(LifeWire) - If you're looking to cut your "bad" cholesterol -- and boost your heart health -- look no further than the nutritionists' familiar "five-a-day (or more!)" refrain. Those five daily servings of fruits and veggies contain closely related substances known as plant sterols and stanols, which have important cardiovascular benefits.
Sterols occur naturally in fruits, vegetables, nuts, seeds, cereals, legumes, vegetable oils and many other plant sources. Stanols are found in many of the same foods but in much smaller quantities.
Foods fortified with plant sterols include spreads (such as Benecol and Take Control), beverages (such as Minute Maid Heart Wise and Rice Dream Heartwise) and snacks (such as Nature Valley Healthy Heart Chewy Granola Bars).
So what exactly are plant sterols? Just as cholesterol is a component of animal cell membranes, plant sterols play a similar role in the cell membranes of plants.
The National Cancer Institute (NCI), part of the National Institutes of Health, explains that plant sterols play a beneficial role, because they can be absorbed in the intestines in place of dietary cholesterol, "resulting in lower blood cholesterol levels." Unlike cholesterol, plant sterols don't have a negative impact on heart health.
In 2000, the Food and Drug Administration first authorized a health claim for plant sterols on the basis of evidence that such compounds reduced the risk for coronary heart disease. In particular, studies showed that 1.3 grams of plant sterols -- or 3.4 grams of plant stanols, a closely related class of compounds -- have significant cholesterol-lowering effects when taken daily.
A Pennington Biomedical Research Foundation of Louisiana State University analysis of 18 sterol and stanol studies concluded that a daily 2-gram intake lowers LDL ("bad") cholesterol by 10 to 15%, producing a 25% decrease in heart disease risk.
The evidence for sterols' health benefits also appears to be expanding. For example, the NCI notes that these plant compounds may have cancer-preventing effects.
"Plant Sterols." pbrc.edu. 2005. Pennington Biomedical Research Foundation. 6 Oct. 2008 <http://www.pbrc.edu/division_of_education/pdf/PNS_plant_sterols.pdf>.
"Dictionary of Cancer Terms: Plant Sterols." cancer.gov. National Cancer Institute, National Institutes of Health. 6 Oct. 2008 <http://www.cancer.gov/templates/db_alpha.aspx?CdrID=44161>.
"FDA Authorizes New Coronary Heart Disease Health Claim for Plant Sterol and Plant Stanol Esters." fda.gov. Sep. 2000. Food and Drug Administration. 6 Oct. 2008 <http://www.cfsan.fda.gov/~lrd/tpsterol.html>.
"US Sterol Foods Market Growing -- But Slowly." functionalingredientsmag.com. Sep. 2006. Functional Ingredients. 6 Oct. 2008 <http://www.functionalingredientsmag.com/fimag/articleDisplay.asp?strArticleId=1089&strSite=FFNSite>.