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October 24, 2008
Cheerios—Clinically Proven to Lower Blood Cholesterol
This slogan has constantly been used to advertise Cheerios, a toasted whole grain oat cereal, as a heart-healthy choice for breakfast. This claim serves to inform consumers about a food choice that can help lower blood cholesterol, a major risk factor for heart disease. According to the National Vital Statistics Report of 2005 for the Center for Disease Control, heart disease is the leading cause of death for American Indians and Alaska Natives, blacks, whites and Hispanics (link 1). However, studies among people with and without heart disease have shown that lowering high blood cholesterol levels can reduce the risk of dying of heart disease and reduce the risk of developing heart disease, respectively.
According to the Cheerios website, Cheerios is the only leading cold cereal that is known to have effects on lowering cholesterol in addition to a low fat diet (link 2). General Mills, the corporation that produces Cheerios, claims state that eating three cups of Cheerios, as part of a diet low in saturated fat, is effective in reducing elevated cholesterol levels. However, many people have begun to question exactly how much of a protective effect do you really see when assessing the results of Cheerios on lowering cholesterol. Should Cheerios really be a necessity in the diets of those who have high cholesterol? Are there other alternatives that may produce more substantial effects?
When addressing this topic, it is first important to define some basic terms used in the literature:
Hypercholesterolemia- condition characterized by extremely high blood cholesterol levels (link 3).
Low-Density Lipoproteins (LDLs)- type of lipoprotein that carries cholesterol in the blood to the body. Also known as the “bad” cholesterol because it can lead to a build up of cholesterol in the arteries and may cause heart disease (link 4).
High-Density Lipoproteins (HDLs)- type of lipoprotein that carries cholesterol away from the blood in to the liver so that it can be excreted from the body. Also know as the “good” cholesterol because it causes a decrease in blood cholesterol levels and can reduce the risk of heart disease (link 4).
Dietary Fiber- parts of plants that cannot be digested, specifically complex carbohydrate. There are two types of dietary fiber: insoluble and soluble (link 5).
Soluble fiber- found in whole grain oats and dissolves to form a gel in your digestive system and then it binds to cholesterol so that it can be excreted from the body (link 6).
Meta-analysis- the statistical procedure of combining data from multiple research studies that are similarly related in order to plan effective methods for further research (link 7).
Beta-glucan- type of cellulose that is the component of soluble fiber in oats. It is the active agent that gives soluble fiber its cholesterol lowering effects (link 8).
Cheerios: The Popular Claim
The Cheerios website states that only certain breakfast cereals can provide the benefits of a soluble fiber, with Cheerios being one of them. Three grams of soluble fiber daily has been proven to substantially lower cholesterol levels; cheerios only contains 1 gram of soluble fiber per cup. Therefore, Cheerios claims that eating three cups of Cheerios cereal daily, in addition to a diet low in saturated fat, will help to reduce elevated blood cholesterol levels. The website offers evidence to support the claim by presenting a clinical study done by Cheerios to test the effects of the cereal on LDL cholesterol levels. The double-blind clinical trial sampled 135 men and women between the ages of 40 and 70, with high cholesterol. First, as a pre-treatment, they were placed on a diet that was low in fat and cholesterol. After this period, participants were randomly placed in treatment and control groups. The treatment group ate a total of 3 ounces of whole grain oat Cheerios per day, which contained 3 grams of soluble fiber, and the control group ate cornflakes that contained no soluble fiber. Results show that the treatment group lowered their cholesterol by 3.8% and their LDL cholesterol levels were lowered by 4.2% compared to the control group. However, the site does not give the source of the clinical study, when it was conducted, or where the information is published. Therefore, consumers should consider that this clinical study may or may not be reliable because there is no verification of publication.
What the experts say
With all the conflicting views on Cheerios and other whole grain cereals containing soluble fiber circulating through the media and the cereal boxes themselves, numerous research projects have been completed to find the true answer to the effects of differing amounts of soluble fiber on lowering cholesterol. While each study used slightly different criteria to asses the effects of different sources of soluble fiber, the benefits of oat products and oat-containing cereals were made evident.
