Note: The health benefits and concerns discussed here are not necessarily associated with all types of cereal; there is considerable variety among different products in terms of their content (e.g. presence or absence of wheat, addition of certain beneficial fibers, etc.).

Atherosclerosis

Regular consumption of whole-grain foods is associated with a coronary heart disease risk reduction of about 26 percent. In general, soluble fiber, such as that found in oats, is most often linked to reductions in cholesterol levels. For unknown reasons, however, diets higher in insoluble fiber, which is found in whole grains and vegetables and is mostly unrelated to cholesterol levels, have been reported to correlate better with protection against heart disease in both men and women. Some trials have used 20 grams of additional dietary fiber per day for several months to successfully lower cholesterol.

Athletic performance

Carbohydrates are the most efficient fuel for energy production, and can be stored as glycogen in muscle and liver, where they function as a readily available energy source during prolonged, strenuous exercise. For these reasons, carbohydrates may be the most important nutrient for sports performance. Depending on training intensity and duration, athletes require up to 4.5 grams of carbohydrates per day per pound of body weight, or 60 to 70 percent of total dietary calories from carbohydrates, whichever is greater. Grains are an important part of a high complex-carbohydrate diet.

Cancer prevention and diet

Whole grains (such as rye, brown rice, and whole wheat) contain high amounts of insoluble fiber—the type of fiber some scientists believe may help protect against a variety of cancers. In an analysis of the data from many studies, people who eat relatively high amounts of whole grains were reported to have low risks of lymphomas and cancers of the pancreas, stomach, colon, rectum, breast, uterus, mouth, throat, liver, and thyroid. Most research focusing on the relationship between cancer and fiber has focused on breast and colon cancers.

Consuming a diet high in insoluble fiber is best achieved by switching from white rice to brown rice and from bakery goods made with white flour or mixed flours to 100%-whole-wheat bread, whole-rye crackers, and whole-grain pancake mixes. Refined white flour is generally listed on food packaging labels as “flour,” ”enriched flour,” ”unbleached flour,” ”durum wheat,” ”semolina,” or “white flour.” Breads containing only whole wheat are often labeled “100% whole wheat.”

Constipation

Fiber, particularly insoluble fiber, is linked with prevention of chronic constipation. Insoluble fiber comes mostly from vegetables, beans, brown rice, whole wheat, rye, and other whole grains. Switching from white bread and white rice to whole wheat bread and brown rice often helps to relieve constipation. It is important to drink lots of fluid along with the fiber—at least 16 ounces (474 ml) of water per serving of fiber. Otherwise, the fiber can act as a “dry sponge” in the system, and worsen the constipation.

In addition, wheat bran can be added to the diet. Doctors frequently suggest a quarter cup or more per day of wheat bran, along with fluid. An easy way to add wheat bran to the diet is to add it to breakfast cereal or to switch to high-bran cereals. Wheat bran often helps to reduce constipation, although not all research shows it to be successful. Higher amounts of wheat bran are sometimes more successful.

Dermatitis herpetiformis (DH)

The cause of DH is mainly an allergic-type reaction (called hypersensitivity) to foods containing gluten. Wheat, barley, and rye all contain gluten. People with DH usually have abnormalities of the intestinal lining identical to that of celiac disease (also called gluten-sensitive enteropathy or celiac sprue), an intestinal disorder also due to gluten sensitivity. Unlike celiac disease however, gastrointestinal symptoms may be mild or absent in DH.

Diabetes

A review of the research revealed that the extent to which dietary fiber helps people with diabetes in the long term is still unknown, and the lack of many long-term studies has led some researchers to question the importance of fiber in improving diabetes. Nevertheless, most doctors advise people with diabetes to eat a diet high in fiber. Focus should be placed on fruits, vegetables, seeds, oats, and whole-grain products.

Heart attack

A high-fiber diet, particularly soluble fiber (high in oats, psyllium seeds, fruits, vegetables, and legumes), is associated with decreased risk of both fatal and nonfatal heart attacks, probably because these fibers are known to lower cholesterol. However, large trials separately studying men and women who were followed for years have linked the greatest protection to insoluble fiber (from whole grains, breads, and cereals), though scientists have yet to understand why. Until the details are better understood, doctors often recommend increasing intake of fruits, vegetables, beans, oats, and whole grains.

Hemorrhoids

Countries in which fiber intake is high have a very low incidence of hemorrhoids. Insoluble fiber—the kind found primarily in whole grains—increases the bulk of stool. Drinking water with a high-fiber meal or a fiber supplement results in softer, bulkier stool, which can move more easily.

High homocysteine

Folic acid supplementation lowers homocysteine levels. In 1996, the FDA required that all enriched flour, rice, pasta, cornmeal, and other grain products contain 140 mcg of folic acid per 3 1/2 ounces (100 grams). This level of fortification has led to a measurable decrease in homocysteine levels. However, even higher levels of food fortification with folic acid have been reported to be more effective in lowering homocysteine, suggesting that the FDA-mandated supplementation is inadequate to optimally protect people against high homocysteine levels. Therefore, people wishing to lower their homocysteine levels should consider taking folic acid supplements despite the FDA-mandated fortification program.

Hypoglycemia

Doctors find that people with hypoglycemia usually improve when they eliminate refined sugars and alcohol from their diet, eat foods high in fiber (such as whole grains), and consume small, frequent meals. Few studies have investigated the effects of these changes, but the research that is available generally supports the observations of doctors. Some symptoms of low blood sugar may be related to, or made worse by, food allergies.

Multiple sclerosis (MS)

Some people with MS avoid gluten (a protein found in wheat, rye, and barley) in hopes of diminishing symptoms because a preliminary study reported that consumption of grains (bread and pasta) was linked to development of MS. However, another trial found that people who ate more cereals and breads had reduced MS risk compared to those who ate fewer of these foods. Other researchers have found that gluten sensitivity is no more common among people with MS than among healthy people. Therefore, the idea that avoiding gluten will help MS remains speculative.

Schizophrenia

For many years there has been speculation that certain dietary proteins may contribute to the symptoms of schizophrenia. Gluten, a protein found in wheat, rye, and barley, has been a target of research on food sensitivities as contributors to schizophrenia. Patients with schizophrenia have been shown to be more likely to have immune-system reactions to these proteins than the general population. In an uncontrolled trial of a gluten-free/dairy-free diet, patients with schizophrenia improved and had shorter hospital stays than those eating normal diets. The results of double-blind trials, however, have been inconsistent. Some, but not all, people with schizophrenia may benefit from a gluten-free/dairy-free diet.

Stroke

A large study found that women who eat higher amounts of whole grains are at lower risk of one type of stroke. Those women who ate more than one whole-grain food on an average day (twice the amount of fiber eaten by the average American) had an approximately 35 percent lower risk of suffering an ischemic stroke (one caused by blockage of blood vessels to the brain) compared with women who ate virtually no whole-grain products on an average day. Which aspects of whole grains are responsible for the lowered risk is unknown. One possibility is the high concentration of nutrients in grains that have been found to be protective against stroke and/or heart disease, but other ingredients may be responsible as well. This study fits with previous research showing that women who consume more whole grains are also at reduced risk for heart disease caused by atherosclerosis.