1a. Objectives (from AD-416)
This award will benefit the people of the United States by producing new knowledge that will significantly improve the evidence base for national food, nutrition and health policies. It will bring together two entities, the ARS and the University of North Dakota, each with strong scientific and technical capabilities to produce a combined effort that is unparalleled in its ability to design and conduct human clinical intervention trials addressing the knowledge gaps critical to policy development for reversing the national epidemic of obesity and its co-morbidities. This research will be among the first to test the efficacy and sustainability of U.S. Dietary Guidelines. It will thus be seminal in supporting the further development of those guidelines as well as related national policy concerning food, nutrition and health. Improved national policy will benefit the people of the United States by reducing the prevalence of obesity and obesity-attributable health care costs.
1b. Approach (from AD-416)
This research will address the prevention of childhood/adult obesity, which involves food choices/patterns, physical activity and energy balance, metabolism/physiology, genotype/phenotypic expression, food access/composition, attitudes/traditions, and processes that can lead to diabetes, cancer, heart disease and osteoarthritis. This demands innovative, translational research to generate new knowledge and improve the evidence base for national nutrition/health/food policy. This will be accomplished in this project by addressing the following areas: 1. U.S. Dietary Guidelines Adherence and Healthy Body Weight. Research to identify barriers/ facilitators to adhering to the Dietary Guidelines. 2. Biology of Obesity Prevention. Research on metabolism/physiology affected by diet/physical activity in maintaining healthy body weight; use of “omics” tools to understand individuals’ responses to interventions and propensities to gain weight. 3. Food Factors in Maintaining Health & Healthy Body Weight. Research examining the effects of food antioxidants on metabolic responses to exercise. 4. Body Weight and Bone Health. Research on the roles of adiposity and body weight on inflammation and bone health. 5. Diet and Physical Activity in Mitigating Obesity-Promoted Carcinogenesis. Research on the effects of adiposity on the metabolism and anticarcinogenic mechanisms of selenium.
3. Progress Report
ARS researchers at the GFHNRC completed a study in which postmenopausal women were supplemented for two years with 600 mg of calcium plus a multi-vitamin containing 400 IU of vitamin D with or without a supplement containing 12 mg of zinc and 2 mg of copper per day. Results showed that the calcium and vitamin supplement slowed bone loss, but that copper and zinc did not enhance that effect in individuals consuming adequate amounts of these minerals according to dietary diaries. Zinc supplementation was beneficial to bone health only in subjects consuming less than the estimated average requirement for zinc. ARS researchers at the GFHNRC conducted a trial to determine whether consuming meat protein is good or bad for calcium nutrition and bone health. They measured dietary calcium retention in healthy post-menopausal women consuming diets that were low in meat protein and potential acid load or high in meat protein and acid load. A diet rich in protein from meat improved calcium absorption, compensated for increases in urinary calcium, and increased a blood hormone known to stimulate bone formation (insulin-like growth factor I, or IGF-I). These findings indicate that consumption of beef and other meats may be beneficial, rather than detrimental to bone health, and provide evidence useful for developing dietary recommendations for meat protein intake to maintain healthy bones. To determine the extent to which obesity exacerbates the altered Se metabolism in individuals, we finished a study design and initiated IRB proposal preparation for new human subject cross sectional study. In addition, we initiated data collection for retrospective analysis of the effect of obesity-associated liver dysfunction on Se distribution in archived samples derived from previous obesity studies.