1. Obesity, Nutrition, Nutrigenonmics – OH MY!
Karen L. Edwards, Ph.D.
Director, UW Center for Genomics and Public Health
Department of Epidemiology and Institute for Public Health Genetics
School of Public Health and Community Medicine
University of Washington

2. Objectives
Be familiar with the evidence for genetic influences on obesity
Be able to define nutrigenomics
Understand current limitations of nutrigenomic testing

3. Outline Background Genetics of Obesity Animals Humans
Environmental effects
Nutrigenomics
Why the interest?
Current products and examples
Why the concern?
Moving from promise to practice
5. Summary and Conclusions

4. Public Health Importance
Mortality
Increased risk of premature death
Morbidity
Diabetes, Heart disease, Hypertension, some Cancers, Breathing Problems, Ischemic Stroke, Arthritis, and Reproductive Complications
Prevalence
59 million (30%) Americans are obese (BMI>= 30)
Rates are increasing faster than ever (epidemic proportions)

5. Risk Factors for Obesity
Diet: high calorie and low nutrient dense foods
Physical Inactivity
Age
Socioeconomic status
Certain medical conditions and medications
Race
Smoking cessation
Family History
Genetic susceptibility

6. Evidence for Genetic Influences on Obesity

7. Evidence for genetic influences: Humans
Familial aggregation
- familial clustering of obesity in families
Twin Studies
- greater concordance among MZ twins compared to DZ twins
Family Studies
- variety of “statistical models” consistent with genetic influences

8. The Search for Obesity Susceptibility Genes
“I found one! I found one!”
Kenneth M. Weiss & Joseph D. Terwilliger
nature genetics • volume 26 • October 2000

9. Candidate Genes and Single Gene Disorders: Chromosomal Location
Image adapted from:
Loos, R. J. and C. Bouchard (2003). J Intern Med 254(5):

10. Genetics of Human Obesity
Common form(s) of obesity are likely due to complex interactions between genes and environment
- body fat pattern
- appetite regulation
- other pathways
Rare monogenic forms do not account for majority of cases

11. Trends in Obesity
From the CDC website: BRFSS Trends Data

12. Trends in Obesity
From the CDC Website: NHANES Study Data

13. Trends in Obesity

14. Nutrigenomics Integrates genomics and nutrition
Goal: Improving health and preventing disease through tailored diet and lifestyle prescriptions

15. Nutrigenomics: Magic, Myths and Maybe’s

16. Nutrigenomics vs. Nutrigenetics
“Nutrigenomics refers to the application of genomics in nutrition research, enabling associations to be made between specific nutrients and genetic factors, e.g. the way in which food or food ingredients influence gene expression…Nutrigenomics should facilitate greater understanding of how nutrition affects metabolic pathways and how this process goes awry in diet-related diseases.” Chadwick R. (2004) Proceedings of the Nutrition Society 63:
Nutrigenetics
“Nutrigenetics is the study of individual differences at the genetic level influencing response to diet. These individual differences may be at the level of single nucleotide polymorphisms rather than at the gene level…It is envisaged that nutrigenetics may lead to individualized dietary advice.” Chadwick R. (2004) Proceedings of the Nutrition Society 63:

17. Nutrigenomics vs. Nutrigenetics
“Nutrigenomics attempts to study the genome-wide influences of nutrition…[and] aims to identify the genes that influence the risk of diet-related diseases on a genome-wide scale, and to understand the mechanisms that underlie these genetic predispositions.” Muller M & Kersten S. (2003) Nature Reviews Genetics 4:
Nutrigenetics
“Nutrigenetics examines the effect of genetic variation on the interaction between diet and disease or on nutrient requirements. Genetics has a pivotal role in determining an individual’s risk of developing a certain disease.” Muller M & Kersten S. (2003) Nature Reviews Genetics 4:

18. Nutrigenomics vs. Nutrigenetics
“Nutrigenetics embodies the science of identifying and characterizing gene variants associated with differential responses to nutrients, and relating this variation to disease states.” Mutch D, et al. (2005) FASEB Journal 19:
“Nutrigenetics examines the effect of genetic variation on the interaction between diet and exercise. This includes…gene variants associated with, or responsible for, differential responses to nutrients.” Ordovas J & Mooser M. (2004) Current Opinion in Lipidology 15:
Nutrigenomics
“Nutrigenomics describes the use of functional genomic tools to probe a biological system following a nutritional stimulus that will permit an increased understanding of how nutritional molecules affect metabolic pathways and homeostatic control.” Mutch D, et al. (2005) FASEB Journal 19:
“Nutrigenomics focuses on the effect of nutrients on the genome, proteome, and metabolome.” Ordovas J & Mooser M. (2004) Current Opinion in Lipidology 15:

