Key points for maximum effectiveness and safety for cholesterol-lowering properties of plant sterols and use in the treatment of metabolic syndrome

Steroid-based tracing of sewage-sourced pollution of river water and wastewater treatment efficiency: Dissolved and suspended water phase distribution

In this work, the environmental distribution of steroid compounds and the level of sewage-derived contamination were assessed using sterol ratios in the confluence area of two major rivers in the Serbian capital, where raw sewage is discharged without any treatment. Special attention was paid to steroids partitioning between the dissolved and suspended phases of river and wastewater samples, since steroids tend to easily bind to particulate matter. The efficiency of sterol removal in two wastewater treatment plants in Serbia was also evaluated. Human/animal sterols coprostanol and cholesterol, and phytosterol β-sitosterol were the dominant compounds in all water samples. The sterol abundance pattern in river water was different from that in raw sewage, indicating a more pronounced biogenic input, as well as greater impact of wastewater discharges on the composition of the suspended phase. Severe contamination of the investigated area was determined, with the Danube being more contaminated than the Sava River due to different hydrodynamic conditions leading to significantly higher sterol levels in the suspended particulate matter. It was also shown that the greater part of human/animal sterols and phytosterols present in river water samples (83.0 ± 11.9 % and 87.1 ± 15.2 %) and wastewater samples (92.1 ± 6.8 % and 95.0 ± 5.7 %) was bound to suspended material compared to the dissolved phase, emphasizing the need to consider and analyze both water phases in the tracing of steroid-based environmental pollution in order to obtain a realistic picture of steroid contamination and their fate in the aquatic environment. A high removal rate (>98 %) of coprostanol and cholesterol during wastewater treatment was determined and only the coprostanol/(coprostanol + cholestanol) ratio was found to be sensitive enough to be affected by an improvement in the quality of treated wastewater.

Plant Sterol-Poor Diet Is Associated with Pro-Inflammatory Lipid Mediators in the Murine Brain

Plant sterols (PSs) cannot be synthesized in mammals and are exclusively diet-derived. PSs cross the blood-brain barrier and may have anti-neuroinflammatory effects. Obesity is linked to lower intestinal uptake and blood levels of PSs, but its effects in terms of neuroinflammation—if any—remain unknown. We investigated the effect of high-fat diet-induced obesity on PSs in the brain and the effects of the PSs campesterol and β-sitosterol on in vitro microglia activation. Sterols (cholesterol, precursors, PSs) and polyunsaturated fatty acid-derived lipid mediators were measured in the food, blood, liver and brain of C57BL/6J mice. Under a PSs-poor high-fat diet, PSs levels decreased in the blood, liver and brain (>50%). This effect was reversible after 2 weeks upon changing back to a chow diet. Inflammatory thromboxane B2 and prostaglandin D2 were inversely correlated to campesterol and β-sitosterol levels in all brain regions. PSs content was determined post mortem in human cortex samples as well. In vitro, PSs accumulate in lipid rafts isolated from SIM-A9 microglia cell membranes. In summary, PSs levels in the blood, liver and brain were associated directly with PSs food content and inversely with BMI. PSs dampen pro-inflammatory lipid mediators in the brain. The identification of PSs in the human cortex in comparable concentration ranges implies the relevance of our findings for humans.

Plant-Based Alternatives to Yogurt: State-of-the-Art and Perspectives of New Biotechnological Challenges

Due to the increasing demand for milk alternatives, related to both health and ethical needs, plant-based yogurt-like products have been widely explored in recent years. With the main goal to obtain snacks similar to the conventional yogurt in terms of textural and sensory properties and ability to host viable lactic acid bacteria for a long-time storage, several plant-derived ingredients (e.g., cereals, pseudocereals, legumes, and fruits) as well as technological solutions (e.g., enzymatic and thermal treatments) have been investigated. The central role of fermentation in yogurt-like production led to specific selections of lactic acid bacteria strains to be used as starters to guarantee optimal textural (e.g., through the synthesis of exo-polysaccharydes), nutritional (high protein digestibility and low content of anti-nutritional compounds), and functional (synthesis of bioactive compounds) features of the products. This review provides an overview of the novel insights on fermented yogurt-like products. The state-of-the-art on the use of unconventional ingredients, traditional and innovative biotechnological processes, and the effects of fermentation on the textural, nutritional, functional, and sensory features, and the shelf life are described. The supplementation of prebiotics and probiotics and the related health effects are also reviewed.

