Margarine sterol ester

The phytosterols are of interest from a nutritional and physiological point of view because they lower the concentration of cholesterol and LDL in the blood plasma (cf. 3.5.1.2). The absorption of cholesterol is inhibited, a significant effect being reached with an intake of 1 g/day of phytosterol. Since the normal dietary intake amounts to only 200-400 mg/day of phytosterol, margarines are enriched with phytosterols. However, as the free sterols are only poorly soluble in the fat phase, sterol esters are used in the production of margarine. Sterol esters are hydrolysed in the digestive tract. The starting material for the extraction of phytosterols is plant oils and tall oil (Swedish tall = pine), which accumulates as a by-product in the production of paper and pulp. Tall oil is rich in phytostanols, mainly P-sitostanol. 

Plant sterols Commercially available margarines containing hydrogenated plant sterols and sterol esters (predominantly sitostanol esters), when used in place of regular margarine, can reduce LDL plasma cholesterol concentrations. The mechanism by which these compounds lower LDL cholesterol concentrations is to inhibit intestinal absorption of dietary cholesterol and cholesterol secreted into the bile. 

Hallikainen, M.A., Sarkkinen, E.S., Gylling, H., Erkkila, A.T., and Uusitupa, MX 2000. Comparison of the effects of plant sterol ester and plant stanol ester-enriched margarines in lowering serum cholesterol concentrations in hypercholesterolaemic subjects on a low-fat diet. Eur. J. Clin. Nutr. 54, 715-725. 

Simons, L.A., Additive effect of plant sterol-ester margarine and cerivastatin in lowering low-density lipoprotein cholesterol in primary hypercholesterolemia. Am. J. Cardiol, 90, 737, 2002. 

Animal fats are subjected to deodorization when a very bland or essentially flavorless fat is desired, such as in margarines or cooking fats. The fats are heated at 200°C to 260°C in the absence of air (to prevent oxidation) and treated with dry steam under a vacuum of 5-10 milliatmospheres. Off-flavor compounds are volatile under these conditions and are captured and removed in the steam stream. In addition to flavor components, free fatty acids, which can also contribute undesirable flavors, and other minor constituents such as peroxides, sterols, sterol esters, toco-pherols, and other natural antioxidants are partially or completely removed from the fat by this treatment. 

Lipases have also been employed to isolate tocopherols and sterols, important antioxidants from deodorizer distillate, a by-product formed during the deodoriza-tion step of seed oil purification, by hydrolyzing MAG and DAG in the distillate, and by esterifying sterols into sterol esters. The latter serves as antioxidant in non-polar food products such as margarine (e.g., Benacol from the Raisio Group, Finland and Take Control from Unilever, Englewood Cliffs, New Jersey, U.S.A.). PUFA-sterol esters would provide the benefits of essential fatty acid intake and antioxidant protection. 

The growing recognition of the health benefits associated with phytosterol esters leads to the marketing of new products. Several companies have marketed stanol and sterol ester products. In 1995/1996, Raisio Company from Finland introduced the margarine Benecol with 9% of sitostanol ester. Benecol was also launched in the United States in May 1999. In 1999, Unilever launched its product. Take Control , which contained vegetable oil derived sterol esters. In addition to existing products on the market in 2000, Phytrol , unesterified taU oil phytosterols, was announced (Hicks and Moreau, 2001). 

Dietary phytosterols have some influence on the biosynthesis of cholesterol in the body, although they are not used for making membranes and in the body they break down. To reduce the amount of cholesterol in blood plasma, the Recommended Daily Intake of phytosterols is about 250 mg. There are now margarines containing about 10% phytosterols (in the form of phytostanol esters derived from tall oil or in the form of sterol esters isolated from soybean oil). The importance of triterpene alcohols in the diet is not known. 

Esterified soy sterols and free stanols were compared by Nestel et al. (2001) in a study in which the sterols (2.5 g/day) were added to breakfast cereal, bread, and margarine. Plasma median total cholesterol levels decreased by 8.5% with sterol esters and by 3.5% with the free stanol, and plasma median LDL cholesterol levels decreased by 13.6% and 8.5% with sterol esters and free stanol, respectively. 

As with the North Karelia Stanol Ester Study, a 12-month study on sterol esters incorporated into margarine was conducted recently in the Netherlands (Brink and Hendriks, 2000 Hendriks et ai, 2001). Adults (185) consumed 1.6 g/day of soy sterols as esters incorporated into margarine. Semm total and LDL cholesterol concentrations reduced rapidly (within 3 weeks) by 5% and 1%, respectively, and remained at the same level for the duration of the experiment. However, surprisingly, the reductions in cholesterol levels were only seen in the male and not in the female participants (Figure 11). 

Netherlands, and Ireland. Thus, the longest experience of consumption of plant stanol ester-enriched products is a 6-year period in Finland. Sterol ester-enriched spreads were first launched in 1999 in the USA by Lipton Ltd as Take Control margarine. Today sterol ester-enriched margarines are available worldwide under brand names such as Take Control , Flora ProActive , Becel ProActive , and Rama Proactive from Unilever/Lipton, or Logicol from Goodman Fielder Ltd. Other spreads include vegetable oil-based cream cheeses available in Finnish, UK, and other European markets. 

Nestel, P, Cehun, M, Pomeroy, S, Ahhey, M and Weldon, G (2001) Cholesterol-lowering effects of plant sterol esters and non-esterified stanols in margarine, butter and low-fat foods. Eur. J. Clin. Nutr., 55,1084—1090. 

