Whole grains

O’Neil and colleagues conducted secondary analysis of cross-sectional data from 1999-2004 National Health and Nutrition Examination Survey to examine the association between whole grain intake and overall diet quality and nutrient intake in adults 19-50 years and 51+ years.  For both groups, the study found that those eating the most whole grains had significantly higher amounts of fiber, energy and polyunsaturated fats in their diet. Intake of all micronutrients, except vitamin B-12 and sodium, was also higher among those who consumed the most whole grains. Additionally, added sugars, monounsaturated fats, saturated fats and cholesterol intake was lower in the diets of those who consumed the most whole grains.
Journal of the American Dietetic Association, Oct 2010;110(10):1461-8.

Penny Kris-Etherton and Kristin Harris at Penn State’s Department of Nutrition Sciences, reviewed research on whole grains and coronary heart disease risk in an effort to explain mixed results from one study to another. They concluded that, “due to the varying nutrition compositions of different whole grains, each could potentially affect CHD risk via different mechanisms.” Whole Grains high in soluble fiber tend to decrease LDL cholesterol and improve insulin response, for example, while those high in insoluble fiber may have a prebiotic effect, while lowering glucose and blood pressure. While intervention studies have not proven the observered epidemiological link between whole grains and weight loss, visceral fat loss has been shown. Differences in processing of whole grains may also affect their heart-healthy potential.
Current Atherosclerosis Reports, September 7, 2010 [Epub ahead of print]

Some carbohydrates found especially in whole grains resist digestion and instead are processed by the body through fermentation in the lower colon. This process creates short chain fatty acids (SCFAs) that show an intriguing range of health benefits. Researchers at Lund University in Sweden carried out an intervention study with 5 healthy women and 10 healthy men, offering each of them 8 different cereal-based dinners in random order on separate evenings. In the mornings, all subjects ate identical breakfasts, after which their glucose response and their blood concentration of butyrate, a SCFA, were measured. Whole grain evening meals high in indigestible carbohydrates, such as barley kernels, resulted in higher butyrate concentrations and lower glucose response than refined-grain meals such as white wheat bread. The researchers hypothesize that this may explain why whole grain is protective against type 2 diabetes and cardiovascular disease.
Journal of Nutrition, September 1, 2010 [Epub ahead of print]

Scientists at the National Institutes of Health, Louisiana State, and SUNY Buffalo worked together to follow 259 healthy pre-menopausal women for two years, to see if whole grain consumption lowered levels of C-reactive protein. They found that women who ate even small amounts of whole grains – up to one serving a day – had, on average, 11.5% lower concentration of hs-CRP in their blood. Women eating a full serving (16g of a 100% whole grain food, in this study) or more of whole grain had, on average, 12.3% lower CRP levels. Since earlier research has found that higher CRP levels are associated with adverse reproductive outcomes, the researchers postulate that whole grain consumption has the potential to improve the health of young women of child-bearing age.
Journal of Nutrition. September 2010; 140(9):1669-1676. doi: 10.3945/jn.110.124164

Project EAT (Eating Among Teens)-II revealed that intake of whole grains among adolescents was lower than recommended amounts. The study of 792 adolescents and 1,668 young adults also discovered a correlation between certain factors and whole grain intake. Home availability of whole-grain bread, self-efficacy to consume at least 3 daily servings of whole grains, and preference for the taste of whole-grain bread were associated with eating more whole grains during adolescence and young adulthood, while fast food intake was associated with eating fewer whole grains.
Journal of the American Dietetic Association, Feb 2010;110(2):230-7.

Nicola McKeown and a team of Tufts researchers studied 434 older (age 60 to 80) adults, comparing their diet to their body fat and abdominal fat composition. No significant association was found between body composition and intake of total fiber or vegetable and fruit fiber. Whole grain intake and cereal fiber intake, however, correlated strongly with lower BMI, lower total percent body fat and lower abdominal (“trunk fat”) mass in older adults.
Journal of Nutrition, October 2009; 139(10);1950-1955. DOI:10.3945/jn.108.103762

Increasing attention is being paid to overall dietary patterns and their relationship to health, rather than single nutrients or foods. In one such study of more than 50,000 African-American women, researchers led by Tanya Agurs-Collins of the U.S. National Cancer Institute found that eating a “prudent diet” (high in fruits, vegetables, fish and whole grains) rather than a “Western diet” (more refined grains, processed meats, sweets) cut the risk of breast cancer. The findings were especially strong for thinner, younger women and for certain types of breast cancer.
American Journal of Clinical Nutrition, September 2009; vol 90, No. 3, 621-628. DOI:10.3945/ajcn.2009.27666

Researchers at Brigham and Women’s Hospital and the Harvard Medical School followed 31,784 men in the Health Professionals Follow-up Study for 18 years, and found that about one-third developed hypertension, or high blood pressure. The researchers found that men who ate the most whole grains had a 19% reduced risk of developing high blood pressure. Those with higher bran consumption had a 15% reduced risk of hypertension, leading researchers to conclude that bran may play an important role in the prevention of hypertension.
American Journal of Clinical Nutrition, July 1, 2009. DOI:10.3945/ajcn.2009.27460

In Quebec, a University of Laval team led by André Tchernof, studied 115 post-menopausal women and found that those with markers showing more consumption of plant lignans had, on average, a BMI 4 points lower than women with the lowest levels of the markers. They also had better blood sugar control and lower blood pressure. Lignans are found in whole grains, as well as in fruits and vegetables.
British Journal of Nutrition, July 2009; 102(2):195-200. Online First View February 2009, DOI:10.1017/S0007114508162092

Italy’s National Research Council (CNR) just published a study showing that healthy middle-age adults lowered total cholesterol by 4.3% and LDL (“bad”) cholesterol by 4.9%, by eating whole grains instead of refined grains. The crossover study randomly assigned the 15 subjects to consume either refined or whole grains, in two equal-calorie diets. After three weeks, both groups took a “washout” break for two weeks, then switched diets. Although researchers reported no changes in blood or fat metabolism, hormones associated with insulin levels, compounds linked to immune response, magnesium levels, or CRP (a marker of inflation) with either diet, the subjects’ fasting cholesterol levels definitely improved on the whole grain diet.
Nutrition, Metabolism, and Cardiovascular Disease, online June 9, 2009. DOI:10.1016/j.numecd.2009.03.025