ArticlePDF Available

Abstract

The paper gives an overview of recent studies investigating the health value of organic foods and presents a framework for estimating the scientific impact of these studies. Furthermore, the problems connected with the different research approaches are being discussed. A number of comparative studies showed lower nitrate contents and less pesticide residues, but usually higher levels of vitamin C and phenolic compounds in organic plant products, as well as higher levels of omega-3 fatty acids and conjugated linoleic acid in milk from organically raised animals. However, the variation in outcomes of comparative studies is very high, depending on plant fertilization, ripening stage and plant age at harvest, and weather conditions. Moreover, there appeared no simple relationship between nutritional value and health effects. It is difficult therefore to draw conclusions from analytical data about the health effects of organic foods. Some in vitro studies comparing health-related properties of organic vs conventional foods showed higher antioxidative and antimutagenic activity as well as better inhibition of cancer cell proliferation of organically produced food. If ‘health effects’ are defined as effects on defined diseases in humans, evidence for such effects is presently lacking. Animal studies carried out so far have demonstrated positive effects of an organic diet on weight, growth, fertility indices and immune system. Recent human epidemiological studies associated consumption of organic foods with lower risks of allergies, whereas findings of human intervention studies were still ambiguous. The hypothesis might be that organic food increases the capacity of living organisms towards resilience. To confirm this, effect studies on specific markers for health are necessary.
Please
cite
this
article
in
press
as:
M.
Huber,
et
al.,
Organic
food
and
impact
on
human
health:
Assessing
the
status
quo
and
prospects
of
research,
NJAS
-
Wageningen
J.
Life
Sci.
(2011),
doi:10.1016/j.njas.2011.01.004
ARTICLE IN PRESS
G
Model
NJAS-75;
No.
of
Pages
7
NJAS
-
Wageningen
Journal
of
Life
Sciences
xxx (2011) xxx–
xxx
Contents
lists
available
at
ScienceDirect
NJAS
-
Wageningen
Journal
of
Life
Sciences
jou
rnal
h
omepage:
www.elsevier.com/locate/njas
Review
Organic
food
and
impact
on
human
health:
Assessing
the
status
quo
and
prospects
of
research
M.
Hubera,,
E.
Rembiałkowskab,
D. ´
Srednickab,
S.
Bügelc,
L.P.L.
van
de
Vijvera
aLouis
Bolk
Institute,
Driebergen,
The
Netherlands
bWarsaw
University
of
Life
Sciences,
Faculty
of
Human
Nutrition
and
Consumer
Sciences,
Department
of
Functional
Food
and
Commodities,
Warsaw,
Poland
cUniversity
of
Copenhagen,
Department
of
Human
Nutrition,
Frederiksberg
C,
Denmark
a
r
t
i
c
l
e
i
n
f
o
Article
history:
Received
28
November
2009
Accepted
19
January
2011
Available online xxx
Keywords:
Review
Organic
food
Health
Humans
Intervention
Observational
In
vitro
studies
a
b
s
t
r
a
c
t
The
paper
gives
an
overview
of
recent
studies
investigating
the
health
value
of
organic
foods
and
presents
a
framework
for
estimating
the
scientific
impact
of
these
studies.
Furthermore,
the
problems
connected
with
the
different
research
approaches
are
being
discussed.
A
number
of
comparative
studies
showed
lower
nitrate
contents
and
less
pesticide
residues,
but
usually
higher
levels
of
vitamin
C
and
phenolic
compounds
in
organic
plant
products,
as
well
as
higher
levels
of
omega-3
fatty
acids
and
conjugated
linoleic
acid
in
milk
from
organically
raised
animals.
However,
the
variation
in
outcomes
of
compara-
tive
studies
is
very
high,
depending
on
plant
fertilization,
ripening
stage
and
plant
age
at
harvest,
and
weather
conditions.
Moreover,
there
appeared
no
simple
relationship
between
nutritional
value
and
health
effects.
