The Power of Diet in Disease Prevention: Understanding Diabetes in Native Americans

1. Welcome! Nutrition and Health: The Power of Diet in Disease Prevention Dr. Barbara Demming-Adams and Dr. Suzanne Nelson

2. The Tongan Fruit bat, Pteropus tonganus

3. Females bear almost the entire mineral cost • of raising their offspring • by donating their own skeletal reserves • Extended lactation: bones porous, osteoporosis, long bones of the wings • Increased risk of wing-bone fractures can affect health and fitness

4. Newsweek, December 6, 1999

5. Diabetes in Native Americans:The interaction between diet and genes

6. Hypertension Type 2 diabetes Cardiovascular Disease (CVD) High Cholesterol Cancers (prostate, breast, colon) Diseases of Civilization Obesity Osteoporosis

7. Completely absent from ancestral diet: • Dairy foods • Separated oils • Commercial processing • Empty calorie foods Plus! Many chronic diseases seen after the onset of the Industrial Revolution (ex. Type 2 Diabetes and frequency in CVD)

8. Ancestral vs Modern diet Ancestral Modern

10. Diabetes is an increasing worldwide concern • Native Americans affected the most in US • Interaction of diet, physical activity and genetic predisposition

11. Diabetes • An insufficient secretion of insulin • Or a resistance of body cells to effects of insulin • Glucose can not enter the cells and will remain in blood, increasing blood sugar levels • Secreted in urine at elevated levels • Linked with inflammation

12. Diabetes – Type 1 • Insulin dependent • Discovered early in life • Need exogenous insulin • Most often seen in children

13. Diabetes – Type -2 • Decrease in insulin sensitivity • Pancreas is able to secrete insulin, may actually be over-secreting insulin • Develops slowly • Used to not be seen until after 40 • Seen more recently in obese children

14. Diabetes – Type-2 • Influenced by environmental factors • May be controllable with diet • Does lead to serious health problems: • Retinal disease • Heart disease • Renal disease • Amputation

15. Diabetes Today • Affects 16 million people in US • Death rate due to diabetes has increased 30% • 220 million worldwide are expected to be diagnosed by 2010

17. Diabetes in Native Americans Today • 2.8 times higher than in overall US population • Pima, Havasupai, Oji-Cree tribes

18. Diabetes in Native Americans Today • 25% of Native American males • 30% of the females -double the total US population From 1994 to 2004, the rate of diagnosed Native Americans and Alaska Natives younger than 35 years increased from 8.5 to 17.1 cases/1000 people.

19. Pima Indians in the US

20. Traditional Pima Indian Diet • Beans • Squash • Maize • Mule deer, pronghorn, cottontail, jackrabbit, wild turkey • Acorns, pinyon nuts, walnuts, prickly pear, strawberries, grapes, local grasses

21. Genetic Predisposition • Inflammation is involved in causing diabetes • Several genes for pro-inflammatory messengers come in different versions: a less active version and a more active one • The more active version is much more frequent in Native Americans and diabetics • All full Pima had two copies of the more active gene • Same genotype found in Afro-Caribbean and Gujarati Indians (have high type-2 diabetes prevalence)

22. Genetic Predisposition • Example of a pro-inflammatory messenger: the cytokine interleukin-6 (IL-6) • Involved in glucose and lipid metabolism • Circulating levels of IL-6 are positively correlated with obesity • Baseline IL-6 levels are predictive of type-2 diabetes development

23. Genetic Predisposition • Chronic inflammation leads to development of insulin resistance – type-2 diabetes • Another example (in addition to IL-6): inflammation-promoting COX-2 gene (the one targeted by aspirin) • Strong association between more active version of COX-2 gene and development of type-2 diabetes within Pima Indians

24. Interaction of Genes and Health • Many chemicals in plant-based foods (“phytochemicals”) are anti-inflammatory - Act as COX-2 inhibitors, lower IL-6 levels - Lack of fruit/veggies/herbs/spices creates pro-inflammatory state • Polyunsaturated fats with moderate ratios of omega-6 to omega-3 fatty acids are anti-inflammatory - However, polyunsaturated fats with high ratios of omega-6/3 (in many packaged/fast foods) = highly pro-inflammatory

25. Genetic Predisposition • Evolutionary advantage to have highly active immune system • Lifespan was shorter • Injury, infectious diseases were more prevalent • Native Americans exposed to repeated epidemics following contact with Europeans • May have led to selection of individuals more resistant to infectious diseases but more prone to diabetes

26. Genetic Predisposition • The thrifty gene hypothesis • Decreased metabolism to preserve fat reserves for long winters “starvation season” • Now, extreme food abundance, types of food available, with genetic combination, results in a food toxic environment.

27. Today’s Lifestyle • Pima Indians: • Less active • Buy (highly processed) food • Unhealthy diet: decreased fiber, decreased phytochemicals, increased omega-6 fats • All promote inflammation • Already genetically predisposed to have increase in inflammation messengers and other proteins

28. Diet and Prevention • Reduce total fat intake and alter fat composition • Substitute unsaturated fatty acids for saturated fats • Moderate n-6/n-3 ratio of unsaturated fats • Eliminate saturated fats, cholesterol, trans-fatty acids • Increase fiber intake • Whole grains, fruits, vegetables • Carbohydrates with low glycemic index • Avoid refined grain products • Highest glycemic index- potatoes

29. Physical Activity • Improves long term weight maintenance • Exercise: • Enhances insulin sensitivity • Improves glucose uptake by the muscles • Improves ability to burn fat • In Pima Indians – improvement in insulin action after weight loss of 10% total body weight

30. Prevention • CSU- Program ENERGY • Denver conference on Native American health and obesity • Greater awareness- requests for Native American health/diabetes prevention programs. • Indigenous news network/ Indiancountrytoday