What is Good Science, and How
Does it Relate to Food
Consumption?
Keith R. Cooper, Ph.D.
June 8, 2004
The Land Grant System
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.
Cook College:
Program priority setting in the future
Food,
Nutrition
& Health
Agriculture
4 & Food
Systems
4
3
2
3
2
2
Environment
4
& Natural
Resources
3
1
2
3
4
Human &
Community
Health
What is Good Science?
• Results from well designed studies that
are based on a testable hypothesis.
• Results that are reproducible by
independent studies or laboratories.
• Results that are statistically defensible.
What is Bad Science?
• When the outcome of the studies are
designed in such a fashion as to give a
predetermined outcome.
• When the study design is too small and
apparent correlations are due too
statistical error.
• When QA/QC protocols are compromised.
How can the same data examined
by different groups give differing
opinions as to risk?
• It may be dependent on the model used
to extrapolate to obtain a risk number.
• It may be dependent on the assumptions
used in the model for unknown
parameters.
• It may be dependent on the endpoint
(cancer-benign vs malignant or noncancer endpoints) examined.
Toxicology of Natural &
Anthropogenic Sources of
Contamination
• Food pathogens (Hepatitis, Vibrio, E. coli,
Algal toxins and others) associated with
waterborne contamination.
• Anthropogenic sources of metals, and
persistent organic compounds.
• These pathogens and contaminants
bioaccumulate into various tissues.
Metals
Mercury
Persistent
Organic
Compounds
2,3,7,8-TCDD
Cl
o
Cl
Cl
Cl
o
Cl
o
Mechanisms of 2,3,7,8-TCDD
Cl
Cl
o
Cl
Receptor binding
TCDD
Activation
TCDD
TCDD
AhR
AhR
AhR
ARNT
ARNT
cytoplasm
Gene products that regulate
proliferation and differentiation
of cells
Translation
Transcription
mRNA
DNA
Nucleus
DRE
Seawater control
Follicle
Maturing egg
Vitellogenin equivalent
in hemolymph (mg/ml)
0.006
0.005
0.004
0.003
Seawater control
0.002
0.001
0
Day 1
Day 14
Day 28
Days
N= 10 oysters/day; No significant difference
Growing egg
Developed
follicle
Equivalents based on ALP levels (mg/ml)
ODC activity
2.00E-05
Matured
eggs
*#
1.50E-05
1.00E-05
5.00E-06
Seawater control
*
#
0.00E+00
Day 1
Day 14
Day 28
Days
N= 10 oysters/day; significantly different
(ANOVA P<0.05)
2,3,7,8-TCDD: 10 pg/gram
Inhibited egg growth
Follicle
Vitellogenin equivalent in
hemolymph (mg/ml)
Follicle
0.006
0.005
0.004
*#
0.003
TCDD
*!
0.002
#!
0.001
0
Day 1
Day 14
Day 28
Days
Abnormal egg
growth
N=10 oyster; significantly different
(ANOVA P< 0.05); Equivalents are
based on ALP levels (mg/ml)
2.00E-05
Inhibited egg
growth and
maturation
ODC activity
Growing egg
1.50E-05
1.00E-05
TCDD
5.00E-06
*
0.00E+00
Day 1
Day 14
Day 28
Days
N=10 oyster; significantly different
(ANOVA P< 0.05)
Integrated Eco-toxicological Modeling
Contamination of Aquatic and Terrestrial
Systems (CATS):Traas and Aldenberg 1992.
Contaminant
Properties
*solubility
*Kow
Contaminant
Properties
Metabolization
assimilation
excetion
Biotic
Characteristics
*foodweb
*function
Abiotic
Characteristics
*hydrology
*geochemistry
*climate
Ecology
Biota
Sorption
leaching
partitioning
Habitat factors
nutrient cycling
Ecology
Abiotic
Conditions
Uniqueness of Mercury Modeling
The primary concern is methyl mercury
which is produced in the environment. In
other words, one must actually model four
mercury species simultaneously.
Collaboration with Dr. Buckley has allowed
us to look at rates of metal speciation,
which are essential in developing rate
constants.
Atmosphere
Mercury Cycling in the Enviroment
Inert Hg Hg II Hg II Hg0
Green Boxes denote particulate bound
While clear denote dissolved
Aqueous Phase
Hg II
Hg0
Hg II
MeHg
MeHg
MeHg
MeHg
Inert Hg
Hg II
Inert Hg
Hg II
Hg0
Benthos
(Adapted From Bale (2000))
Burial to Deep Sediments and Re-entrainment
Comparative Risk/Benefit Ratio
• US Dietary Guidelines potential health benefits
•
•
from eating fish (omega-3 fatty acids reduce risk
of sudden death from cardiac arrest and other
ailments.)
Breastfeeding has been clearly shown for infant
and mother bonding, intervention on reducing
dietary intake of animal fat for children.
Reduction of intake in adult women will have
little effect on stored body burdens.
Cooking methods to reduce high fat containing
portions.