It
is
difficult
therefore
to
draw
conclusions
from
analytical
data
about
the
health
effects
of
organic
foods.
Some
in
vitro
studies
comparing
health-related
properties
of
organic
vs
conventional
foods
showed
higher
antioxidative
and
antimutagenic
activity
as
well
as
better
inhibition
of
cancer
cell
proliferation
of
organically
produced
food.
If
‘health
effects’
are
defined
as
effects
on
defined
diseases
in
humans,
evidence
for
such
effects
is
presently
lacking.
Animal
studies
carried
out
so
far
have
demon-
strated
positive
effects
of
an
organic
diet
on
weight,
growth,
fertility
indices
and
immune
system.
Recent
human
epidemiological
studies
associated
consumption
of
organic
foods
with
lower
risks
of
allergies,
whereas
findings
of
human
intervention
studies
were
still
ambiguous.
The
hypothesis
might
be
that
organic
food
increases
the
capacity
of
living
organisms
towards
resilience.
To
confirm
this,
effect
studies
on
specific
markers
for
health
are
necessary.
© 2011 Royal Netherlands Society for Agricultural Sciences. Published by Elsevier B.V.
All rights reserved.
Contents
1.
Introduction
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2.
Comparative
studies
on
nutritional
value
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2.1.
Plant
products
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2.2.
Animal
products
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3.
Translation
of
compositional
information
to
impact
on
human
health
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.00
4.
Types
of
studies
analysing
the
effects
of
organic
products
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4.1.
Intervention
studies
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4.2.
Observational
studies
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4.3.
Intervention
studies
in
animals
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4.4.
In
vitro
studies
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5.
Recent
in
vitro
studies.
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6.
Recent
animal
studies
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Corresponding
author
at:
Louis
Bolk
Institute,
Dept.
of
Healthcare
&
Nutrition,
Hoofdstraat
24,
NL-3972
LA
Driebergen,
The
Netherlands.
Tel.:
+31
0
343
523
860;
fax:
+31
0
343
515
611.
E-mail
address:
m.huber@louisbolk.nl
(M.
Huber).
1573-5214/$
see
front
matter ©
2011 Royal Netherlands Society for Agricultural Sciences. Published by Elsevier B.V. All rights reserved.
doi:10.1016/j.njas.2011.01.004
Please
cite
this
article
in
press
as:
M.
Huber,
et
al.,
Organic
food
and
impact
on
human
health:
Assessing
the
status
quo
and
prospects
of
research,
NJAS
-
Wageningen
J.
Life
Sci.
(2011),
doi:10.1016/j.njas.2011.01.004
ARTICLE IN PRESS
G
Model
NJAS-75;
No.
of
Pages
7
2M.
Huber
et
al.
/
NJAS
-
Wageningen
Journal
of
Life
Sciences
xxx (2011) xxx–
xxx
7.
Recent
studies
in
humans
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7.1.
Observational
studies
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7.2.
Intervention
studies
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8.
Discussion
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.00
9.
Towards
the
future
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.00
9.1.
Comparative
studies
on
nutritional
value.
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.00
9.2.
Intervention
studies
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.00
9.3.
Observational
studies
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.00
9.4.
In
vitro
models
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.00
Acknowledgement
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.00
References
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.
.00
1.
Introduction
Consumer
studies
continue
to
show
that
expectations
concern-
ing
health
effects
of
organic
food
are
about
the
strongest
motives
for
consumers
to
buy
organic
products,
and
research
results
on
this
topic
can
count
on
high
societal
interest
[1–3].
However,
until
now
these
expectations
lack
sound
scientific
proof
[4].
Different
kinds
of
research
are
being
performed
to
investigate
the
health
value
of
organic
products
compared
with
conventionally
produced
products.
An
increasing
number
of
studies
are
being
published,
including
studies
comparing
the
contents
of
ingredients
of
prod-
ucts
from
conventional
and
organic
production
systems,
as
well
as
review
studies.
