Efficacy of Plant Sterol-Enriched Food for Primary Prevention and Treatment of Hypercholesterolemia: A Systematic Literature Review

The Effect of Dietary Supplementation with Plant Sterols on Total and LDL-Cholesterol in Plasma Is Affected by Adherence to Mediterranean Diet: Insights from the DESCO Randomized Clinical Study

Plant sterols are well-known natural lipid-lowering agents. The DESCO (Diet and plant sterols in the control of cholesterolemia) study was a single-center, randomized, double-blind, placebo-controlled, two-way crossover clinical trial designed to investigate the effect of a once-a-day ready-to-drink dietary supplement containing 2.5 g of phytosterols on the lipid profile, also in relation to the quality of the diet, in a cohort of 50 Italian individuals with polygenic hypercholesterolemia and low global cardiovascular risk. Eligible individuals were enrolled in a run-in period of 2 weeks. Then, participants who qualified for continuation in the study were randomly allocated (1:1) to a 3-week treatment with either phytosterols or placebo. After a 2-week washout period, enrolled individuals were crossed over to receive the alternative treatment. Dietary supplementation with phytosterols was associated with significant improvement in plasma levels of total cholesterol (TC; -11.8 ± 4.0 mg/dL, p = 0.016), low-density lipoprotein cholesterol (LDL-C; -7.8 ± 7.7 mg/dL, p = 0.021), and apolipoprotein B-100 (Apo B-100, -3.7 ± 4.1 mg/dL, p = 0.048) compared to baseline. The changes in TC and LDL-C were also significant compared to placebo, and greater adherence to the Mediterranean diet was significantly associated with greater reductions in LDL-C. Dietary supplementation with phytosterols was well tolerated and adherence to treatment was high. According to the findings of DESCO, the once-a-day ready-to-drink dietary supplement we tested is able to quickly and significantly decrease plasma levels of TC, LDL-C, and Apo B-100, with a greater effect in individuals more adhering to the Mediterranean dietary pattern.

Effects of phytosterol supplementation on lipid profiles in patients with hypercholesterolemia: a systematic review and meta-analysis of randomized controlled trials

Phytosterols (PSs) have been reported to improve blood lipids in patients with hypercholesterolemia for many years. However, meta-analyses of the effects of phytosterols on lipid profiles are limited and incomplete. A systematic search of randomized controlled trials (RCTs) published in PubMed, Embase, Cochrane Library, and Web of Science from inception to March 2022 was conducted according to the 2020 preferred reporting items of the guidelines for systematic reviews and meta-analysis (PRISMA) statement. These included studies of people with hypercholesterolemia, comparing foods or preparations containing PSs with controls. Mean differences with 95% confidence intervals were used to estimate continuous outcomes for individual studies. The results showed that in patients with hypercholesterolemia, taking a diet containing a certain dose of plant sterol significantly reduced total cholesterol (TC) and low density lipoprotein cholesterol (LDL-C) (TC: Weight Mean Difference (WMD) [95% CI] = -0.37 [-0.41, -0.34], p < 0.001; LDL-C: WMD [95% CI] = -0.34 [-0.37, -0.30], p < 0.001). In contrast, PSs had no effect on high density lipoprotein cholesterol (HDL-C) or triglycerides (TGs) (HDL-C: WMD [95% CI] = 0.00 [-0.01, 0.02], p = 0.742; TG: WMD [95% CI] = -0.01 [-0.04, 0.01], p = 0.233). Also, a significant effect of supplemental dose on LDL-C levels was observed in a nonlinear dose-response analysis (p-nonlinearity = 0.024). Our findings suggest that dietary phytosterols can help reduce TC and LDL-C concentrations in hypercholesterolemia patients without affecting HDL-C and TG concentrations. And the effect may be affected by the food substrate, dose, esterification, intervention cycle and region. The dose of phytosterol is an important factor affecting the level of LDL-C.

