The scheme of this narrative review is to recount the potential of lecithin in cardiovascular health and highlight the role of LCAT in modulating cholesterol metabolism. This review was executed by searching for articles in MEDLINE, PubMed and the Scientific Electronic Library Online databases using the Medical Subject terms “lecithin,” “lecithin” and “cardiovascular health,” “LCAT” and “modulation of cholesterol metabolism.” Articles published during the period 2000–2023 in English were put together.

For article selection, clear criteria were established to ensure that only relevant studies were included in the review. Articles were chosen if they directly addressed the relationship between lecithin and cardiovascular health or discussed LCAT's role in modulating cholesterol metabolism. The focus was on articles published between 2000 and 2023 to capture recent findings, and consideration was given exclusively to studies published in English due to language limitations. Both experimental studies and clinical trials were eligible for inclusion to provide a comprehensive overview of the topic. Articles that did not meet these criteria or were duplicates, conference abstracts, reviews without original data or focused on unrelated topics were excluded. Screening of articles was conducted based on titles, abstracts and full texts, when necessary, with eligibility determined by two independent reviewers. Any disagreements in article selection were resolved through discussion or consultation with a third reviewer to reach a consensus. This systematic approach ensured that only relevant articles were included, enhancing the transparency and reproducibility of the review.

Lecithin

Lecithin, identified as egg yolk lecithin, soybean lecithin, soybean phospholipid [2], lecithol, phosphatidylcholine [30], choline phosphoglyceride [31] and phospholutein [32, 33], has a phosphatide or phospholipid component which is found in naturally occurring substances from both plant and animal sources [1]. It occurs naturally as a blend of diglycerides composed of stearic, oleic and palmitic acids, associated with the choline ester of phosphoric acid [2]. In nature, lecithin can have phosphoric acid linked to glycerol in either the alpha or beta position [34].

As a phosphatide present in virtually all living organisms, lecithin constitutes a substantial component of both brain and nervous tissue. It accounts for more than 50 percent of the phospholipids in most cell membranes of mammals [35]. Lecithin is also found on the surface of plasma membranes, forming the outermost layer [36]. The chemical structure of lecithin is displayed in Fig. 1.

Fig. 1

Chemical structure of lecithin

Reports have indicated that lecithin is a significant phospholipid in amniotic fluid and lung surfactant [37,38,39,40,41,42,43,44]. Lecithin constitutes about 2–3% of the total weight of crude soybean oil and has also been found in substantial amounts in corn and wheat oils. Notably, lecithin makes up about 10% of the components of egg yolk [44,45,46].

Lecithin's major property of regulating cholesterol levels is a pivotal aspect of its role in promoting cardiovascular health [47,48,49]. It achieves this regulation through its capacity to reduce excess low-density lipoprotein (LDL), often dubbed as "bad cholesterol." High levels of LDL are associated with an increased risk of atherosclerosis and heart disease [50, 51].

Simultaneously, lecithin facilitates the synthesis of high-density lipoprotein (HDL), recognized as the "beneficial cholesterol" [52]. HDL contributes substantially to the removal of excess cholesterol from the blood circulation, transporting it to the liver for excretion, thus contributing to a healthier cardiovascular profile [53]. An increased presence of HDL is linked to a reduced risk of cardiovascular diseases [53].

Studies, such as the one conducted by Brunet and associates in 2003, have shown that diets rich in lecithin stimulate the secretion of bile acids by enhancing the formation of mixed micelles, which facilitate the solubilization and excretion of cholesterol. This mechanism involves elevated levels of phospholipids and cholesterol compared to diets lacking lecithin [47]. This, in turn, underscores lecithin's significance in maintaining a balanced cholesterol profile and supporting heart health.

Lecithin, a complex mixture of phospholipids, is subject to various chemical reactions, and its breakdown through hydrolysis is a fundamental one [54]. When subjected to complete hydrolysis, lecithin molecules disintegrate into their basic building blocks. This process yields two fatty acid molecules, often including palmitic, oleic and stearic acids [54], a molecule of phosphoric acid, glycerol, and a basic nitrogenous compound, choline [53]. These constituents are vital in understanding the composition and functional properties of lecithin.

Another intriguing chemical behavior of lecithin is its propensity to spontaneously bind with oxygen when exposed to atmospheric air [55]. This phenomenon is attributed to the double bonds present in the unsaturated fatty acids which are found within the triglyceride and phosphoglyceride components of lecithin. These double bonds are vulnerable to oxidation, which can lead to the formation of oxidative products such as epoxides and hydroperoxides [55]. This oxidative reactivity of lecithin has implications for its use in various applications, especially in the food industry and pharmaceuticals, where maintaining product stability and quality is of paramount importance [55]. Lecithin's oxidative reactivity finds various applications in the food sector, functioning as an emulsifier in baked goods and confectionery, stabilizing salad dressings and sauces, and aiding in the mixing of fats and oils in margarine. In therapeutics, it enhances drug solubility, bioavailability and stability in lipid-based drug delivery systems and supplements, while also regulating the release of medications in sustained-release formulations [55]

Global incidence of cardiovascular disease

Cardiovascular diseases (CVDs) present a formidable global health challenge, annually claiming millions of lives across the globe [56]. This overarching term comprises of variety of conditions, such as coronary heart disease, stroke and peripheral artery disease, where the intricate interplay of cholesterol and its counterparts often stands at the heart of the matter [57].