Apart
from
this,
a
much
smaller
number
of
studies
have
been
published
on
effects
of
organic
food
consumption.
These
include
animal
and
human
studies
on
bioavailability
and
health
effects,
in
vitro
studies
comparing
effects
of
organic
and
conven-
tional
products
on
different
parameters
in
the
laboratory.
In
this
paper
an
overview
of
recent
studies
on
the
topic
is
given,
with
a
framework
for
estimating
the
scientific
value
of
these
studies.
In
addition,
the
problems
connected
with
the
different
approaches
are
being
discussed.
A
hypothesis
is
presented
about
the
possible
health
effects
that
organic
products
might
have,
and
suggestions
are
made
for
future
research.
2.
Comparative
studies
on
nutritional
value
2.1.
Plant
products
A
number
of
studies
have
looked
at
the
contents
of
primary
and
secondary
metabolites
of
food
from
different
production
systems,
e.g.,
organic
and
conventional
systems.
The
older
studies
have
been
reviewed
[5,6].
The
main
conclusion
was
that
organic
products
had
a
higher
dry
matter
and
lower
nitrate
content
and
contained
less
pesticide
residues.
Regarding
vitamins
they
concluded
that
there
were
trends
towards
higher
vitamin
C
contents
in
organic
prod-
ucts,
while
data
on
mineral
content
were
inconclusive.
Since
then,
over
200
papers
concerning
nutrient
content
of
organic
vs.
con-
ventionally
produced
foods
have
been
published
and
it
is
evident
that
the
interest
in
this
field
has
increased
dramatically
over
the
years.
However,
conclusions
since
1997
have
not
changed
as
dra-
matically.
In
plants,
the
focus
during
the
last
10
years
has
been
on
the
contents
of
vitamin
C,
carotenoids
and
phenolic
compounds.
Various
fruits
and
vegetables
have
been
investigated
under
differ-
ent
climatic
conditions,
with
different
varieties
and
on
different
soil
types.
In
a
review
paper,
Worthington
[6]
presented
a
meta-analysis
showing
that
in
most
studies
the
level
of
vitamin
C
was
signifi-
cantly
higher
in
organically
than
in
conventionally
produced
plant
foods.
Also
in
more
recent
studies,
higher
vitamin
C
contents
were
found
in
many
organic
products,
e.g.,
peaches
[7]
and
tomatoes
[8,9],
although
other
studies
reported
similar
or
lower
contents
of
vitamin
C
in
organic
tomatoes
[10],
broccoli
[11],
bell
peppers
[9],
pears
and
peaches
[7].
A
higher
carotenoid
content
was
found
in
organically
grown
sweet
peppers,
yellow
plums,
tomatoes
and
carrots
[9,12,13],
whereas
others
[14,15]
found
lower
or
similar
contents
of
carotenoids
in
organically
grown
blanched
carrots
and
tomatoes.
From
a
study
of
Barrett
et
al.
[10]
it
is
known
that
the
con-
tent
of
carotenoids
may
depend
on
soil
type,
genotype,
as
well
as
the
fertilizers
and
pesticides
used.
This
might
explain
the
inconsistency
of
the
findings
in
the
above-mentioned
studies
[10].
An
increasing
number
of
studies
have
measured
the
content
of
phenolic
compounds
that
might
have
a
chemopreventive
role
in
humans
by
modulating
the
cancer
cell
cycle,
inhibiting
prolifer-
ation
and
inducing
apoptosis.
A
number
of
studies
have
actually
shown
that
the
content
of
phenolic
compounds
is
higher
in
organic
products
[7–9,12,16–18],
whereas
other
studies
[9,12]
have
found
similar
or
lower
contents
of
phenolic
compounds
in
organic
prod-
ucts.
In
most
studies
comparing
conventionally
with
organically
grown
cereals,
higher
levels
of
proteins
and
amino
acids
were
found
in
the
conventionally
produced
grain
(reviews
by
Heaton
[20],
Wor-
thington
[6]
and
Benbrook
et
al.
