By Jennifer Copley (Last Updated 24 October 2009)
Whole grain breakfast cereals, breads, pastas, and other products aid weight loss and protect against many diseases, including cancer, diabetes, and heart disease.
Whole grains are unrefined grains in which the germ (plant embryo), bran (protective covering), and endosperm (food for the growing seedling) are preserved. Whole grains include whole wheat, brown rice, maize, oats, rye, triticale, sorghum, barley, and millet.
Beneficial ingredients in whole grains include lignans (a phytoestrogen), dietary fiber, and antioxidants. On a per-serving basis, whole-grain products have similar antioxidant activity to that of vegetables and fruits (Slavin, 2004).
Whole Grains and Cancer
Mounting evidence suggests that the phytoestrogens, antioxidants, fiber, and other ingredients found in whole grains reduce the risk for a variety of cancers, particularly of the thyroid, mouth, throat, upper digestive tract, stomach, uterus, prostate, ovaries, colon, and rectum. A meta-analysis of 40 studies of various cancers found that those who ate diets rich in whole grains reduced their risk of cancer by 34% compared to those who consumed lower amounts of whole grains (Linus Pauling Institute, 2009).
Concerns have been expressed regarding phytoestrogens and breast cancer risk. However, a review of the evidence suggests that phytoestrogens, at the levels consumed via whole foods, are unlikely to increase the risk of breast cancer. As for the ability of phytoestrogens to protect against breast cancer, the evidence thus far is inconclusive, and more research is required (Rajasree & Raghesh, 2009).
Whole Grains and Diabetes
Whole grains (particularly oats), lower overall blood glucose levels and thus have a protective effect against diabetes. Several studies, including the Nurses’ Health Study, the Health Professionals Follow-Up Study, and the Iowa Women’s Health Study, have found that consuming three or more servings of whole grains each day reduces the risk of developing diabetes by 20% to 30% over consumption of just one serving per week (Rajasree & Raghesh, 2009).
Whole Grains and Heart Disease
Numerous large-scale studies have found that consumption of whole-grain, high-fiber foods significantly reduces the risk for cardiovascular disease and ischemic stroke, regardless of age, weight, smoking, exercise rate, alcohol intake, and other factors.
Whole Grains and Weight Loss
In the Nurses’ Health Study, which included more than 200,000 people, those consuming whole grains regularly weighed less on average, and those with the highest rates of dietary fiber intake lowered their risk of major weight gain by 49% over those in the lowest group (Slavin, 2004).
Whole wheat has the fewest calories per 100 grams among the whole grains, while barley is the highest in fiber, so these are particularly good choices for those who wish to lose weight.
Whole Grains and Reduced Overall Mortality
Various large-scale studies have found an overall reduction in mortality with regular whole grain consumption. For example, the Iowa Women’s Health Study of 11,040 postmenopausal women found that those who regularly consumed whole grains had a 17% reduction in overall mortality compared to consumers of refined grains (Rajasree & Raghesh, 2009).
Additional Health Benefits of Whole Grains
The germ and bran of whole grains are rich in zinc, which helps to maintain healthy skin and aids in the healing of wounds. Zinc boosts immune function and can reduce the risk of inflammation in the joints and arteries, as well as helping to maintain healthy bones. In addition, zinc reduces the risk of infertility and impotence in men.
Riboflavin, also abundant in whole grains, protects against cataracts, migraines, depression, and anemia. Low levels of this vitamin are associated with carpal tunnel syndrome, rheumatoid arthritis, multiple sclerosis, and Crohn’s disease. Whole grains are also rich in pantothenic acid, a natural stress reducer, and fiber, which reduces the likelihood of suffering from constipation, hemorrhoids, or gallstones.
Omega 3 fatty acids in whole grains help to prevent depression, arthritis, and cardiovascular disease. In addition, some evidence suggests that a diet rich in whole grains may improve memory and cognition and protect against osteoporosis.
Whole Grain Serving Sizes
Adults in Western countries tend to have just one serving or fewer of whole grains per day, and children and teens even less, but the Dietary Guideline recommendation for whole grains is three servings each day. Examples of single whole grain servings include:
- Brown rice, cooked – ½ cup
- Muffin, whole grain or whole wheat – 1 small
- Oatmeal, cooked – ½ cup (one packet instant)
- Popcorn, popped – 3 cups
- Tortillas, whole wheat or corn – 1 small (6-inch)
- Whole grain bread – 1 slice
- Whole grain cereal, ready-to-eat – 1 ounce (1 cup flaked cereal or 1¼ cups puffed)
- Whole wheat crackers – 5-6
- Whole wheat pancakes – 1 small (4½-inch)
- Whole wheat pasta, cooked – ½ cup
Many products labelled as whole grain are made up predominantly of refined grains with some whole grains added. To ensure that the product really is whole grain, check that:
- Whole grain or whole wheat flour appears first on the ingredients list.
- There are at least two grams of fiber in each serving.
If a product displays the health claim: “Diets rich in whole grain foods and other plant foods and low in total fat, saturated fat, and cholesterol may help reduce the risk of heart disease and certain cancers,” its content must be 51% whole grain or more.
- Anderson, J.W., & Hanna, T.J. (1999). “Whole Grains and Protection Against Coronary Heart Disease: What Are the Active Components and Mechanisms?” American Journal of Clinical Nutrition, 70(3). AJCN.org.
- Linus Pauling Institute. (31 August 2009). “Whole Grains.” Oregon State University, LPIOregonState.edu.
- Rajasree Pai, R., & Raghesh, V. (2009). “Health Benefits Of Whole Grains: A Literature Review.” The
- Internet Journal of Nutrition and Wellness, 4(2). Internet Scientific Publications, ISPUB.com.
- ScienceDaily.com. (11 February 2008). “Whole Grain Diets Lower Risk of Chronic Disease, Study Shows.”
- Slavin, J. (2004). “Whole Grains and Human Health.” Nutrition Research Reviews, 17. WholeGrainsCouncil.org.
- Tham, D.M., Gardner, C.D., & Haskell, W.L. (1998). “Potential Health Benefits of Dietary Phytoestrogens: A Review of the Clinical, Epidemiological, and Mechanistic Evidence.” The Journal of Clinical Endocrinology & Metabolism, 83(7). JCEM.Endojournals.org.