Modulation of Lipid Transport and Adipose Tissue Deposition by Small Lipophilic Compounds

Small lipophilic molecules present in foods of plant origin have relevant biological activities at rather low concentrations. Evidence suggests that phytosterols, carotenoids, terpenoids, and tocopherols can interact with different metabolic pathways, exerting beneficial effects against a number of metabolic diseases. These small molecules can modulate triacylglycerol absorption in the intestine and the biosynthesis of chylomicrons, the lipid carriers in the blood. Once in the bloodstream, they can impact lipoprotein clearance from blood, thereby affecting fatty acid release, incorporation into adipocytes and triglyceride reassembling and deposit. Consequently, some of these molecules can regulate pathophysiological processes associated to obesity and its related conditions, such as insulin resistance, metabolic syndrome and type-2 diabetes. The protective capacity of some lipophilic small molecules on oxidative and chemotoxic stress, can modify the expression of key genes in the adaptive cellular response, such as transcription factors, contributing to prevent the inflammatory status of adipose tissue. These small lipophilic compounds can be incorporated into diet as natural parts of food but they can also be employed to supplement other dietary and pharmacologic products as nutraceuticals, exerting protective effects against the development of metabolic diseases in which inflammation is involved. The aim of this review is to summarize the current knowledge of the influence of dietary lipophilic small biomolecules (phytosterols, carotenoids, tocopherols, and triterpenes) on lipid transport, as well as on the effects they may have on pathophysiological metabolic states, related to obesity, insulin resistance and inflammation, providing an evidence-based summary of their main beneficial effects on human health.

Sea Cucumber Sterol Alleviates the Lipid Accumulation in High-Fat-Fructose Diet Fed Mice

The effect of marine-derived sea cucumber sterol (SS) with a special sulfate group on lipid accumulation remains unknown, although phytosterol has been proved to have many biological activities, including lowering blood cholesterol. The purpose of the present study is to investigate the alleviation of SS on lipid accumulation and the possible underlying mechanism using high-fat-fructose diet fed mice. Dietary administration with SS for 8 weeks reduced significantly the body weight gain and lipid levels in serum and liver. Especially, SS was superior to phytosterol in lowering lipid accumulation due to the great promotion of fatty acid β-oxidation, the inhibition of cholesterol synthesis, and the acceleration of cholesterol efflux. The findings found that sea cucumber sterol exhibited a more significant effect than phytosterol on alleviating HFF-diet-induced lipid accumulation through regulating lipid and cholesterol metabolism, which might be attributed to the difference in the branch chain and sulfate group.

Impact of a Formulation Containing Unusual Polyunsaturated Fatty Acids, Trace Elements, Polyphenols and Plant Sterols on Insulin Resistance and Associated Disturbances

INTRODUCTION

To evaluate the effect of a lipid-based formulation containing unusual polyunsaturated fatty acids, trace elements, polyphenols and plant sterols on insulin resistance and its associated disturbances among adults at risk of diabetes.

METHODS

This was an 8-week, three-arm, open-label randomized clinical trial. We studied individuals aged ≥ 18 years old with diabetes risk given by a body mass index ≥ 25 kg/m² or a FinnRisc score ≥ 13/20. Participants were randomly assigned to receive: 7 ml sunflower oil (control group), 3.5 ml of the study formulation + 3.5 ml of sunflower oil (low-dose group) or 7 ml of study formulation (high-dose group).

RESULTS

We randomized 25 individuals. After one withdrawal in the high-dose group, the study sample comprised nine patients in the control, nine in the low-dose and six in the high-dose groups. The insulin sensitivity increased significantly and in a dose-dependent fashion, up to 10% in the high-dose group. At week 8 the low-dose group exhibited lower glycemic excursions during the oral glucose tolerance test (OGTT), especially 1 h after the glucose challenge (32 mg/dl or 23% lower vs. control group). The incremental area under the glucose curve in the OGTT was 17.1% lower in the low-dose group vs. the control group. Waist circumference increased in the control group, remained constant in the low-dose group and decreased in the high-dose group. C-reactive protein decreased in both formulation groups, up to 50% in the high-dose group. Participants in the formulation groups exhibited increased secretion of GLP-1 and plasma irisin at week 8 vs. the control group.

CONCLUSION

The formulation induced favorable changes in insulin sensitivity, glucose tolerance, abdominal obesity and inflammation. These effects and their durability will need to be assessed in larger studies.

