Do you remember back when you were a child and your mother would nag you constantly to, “Eat your oatmeal! It’s good for you. And don’t forget the apple as well!” Of course you do. It seems that every mother is given a handbook at the hospital on how to make their child eat food that more closely resembles warm cat food than anything “healthy. In fact, I’m not even sure my cat would eat the oatmeal when I was little. But, as with just about everything else in life, in the end mom’s advice turned out to be right.
It may not have much going for it in the taste department, but it turns out that oatmeal can have a significant effect on lowering cholesterol. But what’s in the oatmeal that causes it to lower cholesterol? In a word: Fiber.
Intake of an adequate amount of water soluble fiber, which is found in oatmeal, may lower cholesterol by as much as 20%. This is very good news for oatmeal lovers since oat fiber is one of the most common water soluble fiber food substances. It is important to note that only water soluble fibers such as pectins, gums and mucilages have any beneficial effect upon cholesterol. Non water soluble fibers such as cellulose and lignin have virtually no effect upon cholesterol.
Eating the correct type of water soluble fibers is a very important point to make. It is not enough to simply eat a “high fiber” diet unless you take great care to ensure that the specific types of fiber you are eating have the ability to reduce LDL or “bad” cholesterol.
Some of the most promising studies looking at the cholesterol lowering properties of fiber have been done on beans and oats. Oat bran, which is a very good source of water soluble fiber contains about twice as much fiber as rolled oats in the form of oatmeal (don’t tell mom, she was only partly right). Studies have shown that a 28 day treatment with oat bran can lower total cholesterol by about 5% and lower LDL, or “bad” cholesterol, by almost 9%. In another trial, men were paced on either 100g of oat bran or 115g of pinto or navy beans each day. At the end of 3 weeks an average reduction of total cholesterol was 19%. LDL was lowered by 23% in the oat bran group and 24% in the bean group.
The mechanism by which soluble fiber reduces LDL cholesterol is similar to the action of bile acid-binding resins, which are a type of medication used to control cholesterol levels. The fiber you consume binds to bile acids and inhibits the formation of micelles. Micelles are tiny chemical complexes needed for the absorption of cholesterol and other fats in the gut. If the micelles cannot form, your body cannot absorb cholesterol and fat when you eat it. Bile acids themselves are also prevented from being reabsorbed. This prevention of bile acid resorption disrupts the pool of bile acids that are available to the body. This triggers another mechanism in the liver which causes the conversion of cholesterol into new bile salt acids, thus lowering cholesterol in the blood.
The real difficulty is that people often tire of eating the same food substances daily. Let’s face it, even doused in honey, eating oatmeal and oat bran is quite literally as exciting as eating dry toast. Psyllium fiber, marketed as Metamucil or Fiberall can help. It is also a water soluble fiber with some of the same cholesterol lowering properties. It comes in granular, wafer or compressed tablet form. It is probably more reasonable for people to consume a varied combination of soluble fibers, beans, oat bran and psyllium. This certainly can enhance success in producing a reduction in cholesterol by dietary intervention. And when your mom calls to ask if you’re eating well, you can honestly say “YES!”
