Association of Dietary Phytosterols with Cardiovascular Disease Biomarkers in Humans

Cardiovascular disease (CVD) is a leading cause of death worldwide. Elevated concentrations of serum total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) are major lipid biomarkers that contribute to the risk of CVD. Phytosterols well known for their cholesterol-lowering ability, are non-nutritive compounds that are naturally found in plant-based foods and can be classified into plant sterols and plant stanols. Numerous clinical trials demonstrated that 2 g phytosterols per day have LDL-C lowering efficacy ranges of 8–10%. Some observational studies also showed an inverse association between phytosterols and LDL-C reduction. Beyond the cholesterol-lowering beneficial effects of phytosterols, the association of phytosterols with CVD risk events such as coronary artery disease and premature atherosclerosis in sitosterolemia patients have also been reported. Furthermore, there is an increasing demand to determine the association of circulating phytosterols with vascular health biomarkers such as arterial stiffness biomarkers. Therefore, this review aims to examine the ability of phytosterols for CVD risk prevention by reviewing the current data that looks at the association between dietary phytosterols intake and serum lipid biomarkers, and the impact of circulating phytosterols level on vascular health biomarkers. The clinical studies in which the impact of phytosterols on vascular function is investigated show minor but beneficial phytosterols effects over vascular health. The aforementioned vascular health biomarkers are pulse wave velocity, augmentation index, and arterial blood pressure. The current review will serve to begin to address the research gap that exists between the association of dietary phytosterols with CVD risk biomarkers.     

Molecular Finger Printing of Nutra-Coconut Oil with Improved Health Protective Phytoceuticals and its Efficacy as Frying Medium

Coconut oil is rich in medium chain triglycerides but lacks polyunsaturated fatty acids (PUFA) and bio‐active phytoceuticals. In the present work nutra‐coconut oil was prepared by blending coconut oil and flaxseed oil (70:30) and adding 3000 ppm of flaxseed cake concentrate using ethanol, methanol and 20 % aqueous ethanol. The concentrate prepared from flaxseed was from ethanol as it gave maximum yield. The different bio‐active molecules in flaxseed concentrate observed are polyphenols (39.04 %), tocopherols (4.37 %), ferulic acid (0.17 mg g^?1), p‐coumaric acid (2.24 mg g^?1), chlorogenic acid (16.11 mg g^?1), gallic acid (8.58 mg g^?1), sinapic acid (0.64 mg g^?1) and secoisolariresinol (30.13 mg g^?1). The nutra‐coconut oil was found to have polyphenols (2.86 %), tocopherols (442.96 ppm) and antiradical activity (94 %). The PUFA content was found to increase in nutra‐coconut oil significantly (p < 0.05) (2–22 %). The FT‐IR spectra of nutra‐coconut oil revealed that the peak at 3009 and 1651 cm^?1 was associated with the presence of unsaturated fatty acids. There was no significant (p > 0.05) difference observed in sensory attributes of snack food fried using coconut oil and nutra‐coconut oil indicating that the later could be used as a frying medium and useful for food processing industries.     

Parenteral Lipid Emulsions in Guinea Pigs Differentially Influence Plasma and Tissue Levels of Fatty Acids,Squalene, Cholesterol,and Phytosterols

Lipid emulsions are made by mixing vegetable and/or fish oils with egg yolk and contain different types and amounts of fatty acids and sterols. This study assessed the effects of oral diet, soybean oil (SO)-, fish oil (FO)-, a mixture of olive and soybean oil (OOSO)-, and a mixture of fish, olive, coconut, and soybean oil (FOCS)-based emulsions on plasma triacylglycerols and plasma and tissue fatty acid and sterol content following acute and chronic intravenous administration in the guinea pig. Upon acute administration, peak triacylglycerols were highest with SO and lowest with OOSO. Upon chronic administration, the plasma triglyceride levels did not increase in any group over that of the controls. Fatty acid levels varied greatly between organs of animals on the control diets and organs of animals following acute or chronic lipid administration. Squalene levels increased in plasma following acute administration of OOSO, but plasma squalene levels were similar to control in all emulsion groups following chronic administration. Total plasma phytosterol levels were increased in the SO, OOSO, and FOCS groups following both acute and chronic infusions, whereas phytosterols were not increased following FO infusion. Total phytosterol levels were higher in liver, lung, kidney and adipose tissue following SO and OOSO. Levels were not increased in tissues after FO and FOCS infusion. These results indicate that fatty acid and sterol contents vary greatly among organs and that no one tissue reflects the fatty acid or sterol composition of other tissues, suggesting that different organs regulate these compounds differently.     

