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Preliminary Observations on the Effect of Dietary Brussels Sprouts on Thyroid Function

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M. McMillan
M. McMillan
M. McMillan
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E.A. Spinks
E.A. Spinks
E.A. Spinks
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G.R. Fenwick
G.R. Fenwick
G.R. Fenwick
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Abstract

1 Brassica vegetables are the major source of glucosinolates in the human diet. Certain glucosinolates are readily converted into goitrogenic species, notably 5-vinyloxazolidine-2-thione and thiocyanate ion. The effect of dietary Brussels sprouts, a particularly rich source of such glucosinolates, on thyroid function has been examined. 2 Inclusion of cooked Brussels sprouts (150 g daily for 4 weeks) into a normal diet of 10 volunteer subjects had no effect on thyroid function as determined by measurement of thyrotrophic hormone, thyroxine and tri-iodothyronine even though the sprouts contained high concentrations (220 mg/100 g) of glucosinolates. 3 In view of the reported antithyroid activity of 5-vinyloxazolidine-2-thione it is suggested that this lack of activity of cooked Brussels sprouts is due to inactivation during cooking of myrosinase, the specific glucosinolate-degrading enzyme.
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Preliminary
Observations
on
the
Effect
of
Dietary
Brussels
Sprouts
on
Thyroid
Function
M.
McMillan,
E.
A.
Spinks
1
&
G.
R.
Fenwick
1
Department
of
Chemical
Pathology,
Lewisham
Hospital,
London
SE13
6LH,
and
1
AFRC
Food
Research
Institute,
Colney
Lane,
Norwich
NR4
7UA,
UK
1
Brassica
vegetables
are
the
major
source
of
glucosinolates
in
the
human
diet.
Certain
gluco-
sinolates
are
readily
converted
into
goitrogenic
species,
notably
5-vinyloxazolidine-2-thione
and
thiocyanate
ion.
The
effect
of
dietary
Brussels
sprouts,
a
particularly
rich
source
of
such
gluco-
sinolates,
on
thyroid
function
has
been
examined.
2
Inclusion
of
cooked
Brussels
sprouts
(150
g
daily
for
4
weeks)
into
a
normal
diet
of 10
volunteer
subjects
had
no
effect
on
thyroid
function
as
determined
by
measurement
of
thyrotrophic
hormone,
thyroxine
and
tri-iodothyronine
even
though
the
sprouts
contained
high
concentrations
(220
mg/100
g)
of
glucosinolates.
3
In
view
of
the
reported
antithyroid
activity
of
5-vinyloxazolidine-2-thione
it
is
suggested
that
this
lack
of
activity
of
cooked
Brussels
sprouts
is
due
to
inactivation
during
cooking
of
myrosinase,
the
specific
glucosinolate-degrading
enzyme.
Introduction
Green
vegetables
form
a
significant
part
of
the
UK
diet
and
their
consumption
is
presently
being
actively
encouraged
by
the
medical
profession.
The
majority
of
the
green
vegetables
consumed
in
this
country
are
brassicas,
e.g.
cabbage,
Brussels
sprouts
and
cauli-
flower.
These,
together
with
roots
such
as
swede
and
turnips,
contain
varying
proportions
of
glucosino-
lates
(mustard
oil
glucosides)
(I;
Figure
1),
com-
pounds
generally
considered
to
be
responsible
for
a
range
of
undesirable,
antinutritional
and
toxic
effects
(Fenwick et
al.,
1983a).
Such
effects
have
generally
been
observed
after
the
feeding
to
livestock
and
poultry
of
oilseeds
(especially
rapeseed),
or
their
products,
which
contain
high
levels
of
these
gluco-
sides ;
this
situation
has
resulted
in
the
introduction
and
cultivation
of
new
varieties
containing
very
much
lower
levels
of
these
compounds
(Fenwick,
1984).
Among
the
undesirable
problems
associated
with
glucosinolates
(or,
more
accurately,
with
the
products
of
their
hydrolysis
which
is
brought
about
by
an
enzyme,
myrosinase,
generally
considered
to
be
present
in
all
glucosinolate-containing
plants)
those
affecting
the
thyroid
have
been
studied
in
particular
detail.
The
effect
has
been
linked
to
the
hydrolysis
products
of
two
glucosinolates
(progoitrin,
Ia;
gluco-
brassicin,
Ib),
namely
5-vinyloxazolidine-2-thione
(also
called
goitrin,
II)
and
thiocyanate
ion
(III)
Figure
1
Glucosinolates
in
Brussels
sprouts
and
their
goitrogenic
products.
(Figure
1).
The
former,
derived
from
progoitrin
is
the
more
potent,
exerting
its
effect
via
interference
of
thyroid-hormone
synthesis.
In
contrast,
thiocyanate
ion
competes
with
iodine
for
uptake
by
the
thyroid
gland.