[21],
and
recent
studies
[22]).
The
higher
N-fertilization
rate
in
conventional
production
systems
is
very
likely
to
explain
this
difference.
Some
studies
also
observed
that
the
quality
of
the
amino
acids
was
higher
in
the
organic
products
than
in
the
conventional
products,
meaning
that
more
essential
amino
acids
were
available
in
the
organic
grains.
These
lat-
ter
findings
were
not
confirmed
in
other
studies
[22,23].
Apart
from
the
described
potentially
beneficial
components,
conclusions
can
be
drawn
concerning
lower
amounts
of
pesticide
residues
[24,25],
nitrates
[26,27]
and
equal
or
lower
amounts
of
mycotoxins
[25,28]
in
organic
crops.
2.2.
Animal
products
Also
in
animal
products
differences
between
organic
and
con-
ventional
production
systems
have
been
observed.
Milk
studies
from
the
Netherlands,
UK,
Denmark
and
the
USA
have
shown
that
milk
from
organically
raised
animals
has
higher
contents
of
n-3
linolenic
acids
and
conjugated
linoleic
acid
(CLA)
compared
with
milk
from
conventional
systems
[29,30].
Such
differences
with
con-
ventionally
raised
animals
are
observed
especially
in
summertime,
when
the
organically
raised
animals
have
their
outdoor
grazing
facilities.
A
recent
study
from
the
UK
showed
that
milk
from
low-
input
systems,
both
organic
and
non-organic,
has
higher
contents
of
n-3
linolenic
acid
and
CLA,
although
the
highest
contents
were
found
in
the
non-organic
low-input
system.
Outdoor
grazing,
a
high
biodiversity
in
pastures,
low
levels
of
concentrates
and
no
silage
feeding
were
found
to
be
predominant
factors
for
beneficial
milk
fatty
acids
composition
[31].
Most
recent
are
two
review
papers
from
the
French
and
the
British
Food
Standard
Agencies,
both
of
which
published
in
the
summer
of
2009,
but
presenting
quite
different
results
[32,33].
The
French
AFSSA
paper
[32]
mentions
the
earlier
described
results
of
a
Please
cite
this
article
in
press
as:
M.
Huber,
et
al.,
Organic
food
and
impact
on
human
health:
Assessing
the
status
quo
and
prospects
of
research,
NJAS
-
Wageningen
J.
Life
Sci.
(2011),
doi:10.1016/j.njas.2011.01.004
ARTICLE IN PRESS
G
Model
NJAS-75;
No.
of
Pages
7
M.
Huber
et
al.
/
NJAS
-
Wageningen
Journal
of
Life
Sciences
xxx (2011) xxx–
xxx 3
higher
dry
matter
content,
more
minerals
(Fe,
Mg)
and
more
anti-
oxidants
like
phenols
and
salicylic
acid
in
organic
plant
products,
as
well
as
more
polyunsaturated
fatty
acids
in
organic
animal
prod-
ucts,
apart
from
less
nitrate
in
50%
of
the
products,
94–100%
of
the
products
without
pesticide
residues
and
equal
amounts
of
myco-
toxins.
The
British
FSA
paper
[33]
describes
a
systematic
review
of
50
years
of
publications,
with
strict
inclusion
criteria,
and
mentions
more
phosphorus
and
acidity
and
fewer
nitrates
in
organic
prod-
ucts,
but
no
other
differences.
However,
the
review
did
not
consider
most
of
the
studies
presenting
data
of
well-controlled
field
trials.
Contaminant
contents
were
not
included
in
the
review
paper.
The
latter
paper
has
given
rise
to
a
fierce
debate
concerning
the
in-
and
exclusion
criteria,
which
is
still
ongoing
at
the
moment
the
present
paper
was
submitted.
3.
Translation
of
compositional
information
to
impact
on
human
health
Comparative
studies
on
chemical
composition
of
food
products
from
organic
and
conventional
production
systems
are
valuable
and
may
provide
indications
for
possible
health
effects.