Identification of Correlative Shifts in Indices of Brain Cholesterol Metabolism in the C57BL6/Mecp2tm1.1Bird Mouse,a Model for Rett Syndrome

Rett syndrome (RS) is a pervasive neurodevelopmental disorder resulting from loss‐of‐function mutations in the X‐linked gene methyl‐Cpg‐binding protein 2 (MECP2). Using a well‐defined model for RS, the C57BL6/Mecp2^tm1.1Bird mouse, we have previously found a moderate but persistently lower rate of cholesterol synthesis, measured in vivo, in the brains of Mecp2^?/y mice, starting from about the third week after birth. There was no genotypic difference in the total cholesterol concentration throughout the brain at any age. This raised the question of whether the lower rate of cholesterol synthesis in the mutants was balanced by a fall in the rate at which cholesterol was converted via cholesterol 24‐hydroxylase (Cyp46A1) to 24S‐hydroxycholesterol (24S‐OHC), the principal route through which cholesterol is ordinarily removed from the brain. Here, we show that while there were no genotypic differences in the concentrations in plasma and liver of three cholesterol precursors (lanosterol, lathosterol, and desmosterol), two plant sterols (sitosterol and campesterol), and two oxysterols (27‐hydroxycholesterol [27‐OHC] and 24S‐OHC), the brains of the Mecp2 ^?/y mice had significantly lower concentrations of all three cholesterol precursors, campesterol, and both oxysterols, with the level of 24S‐OHC being ~20% less than in their Mecp2 ^+/y controls. Together, these data suggest that coordinated regulation of cholesterol synthesis and catabolism in the central nervous system is maintained in this model for RS. Furthermore, we speculate that the adaptive changes in these two pathways conceivably resulted from a shift in the permeability of the blood–brain barrier as implied by the significantly lower campesterol and 27‐OHC concentrations in the brains of the Mecp2^?/y mice.     

Plasma Phytosterol Half‐Life and Levels Are Increased in Very Low Birth Weight Preterm Infants with Parenteral Nutrition‐Associated Cholestasis

Parenteral nutrition‐associated cholestasis (PNAC) has been linked to plasma accumulation of phytosterols in infants receiving vegetable‐oil‐based lipid emulsions (LE). To date, information on the ability of infants with PNAC to metabolize intravenous (IV) phytosterols has been very limited. We characterized plasma phytosterol half‐life in very low birth weight (VLBW) preterm infants with PNAC. As part of a prospective cohort study, VLBW infants with PNAC underwent serial blood sample measurements of sitosterol (Sito), campesterol (Camp), and stigmasterol (Stigma). Infants without PNAC served as controls (CTRL, control infants). Thirty‐seven PNAC infants and 14 CTRL were studied. On PN day 7 and PN day 14, PNAC infants had higher plasma phytosterol concentrations compared to those of CTRL (p < 0.05). A significant and positive correlation was found between plasma Camp, Stigma, Sito concentrations, and IV phytosterol intake from birth to PN day 7 (p = 0.001, p = 0.001, and p = 0.005, respectively). Stigma concentration was positively correlated with conjugated bilirubin on PN day 7 (p = 0.012). After stopping IV LE, half‐lives of Camp, Stigma, and Sito became significantly longer in PNAC infants than in CTRL (Camp: 18.8 ±6.2 vs 11.8 ±3.0 days, p = 0.001; Stigma: 13.8 ±5.8 vs 9.4 ±3.4 days, p = 0.023; Sito: 15.3 ±5.0 vs 9.8 ±3.0 days, p = 0.002). In conclusion, phytosterols increased earlier during PN and were eliminated slowly after stopping IV LE in PNAC infants than in CTRL. The Stigma concentration on PN day 7 could represent an early marker of cholestasis. Our results provide additional evidence on the relationship between IV phytosterols and PNAC.     