Solubilization of free β-sitosterol in milk sphingomyelin and polar lipid vesicles as carriers: Structural characterization of the membranes and sphingosome morphology

High consumption of plant sterols reduces the risk of cardiovascular diseases in humans and provides health benefits. Increasing the amount of plant sterols in the diet is therefore necessary to reach the recommended daily dietary intake. However, food supplementation with free plant sterols is challenging because of their low solubility in fats and water. The objectives of this study were to investigate the capacity of milk-sphingomyelin (milk-SM) and milk polar lipids to solubilise β-sitosterol molecules in bilayer membranes organised as vesicles called sphingosomes. The thermal and structural properties of milk-SM containing bilayers composed of various amounts of β-sitosterol were examined by differential scanning calorimetry (DSC) and temperature-controlled X-ray diffraction (XRD), the molecular interactions were studied using the Langmuir film technique, the morphologies of sphingosomes and β-sitosterol crystals were observed by microscopy. We showed that the milk-SM bilayers devoid of β-sitosterol exhibited a gel to fluid L_α phase transition for T_m = 34.5 °C and formed facetted spherical sphingosomes below T_m. The solubilisation of β-sitosterol within milk-SM bilayers induced a liquid-ordered L_o phaseabove 25 %mol (1.7 %wt) β-sitosterol and a softening of the membranes leading to the formation of elongated sphingosomes. Attractive molecular interactions revealed a condensing effect of β-sitosterol on milk-SM Langmuir monolayers. Above 40 %mol (25.7 %wt) β-sitosterol, partitioning occured with the formation of β-sitosterol microcrystals in the aqueous phase. Similar results were obtained with the solubilization of β-sitosterol within milk polar lipid vesicles. For the first time, this study highlighted the efficient solubilization of free β-sitosterol within milk-SM based vesicles, which opens new market opportunities for the formulation of functional foods enriched in non-crystalline free plant sterols.

Could Lowering Phytosterol Absorption as Part of Lipid-Lowering Therapy Have a Beneficial Effect on Residual Risk?

Plant sterols are molecules that are structurally similar to cholesterol and provided only as dietary sources (e.g., vegetables, fruits, nuts, cereals) since they cannot be synthesized by humans. Sterol-enriched diets (≥2 g/day) may decrease total and low-density lipoprotein cholesterol concentrations by 5-10%, either alone or when added to statins, since they antagonize dietary cholesterol absorption in the intestine. On the other hand, increased serum phytosterol concentrations, (including when associated with sitosterolemia, a rare genetic defect) may contribute to atherosclerotic risk, although a threshold for such a role has not been established. Medications such as ezetimibe may effectively reduce cholesterol and phytosterol absorption. Whether the therapeutic approach associated with the reduction of phytosterol absorption is also translated into a reduction in a patient's residual cardiovascular risk needs to be established.

Extraction and Quantitation of Phytosterols from Edible Brown Seaweeds: Optimization, Validation, and Application

Brown seaweeds are known as important marine food sources, from which phytosterols have been recognized as functional food components with multiple health-beneficial effects. However, studies on phytosterol extraction and quantitation from edible brown seaweeds are limited. In the present work, extraction methods for seaweed phytosterols were compared and optimized by one-factor-at-one-time method and response surface methodology. Moreover, the quantitation method of total sterols and major sterol components, including fucosterol, saringosterol, and ostreasterol, was established and validated using ¹H NMR. Furthermore, the developed extraction and determination methods were applied to investigate three common edible seaweeds from Japan (Hijiki, Wakame, and Kombu). As a result, the finally optimized conditions were ultrasound-assisted extraction with CHCl₃-MeOH 2:3 for 15 min followed by saponification with 1.65 mL of 1.85 M KOH for 14.5 h. Based on the developed methods, phytosterols in three seaweeds were compared, and Hijiki showed an abundant total sterol amount (2.601 ± 0.171 mg/g DW), significantly higher than Wakame (1.845 ± 0.137 mg/g DW) and Kombu (1.171 ± 0.243 mg/g DW). Notably, the composition of the sterol components varied in different seaweeds. These findings might help the nutritional investigation and functional food development concerning phytosterols from seaweeds.

Tomato By-Products, a Source of Nutrients for the Prevention and Reduction of Malnutrition

Malnutrition is a global phenomenon that mainly affects children under five years old, the elderly and food insecure people. It can be linked to undernourishment or overnutrition. To prevent it, a healthy and balanced diet, rich in energy and micronutrients, is necessary. The objective of this study was to evaluate the nutritional composition and contribution of tomato by-products to prevent and reduce malnutrition. Thus, standard methods were used for proximate composition and bioactive compounds. Results showed that tomato by-products are rich in macronutrients and micronutrients capable of preventing undernutrition and reducing the incidence of the effects of overnutrition. The average carbohydrate, protein and lipid contents were 15.43%, 11.71% and 5.4% (DM) in peels and for seeds the contents were 58.75%, 15.4% and 22.2%, respectively. The average energy values were 280.47 kcal/100 g and 472.8 kcal/100 g DM for peels and seeds, respectively. The main minerals found were, in decreasing order, potassium, magnesium, sodium, iron and zinc. High contents of phenolic compounds, lycopene, β-carotene and vitamin C were also found in these by-products. They also presented important antioxidant activities. Due to their nutritional and bioactive compounds, tomato by-products may be included in functional food formulation programs to reduce the incidence of nutritional diseases.