Cholesterol, indispensable for cell membranes and various biological functions [58], becomes problematic when low-density lipoprotein (LDL) cholesterol rises to excessive levels, significantly contributing to the development of cardiovascular diseases (CVDs) [59]. Its vital role in cellular structure ensures membrane integrity and fluidity, facilitating essential cell functions and communication. Moreover, as a precursor for steroid hormones, bile acids and vitamin D synthesis, cholesterol plays a crucial role in hormonal regulation, digestion and overall metabolic processes [58. However, dysregulated LDL cholesterol levels can lead to the accumulation of plaque in arteries, contributing to the pathogenesis of CVDs [59]. The accumulation of LDL cholesterol in arteries results in the formation of plaques, which narrow the lumen of blood vessels and impede the flow of blood, thereby setting the stage for heart attacks and strokes [57, 60].

While LDL cholesterol takes the center stage in the narrative of CVD development, its detrimental impact is often heightened by accomplices such as high blood pressure, diabetes and smoking [57]. Furthermore, elevated levels of triglycerides, another type of blood fat, can compound the risk of CVDs, particularly when coupled with high LDL cholesterol [51]. This intricate web of interconnected factors underscores the multifaceted nature of CVD development, emphasizing the critical need for comprehensive approaches in addressing risk factors for effective prevention and management.

This global health challenge extends its reach to Africa, where CVDs contribute significantly to the continent's high mortality rate. Sub-Saharan Africa is home to 25 million people living with CVDs, and this prevalence is anticipated to rise by 25% by 2030 [21]. CVDs, claiming 13% of all deaths, stand as the leading cause of mortality in Africa, with a staggering 7.4 million people succumbing to premature deaths each year before the age of 70 [61].

Several factors contribute to this disproportionate burden in Africa. Inadequate access to healthcare services, poor preventative measures and late diagnosis and treatment options significantly contribute to the high mortality rate from CVDs [62,63,64]. Socioeconomic disparities, including poverty, unemployment and restricted access to good food and physical activity, contribute to the escalating prevalence of CVD risk factors in Africa [65,66,67]. Furthermore, the lack of public awareness about CVDs and their risk factors hampers early diagnosis and intervention, leading to complications and increased mortality [68, 69].

Cardiovascular diseases (CVDs) have risen as a pressing global health issue, and their impact on public health is profound. In 2008, CVDs accounted for nearly half of all reported deaths worldwide, highlighting their significant burden [64]. It is worth noting that this burden is particularly concentrated in low-to-middle-income countries [70], where healthcare resources and access to preventive measures are often limited.

A striking characteristic of CVDs is their association with an aging population, with more than 50 percent of CVD-related deaths occurring in individuals over the age of 70. This demographic shift places additional strain on healthcare systems, as older individuals often require specialized medical care and interventions. The African continent, with its vast and diverse population, is significantly impacted by the CVD epidemic. Sub-Saharan Africa alone reported approximately one million CVD-related deaths in 2013, comprising a substantial portion of global CVD fatalities and a noteworthy fraction of all deaths on the continent [71]. CVDs have become a major contributor to non-communicable disease-related mortality in Africa, reflecting a significant change in the region's disease landscape over the past few decades.

Moreover, there exists a notable disparity in CVD mortality between genders, with more than a 10 percent difference in death rates between females and males [71]. This variation underscores the need for gender-specific health strategies and interventions to address the unique risk factors and healthcare needs of women and men.

The evolving landscape of CVDs in Africa is shaped by epidemiological transitions and population dynamics, particularly in low-resource communities. Sub-Saharan Africa hosts a substantial proportion of the world's impoverished population, making it essential to develop strategies that are tailored to the region's specific socioeconomic and healthcare challenges [72]. Addressing the CVD burden in Africa necessitates a comprehensive and multi-faceted approach that takes into consideration the complex nature of factors contributing to this public health challenge.

Lipid-related cardiovascular risk factors

In recent years, heightened attention has been directed towards cardiovascular risk factors linked to lipids, particularly low-density lipoprotein (LDL) and high-density lipoprotein (HDL) [26]. These factors, including elevated plasma triglycerides, have been extensively researched for prevention and treatment strategies.

