Now showing items 1-5 of 5

• #### Developing Stable Isotope Biomarkers Of Yup'ik Traditional And Market Foods To Detect Associations With Chronic Disease Risk

This dissertation addresses the need for valid measures of dietary intake for use in studies of chronic disease risk in the Yup'ik population of Southwest Alaska. The Yup'ik people have experienced dietary changes over the past century, as consumption of traditional foods has been increasingly supplemented or replaced by market-purchased foods. Determining whether this dietary change is associated with increases in chronic disease risk is important for making nutritional recommendations for disease prevention. However, monitoring dietary change is challenging, in part due to the limitations of self-reported methods of dietary assessment. Dietary biomarkers are promising alternatives to self-reported methods, because they can provide unbiased, reliable estimates of intake. In this dissertation, I present evidence towards the validation of stable isotope dietary biomarkers. Stable isotope ratios vary among foods that are important in Yup'ik diets, and are incorporated into tissues, including several commonly collected biological sample types. They are simple, inexpensive and reliable measures that would be powerful tools for dietary assessment if they could be validated as biomarkers of certain foods. This work was conducted with two Yup'ik study populations that participated in studies conducted by the Center for Alaska Native Health Research. I begin by showing that the nitrogen isotope ratio is a marker of the marine component of traditional food intake, and the carbon isotope ratio is a marker of market food intake. I then calibrate a model of sugar intake based on both the carbon and nitrogen isotope ratios. I focus specifically on sugars because intake of sugary foods and beverages has been linked to obesity-related disease risk in other US populations. Finally, I use this dual isotope model to assess associations of sugar intake with chronic disease risk factors. I find that sugar intake is associated with blood pressure, blood lipids, leptin and adiponectin, suggesting a potential adverse effect of sugar intake on Yup'ik health. The findings of this dissertation provide substantial evidence to support carbon and nitrogen isotope ratios as markers of Yup'ik dietary intake, and demonstrate their potential to be informative in studies of associations between dietary intake and the health of Yup'ik people.
• #### Diet among Siberian Yup'iks of Alaska and the implications for cardiovascular disease

I investigated dietary factors associated with cardiovascular disease and their relation to blood lipids among Siberian Yup'iks. This study was prompted by reports of increasing mortality from cardiovascular disease in Alaska Natives and the need to know to what extent their unique diet may influence cardiovascular disease. Information on dietary intakes was collected in 1992 using two recall methods, from over one-half of the Siberian Yup'ik Eskimos (n = 65) $\geq$40 years-of-age in Gambell, Alaska, as part of a comprehensive screening for diabetes and cardiovascular disease. Based on analysis of 29 nutrients, mean daily intakes of monounsaturated fats and antioxidants--vitamin E, selenium, and vitamin C (among men)--exceeded US recommendations. Mean intake of n-3 fatty acids (7.0 g/d) exceeded the level associated with favorable physiologic responses (>3 g/d) and was comparable to that of Greenlandic Eskimos (8.6 g/d). Although fat intake was high (44% of total energy for men, 42% for women), saturated (11%) and polyunsaturated fats (8%) were not different $(P>$ 0.05), but energy from monounsaturated fat was greater (18% vs. 13%, $P<$ 0.001) than the general US population (NHANES III). Native foods, including walrus, seal and whale, contributed 25% of the energy, >50% of the protein, n-3 fatty acids, arachidonic acid, cholesterol, iron and vitamin B-12, and all of the eicosapentaenoic acid. Nonnative foods were frequent sources of saturated fats. Mean intakes of saturated fat and cholesterol exceeded recommendations. Correlations between foods and blood cholesterol, LDL, HDLI triglycerides and LDL-HDL ratio produced differences by age and sex. Multicollinearity occurred among several nutrients, including $\alpha$-tocopherol and n-6 fatty acids (r = 0.888). When multiple regression was applied among all participants, $\alpha$-tocopherol and fresh bird were associated with reduced LDL-HDL ratio; body-mass index, pizza and syrup were positively associated. Adding obesity to this equation increased the percent of variation explained (42% to 59%). Dietary advice includes maintaining desirable weight, consuming a diet moderate in fat, rich in monounsaturated fats and low in saturated fats, and foods rich in n-3 fatty acids--e.g. Native foods--and vitamin E.
• #### Feasibility Of Farm-To-School In Alaska: A State-Wide Investigation Of Perspectives From School Food Service Professionals