Extraction and Identification of Phytosterols in Manketti (Schinziophyton rautanenii) Nut Oil

Phytosterols of manketti (Schinziophyton rautanenii) nut oil extracted by Soxhlet, mechanical shaking using hexane, screw press and supercritical carbon dioxide, were analyzed by gas chromatography with flame ionization detection and identified by gas chromatography–mass spectrometry. The presence of several phytosterols (campesterol, stigmasterol, β‐sitosterol, Δ⁵‐avenasterol, 22‐dihydrospinasterol and Δ⁷‐avenasterol) previously reported in manketti oil, was confirmed. In addition, another fourteen phytosterols (lanosterol, Δ^5,23‐stigmastadienol, Δ⁷‐campesterol, clerosterol, obtusifoliol, Δ^5,24(25)‐stigmastadienol, α‐amyrin, gramisterol, cycloeucalenol, cycloartenol, stigmasta‐8,24‐dienol‐3‐β‐ol, 28‐methylobtusifoliol, 24‐methylenecycloartenol and citrostadienol) were identified. The phytosterols, β‐sitosterol, Δ⁵‐avenasterol and campesterol, had the highest concentrations in oils extracted by all the methods, whereas stigmasterol and cycloartenol were abundant in oils extracted by mechanical shaking and supercritical carbon dioxide. Total phytosterols and the quantities of individual phytosterols differed significantly (p ≤ 0.05) in oils from the four extraction methods. Mechanical shaking extracted the highest levels of total sterols (22,100 mg/100 g oil), followed by supercritical fluid extraction (9,550 mg/100 g oil). Screw press and Soxhlet extracted oils contained the lowest levels of total sterols, 3,810 mg/100 g oil and 3,350 mg/100 g oil, respectively.     

Phytosterols and human lipid metabolism: efficacy,safety, and novel foods

Plant sterols have been known for several decades to cause reductions in plasma cholesterol concentrations. These plant materials have been granted a conditional health claim in the United States regarding their effects in the prevention of cardiovascular disease and are being sold in functional foods in several countries in Europe as well as in the United States and Australia. It is generally suggested that daily consumption of ∼2 g of plant sterols can lower cholesterol concentrations as part of a dietary prevention strategy. However, phytosterols have been added and tested for their cholesterol-lowering effects mainly in spreads. Consumption of these high-fat foods seemingly flies in the face of current recommendations for the promotion of heart health, which suggest lowering total fat and energy intake to maintain weight. Hence, new food formulations are being evaluated using phytosterols incorporated into low-fat and reduced-fat food items. The purpose of this review is to examine the cholesterol-lowering efficacy of plant sterols, focusing on novel food applications, their mechanism of action, and safety. These novel food formulations include new solubilization processes that lead to improved uses for plant sterols, as well as new foods into which phytosterols have been incorporated, such as breads, cereals, and beef. Such new foods, and formulations should pave the way for greater use of phytosterols in heart health promotion, increasing the longer-term potential for the creation of innovative functional foods containing plant sterols and their derivatives.     

Respective Hydrolysis and Esterification of Esterified and Free Plant Stanols Occur Rapidly in Human Intestine After Their Duodenal Infusion in Triacyl- or Diacylglycerol

Esterification of dietary phytosterols and glycerols may affect intestinal absorption of cholesterol and non-cholesterol sterols. We infused plant stanol esters in triacylglycerol (TAG) (F1) and diacylglycerol (DG) (F2) oils, and free plant stanols in F1 and F2 (F3) to the duodenum of healthy human subjects and sampled the contents from the proximal jejunum (PJ). Free and ester sterols were analysed from the infusates, and intestinal contents before and after ultracentrifuge separation of oil, micelle and sediment phases. During the 60-cm intestinal passage, over 40% of plant stanol esters were hydrolysed (P < 0.05) but around 30% of the infused free plant stanols (P < 0.05) and up to 40% of cholesterol (P < 0.05) were esterified in PJ after infusions. TAG in F1 favoured accumulation of plant stanol esters in the oil phase of the PJ aspirates as compared with respective values of F2 and F3 (P < 0.05 for both). About one third of free plant stanols of F3 had been esterified (P < 0.05) and 17% precipitated mainly in free form in the PJ aspirates (P < 0.05 compared with F1 and F2). In conclusion, DG- and TAG-oils had no profound superiority over each other as intestinal carriers regarding hydrolysis/esterification of administered plant stanol esters and cholesterol and their partition in oil, micellar and sediment phases in the PJ. The unesterified plant stanols experienced partial esterification and sedimentation during their intestinal passage, which might influence their biochemical properties in that segment of the gut where cholesterol is absorbed.     