19. Nutrigenomics & Nutrigenetics: Two Sides of a Coin
Mutch D, et al. (2005) FASEB Journal 19:

20. Nutritional Genomics
The study of how different foods can interact with particular genes to increase the risk of diseases
such as type 2 diabetes, obesity, heart disease and some cancers
Goal: Use of personalized diets to prevent or delay the onset of disease and optimize and maintain human health

21. Nutritional Genomics
van Ommen B. (2004) Nutrition 20:4-8.

22. Why the interest? Improve health of populations United States Globally
Improve athletic performance
Weight loss
Potential economic impact
Functional food and dietary supplements is currently a $40 billion industry
The focus on nutrigenomics could mean an $80 billion dollar industry in 7-10 years

23. What is the evidence? Single Gene Disorders PKU Lactose intolerance
Complex conditions
Genes involved in susceptibility to complex diseases have been identified
Nutritional environment modifies the expression of genes
Metabolism of nutrients may vary by genotype, ultimately affecting health
Singel gene disorders, good evidence for effective nutrition intervention based on genotype
Complex conditions – although the evidence is increasing, evidence is less clear cut, -- efficacy has not been established and there will be challenges to doing this
gene x e is difficult
Large samples
replicaiton

24. What is the public health implication?
Can we use this information along with our increasing knowledge of the genetics of obesity for public health applications?
Obesity epidemic
Singel gene disorders, good evidence for effective nutrition intervention based on genotype
Complex conditions – although the evidence is increasing, evidence is less clear cut, -- efficacy has not been established and there will be challenges to doing this
gene x e is difficult
Large samples
replicaiton

25. Direct to Consumer Marketing
Health Clubs
Vending Machines
Internet
Retail stores

26. On the internet

28. Weight Loss
DNA Diet Builds Customized Weight-Loss Plan
One-size-fits-all diets could be a thing of the past.
NBC station KNSD in San Diego reported that a handful of bio-tech companies are promising a high-tech recipe for losing weight and eating better. The newest weight-loss plan is a customized diet based on your DNA. The DNA diet is a personalized meal plan that claims to be based on your unique genetic blueprint.
Katzin claims that based on your DNA profile she can “determine whether someone should increase the amount of folic acid, B-6 or B-12, for example. So, we would choose foods that are rich in those supplements.”
… “interprets the data and makes a customized meal plan. Her suggestions range from “ taking more vitamins to eating more meat.”

29. Diet Design, One Pair of “Genes” at a Time
Health: You Are What You Eat Oct. 31, 2005 issue - Bruce Morrill is something of a health nut. So when his nutritionist suggested he take a $695 DNA test so she could individualize his diet plan, Morrill, a 42-year-old UPS driver from Reno, Nev., agreed.

30. Currently in the United States, no regulations are in place for evaluating the accuracy and reliability of genetic testing. Most genetic tests developed by laboratories are categorized as services, which the Food and Drug Administration (FDA) does not regulate. This lack of government oversight is particularly troublesome in light of the fact that a handful of companies have started marketing test kits directly to the public. Some of these companies make dubious claims about how the kits not only test for disease but also serve as tools for customizing medicine, vitamins, and foods to each individual's genetic makeup. (doegenomes.org)
Genetic testing to identify alleged risk factors that have no proven corrective measures is simply a waste of money. As noted by Helen Wallace, Ph.D., Deputy Director of GeneWatch UK: "For most people, tailoring your diet to your genetic make-up is about as scientific as tailoring your diet to your star sign."

31. Sciona International company previously based in the UK
Personalized health and nutrition recommendations
Products were available through retail stores
GeneWatch UK called on retail stores to stop offering these tests
Currently based in Boulder, Colorado
Launching a campaign in 4 test markets
Partnerships with retail stores and local health care system

32. In store sales

33. Lund Foods CEO: “…plan is to create a link between the evaluations performed by Sciona and his stores’ food experts, which have long provided consumers with diet and nutritional advice and information.”
Today Food Editor: “The idea, which is a good one, is to help shoppers understand what they can do in their daily food choices to either maintain their good health or help correct certain genetic defects that the test may have identified.”