Childhood obesity is a significant public health concern and schools are a key setting for prevention. The majority of U.S. children are enrolled in school where they consume a large portion of their daily energy. Farm-to-school programs are a promising strategy for preventing childhood obesity in school-aged children. The overall objective of this study was to conduct a baseline assessment of Alaska school food service professionals' perspectives of using local foods. Specific objectives were to: 1) Assess interest in utilizing local foods, 2) Identify perceived barriers to purchasing local foods, and 3) Determine resources needed to facilitate local food procurement. A survey was administered to all school food service professionals in Alaska (n = 74) who oversee the National School Lunch Program in their program site or district. The survey consisted of open and close-ended questions, comprising six domains: interest, perceived benefits, perceived usefulness, perceived barriers, and future needs. Descriptive statistics were performed on all variables. The majority (80-96%) of school food service professionals reported interest in utilizing local foods in the school meal programs. School food service professional's reported concern with finding a reliable supply (67%) and the cost (46%) of locally sourced foods. Nearly all (92%) school food service professional's agreed that information about what foods are available, where to purchase them, and USDA purchasing regulations would be useful. Farm-to-school strategies are attainable in Alaska. Interest is high, and perceived barriers and challenges are consistent with national findings. The most useful resources identified could be accommodated through increased communication and use of existing resources.
• #### Nutritional ecology of moose in an urban landscape

Joint Base Elmendorf-Richardson (JBER), Alaska supports a large population of moose that lives in and around the urban and industrial development of Anchorage. This study evaluates the body condition of adult female moose on JBER and calculates the relative nutritional value of habitat for planning development and for mitigating the effects of development on this population. Body condition of moose on JBER was similar to that of other populations of moose in Alaska. Our nutritional model predicted that shrublands could support 11-81 times more moose than any other habitat on JBER. Activity patterns of JBER moose were similar to those published for non-urban moose, indicating habituation to human activity. Activity levels increased as moose moved through higher quality habitats. Sustained production of this heavily utilized population requires maintaining shrublands in undeveloped portions of the base where moose-vehicle collisions can be minimized.
• #### Vitamin D, cognitive function, and oxidative stress: clues to overtraining syndrome?

Overtraining syndrome (OTS) is characterized by an unexplainable drop in athletic performance. It affects primarily elite, endurance athletes, though sub-elite athletes are also affected. Although the deterioration in performance is often the most pronounced and troublesome symptoms for athletes, others range from severe fatigue and insomnia to depression and lack of mental concentration. There is no known diagnostic tool except for ruling out all other possible explanations for the abnormal performance. The only known remedy for OTS is rest. Some recover within months while others take a year or more. Some athletes never fully recovery and never return to pre-OTS performance levels. The exact mechanism behind OTS is unknown. Consensus has been reached among exercise science professionals that 1) an imbalance between stress load and recovery leads to OTS; 2) OTS exists on a spectrum of possible outcomes from different exercise/rest ratios; and 3) exercise is only one part of systemic stress that can lead to OTS. In addition to physical exercise, other factors such as environmental conditions, family dynamics, schoolwork, job stressors, and social pressures all contribute to the total stress load on the body. A severe and sustained imbalance between stress and rest is a likely contributor to OTS in athletes. I investigated biomarkers and psychological markers that, in concert, could be used to identify athletes who are at the greatest risk for developing OTS before the onset of symptoms. I examined vitamin D, cognitive function, and oxidative stress status in university cross country skiers in addition to athletic performance status during the competitive ski season. This study's results support three primary conclusions. First, collegiate endurance athletes are more prone to vitamin D insufficiency and deficiency than their sedentary counterparts. Second, collegiate cross country ski racers in the circumpolar North are unlikely to maintain adequate vitamin D during a competition season. Furthermore, vitamin D levels are likely to drop in the post-season, recovery period. Third, cognitive function is likely to be significantly higher in the post-season than during the competition season. Fourth, those who experienced a drop in performance during the competition season are more likely to show signs of oxidative stress. These findings may help to produce a screening tool for OTS.