January 2012

Relationship between Whole-Grain Intake, Chronic Disease Risk Indicators, and Weight Status among Adolescents in the National Health and Nutrition Examination Survey, 1999-2004

In Young Hur, PhD, RD and Marla Reicks, PhD, RD

Longitudinal and cross-sectional studies in adults show an association between higher intake of whole-grain foods and lower risk of type 2 diabetes, cardiovascular disease (CVD), and metabolic syndrome. Higher whole-grain intake has also been associated with improvements in many of the risk factors of the previously mentioned chronic diseases, including lower triacylglycerol, total and low-density lipoprotein cholesterol concentrations, lower homocysteine levels, and improvements in markers of glycemic control such as insulin, C-peptide, and leptin.

The purpose of the study is to determine the relationship among chronic disease risk factors, weight status, and whole-grain intake among adolescents (aged 12 to 19 years) by sex.

Three components that make this study timely and appropriate are, although whole-grain intake has been associated with improved chronic disease risk factors and weight status in adults, similar studies are limited among adolescents. The increased prevalence of obesity in adolescents during the past several decades is of concern because of associations between obesity and risk factors for type 2 diabetes and CVD. Lastly, most adolescents are not eating the recommended three or more servings of whole-grain foods per day, estimated daily intake is approximately 0.6 to 0.8 servings daily.

In this study, NHANES from 1999-2000, 2001-2002, and 2003-2004 data sets were combined to form one 1999-2004 data set. Data from 4,928 adolescents (2,495 boys, 2,433 girls) was collected in person at home and in mobile examination centers. Each participant had dietary intake information (in the form of a 24 hr recall), anthropometric measures (height, weight, waist, arm, and thigh circumferences; and subscapular skinfold thickness, as well as, BMI), chronic disease risk factors/laboratory measures (including plasma glucose, insulin, C-peptide, C-reactive protein, serum total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglycerides, serum and red blood cell folate, homocysteine concentrations and systolic blood pressure) and lastly physical activity and smoking

Whole grain consumption was broken up into three groups, none- (n=1,354 and n=1,278), low-0 to 0.5 oz equivalents/day (n=469 and n=568), and high- >0.5 oz equivalents/ day (n=672 and n=587) boys and girls respectively. Less than one third consumed >0.5 whole grain ounce equivalents per day. About half of adolescent boys (52%) and girls (50%) did not consume any whole grains on the days that intake was measured

Higher whole-grain intake was associated with lower body mass index and waist, thigh, and arm circumferences among boys only. In models adjusted for food group intake, higher whole-grain intake was associated with lower fasting insulin levels and higher serum and red blood cell folate levels for boys and girls, with lower C-peptide concentrations for girls and lower homocysteine concentrations for boys. Although results varied by sex, results suggested that whole-grain intake may also be favorably associated with risk factors for type 2 diabetes and CVD.

Young Hur, I., & Reicks, M., (2012). Relationship between Whole-Grain Intake, Chronic Disease Risk Indicators, and Weight Status among Adolescents in the National Health and Nutrition Examination Survey, 1999-2004. Journal of the Academy of Nutrition and Dietetic, 112 (1), 46-55.