One of the best therapeutic approaches may be to prevent absorption of cholesterol from the intestines by inclusion of a higher fiber content in the diet.66 Supplementation with a cholesterol-binding resin may provide additional protection. Plant sterols also interfere with cholesterol absorption. Incorporation of esters of sitostanol into margarine provides an easy method of administration. Supplemental vitamin E may also be of value.q Another effective approach is to decrease the rate of cholesterol synthesis by administration of drugs that inhibit the synthesis of cholesterol. Inhibitors of HMG-CoA reductase,s hh (e.g., vaLostatin) iso-pentenyl-PP isomerase, squalene synthase (e.g.,... 

The use of plant sterols—(3-sitostcrol and sitostanol in consumer products to decrease cholesterol is supported by numerous clinical studies that document their efficacy in lowering mild hyperlipidemia (Jones et al., 1998 Hallikainen and Uusitupa, 1999). Although the normal diet contains plant sterols that range from 160 to 360 mg/day, a 5- to 10-fold increase is required to exert a cholesterol-lowering effect. Consumer products with increased amounts of phytosterols that exceed the content found in the diet have been made available to the consumer. In evaluating the efficacy of including sitostanol ester in margarine as a dietary supplement for children with familial hypercholesterolemia (FH), it was found that serum total cholesterol (TC), intermediate density lipoprotein-cholesterol and LDL-cholesterol levels fell while the HDL-cholesterol/LDL-cholesterol ratio was elevated. 

Temme, E.H. et al.. Effects of a plant sterol-enriched spread on serum lipids and lipoproteins in mildly hypercholesterolaemic subjects, Acta Cardiol, 57, 111, 2002. Plat, J. et al.. Effects on serum lipids, lipoproteins and fat soluble antioxidant concentrations of consumption frequency of margarines and shortenings enriched with plant stanol esters, Eur. J. Clin. Nutr., 54, 671, 2000. 

Miettinen, T.A. et al.. Reduction of serum cholesterol with sitostanol-ester margarine in a mildly hypercholesterolemic population, N. Eng. J. Med., 333, 1308, 1995 Maki, K.C et al.. Lipid responses to plant-sterol-enriched reduced-fat spreads incorporated into a National Cholesterol Education Program Step 1 diet. Am. J. Clin. Nutr., 74, 33, 2001. 

Weststrate, J.A. et al., Safety evaluation of phytosterol esters. Rart 4. Faecal concentrations of bile acids and neutral sterols in healthy normolipidaemic volunteers consuming a controlled diet either with or without a phytosterol ester-enriched margarine. Food Chem. Toxicol, 37, 1063, 1999. 

Phytosterols are industrially isolated from the distillates, resulting from the deodorization of vegetable oils (1, 34—36). Phytosterols are sometimes hydrogenated to produce phytostanols (37). As the solubility of sterols and stanols is very low (< 1% at 25°C), it limits their application in food products. Esterification of sterol and stanols is, therefore, performed to make them fat-soluble and easy to incorporate in food products (37, 38). Two margarines containing 8-9% sterols (Becel Proactiv of Unilever) or stanols (Benecol of Raisio), in the form of esters, are now available in the markets in Europe and the United States. 

Dietary cholesterol is absorbed by intestinal ABC cholesterol transporter (Chapter 41). Once inside the cell, cholesterol is esterified by acyl CoA-cholesterol-acyl transferase (ACAT) to form the hydro-phobic cholesteryl ester. This reaction facilitates and maximises absorption of cholesterol, which is probably an advantage to people deprived of cholesterol-rich food such as meat. Unfortunately, efficient absorption of cholesterol is not an advantage to the affluent. However, margarines enriched with plant sterols have been used to inhibit cholesterol absorption in an attempt to lower blood cholesterol. Research is under way to develop ACAT inhibitors that potentially are cholesterol-lowering drugs. Ezetimibe is a new drug that inhibits cholesterol absorption by inhibition of the intestinal cholesterol-transporter protein NPCILI (Niemann-Pick Cl-like protein 1). 

Miettinen TA, Vuoristo M, Nissinen M, Jarvinen HI, Gylling H (2000) Serum, biliary, and fecal cholesterol and plant sterols in colectomized patients before and during consumption of stanol ester margarine. Am J Clin Nutr 71(5) 1095-1102... 

Plant sterols (such as P-sitosterol, which differs from cholesterol in the structure of the side-chain) and stands (which differ from sterols in having a saturated B-ring see Figure 4.13) inhibit the absorption of cholesterol from the small intestine. As discussed in section 4.3.2.1, in addition to about 500 mg of dietary cholesterol, about 2 g of cholesterol is secreted each day in the bile. Almost all of this is normally reabsorbed any inhibition of cholesterol absorption is therefore likely to have a more marked hypocholesterolaemic effect than might be expected simply by considering the dietary intake. A number of products, such as margarine, yoghurts and cream, that contain plant sterols and/or stand esters have been marketed. 

Table 2. Absorption of certain 4-desmethyl sterols of interest to functional foods before and during sitostanol ester margarine consumption ...

Since free plant sterols can be used in margarines at a concentration of up to 3% (w/w) without causing quality problems (Sierksma et al., 1999), an average margarine consumption of 25 g/day would provide only 0.75 g of plant sterol (and even less stanol). This limitation has been the main stimulus for the development of the more lipid-soluble fatty acid esters of phytosterols and phytostanols. 

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