Quantification and Determination of Composition of Steryl Ferulates in Refined Rice Bran Oils Using an UPLC-MS Method

Gamma-oryzanol contains a mixture of steryl ferulates found in rice bran oil. Several studies have attributed nutraceutical properties to this mixture, such as hypocholesterolemic and anti-inflammatory activities. A method based on ultra-performance liquid chromatography coupled with electrospray ionization mass spectrometry was developed and evaluated for the simultaneous quantification of gamma-oryzanol and identification of five major steryl ferulates directly in refined rice bran oils (RBO) samples. The proposed method was evaluated according to linearity by obtaining standard curves with R ² values above 0.990, and limit of detection values ranged from 1.9 to 5.9 µg/mL, whereas limits of quantification ranged from 5.9 to 17.9 µg/mL; inter- and intraday accuracy and precision were within the range required by the US Food and Drug Administration guidelines; recovery levels ranged from 78 to 85% for gamma-oryzanol, and from 84 to 119% for steryl ferulates. The method can be considered robust in relation to the NH₄OH (ammonium hydroxide) content and cone voltage variations, with coefficient of variation and average relative percentage deviation values lower than 7.0 and 4.4%, respectively. The stability during the storage test was maintained in concentrated samples (18.5 µg/mL), with recovered values between 93 and 113%. This method was successfully applied to the analysis of RBO samples, demonstrating that it could be easily used for quality control purposes.     

The Impact of Microalgae in Food Science and Technology

Microalgae (including cyanobacteria) are promising organisms for sustainable products for use as feedstocks for food, feed, fine chemicals, and biofuels. They can synthesize a broad range of products with medium‐ to high‐value market price such as β‐1,3‐glucan polysaccharide, single‐cell‐protein, carotenoids and phycobilin pigments, and long‐chain polyunsaturated fatty acids that are commercialized in the food industry as dietary supplements and functional foods, in the pharmaceutical and chemical industries as cosmaceuticals and flavorants, and in the therapeutic field as nutraceutical compounds. These microorganisms are also exceptional producers of omega‐3 and omega‐6 fatty acids such as eicosapentaenoic, docosahexaenoic, and arachidonic acids that have been linked to several human health benefits. The aim of this paper is to review the main existing high‐value products that can be derived from microalgae with a particular focus on food science and technology applications. It also describes the gross and fine chemical composition of various algal species and details the nutritive importance of selected constituents. Finally, nutritional quality standards and legislative provisions to ensure food safety in the use of algal biomass are presented.     

The Digestibility and Accumulation of Dietary Phytosterols in Atlantic Salmon (<Emphasis Type="Italic">Salmo salar</Emphasis> L.) Smolt Fed Diets with Replacement Plant Oils

Phytosterols occur in high concentration in canola (Brassica napus L.) and other vegetable oils such as from the borage plant Echium (Echium plantagineum L.). We investigated if Atlantic salmon (Salmo salar) digest and accumulate dietary phytosterols in significant amounts in muscle and liver. Phytosterols are lipid soluble, lower cholesterol and reduce the risk of coronary heart disease in humans. We aimed to determine if fatty fish, such as salmon, can be used as a delivery source of this functional food component. Three diets containing canola oil (CO), Echium oil (EO) and fish oil (FO) were fed to Atlantic salmon smolt over 9 weeks. The digestibility of natural abundances of phytosterols by Atlantic salmon was poor compared to cholesterol. However, phytosterols accumulated in liver and muscle of fish. Significantly increased concentrations of 24-methylenecholesterol, campesterol, beta-sitosterol and total phytosterol occurred in livers of EO fed fish compared to FO fed fish. Campesterol concentrations increased in CO fed fish compared to the FO fed fish. We demonstrated that natural abundances of dietary phytosterols are digested by and accumulated in liver and white muscle of Atlantic salmon smolt. However, phytosterol levels in salmon muscle will not be a major source of phytosterols in human diets and would not be expected to significantly effect human cardiovascular health.     