LDL, a central player in cardiovascular health, undergoes a complex process resulting in the formation of small, dense LDL particles. This intricate process involves the exchange of lipids between triglyceride-rich lipoproteins and LDL, a phenomenon influenced by genetic traits. Aged small, dense LDL particles, with diminished protection against free radical attack, linger longer in the bloodstream. Their increased susceptibility to oxidative modification contributes to the formation of atherosclerotic plaques, as evidenced by studies like the Quebec Heart Study, highlighting a robust connection between small and dense LDL cholesterol concentration and the risk of coronary heart disease [73, 74].

Conversely, high-density lipoprotein (HDL) plays a protective role in cardiovascular health. Reduced levels of HDL are related to an elevated risk of cardiovascular diseases. HDL's atheroprotective function is achieved through the pathway of reverse cholesterol transport (RCT), wherein cholesterol is moved from peripheral tissues to the liver for elimination. This process involves crucial components such as lecithin-cholesteryl ester acyl-transferase (LCAT) and apolipoprotein Apo A1 [26, 75].

Beyond RCT, HDL exhibits various atheroprotective properties, including preventing the development of reactive oxygen species, inhibiting LDL oxidation, protecting endothelial cells from apoptosis and participating in inflammatory and apoptotic processes [76,77,78,79,80,81].

Maintaining healthy lipid levels is crucial for cardiovascular well-being. Factors such as estrogen, reduced body fat, moderate alcohol intake, strenuous exercise and certain medications like niacin and fibrates have been identified to positively impact HDL cholesterol levels and overall cardiovascular health [82, 83].

In unraveling the complexities of lipid dynamics, valuable insights emerge for developing comprehensive strategies aimed at addressing cardiovascular health and managing the associated risk factors linked to cardiovascular diseases.

Atherosclerosis as a cardiovascular disease

Atherosclerosis is one of the most life-threatening cardiovascular diseases, which can affect individuals as early as their twenties. It contributes to an estimated 15.2 million deaths annually worldwide, making it a leading cause of mortality, as reported by the World Health Organization [24]. The initial stage of atherosclerosis is characterized by the accumulation of plaque in the arteries, particularly in large- and medium-sized vessels. This plaque primarily consists of cholesterol derived from low-density lipoproteins (LDLs), fibrin and calcium. The development of plaque can lead to ischemia due to the obstruction of blood flow and may result in the formation of thrombi when the plaque ruptures, leading to the blockage of blood vessels [25].

Atherosclerosis, or the formation of plaque, primarily occurs in the endothelium of arterial walls [26]. Under normal circumstances, the endothelium contributes to blood vessel dilation, reduces the growth of smooth muscle cells and prevents inflammatory responses [84]. However, in the context of atherosclerosis, dysfunction in the endothelium leads to reduced production of nitric oxide, a major vasodilator, resulting in increased vasoconstriction, heightened permeability and the uptake of LDL cholesterol by macrophages. This process leads to the formation of early lesions known as fatty streaks, the first visible sign of atherosclerosis [26].

Inadequate intake of antioxidants such as vitamin E, selenium and a diet low in fiber and unsaturated fats is dietary risk factor for atherosclerosis and dyslipidemias [85,86,87,88,89].

Available remedies for the management of cardiovascular diseases

While statins continue to be the primary treatment for hypercholesterolemia, recent research has explored alternative remedies with promising results. These alternatives aim to address not only cholesterol levels but also potential side effects associated with statin therapy.

Dietary modifications, such as a lecithin-enriched diet, have shown promise in positively impacting lipoprotein metabolism and cholesterol homeostasis, potentially reducing overall cholesterol levels [17, 90]. Plant sterols and stanols, soluble fiber from sources like psyllium and oats, and adherence to the Mediterranean diet are additional dietary approaches with proven efficacy in lowering cholesterol and reducing cardiovascular risk [91,92,93].

Nutraceuticals and supplements, including red yeast rice, berberine, omega-3 fatty acids and Coenzyme Q10, offer additional options for managing hypercholesterolemia [94,95,96,97]. Lifestyle modifications, such as regular exercise, weight management and stress reduction techniques, also play a crucial role in lowering cholesterol levels and improving overall cardiovascular health [98,99,100].

While statins remain a valuable tool in managing hypercholesterolemia, alternative remedies offer promising options for individuals seeking additional support or experiencing side effects. A combination of dietary modifications, nutraceuticals, lifestyle changes and appropriate medical supervision can effectively manage cholesterol levels and reduce cardiovascular risk.

Atherogenic lipoproteins

Several factors influence the atherogenic properties of cholesterol-containing lipoproteins in plasma. One critical factor is particle size, with smaller particles accumulating more rapidly in artery walls than larger particles. The size of the particle also determines its affinity for binding to the subendothelial matrix, with smaller particles binding more readily to proteoglycans [