Differences in the Effect of Plant Sterols on Lipid Metabolism in Men and Women

Phytosterol supplementation in capsules or tablets as adjunctive treatment for hypercholesterolemia: A systematic review of randomized controlled trials

BACKGROUND

The exploration of lipid-lowering resources, such as phytosterols, for the complementary nutritional treatment of hypercholesterolemia is relevant to reduce cardiovascular risk. The use of phytosterols in capsules or tablets can bring advantages in the context of diet therapy, but such format is still less studied when compared to fortified foods.

OBJECTIVE

Systematically review randomized clinical trials on the effects of phytosterol supplementation, in capsules or tablets, on the lipid profile and its use in the treatment of hypercholesterolemia in adults.

DESIGN

A systematic review was carried out in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis, with a PROSPERO protocol registered under number CRD42021249539. The process was conducted by two independent reviewers. Only randomized clinical trials with phytosterol supplementation in adult individuals with hypercholesterolemia were included. The terms were searched in the databases: PubMed/MEDLINE, Cochrane Library/CENTRAL, Embase, LILACS and Web of Science, without restriction of time and language. The manual search was also performed through the list of references of articles included in this review.

RESULTS

The searches resulted in 977 articles. 22 articles were selected, whose full text was read, and according to the eligibility criteria 10 were incorporated into the review. The studies were separated into groups according to the association of the intervention with changes in lifestyle and the characteristics extracted from the studies were summarized and displayed in tables. Most studies have revealed a positive association between phytosterol supplementation and cholesterol reduction, despite the short duration of interventions.

CONCLUSION

The analyzed studies showed that phytosterol supplements can be useful to modulate the lipid profile, helping to reduce the plasma concentration of LDL cholesterol. However, more research with the aforementioned supplementation in such pharmaceutical formats should be encouraged.

Phytosterols: From Preclinical Evidence to Potential Clinical Applications

Phytosterols (PSs) are plant-originated steroids. Over 250 PSs have been isolated, and each plant species contains a characteristic phytosterol composition. A wide number of studies have reported remarkable pharmacological effects of PSs, acting as chemopreventive, anti-inflammatory, antioxidant, antidiabetic, and antiatherosclerotic agents. However, PS bioavailability is a key issue, as it can be influenced by several factors (type, source, processing, preparation, delivery method, food matrix, dose, time of administration into the body, and genetic factors), and the existence of a close relationship between their chemical structures (e.g., saturation degree and side-chain length) and low absorption rates has been stated. In this sense, the present review intends to provide in-depth data on PS therapeutic potential for human health, also emphasizing their preclinical effects and bioavailability-related issues.

Nigella sativa L. (Black Cumin): A Promising Natural Remedy for Wide Range of Illnesses

The seed of Nigella sativa (N. sativa) has been used in different civilization around the world for centuries to treat various animal and human ailments. So far, numerous studies demonstrated the seed of Nigella sativa and its main active constituent, thymoquinone, to be medicinally very effective against various illnesses including different chronic illness: neurological and mental illness, cardiovascular disorders, cancer, diabetes, inflammatory conditions, and infertility as well as various infectious diseases due to bacterial, fungal, parasitic, and viral infections. In spite of limited studies conducted so far, the promising efficacy of N. sativa against HIV/AIDS can be explored as an alternative option for the treatment of this pandemic disease after substantiating its full therapeutic efficacy. Moreover, the strong antioxidant property of this valued seed has recently gained increasing attention with regard to its potential role as dietary supplement with minimal side effects. Besides, when combined with different conventional chemotherapeutic agents, it synergizes their effects resulting in reducing the dosage of concomitantly used drugs with optimized efficacy and least and/or no toxicity. A number of pharmaceutical and biological properties have been ascribed to seeds of N. sativa. The present review focuses on the profile of high-value components along with traditional medicinal and biological principles of N. sativa seed and its oil so as to explore functional food and nutraceutical potential of this valued herb.

LDL-Cholesterol Lowering of Plant Sterols and Stanols-Which Factors Influence Their Efficacy?

The LDL-cholesterol (LDL-C) lowering effect of plant sterols/stanols (PSS) is summarized in several meta-analyses showing a dose-response relationship with intakes of 1.5 to 3 g/day lowering LDL-C by 7.5% to 12%. This review summarizes evidence for the impact of various factors potentially influencing the LDL-C-lowering efficacy of PSS. PSS are efficacious in all food formats and in food supplements. Some factors related to food format, e.g., solid vs. liquid foods, seem to impact efficacy, while there is no difference between free PSS and esters. Compared to multiple daily intakes, once-a-day intake of PSS, especially in the morning with light breakfast, leads to a sub-optimal LDL-C lowering. However, intake frequency seems influenced by intake occasion, i.e., with or without a meal, and time of day. Meal intake is a critical factor for an optimal LDL-C lowering efficacy of PSS. While age has no impact, gender is suggested to influence the LDL-C lowering effect of PSS with greater reductions reported for men than women; but overall evidence is inconclusive and larger studies show no gender by treatment interaction. In conclusion, PSS are efficacious in all foods and food supplements; for optimal efficacy they should be consumed with a (main) meal and twice daily.