftiness' leads to insulin resistance, which has the effect of both protecting the individual cell from excessive growth/inflammatory stress, while ensuring energy is channelled to the brain, the immune system, and for storage. We also suggest that fine tuning of redox-thriftiness is achieved by hormetic (mild stress) signals that stimulate mitochondrial biogenesis and resistance to oxidative stress, which improves metabolic flexibility. However, in a non-hormetic environment with excessive calories, the protective nature of this system may lead to escalating insulin resistance and rising oxidative stress due to metabolic inflexibility and mitochondrial overload. Thus, the mitochondrially-associated resistance to oxidative stress (and metabolic flexibility) may determine insulin resistance. Genetically and environmentally determined mitochondrial function may define a 'tipping point' where protective insulin resistance tips over to inflammatory insulin resistance. Many hormetic factors may induce mild mitochondrial stress and biogenesis, including exercise, fasting, temperature extremes, unsaturated fats, polyphenols, alcohol, and even metformin and statins. Without hormesis, a proposed redox-thriftiness tipping point might lead to a feed forward insulin resistance cycle in the presence of excess calories. We therefore suggest that as oxidative stress determines functional longevity, a rather more descriptive term for the metabolic syndrome is the 'lifestyle-induced metabolic inflexibility and accelerated ageing syndrome'. Ultimately, thriftiness is good for us as long as we have hormetic stimuli; unfortunately, mankind is attempting to remove all hormetic (stressful) stimuli from his environment.

The integration of lipid-sensing and anti-inflammatory effects: how the PPARs play a role in metabolic balance

The peroxisomal proliferating-activated receptors (PPARs) are lipid-sensing transcription factors that have a role in embryonic development, but are primarily known for modulating energy metabolism, lipid storage, and transport, as well as inflammation and wound healing. Currently, there is no consensus as to the overall combined function of PPARs and why they evolved. We hypothesize that the PPARs had to evolve to integrate lipid storage and burning with the ability to reduce oxidative stress, as energy storage is essential for survival and resistance to injury/infection, but the latter increases oxidative stress and may reduce median survival (functional longevity). In a sense, PPARs may be an evolutionary solution to something we call the 'hypoxia-lipid' conundrum, where the ability to store and burn fat is essential for survival, but is a 'double-edged sword', as fats are potentially highly toxic. Ways in which PPARs may reduce oxidative stress involve modulation of mitochondrial uncoupling protein (UCP) expression (thus reducing reactive oxygen species, ROS), optimising forkhead box class O factor (FOXO) activity (by improving whole body insulin sensitivity) and suppressing NFkB (at the transcriptional level). In light of this, we therefore postulate that inflammation-induced PPAR downregulation engenders many of the signs and symptoms of the metabolic syndrome, which shares many features with the acute phase response (APR) and is the opposite of the phenotype associated with calorie restriction and high FOXO activity. In genetically susceptible individuals (displaying the naturally mildly insulin resistant 'thrifty genotype'), suboptimal PPAR activity may follow an exaggerated but natural adipose tissue-related inflammatory signal induced by excessive calories and reduced physical activity, which normally couples energy storage with the ability to mount an immune response. This is further worsened when pancreatic decompensation occurs, resulting in gluco-oxidative stress and lipotoxicity, increased inflammatory insulin resistance and oxidative stress. Reactivating PPARs may restore a metabolic balance and help to adapt the phenotype to a modern lifestyle.

Dairy fat: perceptions and realities.

Milk provides many key nutrients but the saturated and trans fatty acids in milk fat are associated with perceived negative effects on human health, especially cardiovascular disease. Recent epidemiological studies and dietary intervention trials challenge this perception, however; available evidence does not support the concept that consumption of saturated fats or dairy products adversely affects the risk of coronary heart disease (although replacing some saturated fats with mono or polyunsaturated fats is likely to provide benefit). Furthermore, the trans fats found in dairy products are consumed in very low amounts and do not appear to have the negative health effects associated with the consumption of industrial sources of trans fat. Milk fat is an excellent source of oleic acid that originates mainly by endogenous synthesis from stearic acid, but increasing the milk fat content of unsaturated fatty acids requires dietary formulations that bypass rumen biohydrogenation. Recent research indicates that long-chain omega-3 fatty acids and conjugated linoleic acids have potential beneficial effects in health maintenance and the prevention of chronic diseases. Enhancing the milk fat content of these fatty acids offers exciting possibilities, but educating consumers about inaccurate and inappropriate generalisations about fat remains the primary challenge. Finally, individuals do not simply consume milk-fat-derived fatty acids on their own, but rather as components in dairy foods which are highly complex and may contain many beneficial ingredients. Overall, dairy products are critical in providing many of the essential nutrients in the human diet. Nevertheless, dairy products vary in their nutrient composition, including fat, and this needs to be considered in the context of dietary recommendations and our need to consume a balanced diet.

