Plant Stanol/Sterol Fortified Foods, Part 2 

How do they work in lowering LDL cholesterol?
How should they be incorporated into the daily diet?

How do they work?

• Plant stanols and sterols are structurally similar to cholesterol.  Because of this similarity, they can compete with cholesterol for incorporation into the mixed micelles that are necessary for absorption of dietary and biliary cholesterol from the intestinal lumen into the intestinal cell. Thus, less cholesterol is incorporated into mixed micelles and less intestinal cholesterol is delivered to the liver.  Because of this, the liver is stimulated to increase LDL receptor activity to increase uptake of cholesterol from the blood.
  
  
• The intestinal cholesterol pool consists of ~70% biliary cholesterol and ~30% dietary cholesterol.  Plant stanols/sterols interfere with absorption of both biliary and dietary cholesterol.  Thus, even in people already eating low cholesterol diets, cholesterol absorption is still significantly lowered because most of the cholesterol in the intestine is endogenous cholesterol.
  
  
• Plant stanols/sterols interfere with incorporation of cholesterol into mixed micelles but are absorbed only in very small amounts.  Sterols are absorbed to a greater degree than stanols.
  
  
• The amount needed for this competition to take place is at least 1g per day and is maximal at 2g to 3 g per day of plant stanols/sterols.  Usual daily intake from plant-based foods is about 300mg/day in peopleeating American/Western European diets, not enough to interfere with cholesterol absorption.
  
  
• Research determined that fat-based foods serve as the most effective vehicles for delivering plant stanols/sterols to the upper small intestine, where cholesterol absorption takes place.

How should plant stanol/sterols be incorporated into the diet?

• LDL cholesterol is lowered by 10% to 15% when 2-3 g/day are incorporated into the diet, regardless of the composition of the background diet.
  
  
• In the commercial products available, 1 serving of the product is formulated to contain ~1 gram of  plant stanols (Benecol) or plant sterols (Take Control). To obtain the maximal effect, 2 to 3 servings of these products should be consumed daily.
  
  
• Currently, only margarine spreads fortified with plant stanols/sterols are available in the United States.  Other formulations of plant stanol fortified foods are available in Europe such as yogurt and cream cheese spreads.
  
  
• Benecol spreads are available in the regular and light formulations.  The regular Benecol can be used in baking, frying, freezing.  The Benecol Light and Take Control formulations are intended as table spreads and less conducive to cooking.  Benecol Light and Take Control contain fewer calories per serving (~50 calories per serving vs. 80 calories per serving with regular Benecol). 
  
  
• LDL cholesterol is lowered an additional 10%-15% when plant stanols/sterols are added to the diets of patients already on statin therapy.  Addition of 2-3 servings daily of plant stanols/sterols to the diet results in greater LDL cholesterol reduction than doubling the dose of a statin.

References:

Miettinen TA, Puska P, Gylling H, Vanhanen H, Vartiaianen E.  Reduction of serum cholesterol with sitostanol-ester margarine in a mildly hypercholesterolemic population. N Engl J Med 1995; 333: 1308-12.

Cater NB.  Plant stanol ester: review of cholesterol-lowering efficacy and implications for coronary heart disease risk reduction.  Prev Cardiol 2000; 3: 121-130.

Grundy SM.  Stanol esters as dietary adjunct to cholesterol-lowering therapies.  Eur Heart J 1999; 1: S132-S138.

Blair SN, Capuzzi DM, Gottlieb SO, Nguyen TT, Morgan JM, Cater NB.  Incremental reduction of serum total cholesterol and low-density lipoprotein cholesterol with the addition of plant stanol ester-containing spread to statin therapy.  Am J Cardiol 2000; 86: 46-52.

Westrate JA, Meijer GW.  Plant sterol-enriched margarines and reduction of plasma total and LDL cholesterol concentrations in normocholesterolemic and mildly hypercholesterolemic subjects.  Eur J Clin Nutr 1998; 52; 334-43.