Plant Sterols and Stanols (Phytosterols)
Phytosterols look enough like cholesterol to crash the party. They shove into intestinal micelles ahead of your dietary and biliary cholesterol, hogging the spots that would have absorbed it. Less cholesterol gets absorbed. Your LDL receptors ramp up clearance to compensate. Circulating LDL-cholesterol comes down. That's the mechanism, plain and effective.
Evidence
This one's well-replicated: RCTs and meta-analyses keep landing on an 8-12% LDL-cholesterol drop at about 2 grams a day, climbing higher if you push toward 3 grams. So why moderate and not strong? Because nobody's run the trial proving lower LDL from phytosterols translates into fewer heart attacks. The biomarker move is the accepted stand-in. Real number. Borrowed proof.
Interactions
Reduces absorption of fat-soluble carotenoids (beta-carotene) and modestly of some fat-soluble vitamins; can be combined with statins/ezetimibe for additive LDL lowering.
Cautions
Avoid in sitosterolemia (phytosterolemia), a rare genetic disorder in which phytosterols accumulate. Elevated serum phytosterol levels have been associated in some observational data with atherosclerosis, so intake above recommended amounts is not advised.
Food sources
Naturally in vegetable oils, nuts, seeds, whole grains, and legumes; concentrated in fortified spreads, yogurts, and drinks. Ordinary diets supply only ~0.3 g/day, below the effective dose.