Investigations into the formation and characterization of phospholipid microemulsions. IV. Pseudo-ternary phase diagrams of systems containing water-lecithin-alcohol and oil; The influence of oil

Phase studies have been performed for quaternary systems composed of egg lecithin, cosurfactant, water and oil. The lecithin used was the commercially available egg lecithin Ovothin 200 (which comprises ≥ 92% phosphatidylcholine). The cosurfactants employed were propanol and butanol, and these were used at lecithin/cosurfactant mixing ratios (Km) of 1:1 and 1.94:1 (weight basis). Six polar oils were investigated, including the alkanoic acids, octanoic and oleic, their corresponding ethyl esters and the medium and long chain triglycerides, Miglyol 812 and soybean oil. All oils, irrespective of the alcohol and the Km used, gave rise to systems that produced a stable isotropic region along the surfactant/oil axis (designated as a reverse microemulsion system). In addition, the systems incorporating propanol at both Km and butanol at a Km of 1.94: 1, generally gave rise to a liquid crystalline region and, in some cases, a second isotropic non-birefingent area (designated as a normal microemulsion system). The phase behaviour observed was largely dependent upon the alcohol and Km used and the size and the polarity of the oil present.

Polyphenols, glucosinolates, dietary fibre and colon cancer: Understanding the potential of specific types of fruit and vegetables to reduce bowel cancer progression

Colorectal cancer is the third most prevalent cancer worldwide and the most common diet-related cancer, influenced by diets rich in red meat, low in plant foods and high in saturated fats. Observational studies have shown that fruit and vegetable intake may reduce colorectal cancer risks, although the precise bioactive components remain unclear. This review will outline the evidence for the role of polyphenols, glucosinolates and fibres against cancer progression in the gastrointestinal tract. Those bioactive compounds are considered protective agents against colon cancer, with evidence taken from epidemiological, human clinical, animal and in vitro studies. Various mechanisms of action have been postulated, such as the potential of polyphenols and glucosinolates to inhibit cancer cell growth and the actions of insoluble fibres as prebiotics and the evidence for these actions are detailed within. In addition, recent evidence suggests that polyphenols also have the potential to shift the gut ecology in a beneficial manner. Such actions of both fibre and polyphenols in the gastrointestinal tract and through interaction with gut epithelial cells may act in an additive manner to help explain why certain fruits and vegetables, but not all, act to differing extents to inhibit cancer incidence and progression. Indeed, a focus on the individual actions of such fruit and vegetable components, in particular polyphenols, glucosinolates and fibres is necessary to help explain which components are active in reducing gastrointestinal cancer risk.

Aqueous enzyme assisted oil extraction from oilseeds and emulsion de-emulsifying methods: a review

Regulatory, safety, and environmental issues have prompted the development of aqueousenzymatic extraction (AEE) for extracting components from oil-bearing materials. The emulsion resulting from AEE requires de-emulsification to separate the oil; when enzymes are used for this purpose, the method is known as aqueous enzymatic emulsion de-emulsification (AEED). In general, enzyme assisted oil extraction is known to yield oil having highly favourable characteristics. This review covers technological aspects of enzyme assisted oil extraction, and explores the quality characteristics of the oils obtained,focusing particularly on recent efforts undertaken to improve process economics by recovering and reusing enzymes.

Edible oil from Tiger nut (Cyperus esculentus L.): mechanical pressing and aqueous enzymatic extraction methods

The tiger nut tuber of the Cyperus esculentus L. plant is an unusual storage system with similar amounts of starch and lipid. The extraction of its oil employing both mechanical pressing and aqueous enzymatic extraction (AEE) methods was investigated and an examination of the resulting products was carried out. The effects of particle size and moisture content of the tuber on the yield of tiger nut oil with pressing were initially studied. Smaller particles were found to enhance oil yields while a range of moisture content was observed to favour higher oil yields. When samples were first subjected to high pressures up to 700 MPa before pressing at 38 MPa there was no increase in the oil yields. Ground samples incubated with a mixture of α- Amylase, Alcalase, and Viscozyme (a mixture of cell wall degrading enzyme) as a pre-treatment, increased oil yield by pressing and 90% of oil was recovered as a result. When aqueous enzymatic extraction was carried out on ground samples, the use of α- Amylase, Alcalase, and Celluclast independently improved extraction oil yields compared to oil extraction without enzymes by 34.5, 23.4 and 14.7% respectively. A mixture of the three enzymes further augmented the oil yield and different operational factors were individually studied for their effects on the process. These include time, total mixed enzyme concentration, linear agitation speed, and solid-liquid ratio. The largest oil yields were obtained with a solid-liquid ratio of 1:6, mixed enzyme concentration of 1% (w/w) and 6 h incubation time although the longer time allowed for the formation of an emulsion. Using stationary samples during incubation surprisingly gave the highest oil yields, and this was observed to be as a result of gravity separation occurring during agitation. Furthermore, the use of high pressure processing up to 300 MPa as a pre-treatment enhanced oil yields but additional pressure increments had a detrimental effect. The quality of oils recovered from both mechanical and aqueous enzymatic extraction based on the percentage free fatty acid (% FFA) and peroxide values (PV) all reflected the good stabilities of the oils with the highest % FFA of 1.8 and PV of 1.7. The fatty acid profiles of all oils also remained unchanged. The level of tocopherols in oils were enhanced with both enzyme aided pressing (EAP) and high pressure processing before AEE. Analysis on the residual meals revealed DP 3 and DP 4 oligosaccharides present in EAP samples but these would require further assessment on their identity and quality.