34. Heart Health
“Analyzes thirteen of your genes that may play an important role in determining how your body manages overall heart health”
“…assesses nine key diet and lifestyle action areas”

35. Bone Health
“Analyzes four of your genes that may play an important role in determining how your body manages overall bone health
“..assesses seven key diet and lifestyle action areas”

36. Insulin Resistance
“Analyzes five of your genes that may play an important role in determining how your body manages overall insulin resistance”
“..assesses five key diet and lifestyle action areas”

37. Genetic Assessment for Antioxidant and Detoxification
“Analyzes six of your genes that may play an important role in determining how your body manages overall antioxidant/ detoxification health”
“..assesses four key diet and lifestyle action areas”

38. Inflammation Health
“Analyzes six of your genes that may play an important role in determining how your body manages inflammation”
“..assesses four key diet and lifestyle action areas”

40. Consumer Demand?
Sciona claims to have sold 10,000 kits in Europe, Asia and the US
Current use is likely limited to those who can afford to pay
HealthSyles Survey indicates that only 14% of US population are aware of these tests, and only 0.6% have used a test
- age and income are associated with awareness
(Goddard et al., GIM 2007;9:510-7)

41. Why the Concern?
Currently in the United States, no regulations are in place for evaluating the accuracy and reliability of genetic testing. Most genetic tests developed by laboratories are categorized as services, which the Food and Drug Administration (FDA) does not regulate. This lack of government oversight is particularly troublesome in light of the fact that a handful of companies have started marketing test kits directly to the public. Some of these companies make dubious claims about how the kits not only test for disease but also serve as tools for customizing medicine, vitamins, and foods to each individual's genetic makeup. (doegenomes.org)
Genetic information is unlike other health information, in that it also provides information about your family members
Genetic testing to identify alleged risk factors that have no proven corrective measures is simply a waste of money. As noted by Helen Wallace, Ph.D., Deputy Director of GeneWatch UK: "For most people, tailoring your diet to your genetic make-up is about as scientific as tailoring your diet to your star sign."

42. “Buyer Beware” A recent report by the Government Accountability Office
highlighted a few of the concerns with four examples of DTC
nutrigenomic tests. The GAO report raised concerns that
the tests may mislead consumers by making unsound and ambiguous
predictions about health risks. In addition, the test
results frequently include recommendations for the consumer
to purchase dietary supplements that may be significantly
overpriced compared with similar products available through
a supermarket or pharmacy and that may, in fact, be harmful
for some individuals.

43. Potential Benefits Increased focus on a healthy diet and lifestyle
Motivate positive behavior change
Increased awareness of risk of certain conditions
Improved health and quality of life
Focus on prevention
Decreased morbidity and premature mortality
Reduced health care costs
Identify subgroups who might be particularly responsive or resistant to environmental (dietary) intervention
Better understanding of the mechanisms involved in disease susceptibility

44. Potential Harms
Attention is drawn away from other modifiable risk factors
Decreased use of other services
False sense of security
Focus on specific nutrients/foods
Ineffective or harmful
Misleading claims
Dilute or contradict public health messages

45. Potential Harms, cont.
Increased costs associated with personalized diets and designer foods
Targeting vulnerable populations
Concerns surrounding confidentiality, insurance
Biobanking of samples, informed consent
Unintended consequences

46. From Promise to Practice
Consistent evidence
Evidence for clinical utility – added value
Understand how information is used
Culturally specific translation
Thoughtful integration based on evidence
Holistic approach
Address ELSI issues prior to integration
Access to services and “treatment”
What will be required to move this into practice
Before we can do evidence based reviews need good quality studies
Need to evaluate gxe

47. Summary Potential is exciting
Range of opinions regarding readiness of current applications
Many parallels to pharmacogenomics
Dr. Arno Motulsky: “ the total promise of PGX is often overstated and is unlikely to lead to a revolution in therapeutics”
May provide benefits to some individuals, but probably not as broadly as currently predicted

48. Conclusions Obesity is influenced by both genes AND environment
Obesity is associated with poverty, SES and education
Diet is important
High-fat energy-dense foods are often the cheapest options for the consumer
Health foods cost more
Nutrigenomic testing is not ready for prime time

49. UW Center for Genomics and Public Health
Funded as part of the ASPH/CDC/ATSDR cooperative agreement
Office of Genomics and Disease Prevention
Centers for Disease Control and Prevention
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