Choose whole grains instead of refined
Whole grains offer a “complete package” of health benefits, unlike refined grains, which are stripped of valuable nutrients in the refining process.
- Whole grains contain bran and fiber, which slow the breakdown of starch into glucose –thus maintaining a steady blood sugar rather than causing sharp spikes.
- Fiber helps lower cholesterol as well as move waste through the digestive tract.
- Fiber may also help prevent the formation of small blood clots that can trigger heart attacks or strokes.
- Phytoestrogens (plant estrogens) and essential minerals such as magnesium, selenium and copper found in whole grains may protect against some cancers.
The invention of industrialized roller mills in the late 19th century changed the way we process grains. Milling strips away the bran and germ, making the grain easier to chew and digest, but such highly processed grains are much lower in nutritional quality. Refining wheat creates fluffy flour that makes light, airy breads and pastries, but the process strips away more than half of wheat’s B vitamins, 90 percent of the vitamin E, and virtually all of the fiber.
A growing body of research shows that choosing whole grains and other less-processed, higher-quality sources of carbohydrates, and cutting back on refined grains, improves health in many ways.
For a closer look at carbohydrates, check out our Carbohydrate Guide.
Be careful when choosing whole grains: “Whole grain” doesn’t always mean healthy.
One study revealed that inconsistent food labeling means that foods identified as “whole grain” are not always healthy.
- The study assessed five USDA guidelines that appear on labels of whole grain foods: any whole grain as the first ingredient, any whole grain as the first ingredient without added sugars in the first three ingredients, the word “whole” before any grain ingredient, a carbohydrate to fiber ratio of less than 10:1, and the Whole Grain Stamp.
- The Whole Grain Stamp is a widely used marker on food products. The stamp, while designed to steer consumers towards healthy whole grains, actually identified products that were low in trans fats but higher in sugar and calories than whole grain foods without the stamp.
- The other three USDA guidelines had mixed results in identifying healthier whole grain products, but the carbohydrate to fiber ratio of less than 10:1 proved to be the most effective measure of healthfulness. Foods that met this criterion were low in trans fats, sodium, sugar, and calories.
Because calculating the carbohydrate to fiber ratio may be difficult and not readily available for a consumer reading a label, the study suggests that labeling guidelines appearing on whole grains foods should be improved. Consumers should steer towards whole grain breads that are high in fiber and that have few ingredients in addition to whole grain. In addition, eating whole grains in their whole forms, such as brown rice, barley, oats, corn, and rye are healthy choices because they pack in the nutritional benefits of whole grains without any additional ingredients.
Whole Grains and disease
As researchers have begun to look more closely at carbohydrates and health, they are learning that the quality of the carbohydrates you eat is at least as important as the quantity. Most studies, including some from several different Harvard teams, show a connection between whole grains and better health.
- An intriguing report from the Iowa Women’s Health Study linked whole-grain consumption with fewer deaths from non-cardiac, non-cancer causes. Compared with women who rarely or never ate whole-grain foods, those who had at least two or more servings a day were 30 percent less likely to have died from an inflammation-related condition over a 17-year period. (1)
Eating whole instead of refined grains substantially lowers total cholesterol, low-density lipoprotein (LDL, or bad) cholesterol, triglycerides, and insulin levels.
- In the Harvard-based Nurses’ Health Study, women who ate 2 to 3 servings of whole-grain products each day were 30 percent less likely to have a heart attack or die from heart disease over a 10-year period than women who ate less than 1 serving per week. (2)
- A recent meta-analysis of seven major studies showed that cardiovascular disease (heart attack, stroke, or the need for a procedure to bypass or open a clogged artery) was 21 percent less likely in people who ate 2.5 or more servings of whole-grain foods a day compared with those who ate less than 2 servings a week. (3)
Type 2 Diabetes
- In a study of more than 160,000 women whose health and dietary habits were followed for up to 18 years, those who averaged 2 to 3 servings of whole grains a day were 30 percent less likely to have developed type 2 diabetes than those who rarely ate whole grains. (4)When the researchers combined these results with those of several other large studies, they found that eating an extra 2 servings of whole grains a day decreased the risk of type 2 diabetes by 21 percent.
More recent findings from this study (the Nurses’ Health Studies I and II) and the Health Professionals Follow-Up Study suggest that swapping white rice for whole grains could help lower diabetes risk:
- Researchers found that women and men who ate the most white rice—five or more servings a week—had a 17 percent higher risk of diabetes than those who ate white rice less than one time a month. Those who ate the most brown rice—two or more servings a week—had an 11 percent lower risk of diabetes than those who rarely ate brown rice. Researchers estimate that swapping whole grains in place of even some white rice could lower diabetes risk by 36 percent. (5)
The data on cancer are mixed, with some studies showing a protective effect and others showing none. (6)
- A large, five-year study among nearly 500,000 men and women suggests that eating whole grains, but not dietary fiber, offers modest protection against colorectal cancer. (7,8)
By keeping the stool soft and bulky, the fiber in whole grains helps prevent constipation, a common, costly, and aggravating problem. It also helps prevent diverticular disease (diverticulosis) by decreasing pressure in the intestines.
1. Jacobs DR, Jr., Andersen LF, Blomhoff R. Whole-grain consumption is associated with a reduced risk of noncardiovascular, noncancer death attributed to inflammatory diseases in the Iowa Women’s Health Study. Am J Clin Nutr. 2007;85:1606-14.
2. Liu S, Stampfer MJ, Hu FB, et al. Whole-grain consumption and risk of coronary heart disease: results from the Nurses’ Health Study. Am J Clin Nutr. 1999;70:412-9.
3. Mellen PB, Walsh TF, Herrington DM. Whole grain intake and cardiovascular disease: a meta-analysis. Nutr Metab Cardiovasc Dis. 2008;18:283-90.
4. de Munter JS, Hu FB, Spiegelman D, Franz M, van Dam RM. Whole grain, bran, and germ intake and risk of type 2 diabetes: a prospective cohort study and systematic review. PLoS Med. 2007;4:e261.
5. Sun Q, Spiegelman D, van Dam RM, et al. White rice, brown rice, and risk of type 2 diabetes in US men and women. Arch Intern Med. 2010;170:961-9.
6. Jacobs DR, Jr., Marquart L, Slavin J, Kushi LH. Whole-grain intake and cancer: an expanded review and meta-analysis. Nutr Cancer. 1998;30:85-96.
7. Schatzkin A, Mouw T, Park Y, et al. Dietary fiber and whole-grain consumption in relation to colorectal cancer in the NIH-AARP Diet and Health Study. Am J Clin Nutr. 2007;85:1353-60.
8. Strayer L, Jacobs DR, Jr., Schairer C, Schatzkin A, Flood A. Dietary carbohydrate, glycemic index, and glycemic load and the risk of colorectal cancer in the BCDDP cohort. Cancer Causes Control. 2007;18:853-63.
The aim of the Harvard School of Public Health Nutrition Source is to provide timely information on diet and nutrition for clinicians, allied health professionals, and the public. The contents of this Web site are not intended to offer personal medical advice. You should seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this Web site. The information does not mention brand names, nor does it endorse any particular products.