Stanol esters is a heterogeneous group of chemical compounds known to reduce the level of low-density lipoprotein (LDL) cholesterol in blood when ingested, [1] though to a much lesser degree than prescription drugs such as statins. [2] The starting material is phytosterols from plants. These are first hydrogenated to give a plant stanol which is then esterified with a mixture of fatty acids also derived from plants. Plant stanol esters are found naturally occurring in small quantities in fruits, vegetables, nuts, seeds, cereals, legumes, and vegetable oils.
Stanol ester is often added to rapeseed oil-based margarine or other foods for its health benefits. Studies have indicated that consumption of about 2-3 grams per day provides a reduction in LDL cholesterol of about 10-15%. [3]
The compound itself passes through the gut, with very little entering the blood stream or lymph. Its presence in the gut, however, reduces both the amount of cholesterol the body absorbs from food and the reabsorption of the cholesterol component of bile. Despite a well documented cholesterol lowering effect, there are no data available indicating that functional foods supplemented with plant sterol esters reduce cardiovascular events. [4] They are used in food products such as Benecol.
Sterol esters can also be used for the same purpose. These compounds have the same effect to LDL, but they are partially absorbed by the body. The effects of higher serum plant sterol levels are so far not completely understood.
Plant sterols are cholesterol-like molecules found in all plant foods, with the highest concentrations occurring in vegetable oils. Plant sterols are plant equivalents of cholesterol and have a very similar molecular structure. According to their structure, they can be divided into sterols and stanols, stanols being a saturated subgroup of sterols.[ citation needed ]
Plant stanols are present in small amounts in human diet. Their main sources are whole-grain foods, mostly wheat and rye. The daily intake of stanols in the average western diet is about 60 mg/d, whereas the intake of plant sterols is about 150–300 mg/d and that of cholesterol is 500–800 mg/d. The relatively low natural levels of stanols in the diet are too low to have a significant effect on serum cholesterol levels.[ citation needed ]
Following evidence from toxicological studies and numerous clinical trials, stanols are characterised as safe by authorities in several European Union countries and by the US Food and Drug Administration (FDA).[ citation needed ]
Stanol esters are a saturated subgroup of sterol esters. Plant stanol esters in Benecol products are fatty acid esters of plant sterols. The sterol part of the molecule is sitostanol or campestanol while the fatty acid residue originates from different vegetable oils.
Plant stanol esters have the following physical properties:
These physical properties can be tailored by changing the fatty acid composition. In different technological applications of Benecol products, the fatty acid part is selected so that the melting properties, texture and other characteristics of the plant stanol ester closely resemble the properties of the fat it replaces.
Under normal storage and food preparation conditions, plant stanol esters are very stable because they are more resistant to oxidation than the commonest vegetable oils.
Using plant stanol esters in food applications instead of conventional fats does not decrease the shelf life of the end product. As is the case for all fats and oils, stanol esters should be protected from heat, air and light to prevent oxidation. If long-term storage is required, plant stanol esters are typically refrigerated in solid form. Furthermore, the usual antioxidants can be added to plant stanol ester products as they are to other oils or fats to minimise oxidation.
Esterified plant stanols have been proven to reduce cholesterol in a number of randomised, placebo-controlled double-blind clinical trials. However absolutely no effect on clinical endpoints such as CVD or mortality was demonstrated.
Plant stanols reduce both cholesterol and plant sterol levels in serum. This may be of importance since elevated plant sterol concentrations have been identified as an independent risk factor for coronary heart disease (CHD). Two ABC transporters (ABCG5 and ABCG8) play an important role in the regulating the intestinal absorption of plant sterols by resecreting previously absorbed plant sterols from the enterocytes back into the intestinal lumen.
