LAB NAME: Nutritional Epidemiology 1. Using an epidemiologic approach, investigate the role of foods and food components such as carbohydrates sources (e.g., whole grains, sugar sweetened beverages), selected nutrients (e.g., folate, vitamin B12, magnesium), other bioactive food components (e.g., flavonoids, carotenoids), healthy dietary patterns (Dietary Guidelines for Americans, Mediterranean Diet) and gene-diet interactions in preventing age-related conditions such as weight gain, inflammation, insulin resistance and type 2 diabetes mellitus, cardiovascular disease, cancer, cognitive decline, musculoskeletal disorders, vision disorders and kidney disease. 1.A. Determine if higher sugar consumption is associated with cardiometabolic risk factors such as abdominal obesity, ectopic fat accumulation in liver and visceral depots, and inflammation and insulin resistance. 1.B. Determine the role that vitamin B6 plays in chronic inflammation and if modulation of vitamin B6 status can influence risk of inflammation. 1.C. Determine if inadequate vitamin B12 status is associated with reduced muscle power in older adults. 1.D. Determine if consumption of diets consistent with the 2010 Dietary Guidelines for Americans recommendations is associated with maintenance of healthy weight, normal metabolic function, and reduced risk of age-related chronic diseases. 1.E. Determine if lower dietary choline intake is related to accelerated brain aging and increased risk for dementia, and whether omega-3 fatty acids modifies these relationships. 1.F. Determine if specific flavonoids may reduce the risk of age-related chronic disease, including CVD, type 2 diabetes, and dementia. 1.G. Determine if dairy foods or components of dairy foods may help to prevent the development of age-related chronic disease. 2. Using an epidemiologic approach, examine the health effects of high folic acid intakes and the interaction between high folic acid intake and vitamin B12 status to investigate safe upper limits for intake of folic acid in older individuals (in collaboration with the HNRCA Vitamin and Metabolism Laboratory). 3. Using an experimental approach, conduct separate food-based intervention studies to examine the impact of dietary modification with individual foods (including whole grain, dietary fiber, added sugar, and fermented dairy) on weight change and ectopic fat depots (in collaboration with the HNRCA Energy Metabolism Laboratory), microbiota or intermediate metabolic markers of disease risk.
LAB NAME: Nutritional Epidemiology Many age-related conditions that result in disability and premature death, such as weight gain, type 2 diabetes, cardiovascular disease, cancer, cognitive decline, and musculoskeletal disorders, appear to have strong nutritional connections. However, the development of nutritional recommendations and public health interventions requires a greater understanding of the presumptive role that nutrition plays in healthy aging. Our project objectives will be achieved through the application of observational epidemiologic methods in community-based aging population samples to identify dietary patterns, foods and food components associated with age-related health outcomes and testing of these candidate foods and food components in intervention trials of intermediate markers of age-related disease risk.
This report documents research conducted under 1 project in a Non-Assistance Cooperative Agreement between ARS and TUFTS UNIVERSITY. Additional details for the research are associated with project 8050-51530-01S, Epidemiology, Nutrition and Problems of Aging. Our research relating nutrition to age-related chronic disease risk (Objective 1) demonstrated progress on projects related to cardiovascular, musculoskeletal, renal and liver health, and longevity. We made significant progress on multiple projects examining diet and cardiometabolic health. As part of our research on the relationship between added sugars and cardiometabolic health, we examined the relationship between both diet soda and sugar-sweetened soda consumption and subclinical cardiac remodeling resulted in a published paper that reported diet soda consumption was associated with cardiac remodeling (greater left atrial density and greater left ventricular mass), but that this relationship disappeared after accounting for body weight. A second project on added sugar and cardiometabolic health that is examining the possible genetic modifiers of the cardiometabolic consequence of added sugar consumption, focusing on Carbohydrate Responsive Element Binding Protein, received funding and has been initiated. Our research on dairy food consumption and cardiometabolic health resulted in a paper showing that higher consumption of skim/low-fat milk could delay the onset of hypertension and that yogurt consumption could prevent the development of hypertension. A second published paper, a follow-up to earlier work showing better diet quality and metabolic heath in adult yogurt consumers, was replicated in children with similar findings. An ongoing study of flavonoid intake and CVD incidence is in preparation for publication, and analyses are nearing completion on a third project examining the relationship between flavonoid intake and risk of pre-diabetes. As part of our work on kidney health, we published two papers. The first showed that a higher overall diet quality was associated with a decreased risk of developing a low estimated glomerular filtration rate (eGFR), and rapid eGFR decline. The second showed that higher vitamin B12 status was associated with reduced kidney function in two independent cohorts. Finally, we published a paper examining the relationship between over 200 plasma metabolites and their relationship to longevity (defined as attaining 80 years of age) among a large cohort followed for 20 years, and observed that higher concentrations of the citric acid cycle intermediate, isocitrate, and the bile acid, taurocholate were associated with decreased longevity.
