We all know that high levels of LDL (bad) cholesterol in our blood is a bad thing. But did you know that our bodies actually need cholesterol to function?
When we eat, the liver and gallbladder squeeze bile into the intestine to help digest food. It turns out that bile contains a lot of cholesterol. In fact, one of the ways our body uses LDL cholesterol is to make bile. Because our systems are very efficient, any leftover bile from the digestive process gets reabsorbed into the blood stream increasing our levels of LDL cholesterol.
That means a good way to lower LDL cholesterol levels in our blood is to prevent cholesterol in unused bile from being reabsorbed.
The original cholesterol-lowering medications worked by leveraging this internal cholesterol circulation. They were called bile acid resins or bile acid sequestrants and they trapped unused bile inside the gut so that you would eventually excrete it out. These resins worked pretty well, but were unpopular because they were messy to use, had to be taken with meals, and often caused intestinal upset. When statins came along, these medications all but disappeared from use.
Dietary fiber diet acts a bit like those resins. We can’t digest fiber so when a bile molecule attaches itself to a fiber molecule, it will try to digest it, try to digest it, try to digest it, and eventually drift past the point where it can be reabsorbed into the blood stream. The bile molecule needs to be replaced and more LDL cholesterol goes back to the liver, causing blood cholesterol levels to drop.
To get the most out of this effect, you have to consume your fiber WITH food.