There is uncertainty about the effects of soluble fiber on lowering cholesterol because the range of effects varies greatly. The reason for the variation includes varying dietary control and background diets, small sample sizes, changes in body weight, different dosages of fiber and different types of subjects. Therefore, a meta-analysis of 67 controlled trials was performed in order to quantify the cholesterol-lowering effects of major dietary fibers (Brown et al., 1999). The trials tested the effects of soluble fiber products such as oats, psyllium, pectin, and guar gum. The average dose of 9.5 g soluble fiber was administered over a 49 day treatment period, while 38 studies show subjects who used the subject’s usual diet as the background diet and 29 studies had subjects who whose background diets were low in fat and cholesterol. The diets of the participants before the study is important because soluble fiber is known to be more efficient in lowering cholesterol in addition to a diet low in saturated fat and cholesterol. Furthermore, 85% of the studies used in the meta-analysis the control fiber group that used wheat bran and corn flakes, both low in soluble fiber, and a cellulose-based placebo.
The results of the meta-analysis show that normal doses of soluble fiber from oats, psyllium, pectin, and guar gum each significantly reduced both total and LDL cholesterol. However, none of the soluble fibers had a significant influence on HDL cholesterol. Most importantly, the meta-analysis concluded that the dosage of soluble fiber is very crucial to its effects. The normal range of intake is, for example, 3g soluble fiber from oats, but only decreases the total and LDL cholesterol by 2%. Therefore, the higher intake of soluble fiber, the more of a protective effect it will have in lowering cholesterol levels. However, it is important not to consume too much soluble fiber because side effects such as gas, bloating, and abdominal cramps may result. Diet is also a necessary co-factor in addition to soluble fiber in order to reduce cholesterol. Some of the studies in this meta-analysis reported subjects who were on a diet low in saturated fat and cholesterol and others that continued with their regular diets before the study. Results may have been more stable and even higher if data was recorded for more subjects that were all on a similar diet low in saturated fat and cholesterol.
Furthermore, a study assessed the cholesterol-lowering benefits of oat-containing cereal in Hispanic Americans (Karmally et al., 2005). One-hundred fifty-two Hispanic American women ages 30-70, with low-density LDL cholesterol levels between 120 and 190 mg/dl were included in the study. The participants were placed on a Step 1 diet for five weeks, and then randomly assigned to either a control group of an unbranded corn cereal without soluble fiber or and an experimental group of Cheerios containing beta -glucan. The daily dose of beta-glucan was 3g, the known dosage of soluble fiber needed to produce positive effects. Following testing, the experimental group showed a reduction in LDL and total cholesterol levels, while the control group did not experience an effect on LDL or total cholesterol levels. However, it is noted that both groups were on a low saturated fat Step 1 diet approved by the National Cholesterol Education Program. Therefore, the results of the study “support the FDA-approved health claim that 3g of soluble fiber will lower cholesterol and thus reduce risk of heart disease if consumed with a low-saturated fat, low-cholesterol diet” (Karmally et al., 2005). However, the participants of this study had low-density LDL cholesterol levels. Possibly, the study may have shown more reduction in cholesterol levels if participants with high LDL cholesterol levels were tested instead. Studies show that larger reductions in cholesterol levels are seen in trials in which subjects have an initial high blood cholesterol level (greater than or equal to 229 mg/dl) particularly when a dose of 3g or more of soluble fiber is consumed (Ripsin et al., 1992).
Interestingly, the difference in oat bran and wheat bran products has been the key to the effectiveness of lowering cholesterol levels. Multiple studies have also demonstrated that incorporating oat products into a diet causes a modest reduction in blood cholesterol levels (Ripsin et al., 1992). One such study tests the effects of oat bran and wheat bran on plasma cholesterol concentrations by randomly assigning twenty-three men with mild hypercholesterolemia to either an oat bran or wheat bran cereal diet (Whyte et al., 1992). The study determined that 12 g of oat bran fiber per day lowered plasma cholesterol levels 6% more than 12 g of wheat bran fiber, which contained less soluble fiber. Since men with extremely high cholesterol levels would help to detect major decreases in blood cholesterol, the efficacy of this study may be valid. However, only twenty-three men were tested, which is not a very large sample size. Furthermore, participant’s diets were identical with respect to average consumption of total fat and saturated fat. Therefore, this factor excluded the absence of fat as an explanation for lower cholesterol levels by oat bran. Conclusively, oat bran lowered blood cholesterol levels even in the presence of saturated fat in the diet simply because it contains a greater amount of soluble fiber than other oat products.
