1a. Objectives (from AD-416)
LAB: Epidemiology 1. Using an epidemiologic approach, investigate the role of whole grains, selected nutrients, other bioactive food components, and healthy dietary patterns in preventing age-related development of metabolic risk factors for type 2 diabetes mellitus, cardiovascular disease, cancer and musculoskeletal disorders. 1A. Determine if higher whole-grain intake is associated with less visceral adiposity and a lower waist circumference. 1B. Determine if diet differs between “metabolically healthy but obese" (MHO) individuals and “metabolically abnormal obese” (MAO) individuals. 1C. Determine if higher intakes of various classes of flavonoids are associated with a healthier profile of intermediate markers of CVD risk. 1D. Determine if a plant-based diet will improve the diet quality and consequently affect disease risk through its effects on underlying inflammation, lipid metabolism, insulin sensitivity and endothelial function. 1E. Determine if higher whole grain intake is associated with a lower risk congestive heart failure (CHF) 2. Determine the validity of biomarkers for whole grain intake, their use in assessing relationships between whole grains intake and disease risk, and the relationship between these biomarkers and insulin resistance phenotypes. 3. Using an epidemiologic approach, examine determinants of adherence to the recommended dietary patterns in the Dietary Guidelines for Americans (DGA) and the relation between adherence to these patterns and prevention of age-related weight gain, abdominal obesity, and related metabolic disorders such as inflammation, endothelial dysfunction and insulin resistance. 4. Using an epidemiologic approach, investigate safe upper limits for the dietary intake of folic acid. 5. Using an epidemiologic approach, determine relationships between B-vitamin status, homocysteine levels, genetic mutations and the prevention of age-related cognitive decline in humans. 6. Using an epidemiologic approach, examine the relationships between vitamin D and fatty acid intakes and age-related eye diseases, including cataract and maculopathy. LAB: Dietary Assessment 1. Use an epidemiologic approach to determine if micronutrient intake and dietary patterns are associated with bone status and fracture risk in older adults. 2. Use an epidemiologic approach to determine if micronutrient intake and dietary patterns are associated with depression and cognitive function in older adults. 3. Use an epidemiologic approach to identify behavioral factors that are associated with obesity in diverse population groups. 4. Use an epidemiologic approach to determine how genetic polymorphisms modify dietary effects on risk of diabetes in older adults. 5. Use an epidemiologic approach to determine associations between stress, diabetes and physical disability in older Puerto Rican adults, and the role of dietary patterns in moderating these associations.
1b. Approach (from AD-416)
LAB: Epidemiology Many age-related conditions, such as cardiovascular disease, diabetes, dementia, cancer, musculoskeletal disorders and age-related eye disease, appear to have strong nutritional components. Improved nutrition through public health recommendations and interventions could have a tremendous impact on the economic and societal costs associated with these disabilities, but development of recommendations and interventions requires a greater understanding of the presumptive role that nutrition plays in delaying the onset of disease and disability. Epidemiologic methods applied to community-based investigations of aging populations provide a valuable tool to help meet this need. We will use these methods to address project objectives. LAB: Dietary Assessment We will achieve project objectives by continuing to work with existing cohorts of aging adults in the US population, including our own Boston Puerto Rican Health Study and Nutrition and Memory in the Elderly Study, and through active collaboration with the Framingham Studies, the Baltimore Longitudinal Study on Aging and the VA Normative Aging Study. In each of these, we either collect and analyze or interpret dietary intake and/or biochemical measures and relate them to health outcomes. In addition, we will collaborate across the ARS Human Nutrition Research Centers to conduct a new multi-center assessment of barriers and facilitators of adherence to dietary guidelines to prevent obesity. Together this body of work will contribute to a better understanding of the importance of specific foods, nutrients and dietary patterns in health maintenance with aging and in prevention of obesity and related chronic conditions.
3. Progress Report
This project includes the work of two subordinate projects at the HNRCA funded through a Specific Cooperative Agreement with Tufts University. For further information and progress reports, see 1950-51530-009-01S, (Epidemiology, Nutrition and the Problems of Aging) and 1950-51530-009-02S, (Dietary Assessment and Epidemiology).
1. Stress is associated with chronic disease in Puerto Ricans. (LAB: DIETARY ASSESSMENT AND EPIDEMIOLOGY). ARS-funded researchers from Tufts University in Boston, MA studied the association of physical measures of stress to chronic diseases in older Puerto Ricans in the Boston area. Puerto Ricans living in the United States mainland have a high prevalence of chronic diseases, relative to other racial and ethnic groups. This study determined that among participants of the Boston Puerto Rican Health Study, a combined measure of physiologic indicators of stress was significantly associated with abdominal obesity, hypertension, diabetes and self-reported cardiovascular disease and arthritis, but not with self-reported cancer. The combined stress measure showed a stronger association with these conditions than did metabolic syndrome, suggesting that this cumulative measure may be a better predictor of disease, and that sources of stress should be studied and considered when planning interventions.