However,
it
should
be
recognized
that
hypotheses
about
effects
of
compounds
are
often
revised.
Considering
that
plant
physiologists
estimate
the
plant
world
to
contain
up
to
75,000
or
even
100,000
different
com-
pounds,
or
7500–10,000
per
plant,
that
act
synergistically
in
the
plant
organism,
it
becomes
clear
that
even
advanced
methods,
like
in
systems
biology
that
analyse
hundreds
or
even
thousands
of
compounds,
only
portray
the
top
of
the
iceberg
of
plant
chemistry.
Let
alone
the
interaction
between
such
a
complex
food
product
and
the
likewise
complex
organism
of
the
consumer.
The
first
clear
complicating
factor
is
the
way
in
which
compounds
are
resorbed
by
an
organism,
measured
as
bioavailability.
Secondly,
it
is
not
pre-
dictable
how
the
consuming
organism
will
react
biologically
to
a
food
product,
as
this
depends
on
individual
constitutional
differ-
ences,
as
well
as
the
actual
health
status.
And
in
real
life,
products
are
integrated
in
a
food
matrix,
with
chemical
interactions
between
products.
This
complicates
the
question
about
hypothesized
effects
even
more.
So
some
reticence
in
speculations
about
effects
based
on
analytical
outcomes
is
due
here.
This
is
why
studies
that
mea-
sure
factual
effects
of
food
products
are
more
informative,
although
not
simple.
Some
approaches
will
be
described,
with
a
framework
for
estimating
the
scientific
value
of
these
study
designs.
4.
Types
of
studies
analysing
the
effects
of
organic
products
4.1.
Intervention
studies
Societal
interest
in
health
effects
of
organic
products
comes
from
consumers.
Seeking
for
scientific
proof
to
answer
the
inquiries
of
this
group,
studies
among
humans
are
most
convincing,
especially
so-called
‘intervention
studies’.
In
this
study
design
as
many
fac-
tors
as
possible
need
to
be
controlled
for
a
group
of
people
(as
so
many
factors
other
than
nutrition
do
affect
people’s
health
and
well-being)
and
only
the
food
under
study
is
clearly
varied
in
order
to
make
possible
effects
become
visible.
So
either
a
set-up
needs
to
be
created
where
a
group
of
people
is
brought
voluntarily
into
a
controlled
situation,
or
special
situations
need
to
be
found
where
groups
of
people
live
daily
under
the
same
conditions
and
in
the
same
routine,
like
children’s
homes,
monasteries
or
prisons.
In
such
a
controlled
situation
ideally
two
matched
groups
should
consume
parallel
either
organically
or
conventionally
grown
food,
blinded.
Or
a
‘cross-over’
situation
is
created
where
the
different
test
foods
are
presented,
one
after
the
other
with
sufficient
time
in
between.
Health
effects
will
be
measured
using
‘biomarkers’,
identified
as
reliable
reflection
measurements
for
a
person’s
health
status,
and
that
can
in
such
a
study
design
be
measured
in
all
study
objects
at
the
same
moment.
The
choice
of
food
products
and
the
way
in
which
they
are
presented
are
factors
to
take
into
consideration.
This
point
will
be
touched
upon
later.
4.2.
Observational
studies
Another
way
to
study
health
effects
in
humans
are
the
so-called
observational
or
epidemiological
studies,
where
a
large
group
of
people
is
studied
using
questionnaires
usually
supplemented
with
some
measurements
in
a
smaller
part
of
the
group.
Control
is
much
less
as
people
themselves
report.
Investigations
can
look
back
at
eating
habits
in
the
past,
being
‘retrospective’,
or
follow
a
group
from
a
certain
moment
into
the
future,
being
‘prospective’.
Ques-
tions
need
to
address
many
more
factors
than
food,
e.g.,
life-style
factors
and
social
status,
to
be
able
to
rule
out
confounding.
So
a
large
group
of
people
needs
to
be
included
in
the
study.
