By Daniel G. Graetzer, Ph.D.
Faculty Member, School of Health Sciences
The cholesterol-lowering effects of oats were first discovered in the early 1960s when researchers discovered that adding high-fiber oat bran to a low-fat diet reduced the body’s total cholesterol and low-density lipoprotein cholesterol (LDL-C). High total cholesterol is a primary risk factor for coronary artery disease (atherosclerosis). In fact, it kills at least one in five Americans, according to 2020 American Heart Association statistics.
LDL-C (the “bad” cholesterol) serves to transport cholesterol and triglycerides from the liver and intestines to the arteries. Over time, these arteries become caked with excess cholesterol and plaque, restricting blood circulation. If a blood clot becomes lodged in a cholesterol-clogged artery leading to the heart or brain (embolism), a heart attack or stroke is the result.
The History Behind Including Oat Bran in Our Diets
Research into cardiovascular disease in young adults in the late 1960s and early ‘70s stunned the medical community. Several landmark articles revealed a high incidence of advanced atherosclerosis in wartime casualties killed in Korea and Vietnam. Upon autopsy, a buildup of cholesterol in coronary arteries was evident in 77% of active and otherwise healthy U.S. soldiers, whose average age was 22 years.
These statistics quickly sent American beef companies into a state of panic. By 1989, the sales of low-fat and oat-based products skyrocketed to over $100 million annually. Promotion of oat bran promotion began to slow in the 1990s when studies showed that adding cream of wheat (a low-fat fiber) lowered cholesterol about as well as adding oatmeal (a high-fiber cereal) to one’s diet.
It was also further established through a study that a high-fiber diet on its own probably does not control cholesterol as much as previously thought. Ideally, some high-fiber foods should be incorporated into a low-fat diet.
The Typical American Diet
The typical American diet contains approximately 40% total fat, 15% to 20% of which is saturated fat, and a cholesterol intake of 350 to 450 milligrams (mg) per day. The American Heart Association recommends that total fat intake be less than 30% of total calories, 10% or less of which should be saturated fat, and cholesterol intake should not exceed 100 mg/1,000 calories or 300 mg/day. Meeting these AHA guidelines would require a 30% to 50% reduction in cholesterol and saturated fat in the average American diet.
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Is Oat Bran Still Worth Consuming?
So is oat bran still worth eating? Yes, but it is certainly not the only form of fiber we should consume as a part of our daily diet.
Two types of fiber (non-soluble and soluble) should be eaten daily. Both types of fiber hold water, but in different ways.
Non-soluble fiber (also called bulking fiber) is found mostly in whole-grain products. Whole-grain foods can be easily identified by looking for the yellow and black Whole Grain Stamp on a food’s packaging.
This type of fiber absorbs water in your stomach during digestion (making you feel full sooner) and binds carcinogens (cancer-causing agents), reducing cancer formation in the colon.
Soluble fiber (also called gel-forming fiber) is found in fruits, vegetables, beans and legumes. It is also found in psyllium-fiber solutions (such as Metamucil®) and grains such as barley, corn, oat, and rice. In the stomach, these fibers absorb water and form a gel (similar to a jelly). They hold onto cholesterol and fat, decreasing their absorption into the bloodstream and increasing their excretion from the body.
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Pay Careful Attention to the Amount of Fiber You Eat
The only bad news about eating fiber is that soluble fiber increases fermentation in the stomach, causing gas. Some research suggests that adding 15 to 45 grams of soluble fiber per day to one’s diet can reduce cholesterol up to 19%, but this amount can be uncomfortable for many people, especially for those on a reduced-calorie diet. An easier way to reduce one’s cholesterol is to add 20 to 35 grams of total fiber per day, using 6 to 10.5 grams of soluble fiber.
Oat bran is certainly not the only food rich in fiber. Adding a variety of foods to your daily diet not only prevents boredom, but also provides you with healthy vitamins and minerals. If you want to lose weight but have trouble reducing how much you eat, adding both non-soluble and soluble fiber to your diet will reduce your fat intake and make you feel fuller following a meal.
Start off slow when you’re adding fiber to your diet, spread your fiber consumption throughout the day and drink plenty of water.
Interested in learning more about nutrition and health? The School of Health Sciences offers several online programs with nutrition courses, including:
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