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‰