Co-crystals of Beeswax and Various Vegetable Waxes with Sterols Studied by X-ray Diffraction and Differential Scanning Calorimetry

In this study, mixtures of purified wax and sterols were melted and subsequently cooled. Using X-ray diffraction of the mixed, solid phase, it was shown that for up to 30–40 wt% sterols no measurable re-crystallisation of sterols occurred, i.e. the sterols became dissolved at a molecular level. Probably a form of amorphous co-crystals of sterols and wax is formed if the molecular ratio does not exceed 1:1. Differential scanning calorimetry (DSC) suggests that a minor amount of pure sterols could already be present at lower sterol levels. This may be because of the higher temperature at which the microstructure is probed when using DSC—melting of the wax might lead to crystallisation of the sterols. For application in foods, the structure as probed by X-rays at ambient temperatures is more relevant. When sunflower wax and rice bran wax are used, prevention of sterol crystallisation is even more pronounced, probably because the melting temperatures of these waxes are closer to the melting temperature of sterol crystals. Replacing the beeswax with a saturated fat (heRP70), sunflower oil, or jojoba wax (a liquid wax) substantially increases the amount of crystalline sterols. The difference between the various waxes and fats was qualitatively the same for X-ray diffraction and DSC. Stanols can be incorporated in the same manner and up to similar concentrations. Another insoluble nutritional compound, ursolic acid, has a greater tendency to crystallise in wax. This is probably because the melting temperature of ursolic acid is much higher than that of wax.     

Phytosterols,triterpene alcohols,and phospholipids in seed oil from white lupin

This study was conducted to determine effects of genotypes and growing environment on phytosterols, triterpene alcohols, and phospholipids (PL) in lupin (Lupinus albus L.) oil from seven genotypes grown in Maine and Virginia. The unsaponifiable lipid (UNSAP) and phospholipid (PL) fractions ranged from 2.1 to 2.8% and from 2.6 to 2.8% of oil, respectively. UNSAP in lupin oil contained 19.9 to 28.7% sterols and 17.3 to 22.0% triterpene alcohols. Growing location significantly affected contents of total PL, PS, phosphatidylglycerol, β-sitosterol, campesterol, and β-amyrin. Genotypic effects were significant for stigmasterol. PC (32.6 to 46.3% of PL), PE (21.6 to 32% of PL), and PS (11.2 to 17.9% of PL) were the major PL in lupin oil. The concentration of PL classes in lupin oil were in the following descending order: PC>PE>PS>PI>phosphatidic acid > lysophosphatidylcholine > phosphatidylglycerol > diphosphatidylglycerol. In descending order of abundance, the sterols present in lupin oil were: β-sitosterol > campesterol > stigmasterol > Δ⁵-avenasterol > Δ⁷-stigmastenol Lupeol was the most prominent triterpene alcohol in lupin seed oil. In general, growing environment had a much greater influence on lupin oil characteristics than the genotypes.     

Optimization of Spray Drying of an Innovative Functional Food: Fermented Mixed Juice of Carrot and Watermelon

This work deals with formulation and drying of a newly developed functional food. A watermelon and carrot juice mixture in the ratio 70:30 by volume was fermented at 37°C with Lactobacillus acidophilus to produce an innovative non-dairy-based food formulation with good flavor and high nutritional value. Viable count, pH, titrable acidity, protein content, and reducing sugar were measured during fermentation. The probiotic juice was spray dried at air temperature of 120 to 160°C and flow rate of 2.0 to 5.0 mL/min. Maltodextrin concentration of 10 to 15% by weight was used as an additive. Response surface methodology (RSM) was employed to optimize the drying process conditions. Physical properties (e.g., moisture content, density, porosity, and yield), biological properties (e.g., viability and lycopene and beta carotene content), and solubility data were examined as the response variables. Elevated temperatures and longer exposure times at lower feed rate reduced viability and lycopene and beta carotene content of the dried powder. Increased atomization pressure increased the cohesiveness but decreased flowability of the dried powder because the particle size was lowered. The probiotic powder was further analyzed using scanning electron microscopy (SEM) and differential scanning calorimetry (DSC).