TRIAL REGISTRATION

NCT03512665.

FUNDING

Team Foods Colombia.

Phytosterols in the Treatment of Hypercholesterolemia and Prevention of Cardiovascular Diseases

Phytosterols are bioactive compounds found in foods of plant origin, which can be divided into plant sterols and plant stanols. Clinical studies consistently indicate that the intake of phytosterols (2 g/day) is associated with a significant reduction (8-10%) in levels of low-density lipoprotein cholesterol (LDL-cholesterol). Thus, several guidelines recommend the intake of 2 g/day of plant sterols and/or stanols in order to reduce LDL-cholesterol levels. As the typical western diet contains only about 300 mg/day of phytosterols, foods enriched with phytosterols are usually used to achieve the recommended intake. Although phytosterols decrease LDL-cholesterol levels, there is no evidence that they reduce the risk of cardiovascular diseases; on the contrary, some studies suggest an increased risk of atherosclerosis with increasing serum levels of phytosterols. This review aims to address the evidence available in the literature on the relationship between phytosterols and risk of cardiovascular disease.

Oxidative status of a yogurt-like fermented maize product containing phytosterols

This work describes the formulation of a functional yogurt-like product based on fermented maize with added phytosterols and its oxidative stability during cold storage. The technological challenge was to stabilize 3.5% esterified phytosterols (between 2 and 3 g of free sterols) in a low-fat emulsion and to preserve the obtained product throughout processing and storage. The natural bioactive compounds: lutein, zeaxanthin, β-cryptoxanthin, β-carotene and γ-tocopherol were detected in the yogurt, and remained stable during 12 days of refrigeration. Higher content of C18:1 n-9 and C18:3 n-3 (six and ninefold, respectively) were obtained in samples with phytosterols. This was desirable from a nutritional point of view, but at the same time it induced lipid oxidation that was 1.4-fold higher in the product with phytosterols than in the controls. The use of a multivariate approach served to find descriptors which were related to treatments, and to explain their behavior over time.

Sitosterol prevents obesity-related chronic inflammation

The physiological roles of phytosterols in chronic inflammation, which are believed to be involved in the underlying mechanisms for metabolic diseases, have yet to be elucidated. Therefore, in the present study, we aimed to elucidate the physiological roles of phytosterols in both clinical studies and animal experiments. We observed the existence of rather specific negative correlations between the serum sitosterol level and the serum IL-6 and the TNF-α levels in both diabetic subjects (n=46) and non-diabetic subjects (n=178). Multiple regression analyses also revealed that the serum IL-6 and TNF-α levels exhibited strong negative correlations with the serum sitosterol levels. When ABCG5/8 KO mice with markedly elevated plasma sitosterol levels and ABCG5/8 hetero mice were fed a high-fat diet, we observed that the increase in body weight, the fatty liver changes, and the expansion of perigonadal adipose tissues were suppressed in ABCG5/8 KO mice without any modulation of food intake. We also observed that the plasma IL-6 and TNF-α levels, the expressions of TNF-α and PAI-1 in the liver and the expressions of the IL-6, TNF-α, and MCP-1 levels in the adipose tissue were lower in ABCG5/8 KO mice. These results suggest that sitosterol might suppress obesity-related chronic inflammation and might be applicable to the treatment of metabolic diseases.

Traditional Small-Size Citrus from Taiwan: Essential Oils, Bioactive Compounds and Antioxidant Capacity

Background: The calamondin (Citrus microcarpa Bunge) and the kumquat (Fortunella crassifolia Swingle) are two small-size citrus fruits that have traditionally been consumed in Taiwan; however, there has been a lack of scientific research regarding the active compounds and functionalities of these fruits. Methods: Analysis of volatile composition of essential oil and phytosterol was carried out using Gas Chromatography–Mass Spectrometry (GC-MS). Flavonoid and limonoid were analyzed by High Performance Liquid Chromatography (HPLC). Moreover, antioxidant capacity from their essential oils and extracts were assessed in vitro. Results: The compositions of the essential oils of both fruits were identified, with the results showing that the calamondin and kumquat contain identified 43 and 44 volatile compounds, respectively. In addition, oxygenated compounds of volatiles accounted for 4.25% and 2.04%, respectively, consistent with the fact that oxygenated compounds are generally found in high content in citrus fruits. In terms of flavonoids, the calamondin exhibited higher content than the kumquat, with disomin-based flavonoids being predominant; on the other hand, phytosterol content of kumquat was higher than that of calamondin, with amyrin being the dominant phytosterol. Both of them contain high amounts of limonoids. The ethanol extracts and essential oils of small-sized citrus fruits have been shown to have antioxidant effects, with those effects being closely related to the flavonoid content of the fruit in question. Conclusions: The present study also reviewed antioxidant activity in terms of specific bioactive compounds in order to find the underlying biological activity of both fruits. The calamondin and kumquat have antioxidant effects, which are in turn very important for the prevention of chronic diseases.

