WHOLE GRAIN INTAKE, METABOLIC SYNDROME AND MORTALITY AMONG OLDER ADULTS

Authors: SAHYOUN, NADINE - UNIVERSITY OF MARYLAND; JACQUES, PAUL - TUFTS/HNRCA; ZHANG, XINLI - UNIVERSITY OF MARYLAND; JUAN, WENYEN - CTR NUTR POLICY, USDA VA; MCKEOWN, NICOLA - TUFTS/HNRCA

Submitted to: The American Journal of Clinical Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/5/2005
Publication Date: 1/1/2006
Citation: Sahyoun, N.R., Jacques, P.F., Zhang, X.L., Juan, W., Mckeown, N.M. 2006. Whole grain intake, metabolic syndrome and mortality among older adults. American Journal of Clinical Nutrition. 83(1):124-131.

Interpretive Summary: Whole grain foods have higher amounts of certain nutrients than refined grains, such as vitamin E, magnesium and fiber. Foods that are whole grain include some breakfast cereals, dark bread, popcorn, cooked oatmeal, wheat germ and brown rice. Consumption of whole grains is associated with potential health benefits, including a reduction in risk of a disease condition know as the metabolic syndrome. Higher levels of blood glucose and higher body weight increase the risk of developing the metabolic syndrome, and metabolic syndrome increases the risk of cardiovascular disease and diabetes. We undertook the present study to determine if people who ate more whole grain foods had 1) lower body weight and glucose levels than people who ate more refined grains 2) were less likely to have metabolic syndrome, and 3) were less likely to die from cardiovascular disease. Our findings indicated that people who ate approximately 2.5 or more servings of whole-grains a day compared to those who ate less than 1 serving a day were 50% less likely to have the metabolic syndrome. We also demonstrated that people who ate more whole grains were less likely to have the metabolic syndrome. In addition, cardiovascular disease mortality was almost 50% lower in people who ate 2.5 or more servings of whole grains compared to those eating less than one serving per day. Diets rich in refined grains do not appear to affect the risk of metabolic syndrome or cardiovascular disease mortality in this population. The findings in this study support current recommendations that individuals should consume 3 or more one ounce-equivalents of whole grain products per day.

Technical Abstract: We examined the association between whole grain intake, cardiovascular risk factors (CVD), metabolic syndrome, and incidence of CVD mortality in 550 healthy individuals, aged 60 to 98 years. Participants kept a three-day food record and had blood tested for CVD risk factors and metabolic syndrome. Metabolic syndrome was defined according to the Third Report of the National Cholesterol Education Program and vital status of participants was identified as of October 1995. Fasting glucose and BMI decreased across increasing quartile categories of whole grain intake (p trend 0.01 and 0.03, respectively), after adjustment for confounders. Refined grain was associated with higher fasting glucose (p for trend 0.03) and lower HDL cholesterol (p for trend 0.04). There was a significant inverse trend between whole grain intake and metabolic syndrome (p for trend 0.02) and mortality from CVD (p for trend 0.04), even after controlling for confounders. The risk of CVD death for individuals in the highest quartile category of whole grain intake was approximately 50% lower than the risk for those in the lowest intake quartile category (RR=0.53, CI=0.28-1.01). Whole grain intake is one modifiable dietary risk factor that may lead to substantial health benefits at the population level. Individuals should be encouraged to increase their daily intake of whole grains to three or more servings a day by substituting whole grain for refined grain foods.