How Fiber Lowers Cholesterol

We’ve covered a bunch of ways nuts may cut heart disease risk—boosting nitric oxide production in our arteries because of the arginine content in nuts; cutting down our risk of sudden cardiac death because of the magnesium content; and lowering the risk of our bad cholesterol because of…why, exactly? How do nuts lower our cholesterol? What are the “potential mechanisms?”

This is where it gets a little complicated. These may be the various nutrients responsible for bad cholesterol reduction. Let me just touch on two—first, fiber; then, phytosterols.

What’s flowing through our intestines right now is going to end up as waste. That’s the default, unless any bits can be absorbed. We can imagine our enterocytes—the cells lining our intestinal wall—as a vast array of trash pickers; resource recovery workers. They’re sifting through the river of potential garbage flowing past, and picking up anything of use—a vitamin here, a mineral there, such that by the end, there really isn’t much left that’s desirable and truly gets dumped.

So, our gut also acts as our body’s disposal system. Anything it wants to get rid of, it throws down the trash chute—like excess cholesterol.

Cholesterol plays a vital role in the body, and that’s why our liver makes as much as we need. But if our liver feels there’s just too much cholesterol circulating around, it dumps the excess into the gut to get rid of it—knowing full well there’ll be an everflowing torrent to flush it out to sea.

We did, after all, evolve for millions of years on a plant-based diet, like our great ape ancestors. And so, we weren’t designed for burgers and milkshakes; we were designed for fiber, and lots of it. A hundred grams a day, or more. A massive, quick-flowing stream.

And so, when our body throws some cholesterol down the trash chute, it knows it’s going to zip right out. But, what if our river dries up—just a slow trickle of sludge, because we’re not eating enough whole plant foods? We still have the same number of trash pickers, but the volume and speed of the flow is way down on a fiber-deficient diet.

So, they’re finding all sorts of stuff that otherwise would have been lost. So, they’re picking back up estrogen that our body dumps; cholesterol; and putting it right back into the system.

It’s like if you litter, and someone comes by and picks it up and says, “Excuse me; did you drop that?” Fiber bulks up the flow, speeds it up, and dilutes everything, so lots of stuff may never even make it to the banks of the intestinal river to be picked up and inappropriately saved.

To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video. This is just an approximation of the audio contributed by Kerry Skinner.

Please consider volunteering to help out on the site.

• Berryman CE, Preston AG, Karmally W, Deckelbaum RJ, Kris-Etherton PM. Effects of almond consumption on the reduction of LDL-cholesterol: a discussion of potential mechanisms and future research directions. Nutr Rev. 2011 Apr;69(4):171-85.
• Jew S, AbuMweis SS, Jones PJ. Evolution of the human diet: linking our ancestral diet to modern functional foods as a means of chronic disease prevention. J Med Food. 2009 Oct;12(5):925-34.

Images thanks to RedAndr via Wikimedia; Cindi Pierce; Renee Comet; National Cancer Institute; and Gastrolab.

• cardiovascular disease
• cholesterol
• fiber
• heart disease
• nuts
• Plant-Based Diets