2. Physical function and health status in older Puerto Rican adults. (LAB: DIETARY ASSESSMENT AND EPIDEMIOLOGY). ARS-funded researchers from Tufts University in Boston, MA examined physical function in Puerto Rican older adults in the Boston area and the associations between health status, physical function and disability. They determined that physical disability was highly prevalent in this community, particularly among older women (60-75 years). Poor physical function was associated with obesity, diabetes, depression, history of heart attack, stroke, and arthritis. The study identified an important health disparity and some of its correlates and illustrates the need for intervention in this high risk population.
3. Vitamin D may have a potential neuroprotective role. (LAB: DIETARY ASSESSMENT AND EPIDEMIOLOGY). ARS-funded researchers from Tufts University in Boston, MA investigated the effect of vitamin D status on cognitive function and risk of stroke in the elderly. Evidence shows that vitamin D deficiency has potential adverse effects on these outcomes. However, very few studies have previously examined these associations. This study showed that vitamin D insufficiency and deficiency was associated with all-cause dementia, Alzheimer disease, stroke (with and without dementia symptoms), and MRI indicators of cerebrovascular disease. These findings suggest that vitamin D may be protective against cognitive decline and vascular disease.
4. Whole-Grain Intake and Cereal Fiber Are Associated with Lower Abdominal Adiposity. (LAB: EPIDEMIOLOGY, NUTRITION AND PROBLEMS OF AGING). Foods high in dietary fiber may play an important role in regulating body weight. Few observational studies have examined the relationship between dietary fiber from different sources and body fat. ARS-funded researchers from Tufts University in Boston, MA examined the relation between grain intake (whole and refined), and measures of body fat. They observed that higher whole-grain and cereal fiber intakes were associated with a lower body mass index (a higher body mass index is a marker of overweight), percent total body fat, and percent trunk fat mass (trunk fat is a surrogate measure for abdominal fat mass, which is more strongly associated with risk of metabolic disorders than other fat depots). This research suggests that higher intakes of cereal fiber, particularly from whole-grain sources, may be one means of limiting body fat mass, particularly in the abdominal region.
5. Plasma 25-Hydroxyvitamin D Is Associated with Insulin Resistance in Nondiabetic Adults. (LAB: EPIDEMIOLOGY, NUTRITION AND PROBLEMS OF AGING). Insulin resistance is the main defect that characterizes the development of type 2 diabetes, but there is little information on the relationship between vitamin D status and insulin resistance. To advance our understanding of the role of vitamin D status in the development of insulin resistance, ARS-funded researchers from Tufts University in Boston, MA examined the association between insulin resistance and plasma vitamin D levels. They observed that individuals with higher plasma vitamin D concentrations had less insulin resistance. These results suggest that maintaining optimal vitamin D status might be important for the prevention of type 2 diabetes.
6. Mediterranean-Style Dietary Pattern is Associated with a Reduced Risk of Metabolic Syndrome Traits and Incidence. (LAB: EPIDEMIOLOGY, NUTRITION AND PROBLEMS OF AGING). There is evidence of the benefit of the Mediterranean-style dietary pattern on disease risk in Mediterranean countries, but the health benefits of consuming a Mediterranean-style dietary pattern based on foods available in the American diet has not been demonstrated. Therefore, ARS-funded researchers from Tufts University in Boston, MA examined the relation between consumption of a Mediterranean-style dietary pattern and insulin resistance, metabolic syndrome and its component risk factors(larger waist circumference, elevated blood glucose and triglyceride levels, and hypertension, and low HDL-cholesterol) in a population-based sample of adult Americans. They observed that individuals whose diets had greater conformity to the Mediterranean-style dietary pattern had smaller increases in waist circumference, blood glucose and triglyceride levels, and greater increases in HDL-cholesterol; were less likely to develop insulin resistance; and had a lower incidence of metabolic syndrome. These findings suggest that consumption of a diet consistent with the principles of the Mediterranean-style diet may be protective against developing metabolic syndrome, a potent risk factor for both diabetes and cardiovascular disease risk, in an American population.
Mckeown, N.M., Yoshida, M., Shea, M., Jacques, P., Lichtenstein, A.H., Rogers, G., Booth, S.L., Saltzman, E. 2009. Whole-grain intake and cereal fiber are associated with lower abdominal adiposity in older adults. Journal of Nutrition. 139(10):1950-1955.