Mutations in these transporter proteins lead to a rare congenital disease called sitosterolaemia, which is characterised by:
It was recently shown that polymorphisms in the ABCG5 and ABCG8 genes contribute to modifying serum plant sterol levels in healthy, non-sitosterolaemic individuals. Furthermore, several epidemiological studies have shown that the risk of developing heart disease seems to be increased even at more "normal" plant sterol levels. [1] [4] [5] [6] [7] Since statins were shown to increase serum plant sterol concentrations, [8] [9] patients should probably not be treated with statins alone but with a combination therapy focusing simultaneously on improving the serum lipoprotein profile and lowering serum plant sterol concentrations.
The molecular mode of actions of stanols has been described in several preclinical and clinical trials and can be divided into two steps:
As a consequence of the reduced absorption of cholesterol, the absorption of fat-soluble components other than cholesterol, such as vitamins and antioxidants, may also be reduced. Like cholesterol, carotenoids and tocopherols are transported by lipoproteins. Since the number of LDL particles in circulation decreases after consumption of plant sterols or stanols, plasma concentrations of carotenoids and tocopherols also decrease. This is why these antioxidants are often standardized to plasma lipid concentrations.
The results of randomised, placebo-controlled trials on the effects of plant sterols or stanols on fat-soluble vitamins and antioxidants were summarised in 2003. [10] Significant reductions were only seen in clinical trials for hydrocarbon carotenoids. These reductions are probably caused by reduced absorption and lower plasma concentrations of the carrier, LDL.
After correcting for cholesterol levels, only the reduction in the β-carotene level remained. It is important, however, that carotenoid and tocopherol levels remained within the normal ranges. Clinical trials also showed that when following the recommended diet, including consumption of vegetables and fruit, carotenoid levels did not decrease. [11] [12] Plasma concentrations of retinol (vitamin A), 25-hydroxyvitamin D and vitamin K are unaffected by dietary plant sterols and stanols.
Cholesterol is the principal sterol of all higher animals, distributed in body tissues, especially the brain and spinal cord, and in animal fats and oils.
In nutrition, biology, and chemistry, fat usually means any ester of fatty acids, or a mixture of such compounds, most commonly those that occur in living beings or in food.
Lipids are a broad group of organic compounds which include fats, waxes, sterols, fat-soluble vitamins, monoglycerides, diglycerides, phospholipids, and others. The functions of lipids include storing energy, signaling, and acting as structural components of cell membranes. Lipids have applications in the cosmetic and food industries, and in nanotechnology.
Low-density lipoprotein (LDL) is one of the five major groups of lipoprotein that transport all fat molecules around the body in extracellular water. These groups, from least dense to most dense, are chylomicrons, very low-density lipoprotein (VLDL), intermediate-density lipoprotein (IDL), low-density lipoprotein (LDL) and high-density lipoprotein (HDL). LDL delivers fat molecules to cells. LDL is involved in atherosclerosis, a process in which it is oxidized within the walls of arteries.
Margarine is a spread used for flavoring, baking, and cooking. It is most often used as a substitute for butter. Although originally made from animal fats, most margarine consumed today is made from vegetable oil. The spread was originally named oleomargarine from Latin for oleum and Greek margarite. The name was later shortened to margarine.
Coconut oil is an edible oil derived from the kernels, meat, and milk of the coconut palm fruit. Coconut oil is a white solid fat below around 25 °C (77 °F), and a clear thin liquid oil in warmer climates. Unrefined varieties have a distinct coconut aroma. Coconut oil is used as a food oil, and in industrial applications for cosmetics and detergent production. The oil is rich in medium-chain fatty acids.
Hypercholesterolemia, also called high cholesterol, is the presence of high levels of cholesterol in the blood. It is a form of hyperlipidemia, hyperlipoproteinemia, and dyslipidemia.
Oleic acid is a fatty acid that occurs naturally in various animal and vegetable fats and oils. It is an odorless, colorless oil, although commercial samples may be yellowish. In chemical terms, oleic acid is classified as a monounsaturated omega-9 fatty acid, abbreviated with a lipid number of 18:1 cis-9, and a main product of Δ9-desaturase. It has the formula CH3−(CH2)7−CH=CH−(CH2)7−COOH. The name derives from the Latin word oleum, which means oil. It is the most common fatty acid in nature. The salts and esters of oleic acid are called oleates. It is part of many oils and thus used in a lot of artificial food, as well as for soap.