Effect of Phytosterols on the Crystallization Behavior of Oil-in-Water Milk Fat Emulsions

Milk has been used commercially as a carrier for phytosterols, but there is limited knowledge on the effect of added plant sterols on the properties of the system. In this study, phytosterols dispersed in milk fat at a level of 0.3 or 0.6% were homogenized with an aqueous dispersion of whey protein isolate (WPI). The particle size, morphology, ζ-potential, and stability of the emulsions were investigated. Emulsion crystallization properties were examined through the use of differential scanning calorimetry (DSC) and Synchrotron X-ray scattering at both small and wide angles. Phytosterol enrichment influenced the particle size and physical appearance of the emulsion droplets, but did not affect the stability or charge of the dispersed particles. DSC data demonstrated that, at the higher level of phytosterol addition, crystallization of milk fat was delayed, whereas, at the lower level, phytosterol enrichment induced nucleation and emulsion crystallization. These differences were attributed to the formation of separate phytosterol crystals within the emulsions at the high phytosterol concentration, as characterized by Synchrotron X-ray measurements. X-ray scattering patterns demonstrated the ability of the phytosterol to integrate within the milk fat triacylglycerol matrix, with a concomitant increase in longitudinal packing and system disorder. Understanding the consequences of adding phytosterols, on the physical and crystalline behavior of emulsions may enable the functional food industry to design more physically and chemically stable products.

Nutraceuticals in Lipid-Lowering Treatment

Lipid-lowering drugs may cause adverse effects and, although lipid targets may be achieved, a substantial residual cardiovascular (CV) risk remains. Treatment with agents mimicking proteins present in the body, such as incretin-based therapies, provided promising results. However, in order to improve lipids and CV risk, lifestyle measures remain important. Some researchers focused on nutraceuticals that may beneficially affect metabolic parameters and minimize CV risk. Chitosan, a dietary fiber, can regulate lipids with benefit on anthropometric parameters. The beneficial properties of dietary supplements (such as green tea extract, prebiotics, plant sterols, and stanols) on plasma lipids, lipoproteins, blood pressure, glucose, and insulin levels and their anti-inflammatory and anti-oxidant effects are documented. However, larger, prospective clinical trials are required to confirm such benefits. Such treatments may be recommended when lipid-lowering drugs are neither indicated nor tolerated as well as in order to achieve therapeutic targets and/or overcome residual CV risk.

24-Branched Δ5 sterols from Laurencia papillosa red seaweed with antibacterial activity against human pathogenic bacteria

Methanol extract of thirty-eight seaweeds samples were first screened against Gram-positive (Staphylococcus aureus ATCC 25923 and Bacillus subtilis ATCC 6051) and -negative (Escherichia coli ATCC 8739 and Pseudomonas aerugenosa ATCC 9027) bacteria. Laurencia papillosa (Ceramiales, Rhodomelaceae, Rhodophyta) gave maximum antimicrobial activity against these bacteria. It was finally tested against four clinical Gram-negative isolates (E. coli, P. aerugenosa, Klebsiella pneumoniae and Shigella flexineri) and exhibited antibacterial activity. The extract was fractionated by column chromatography and the active fraction was identified as a cholesterol derivative, 24-propylidene cholest-5-en-3β-ol using gas chromatography mass spectrometry (GC-MS). The electrospray ionization mass spectrometry (ESI-MS) and FT-IR spectroscopic analysis also supported the structure of the compound. The minimum inhibitory concentration ranged from 1.2 to 1.7 μg/mL (IC50) against clinical isolates. This is the first report of antibacterial activity of this cholesterol derivative. This compound could be exploited as potential lead molecule against broad spectrum drug development. The results also affirm the potential of seaweeds as an important natural source of antimicrobial compounds for pharmaceutical industries.