1. Whole Grains Enhance the Effect of Statins. The proven efficacy of statins in treating hypercholesterolemia may cause doctors prescribing statins and patients using statins to focus less on lifestyle modifications, such as diet, for maintaining healthy cholesterol levels. To examine if a healthy diet benefited cholesterol among statin users, ARS funded researchers at the Human Nutrition Research Center on Aging at Tufts University in Boston, Massachusetts, examined the relationship between whole grain consumption and lipoprotein profiles in 4,284 adults aged 45 years and older participating in the National Health and Nutrition Examination Survey (NHANES) between 2003–2006. They demonstrated that statin users consuming higher amounts of whole grains (more than one serving per day) had lower non-high-density lipoprotein (HDL) and total cholesterol levels than statin users consuming less than one serving per day of whole grain. These findings indicate that combining whole grains, a healthy dietary component, with statin treatment may improve the efficacy of statins.
2. Anti-inflammatory benefits of flavonoids. Inflammation is now recognized as a common factor in many different chronic diseases and conditions, such as cardiovascular disease, diabetes, cancer and obesity, and preventing or limiting the degree of inflammation may help to ameliorate the consequences of many of these chronic conditions. Evidence from human and experimental studies indicates that dietary flavonoids, commonly found in some fruits and vegetables, tea, chocolate and red wine, may play a protective role in many of these same chronic conditions; however, their mechanism of action is uncertain. ARS funded researchers at the Human Nutrition Research Center on Aging at Tufts University in Boston, Massachusetts, examined the hypothesis that dietary flavonoids provide health benefits through anti-inflammatory effects. Using a composite inflammation score based on 12 individual biomarkers of inflammation, these investigators tested this hypothesis in a population of 2,375 Framingham Heart Study Offspring Cohort participants and observed that individuals with the highest intakes of two types of flavonoids, anthocyanins and flavonols, had the lowest overall levels of inflammation. These findings highlight the potential importance of flavonoids in reducing risk of inflammation, and a probable role for the relationship between flavonoid intake and lower risks of various chronic diseases.
3. Sugar-sweetened beverage consumers have increased fatty liver disease. Non-alcoholic fatty liver disease (NAFLD), the buildup of extra fat in liver cells that is not caused by alcohol, affects 75-100 million United States adults and is increasingly recognized worldwide. NAFLD may lead to liver scarring (cirrhosis) and may even liver cancer or liver failure. To date, there is relatively little evidence indicating whether habitual intake of added sugars is associated with fatty liver disease in otherwise healthy adults. To better understand the role of habitual added sugar consumption and NAFLD, ARS funded researchers at the Human Nutrition Research Center on Aging at Tufts University in Boston, Massachusetts, examined the relationship between sugar sweetened beverages (the leading source of added sugars in the American diet) and prevalence of NAFLD in a 2,634 participants from the Framingham Offspring cohort. They observed that daily consumers of sugar-sweetened beverages were 50% more likely to have NAFLD than those who rarely or never consumed these beverages. This finding, that added sugars in levels typically consumed in the American diet may also be associated with risk of liver disease, add to existing evidence that added sugars increase metabolic risk through obesity and visceral fat accumulation and supports recommendation to reduce added sugar intake.