4.3.
Intervention
studies
in
animals
As
highly
controlled
blinded
human
dietary
intervention
stud-
ies,
especially
if
intended
to
examine
long-term
physiological
responses,
are
very
expensive
and
difficult
to
realize,
health
effects
of
foods
are
usually
tested
in
animal
models.
Similar
to
human
intervention
studies,
in
such
experiments
laboratory
animals
such
as
rats,
mice,
chickens
and
rabbits
are
fed
organically
or
convention-
ally
grown
feeds,
and
selected
physiological
parameters
reflecting
measurements
of
health
status
are
analysed.
By
choosing
geneti-
cally
homogenous
populations
of
animals
and
keeping
them
under
highly
controlled
conditions
it
is
easier
to
point
out
health
effects
of
a
diet.
Moreover,
the
short
life
cycle
of
animals
allows
examining
effects
of
diets
on
more
than
one
generation.
Systematic
reviews
of
such
animal
studies
can
give
indications
of
possible
health
effects,
though
differences
between
animals
and
men
need
to
be
taken
into
account.
Final
confirmations
of
hypothesized
effects
need
eventu-
ally
to
be
verified
in
humans.
4.4.
In
vitro
studies
The
so-called
in
vivo
studies,
referring
to
experimentation
using
a
whole,
living
organism,
are
often
substituted/preceded
by
low-
cost
in
vitro
experiments.
This
type
of
research
aims
at
describing
the
effects
of
experimental
variables
on
the
organism’s
constituent
parts
(e.g.,
organs,
tissue-
or
cell
cultures,
cellular
components)
in
a
controlled
environment
outside
the
organism
(test
tubes,
Petri
dishes).
In
vitro
studies
are
highly
focused,
enabling
to
deduce
mechanisms
of
actions
and
to
control
many
confounding
variables.
However,
weakness
of
this
type
of
studies
is
the
uncertainty
that
the
effects
observed
at
cell
level
would
occur
in
the
‘real
world’
of
the
complex
living
organism.
The
scientific
value
of
different
study
designs
concerning
the
comparison
of
organically
and
conventionally
produced
food
is
pre-
sented
in
Table
1.
5.
Recent
in
vitro
studies
To
our
knowledge,
in
recent
years,
two
in
vitro
studies
have
been
published
comparing
health-related
properties
of
organic
vs
conventional
foods.
The
first
study
analysed
antioxidative
and
antimutagenic
activity
of
organically
vs
conventionally
produced
green
vegetables
(qing-gen-cai,
Chinese
cabbage,
spinach,
Welsh
onion
and
green
pepper)
[34].
The
authors
found
antioxidative
activity
in
the
organic
vegetables
to
be
much
higher
than
that
in
the
conventional
ones.
Moreover,
organic
vegetable
juices
exhib-
ited
significantly
stronger
suppresive
effects
against
mutagens.
The
second
study
compared
the
effects
of
extracts
from
organically
and
Please
cite
this
article
in
press
as:
M.
Huber,
et
al.,
Organic
food
and
impact
on
human
health:
Assessing
the
status
quo
and
prospects
of
research,
NJAS
-
Wageningen
J.
Life
Sci.
(2011),
doi:10.1016/j.njas.2011.01.004
ARTICLE IN PRESS
G
Model
NJAS-75;
No.
of
Pages
7
4M.
Huber
et
al.
/
NJAS
-
Wageningen
Journal
of
Life
Sciences
xxx (2011) xxx–
xxx
Table
1
Scientific
value
of
different
study
designs
for
comparing
organically
and
conventionally
produced
food,
with
examples.
Study
design
Examples
Intervention
studies
Controlled
studies
in
humans
Power of the proof
Observational
or
epidemiological
studies Prospective
cohort
studies
Retrospective
cohort
studies
Intervention
studies
Controlled
studies
in
animals
Supportive
studies
Bioavailability
studies
In
vitro
studies
Adapted
from
GRADE
Working
Group
[60].
conventionally
grown
strawberries
on
the
proliferation
of
colon-
and
breast-cancer
cells
[35].
