What is Good Science, and What is Good Science, and How Does it Relate to Food How Does it Relate to Food

Consumption?Consumption?

Keith R. Cooper, Ph.D.Keith R. Cooper, Ph.D.

June 8, 2004June 8, 2004

Land Grant Institutions receive direct federal, state and county appropriations to

extend the boundaries of traditional colleges and universities to provide mission-oriented science-based solutions to targeted problems

and deliver services to stakeholders.

The Land Grant SystemThe Land Grant System

Cook College:Cook College:Program priority setting in the futureProgram priority setting in the future

Agriculture & FoodSystems

Food, Nutrition& Health

Environment & Natural Resources

Human & CommunityHealth

12 2

2 23

3

3

34 4

44

What is Good Science?What is Good Science?

• Results from well designed studies Results from well designed studies that are based on a testable that are based on a testable hypothesis.hypothesis.

• Results that are reproducible by Results that are reproducible by independent studies or laboratories.independent studies or laboratories.

• Results that are statistically Results that are statistically defensible.defensible.

What is Bad Science?What is Bad Science?

• When the outcome of the studies are When the outcome of the studies are designed in such a fashion as to give designed in such a fashion as to give a predetermined outcome.a predetermined outcome.

• When the study design is too small When the study design is too small and apparent correlations are due and apparent correlations are due too statistical error.too statistical error.

• When QA/QC protocols are When QA/QC protocols are compromised.compromised.

How can the same data How can the same data examined by different groups examined by different groups give differing opinions as to give differing opinions as to risk?risk?• It may be dependent on the model It may be dependent on the model

used to extrapolate to obtain a risk used to extrapolate to obtain a risk number.number.

• It may be dependent on the It may be dependent on the assumptions used in the model for assumptions used in the model for unknown parameters.unknown parameters.

• It may be dependent on the endpoint It may be dependent on the endpoint (cancer-benign vs malignant or non-(cancer-benign vs malignant or non-cancer endpoints) examined.cancer endpoints) examined.

Toxicology of Natural & Toxicology of Natural & Anthropogenic Sources of Anthropogenic Sources of ContaminationContamination• Food pathogens (Hepatitis, Vibrio, E. Food pathogens (Hepatitis, Vibrio, E.

coli, Algal toxins and others) coli, Algal toxins and others) associated with waterborne associated with waterborne contamination.contamination.

• Anthropogenic sources of metals, Anthropogenic sources of metals, and persistent organic compounds.and persistent organic compounds.

• These pathogens and contaminants These pathogens and contaminants bioaccumulate into various tissues. bioaccumulate into various tissues.

Metals PersistentOrganicCompoundsMercury

2,3,7,8-TCDD

mRNA

TCDD

AhR

TCDD

AhR

ARNT

TCDD

AhR

ARNT

DRE

TranscriptionTranslation

DNA

Receptor binding Activation

Gene products that regulate proliferation and differentiation of cells

cytoplasm

Nucleus

Mechanisms of 2,3,7,8-TCDDo

o

Cl

Cl

Cl

Cl

o

o

Cl

Cl

Cl

Cl

o

o

Cl

Cl

Cl

Cl

o

o

Cl

Cl

Cl

Cl

0.00E+00

5.00E-06

1.00E-05

1.50E-05

2.00E-05

Day 1 Day 14 Day 28

Days

OD

C a

ctiv

ity

Seawater control

Seawater control

N= 10 oysters/day; No significant difference

Equivalents based on ALP levels (mg/ml)

N= 10 oysters/day; significantly different (ANOVA P<0.05)

*#

* #

Matured eggs

Maturing egg

Developed follicle

Follicle

Growing egg

0

0.001

0.002

0.003

0.004

0.005

0.006

Day 1 Day 14 Day 28

Days

Vite

lloge

nin

equi

vale

nt in

hem

olym

ph (m

g/m

l)

Seawater control

0.00E+00

5.00E-06

1.00E-05

1.50E-05

2.00E-05

Day 1 Day 14 Day 28

DaysO

DC

act

ivity

TCDD

2,3,7,8-TCDD: 10 pg/gram

N=10 oyster; significantly different (ANOVA P< 0.05); Equivalents are based on ALP levels (mg/ml)

N=10 oyster; significantly different (ANOVA P< 0.05)

*

Follicle Follicle

Abnormal egg growth

Inhibited egg growth and maturation

Growing egg

Inhibited egg growth

0

0.001

0.002

0.003

0.004

0.005

0.006

Day 1 Day 14 Day 28

Days

Vite

lloge

nin

equi

vale

nt in

he

mol

ymph

(mg/

ml)

TCDD*#

*!

#!

Integrated Eco-toxicological ModelingIntegrated Eco-toxicological ModelingContamination of Aquatic and Contamination of Aquatic and Terrestrial Systems (CATS):Terrestrial Systems (CATS):Traas and Traas and Aldenberg 1992.Aldenberg 1992.

BioticCharacteristics*foodweb*function

ContaminantProperties*solubility*Kow

AbioticCharacteristics*hydrology*geochemistry*climate

Toxi

colo

gy

EcologyEnvironm

ental Chem

istry

EcologyTo

xico

logy

Environmental C

hemistry

ContaminantProperties

AbioticConditions

Biota

Sorptionleachingpartitioning

Metabolizationassimilationexcetion

Habitat factorsnutrient cycling

Uniqueness of Mercury Uniqueness of Mercury ModelingModeling

The primary concern is methyl mercury The primary concern is methyl mercury which is produced in the environment. which is produced in the environment. In other words, one must actually In other words, one must actually model four mercury species model four mercury species simultaneously. Collaboration with Dr. simultaneously. Collaboration with Dr. Buckley has allowed us to look at rates Buckley has allowed us to look at rates of metal speciation, which are of metal speciation, which are essential in developing rate constants. essential in developing rate constants.

Burial to Deep Sediments and Re-entrainment

Inert Hg

Benthos

Atmosphere

Inert Hg

Aqueous Phase

Hg0

Hg0

Hg II

Hg II

Hg II

Hg IIMeHg

MeHg

MeHg

MeHg

(Adapted From Bale (2000))

Green Boxes denote particulate boundWhile clear denote dissolved

Hg IIInert Hg Hg II Hg0

Mercury Cycling in the Enviroment

Comparative Risk/Benefit Comparative Risk/Benefit RatioRatio• US Dietary Guidelines potential health US Dietary Guidelines potential health

benefits from eating fish (omega-3 fatty benefits from eating fish (omega-3 fatty acids reduce risk of sudden death from acids reduce risk of sudden death from cardiac arrest and other ailments.)cardiac arrest and other ailments.)

• Breastfeeding has been clearly shown for Breastfeeding has been clearly shown for infant and mother bonding, intervention on infant and mother bonding, intervention on reducing dietary intake of animal fat for reducing dietary intake of animal fat for children. Reduction of intake in adult children. Reduction of intake in adult women will have little effect on stored body women will have little effect on stored body burdens.burdens.

• Cooking methods to reduce high fat Cooking methods to reduce high fat containing portions.containing portions.