Randomized, Double-Blind, Placebo-Controlled Trial to Test the Effects of a Nutraceutical Combination Monacolin K-Free on the Lipid and Inflammatory Profile of Subjects with Hypercholesterolemia

BACKGROUND

Nutraceutical combinations (NCs) against hypercholesterolemia are increasing in the marketplace. However, the availability of NCs without monacolin K is scarce even though the statin-intolerant population needs it.

METHODS

This study is a parallel-group, randomized, placebo-controlled, double-blind trial. We evaluated the effects of the NC containing phytosterols, bergamot, olive fruits, and vitamin K₂ on lipid profile and inflammatory biomarkers in 118 subjects (mean age ± SD, 57.9 ± 8.8 years; 49 men and 69 women) with hypercholesterolemia (mean total cholesterol ± SD, 227.4 ± 20.8 mg/dL) without clinical history of cardiovascular diseases. At baseline and 6 and 12 weeks of treatment, we evaluated lipid profile (total, LDL and HDL cholesterol, and triglycerides), safety (liver, kidney, and muscle parameters), and inflammatory biomarkers such as hs-CRP, leukocytes, interleukin-32, and interleukin-38 and inflammatory-microRNAs (miRs) miR-21, miR-126, and miR-146a.

RESULTS

Compared to the placebo, at 6 and 12 weeks, NC did not significantly reduce total cholesterol (p = 0.083), LDL cholesterol (p = 0.150), and triglycerides (p = 0.822). No changes were found in hs-CRP (p = 0.179), interleukin-32 (p = 0.587), interleukin-38 (p = 0.930), miR-21 (p = 0.275), miR-126 (p = 0.718), miR-146a (p = 0.206), myoglobin (p = 0.164), and creatine kinase (p = 0.376). Among the two reported, only one adverse event was probably related to the nutraceutical treatment.

CONCLUSIONS

The evaluated nutraceutical combination did not change serum lipid profile and inflammatory parameters, at least not with the daily dose applied in the present study.

Dietary Plant Sterols and Phytosterol-Enriched Margarines and Their Relationship with Cardiovascular Disease among Polish Men and Women: The WOBASZ II Cross-Sectional Study

Dietary cholesterol has been suggested to increase the risk of cardiovascular disease (CVD). Phytosterols, present in food or phytosterol-enriched products, can reduce cholesterol available for absorption. The present study aimed to investigate the association between habitual intake of total and individual plant sterols (β-sitosterol, campesterol, and stigmasterol) or a diet combined with phytosterol-enriched products and CVD in a cross-section of Polish adults, participants of the Multicenter National Health Survey II (WOBASZ II). Among men (n = 2554), median intakes of plant sterols in terciles ranged between 183−456 mg/d and among women (n = 3136), 146−350 mg/d in terciles. The intake of phytosterols, when consumed with food containing phytosterols, including margarine, ranged between 184−459 mg/d for men and 147−352 mg/d for women. Among both men and women, beta-sitosterol intake predominated. Plant sterol intake was lower among both men and women with CVD (p = 0.016) compared to those without CVD. Diet quality, as measured by the Healthy Diet Index (HDI), was significantly higher in the third tercile of plant sterol intake for both men and women and the entire study group (p < 0.0001). This study suggests that habitual dietary intake of plant sterols may be associated with a lower chance of developing CVD, particularly in men.

Property of Phytosterols and Development of Its Containing Mayonnaise-Type Dressing

Phytosterols are functional ingredients with known efficacy and safety. Phytosterols are found as free sterols or as their esters with fatty acids. Although phytosterol esters are soluble in oil and have been used in many commercial foods, it has been difficult to similarly use free phytosterols since they are insoluble in water and practically insoluble in oil. We have developed mayonnaise-type dressing materials using free phytosterols since people who are conscious about cholesterol intake are likely to be conscious about oil. In this review article, we summarized pieces of evidence for the development of phytosterol-containing mayonnaise-type dressing materials.