The
results
showed
higher
antiprolif-
erative
activity
of
extracts
from
organically
grown
strawberries
on
both
types
of
cancer
cells,
which
was
probably
due
to
a
higher
con-
tent
of
secondary
metabolites
with
anticarcinogenic
properties
in
these
fruits.
These
results
suggest
a
possible
mechanism
by
which
organic
foods
could
reduce
human
cancer
risks.
6.
Recent
animal
studies
During
the
last
50
years
several
animal
dietary
intervention
studies
have
been
carried
out
investigating
the
health
effects
of
organic
vs
conventional
feeds
[36].
Most
of
these
studies
con-
firmed
beneficial
effects
of
organic
feeds
on
development
rate
and
reproductive
abilities
of
laboratory
animals
[37–39].
Moreover,
ani-
mal
studies
published
in
recent
years
indicated
increased
immune
parameters
in
organically
fed
laboratory
animals.
In
a
dietary
study
with
rats,
comparing
the
effects
of
protein-poor
organic
and
con-
ventional
feed
Finamore
et
al.
[40]
found
higher
levels
of
stimulated
lymphocyte
proliferation
in
the
rats
fed
organic
feed.
Lauridsen
et
al.
[41]
found
higher
immune
system
reactivity
in
organically
fed
rats,
indicated
by
the
level
of
IgG
in
blood
serum,
as
well
as
a
lower
amount
of
fat
tissue
and
more
relaxed
behaviour.
A
pilot
experiment
by
Bara ´
nska
et
al.
[42]
showed
higher
splenocyte
prolif-
eration
in
male
organically
fed
rats.
According
to
a
study
performed
in
the
Netherlands
[43],
chickens
fed
an
organic
diet
had
lower
body
weights,
higher
immune
reactivity
and
stronger
catch-up
growth
after
a
challenge.
In
this
study
the
concept
of
‘resilience’
was
proposed,
as
to
indicate
physiological
elasticity
to
come
back
to
homeostasis
after
a
disturbance.
Resilience
is
a
well
known
concept
in
ecology
and
psychology
[44],
and
is
worth
investigating
for
its
value
in
evaluating
physiological
effects
of
organic
food
products,
as
these
are
grown
with
the
aim
to
be
more
‘robust’
than
conventional
products.
In
summary,
animal
studies
on
the
health
effects
of
organic
vs
conventional
feeds
are
sparse.
Therefore
further,
well-planned
long-term
experiments
are
necessary
to
evaluate
the
overall
health
status
of
laboratory
animals
fed
on
feeds
from
different
agricultural
production
systems.
7.
Recent
studies
in
humans
7.1.
Observational
studies
To
our
knowledge,
only
a
few
observational
studies
investi-
gating
the
health
effects
on
humans
of
organic
compared
with
conventional
foods
have
been
performed
in
recent
years.
Accord-
ing
to
one
of
these
studies,
commonly
named
the
PARSIFAL
study
(14,000
children,
5
European
countries),
children
representing
an
anthroposophical
lifestyle
(including
biodynamic
and
organic
food)
were
found
to
have
less
allergies
and
a
(not
statistically
significant)
lower
body
weight
compared
with
a
group
consuming
convention-
ally
produced
foods
[45].
At
the
same
time
the
results
of
the
KOALA
Birth
Cohort
Study
in
the
Netherlands
(about
2700
newborns)
asso-
ciated
the
lower
eczema
risk
in
children
at
the
age
of
2
years
with
the
consumption
of
organic
dairy
products
[46].
Moreover,
organic
dairy
consumption
resulted
in
higher
CLA
levels
in
breast
milk
of
their
mothers
[47].
According
to
a
study
of
Rembiałkowska
et
al.
[48]
consumers
of
organic
food
assessed
their
health
status
signifi-
cantly
better
than
consumers
of