Oat Bran or Whole Grain Oats…What’s the difference?
Cheerios are made from whole grain oats, which include all three parts of the grain kernel: the fiber-rich bran, the starchy endosperm, and the nutrient-filled germ. On the other hand, oat bran consists of only the bran portion of the grain seed, which contains B vitamins, trace minerals, and the most fiber out of all three layers (link 10). Fiber content of whole grains varies—many high fiber foods, such as bran cereals, are not whole grain, while some whole grain foods may not be rich in fiber (link 11). Therefore, oat bran is guaranteed to have higher soluble fiber content than whole grains because it contains the one part of the grain kernel that contains the most fiber. According to an article, the consumption of an adequate amount of soluble fiber may reduce cholesterol levels by 10 to 20 percent (Nuovo, 1989).
Consumers don’t be fooled!
Soluble fiber plays a major role in lowering high cholesterol. Specifically, Cheerios a leading brand of cereal has had minimal effects on lowering blood cholesterol levels. The recommended intake of 3g of soluble fiber or more can substantially lower blood cholesterol if consumed in addition to a diet low in saturated fat and cholesterol. Therefore, Cheerios recommends that eating 1-1/2 cups twice a day or roughly 3 cups of Cheerios per day Cheerios will lower blood cholesterol because the cereal only contains 1g of soluble fiber per cup. This means that consumers would have to eat 3 bowls of Cheerios per day in order to obtain its positive effects of soluble fiber. However, while adding fiber to their diet, consumers would also be adding sugar and three times as many calories. Thus, eating 3 cups of Cheerios in order to achieve the recommended 3g of soluble fiber is not a practical approach. Therefore, Cheerios does not realistically produce the substantial benefits of lowering cholesterol as advertised by General Mills.
Moreover, since the dosage of soluble fiber is critical to its protective effects, consumers should consider other products that contain a more concentrated soluble fiber content such as oat bran (6.3g soluble fiber per 100g) and oatmeal (5.1g soluble fiber per 100g). The daily recommended intake of dietary fiber recommends 14g of soluble fiber per 1,000 calories, which is roughly 28g for a 2,000 calorie diet (link 12). Most importantly, consumers should make sure not to add butter, sugar, and other condiments that may add extra calories and fat if they are simply seeking the benefits of the high fiber content in these foods. Additionally, consumers must remember that in addition to a diet high in soluble fiber, they must consume food low in saturated fat and cholesterol. Conclusively, for the most beneficial results choose oatmeal or oat bran over Cheerios, because they have more of a protective effect in lowering high cholesterol and therefore, Cheerios is not the only key to a heart-healthy breakfast.
Anderson, J.W., Spencer, D.B., Hamilton, C.C., Smith S.F. et al. (1990). Oat-bran cereal lowers serum total and LDL cholesterol in hypercholesterolemic men. American Journal of Clinical Nutrition, 52(3), 495-499.
Brown, L., Rosner, B., Willet, W.W., Sacks, F. (1999). Cholesterol-lowering effects of dietary fiber: a meta-analysis. American Journal of Clinical Nutrition, 69, 30-42.
Karmally, W., Montez, M., Palmas, W., Martinez, W., Bransetter, A. et al. (2005). Cholesterol-Lowering Benefits of Oat-Containing Cereal in Hispanic Americans. Journal of the American Dietetic Association, 105, 967-970.
Nuovo, J. (1989). Use of dietary fiber to lower cholesterol. American Family Physician, 39(4), 137-140.
Poulter, N., Chang, C.L., Cuff, A., Poulter, C. et al. (1993). Lipid profiles after the daily consumption of an oat-based cereal: a controlled crossover trial. American Journal of Clinical Nutrition, 58, 66-69.
Ripsin, C.M., Keenan, J.M., Jacobs, D.R., Jr., Elmer, P.J. et al. (1992). Oat products and lipid lowering. A meta-analysis. Journal of the American Medical Association, 267(24), 3317-3325.
Whyte, J.L., McArthur, R., Topping, D., Nestel, P. (1992). Oat bran lowers plasma cholesterol levels in mildly hypercholesterolemic men. Journal of the American Dietetic Association, 92(4), 446-449.
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