Becel is a brand of margarine produced by Dutch company Upfield. In France, it is sold as Fruit D'or, and in the United States as Promise.
Hyperlipidemia is abnormally high levels of any or all lipids or lipoproteins in the blood. The term hyperlipidemia refers to the laboratory finding itself and is also used as an umbrella term covering any of various acquired or genetic disorders that result in that finding. Hyperlipidemia represents a subset of dyslipidemia and a superset of hypercholesterolemia. Hyperlipidemia is usually chronic and requires ongoing medication to control blood lipid levels.
Palm kernel oil is an edible plant oil derived from the kernel of the oil palm tree Elaeis guineensis. It is related to other two edible oils: palm oil, extracted from the fruit pulp of the oil palm, and coconut oil, extracted from the kernel of the coconut.
Phytosterols are phytosteroids, similar to cholesterol, that serve as structural components of biological membranes of plants. They encompass plant sterols and stanols. More than 250 sterols and related compounds have been identified. Free phytosterols extracted from oils are insoluble in water, relatively insoluble in oil, and soluble in alcohols.
Sterol esters are a heterogeneous group of chemical compounds. They are created when the hydroxyl group of a sterol and a fatty acid undergo an esterification reaction. They can be found in trace amounts in every cell type but are highly enriched in foam cells and are common components of human skin oil.
Campesterol is a phytosterol whose chemical structure is similar to that of cholesterol, and is one of the ingredients for E number E499.
Benecol is a brand of cholesterol-lowering food products owned by the Finnish company Raisio Group, which owns the trademark.
Sitosterolemia is a rare autosomal recessively inherited lipid metabolic disorder. It is characterized by hyperabsorption and decreased biliary excretion of dietary sterols. Healthy persons absorb only about 5% of dietary plant sterols, but sitosterolemia patients absorb 15% to 60% of ingested sitosterol without excreting much into the bile. The phytosterol campesterol is more readily absorbed than sitosterol.
The chronic endothelial injury hypothesis is one of two major mechanisms postulated to explain the underlying cause of atherosclerosis and coronary heart disease (CHD), the other being the lipid hypothesis. Although an ongoing debate involving connection between dietary lipids and CHD sometimes portrays the two hypotheses as being opposed, they are in no way mutually exclusive. Moreover, since the discovery of the role of LDL cholesterol (LDL-C) in the pathogenesis of atherosclerosis, the two hypotheses have become tightly linked by a number of molecular and cellular processes.
Therapeutic Lifestyle Changes, also known as the TLC Diet, is a dietary pattern recommended by the National Cholesterol Education Program, part of the National Institutes of Health, to control hypercholesterolemia. This pattern focuses on saturated fats and cholesterol, dietary options to enhance LDL cholesterol lowering, weight control, and physical activity.
Cooking oil is a plant or animal liquid fat used in frying, baking, and other types of cooking. Oil allows higher cooking temperatures than water, making cooking faster and more flavorful, while likewise distributing heat, reducing burning and uneven cooking. It sometimes imparts its own flavor. Cooking oil is also used in food preparation and flavoring not involving heat, such as salad dressings and bread dips.
Trans fat, also called trans-unsaturated fatty acids, or trans fatty acids, is a type of unsaturated fat that occurs in foods. Trace concentrations of trans fats occur naturally, but large amounts are found in some processed foods. Since consumption of trans fats is unhealthy, artificial trans fats are highly regulated or banned in many nations. However, they are still widely consumed in developing nations, resulting in hundreds of thousands of deaths each year. The World Health Organization (WHO) has set a goal to make the world free from industrially produced trans fat by the end of 2023.