Phytosterols health benefits

Kritchevsky, D. S.C. Chen. Phytosterols-health benefits and potential concerns a review. Nutr. Res. 2005,25, 413-428. 

Natural products have been noted for their potential health benefits from time immemorial and are the basis of Ayurveda, an ancient Indian medical practice (Bushkin and Bushkin, 2002). However, the potential benefits of several natural products reside in one or two active ingredients. For example green tea stands for polyphenols, soy for soy estrogens, broccoli for isothiocyanates and grape seed for polyphenols. The beauty of rice bran is that there are more than 100 antioxidants, several categories of bioactive phytonutrients, such as IP6, polyphenols, phytosterols, tocotrienols, y-oryzanol, B vitamins, minerals and trace minerals in addition to fat, protein, fiber, polysaccharides and other nutrients. These phytonutrients and antioxidants of rice bran are believed to act at the cellular level, and their synergestic function is responsible for the positive health benefits. 

Health benefits of phytosterols have been a topic of intense research in recent years. The main physiological effect of consuming phytosterols (2-3 g/day for 21-30 days) is their reported lowering of low density lipoprotein (LDL) cholesterol by 10-15%. The Food and Drug Administration (FDA) allows a health claim for food containing phytosterols because of the association with reduced risk of coronary heart disease (Federal Register, 2000). 

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). 

The study of plant bioactives has been of considerable importance in recent years with the recognition that they are involved in many vital biological and metabolic processes in plants as well as in the human body when consumed as part of a normal human diet This chapter deals mainly with the bioactives identified in Brazil nut. The potential health benefits of Brazil nut are also discussed. Several groups of plant bioactives have been identified in Brazil nut, including MUFA, PUFA, phenolics (mainly tocopherols), selenium, phytosterols, phytostanols, squalene, and other minor bioactives. 

This chapter reviews the health benefits of pistachio in relation to the phytochemicals found in pistachio kernels and peels. Phytochemicals previously identified from pistachios include phytosterols, lutein, resveratrol, and anthocyanins. Pistachios are unique among tree nuts both in having anthocya-nins in their peels and significant amounts of lutein both in the peel and the kernel of the nut. 

Com oil contains a significant amount of ubiquinone and high amoimts of gamma-tocopherols (vitamin E). Com oil contains a significant amount of ubiquinone and high amounts of gamma-toeopherols (vitamin E) (Table 1). These high contents of PUFA, phytosterols and vitamin E may contribute to the health benefits of eom oil consumption. 

The new trend in cereal breeding programs is to select genotypes with special uses and with better nutraceutical properties. These new genotypes are rich in carotenes (P-carotenes, lutein, zeaxanthin), phytosterols, phenolics, anthocyanins, tannins, and other antioxidants. These value-added grains will gradually gain market because of their proven health benefits. 

There has been much interest in the health benefits of consuming phytosterols, especially since the FDA issued a health claim for their use. These phytochemicals inhibit the absorption of cholesterol from the small intestine, thus effectively lowering total blood cholesterol, and LDL. An amount of only 1 to 3 g per day reduces cholesterol by 5% to 20%. A typical dietary intake of phytosterols varies from 200 to 400 mg per day (White and Weber 2003). The main sterol present in the whole oat kernel and extracted oil is P-sitosterol, followed by campesterol, and stigmasterol. The second dominant sterol in oats is avenasterol (Chung and Ohm 2000). 

The demand for healthy foods has led to the development of several entirely new healthy ingredient and additive categories (Heasman and Mellentin 2001 Sloan 2004). An entirely new sector of functional food ingredients has developed, including products such as omega-3 fatty acids and phytosterols for cardiovascular health, prebiotics and probiotics for gut health, antioxidants, polyphenols and phytochemicals, and bioactive peptides. The established vitamins and minerals sector has also benefited from this functional food trend, with more and more products being fortified with beneficial vitamins and minerals. 

The common pumpkin seed has been extensively studied for its beneficial effect on prostate health. Seed extracts inhibit 5-alpha-reductase conversion of testosterone to dihydrotestosterone. The mechanism of action seems to be different from that of saw palmetto, nettle root, or pygeum. Researchers speculate that betasitosterol (a phytosterol) competes with androgens, thus decreasing esposure of the prostate to hormonal stimulation. Eating pumpkin seeds (1 to 2 ounces per day) or taking gel capsules (2 to 4 per day) has shown benefits in reducing inflammation and other prostatic symptoms. 

Cashew nut and its coproducts provide a complex food rich in macronutrients and micronutrients, as well as small quantities of various antioxidants and bioactive compounds that are relevant to many health beneficial attributes. These bioactive compounds include MUFA, PUFA, phenolics, phytosterols, phytostanols, tocopherols, and phytates. While benefits of cashew nut and its coproducts for human health appear promising, further research on bioavailability and bioaccessibility of cashew bioactive compounds as well as potential allergenic reaction is required for a better understanding of the role of cashew nut and its coproducts in human health. 

There is an increasing interest in the lipid characteristics of nut oils as they seem to be an interesting source of bioactive constituents and functional ingredients [170,174,187]. Among tree nuts, hazelnut has many beneficial health attributes and is among three most popular and commonly consumed tree nuts in Europe [188] and other Western populations [179]. The benefits of hazelnut inclusion into the human diet is partly related to its fat components (around 60%), most of which are highly rich in MUEA (primarily oleic acid), tocols (a-tocopherol), phytosterols (p-sitosterol), polyphenols, and squalene [10,12,99,104,117,160,170,189]. 

While a number of margarines and spreads have been introduced that claim or infer benefits to gut health or bone health, the major focus of activity in this sector has been in phytosterol-enriched heart-benefit products. The first of these were laimched in Finland in 1995, but the sector did not really take off until 1999, when a number of products were launched in the USA, Europe and Australia. While heart-benefit spreads have been introduced based on n-3 (also known as omega-3 or co-3) fatty acids, these have not enjoyed anything like the commercial success of their phytosterol-enriched counterparts. 

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