ARS | Publication request: Whole grain and fiber consumption are associated with lower body weight measures in US adults: National Health and Nutrition Examination Survey 1999-2004

Submitted to: Nutrition Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 26, 2010
Publication Date: December 10, 2010
Citation: O'Neil, C.E., Zanovec, M., Cho, S., Nicklas, T.A. 2010. Whole grain and fiber consumption are associated with lower body weight measures in US adults: National Health and Nutrition Examination Survey 1999-2004. Nutrition Research. 30:815-822.

Interpretive Summary: Studies of intake of whole grains and their potential health benefits have been complicated by lack of a standard definition and understanding by consumers of what constitutes a whole grain. Since different studies have used different definitions, it has been difficult to interpret and compare results. Consumption of three or more servings of whole grains in adults was inversely associated with weight; however, this association was attenuated by cereal fiber. Data from this study using the current definition of whole grains (excluding bran) were used to examine and compare associations of body weight measures with and without adjustment for cereal fiber. Overall consumption of whole grains was low. Nutrition education programs that increase awareness, health benefits, and consumption of whole grains should be designed. More studies are needed to separate the independent effects of whole grain and fiber on health. Data from this study suggests that cereal fiber is an important component of whole grains and may be more important on body weight measures than whole grain alone. Data from this study suggests that cereal fiber is an important component of whole grains and may be more important on body weight measures than whole grain alone.

Technical Abstract: This study examined the association of whole grain consumption with body weight measures and prevalence of overweight/obesity in a recent, nationally representative sample of adults. A secondary analysis of 1999-2004 National Health and Nutrition Examination Survey (NHANES) data was conducted using adults 19 to 50 years of age (y) (n equal to 7,039) and 51+ y (n equal to 6,237). Participants were categorized by whole grain consumption: greater than or equal to 0 to b0.6, greater than or equal to 0.6 to b1.5, greater than or equal to 1.5 to b3.0, and greater than or equal to 3.0 servings/day. Main outcome measures included body mass index (BMI), waist circumference (WC), and prevalence of overweight/obesity. Sample weights were applied and the number and percentages of adults in whole grain consumption groups were determined. Least-square means and standard errors were calculated for body weight measures. Two regression models were developed and compared. Model 1 covariates included age, gender, ethnicity, and total energy intake; Model 2 was extended to include cereal fiber. Trend analysis was conducted to test for differences between least square means. Significance was set at P less than or equal to.05. Adults 19-50 and 51+ y consumed a mean of 0.63 and 0.77 servings of whole grains/day, respectively. A significant trend was observed in both age groups for increased consumption of whole grains with lower BMI, WC, and percentage overweight or obese (Model 1); however, a significant trend was not observed when cereal fiber was added as a covariate (Model 2). Results confirm overall whole grain intake well below recommendations, and adults who consumed the most servings of whole grains had lower body weight measures. Results also suggest that fiber in whole grain foods may mediate associations with weight measures in adults. Intake of whole grain foods should be encouraged by health professionals.