Are Plant Sterols Effective for Lowering Cholesterol?

The dietary guidelines cite the nationalmies in recommending that dietary cholesterol consumption be as low as possible. While eggs are the most concentrated source of cholesterol, gram for gram, the greatest contribution in the American diet is meat, including poultry and fish. But even if our cholesterol intake is zero, if you remember from my earlier video, our liver dumps excess cholesterol into our digestive tract through the bile, expecting there to be about a 100 grams of fiber in there every day to trap it and flush it out of the body. But when people are getting five to 10 times less fiber than nature intended, much of that cholesterol gets reabsorbed and can circulate back through our system. That's [snorts] why one of the components of the cholesterol-lowering portfolio diet are foods like oatmeal that are high in sticky fiber that traps cholesterol. But the diet also includes phytosteriles, plant steriles. This is what cholesterol looks like. This is what one of the phytosteriles looks like. It's almost identical. And the receptor here in the lining of our intestines can't tell the difference. So the phytosteriles compete with cholesterol to squeeze in through this receptor. So if there's lots of phytosteriles in the gut, some of the cholesterol can't get in or back in and ends up in the toilet instead of our bloodstream. Here's fecal cholesterol excretion in people eating different amounts of phytosteriles. The black is the amount of dietary cholesterol that's being pooped out. And the white is the amount of cholesterol that our liver dumps into our intestine through the bile. With more and more phytosterile consumption, more and more cholesterol is being flushed out of the body. Now, [clears throat] even if you eat a strictly plant-based diet without any dietary cholesterol, you'd still be getting rid of more cholesterol, be eating more phytosteriles. Unfortunately, like fiber intake, plant sterile intake is way down in modern diets. We probably evolve getting about 1,000 milligs a day, but these days we may only be getting about 300 milligrams a day, though those eating more plant foods may be getting twice that. Little bits are found throughout the plant kingdom in vegetables, grains, legumes, and fruits. But the highest whole food sources tend to be nuts and seeds. Phytosteriles may help explain the cholesterol-lowering effects of nuts, but nuts are already a part of the portfolio diet. Why add phytosteriles, too? Well, if you look at the x-axis, people may only be getting a few hundred milligrams a day from nuts. It turns out there's a continuous dose response relationship between phytosterile intake and LDL cholesterol lowering. Yeah, going from very few plant foods to lots of plant foods can draw more cholesterol out of the body, but two grams a day can draw out even more and that translates into lower LDL cholesterol in the blood. So, a really healthy diet's worth may drop our LDL by about 6%, but two or three grams a day can drop our LDL more like 10%. And that alone could reduce our risk of heart disease by about 10% over a decade or 20% over a lifetime. That's why we see heart health guidelines recommending the use of phytosteriles as a supplementary strategy alongside lifestyle modifications to decrease blood cholesterol levels. Okay, so phytosteriles are effective, but are they safe? I'll address that next.