Conclusions
Based on the positive results from studies examining the effects of low doses of free plant sterols and sterol esters, there is a good likelihood that a minimum dose of 0.8–1.0 g of free sterol and free sterol equivalents will reduce LDL cholesterol by 5% or more, and that this reduction in LDL cholesterol will correlate with an approximate 6–10% reduction in coronary heart disease risk at age 70 [35,36]. There is also a good likelihood that the reduction in LDL cholesterol within this same dosage could be higher if full compliance of the plant sterol dosage were assured. In studies where subjects were monitored to ensure full compliance, efficacy with a 1.5 to 2 g/d dose ranged from 12–16%. For maximum efficacy of free plant sterols, the plant sterols must be administered in a soluble or microcrystalline form. Efforts must be taken to assure that the free plants sterols remain in this bio-efficacious form during the shelf life of the product. Our dosage recommendation of 0.8–1.0 g of free sterol and free sterol equivalents compares favorably with the FDA interim final rule 21 CFR 101.83 recommending 0.65 g of sterol esters per serving, twice per day in spreads, which is equivalent to 0.8 g of free sterol equivalents per day. As of January 2003, the FDA recognized that the scientific literature supports expanding the health claim to include free forms of plant sterols and stanols, and to include a wider range of products, including low-fat products. The FDA further stated that the science (as of January 2003) shows that the lowest effective daily intake of free phytosterols is 800 mg/d http://vm.cfsan.fda.gov/~dms/ds-ltr30.html.
In addition to their cholesterol lowering properties, plant sterols have other promising effects, including anti-cancer, anti-inflammation, anti-atherogenicity, and anti-oxidation activities. Despite the fact that plant sterols reduce the carotenoid levels in adults, it seems that an intake of plant sterols between 0.8–1.0 g is essential to prevent chronic diseases in adult population. The carotenoid lowering effect of plant sterols can be corrected by increasing intake of food that is rich in carotenoids. However, more studies are needed in pregnant and lactating women as well as on children in order to verify the dose required to decrease blood cholesterol without affecting fat-soluble vitamins and carotenoid status.
Plant sterols are naturally occurring molecules that humanity has evolved with, which partially counter the absorption of dietary cholesterol and have other important biological functions described above. The myriad of factors that can affect the efficacy of plant sterols have been explored. The resonating conclusion is that properly solubilized 4-desmetyl plant sterols, in ester or free form, in reasonable doses (0.8–1.0 g of equivalents per day) and in various vehicles including natural sources, and as part of a healthy diet and lifestyle, are important dietary components for maintaining good heart health. Consumption from natural sources should be encouraged for all persons, and consumption of plant sterols in enriched sources should be encouraged following consultation with a clinician. The clinician should be assured that the individual is a responder to plant sterols, and achieves a reduction in LDL cholesterol. Along these lines, it would be fruitful to monitor individuals for markers of cholesterol absorption before recommending consumption of enriched plant sterols. Those persons who are poor absorbers of dietary cholesterol (on the basis of low levels of serum cholestanol and plant sterols) [175] may not be ideal candidates for consuming plant sterols to lower plasma LDL cholesterol, but may still benefit from plant sterols' other positive effects.