Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.
The Dietary Guidelines cite the National Academies in recommending that “dietary cholesterol consumption to 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 100 grams of fiber in there to trap it and flush it out of our body…but when people are getting 5 to 10 times less fiber than nature intended, much of that cholesterol gets reabsorbed and can circulate back through our system. That’s 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 it also includes phytosterols, plant sterols.
This is what cholesterol looks like. This is what one of the phytosterols looks like. It’s almost identical. And the receptor here in the lining of our intestine can’t tell the difference; so, the phytosterols compete with cholesterol to squeeze through this receptor. So, if there’s a lot of phytosterols in the gut, some of the cholesterol can’t get through and ends up in the toilet instead of our bloodstream.
Here’s fecal cholesterol excretion in people eating different amounts of phytosterols. 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 phytosterol consumption, more and more cholesterol is being flushed out of the body. Note that even if you eat a strictly plant-based diet without any dietary cholesterol, you’d still be getting rid of more cholesterol by eating more phytosterols.
Unfortunately, like fiber intake, plant sterol intake is way down in modern diets. We probably evolved getting about a thousand milligrams a day. But these days we may only be getting about 300 mg/day, though those who eat more plant foods may get 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. Phytosterols may help explain the cholesterol-lowering effects of nuts. But nuts are already a part of the Portfolio Diet; why not phytosterols 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 phytosterol intake and LDL-cholesterol lowering. Yeah, going from very few plant foods to lots of plant foods can draw more cholesterol out of our body, but 2 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 2 or 3 grams a day can drop LDL by 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 phytosterols as a supplementary strategy alongside lifestyle modifications to decrease blood cholesterol levels.
We know phytosterols are effective, but are they safe? I’ll address that, next.
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