Stable Carbon Isotope Signatures in Human Blood from 200 Individuals:
A Potential Biochemical Assay for the Consumption of High Fructose Corn Syrup
Rebecca KraftCenter for a Livable Future Research Day
April 8, 2008
Advisor: Dr. A. Hope Jahren
Obesity as a sustainability issue in health
1986198819901992199419961998200020022004
No Data <10% 10% –14% 15% –19% 20% –24% ? 25%
• Since the 1976 prevalence of obesity among adults in the United States has increased from under 15% to 33% (2004)
Cause of death %
1. Heart disease 27
2. Cancer 24
3. Accidents 6
4. Stroke 5
5. Respiratory 5
6. Diabetes 3
7. Pneumonia 2
8. Suicide 2
9. Kidney disease 2
10.Alzheimer’s 2
(*BMI ≥30, or ~ 30 lbs overweight for 5’ 4” person)
Health consequences
Type 2 DiabetesHypertensionDyslipidemiaCoronary heart diseaseStrokeGallbladder diseaseSleep apneaEndometrial cancerBreast cancerColon cancer…
Dietary change and obesity
overweight
obese
HFCS
Barriers to understanding food consumption and diet-related disease:
• Questionnaires are not reliable
• Meal components are not always known
• People are forgetful
• People lie
How do we study diet-related disease?
Exploring health from the perspective of an earth scientist
Carbon cycle diagram taken from http://earthobservatory.nasa.gov/Library/CarbonCycle/carbon_cycle4.htmHuman anatomy diagram taken from http://www.agen.ufl.edu/~chyn/age2062/lect/lect_19/147a.gif
Stable isotopes
= ‰
Sample collection
– 200 individuals analyzed (100 males, 100 females)
– Blood collected without additives– Serum and clot separated by
centrifugation– 0.05 to 0.35 mg of serum and clot
transferred into high-purity tin capsules– Samples analyzed in triplicate– Analytical uncertainty: 0.01‰
Carbon stable isotopes in blood
Total population serumMean: -18.8Min: -22.9Max: -15.6Range: 7.2
Total population clotMean: -18.9Min: -23Max: -16.1Range: 6.9
Female SerumMean: -18.8Min: -22.9Max: -15.6Range: 7.2
Male SerumMean: -18.7Min: -20.9Max: -16.1Range: 4.8
Female ClotMean: -19.1Min: -23Max: -16.1Range: 6.9
Male ClotMean: -18.8Min: -21Max: -16.8Range: 4.2
13CVPBD (‰)
What is the relationship between clot and serum?
Blood carbon signatures in context
The next steps
In progress
– Feeding study in partnership with the USDA
– Several studies correlating survey data consumption with blood stable isotope data
The future
– Blood archive study examining blood isotopic composition in relation to obesity and diabetes
– Isotopic composition of other blood components
Project collaborators and funding
Funding– Center for a Livable Future Innovation Grant
Collaboration: This project and our continuation of research is made possible by the cooperation of a diverse group of researchers spanning JHU, JHSPH, JHMI, and the USDA
Is there a relationship between carbon and nitrogen?
–No significant correlation between carbon and nitrogen in clot or serum
–May be possible to see a correlation among smaller populations grouped by consumption6
7
8
9
10
11
−22 −21 −20 −19 −18 −17
δ13
CVPBD
(‰)
Female serumMale serumFemale clotMale clot
Animal or vegetable?
Geochemical tool applied to health
C4 photosynthesis
-10 to -14‰