Elfving
(1980)
has
considered
5-vinyl-
oxazolidine-2-thione
to
be
one
of
the
aetiological
factors
associated
with
endemic
goitre
in
Finland
and
there
have
been
a
number
of
reports
of
the
screening
16
of
milk
and
dairy
products
for
traces
(<
50
wg/1)
of
this
compound
(Benns
et
al.,
1979;
Josefsson,
1979).
As
part
of
a
continuing
study
(Heaney
&
Fenwick,
1980;
Fenwick
et al. ,
1983b;
Sones
et al. ,
1984a)
into
the
presence
and
properties
of
glucosinolates
and
their
hydrolysis
products
in
food
and
feedstuffs,
we
have
determined
the
levels
of
these
compounds
in
the
brassica
vegetables
and,
recently,
have
estimated
the
mean
daily
intake
of
glucosinolates
in
the
UK
(Sones
et
al.,
1984b).
The
results
obtained
suggested
that,
based
on
previous
assessment
of
its
goitrogenicity
in
humans,
the
amount
of
5-vinyloxazolidine-2-thione
potentially
present
in
the
diet
of
a
minority
(5%)
of
the
UK
population
would
be
expected
to
produce
a
discernible
effect.
The
following
study
was
therefore
conducted
to
examine
the
effect
of
a
realistic
intake
of
those
gluco-
sinolates
capable
of
yielding
goitrogenic
products
(via
the
consumption
of
Brussels
sprouts)
on
normal
thyroid
function
and
metabolism.
Materials
and
methods
From
previous
work
(Heaney
&
Fenwick,
1980)
it
was
possible
to
identify
a
variety
of
Brussels
sprout
particularly
rich
in
progoitrin.
These
sprouts
were
obtained
from
a
local
source
and
stored
at
+4°C
before
being
sent,
in
weekly
batches,
to
Lewisham
Hospital,
London,
UK.
Each
batch
was
analysed
individually
and
all
showed
a
content
of
glucosinolates
consistent
with
that
expected
of
this
variety.
The
feeding
trial
was
conducted
with
10
volunteer
subjects
(seven
male,
three
female)
who
were
healthy
non-resident
hospital
staff.
For
the
first
period
(phase
A)
of
2
weeks
they
maintained
their
normal
diet,
recording
any
consumption
of
brassica
vegetables,
to
establish
baseline
thyroid
hormone
concentrations.
Then,
in
the
second
period
(phase
B)
of
4
weeks,
150
g
of
sprouts,
boiled
or
steamed
for
a
standard
time
of
9
min,
were
included
daily
in
the
evening
meal.
In
the
third
period
(phase
C)
of
2-3
weeks
volunteer
subjects
excluded
brassicas
from
their
diet.
Over
the
whole
experimental
period
venous
blood
samples
were
collected
between
09.00
and
11.00
hours,
two,
three
or
four
times
per
week,
the
serum
was
separated
without
delay
and
stored
at -20°C
before
analysis
for
thyrotrophic
hormone
(TSH),
total
and
free
thyroxine
(T4)
and
total
tri-iodothyronine
(T3).
For
each
analyte
all
specimens
from
an
indivi-
dual
patient
were
included
in
the
same
assay
batch
together
with
appropriate
internal
quality-control
specimens.
All
assays
were
satisfactory
under
the
surveillance
of
national
external
quality
assessment
schemes.
Serum
TSH
was
measured
by
immunoradiometric
assay
employing
’ZSI-labelled
monoclonal
antibody
to
human
TSH,
immobilization
by
incubation
with
a
second
anti-TSH
monoclonal
antibody
coupled
to
solid
phase
and
separation
by
layering
in
sucrose
solution
(Boots-Celltech
Diagnostics
Ltd,
Slough,
Buckinghamshire,
UK).
The
limit
of
sensitivity
of
this
system
was
found
to
be
0.06-0.08
milli-units
(Ekins,
1970),
the
maximum
precision
was
1.8-2.8%
CV
with
CV
less
than
10%
at
analyte
concentrations
as
low
as
0.4-1.0
milli-units.
Serum
total
T4
was
determined
by
an
in-house
radioimmunoassay
with
double
antibody
separation.
Serum
total
T3
was
by
in-house
radioimmunoassay
with
polyethylene
glycol-assisted
double-antibody
separation.
Serum
free
T4
was
determined
by
using
the
Amerlex
kit
(Amersham
International).
Glucosinolate
contents
of
the
fresh
and
cooked
Brussels
sprouts
were
analysed
by
high-performance
liquid
chromatography
(Spinks et
al.,
1984).
The
cooked
material
was
set
aside,
randomly,
two
samples
per
week,
stored
at
-20°C
and
analysed
separately.
5-Vinyloxazolidine-2-thione
was
analysed
as
de-
scribed
by
Benns et
al.
(1979)
and
thiocyanate
ion
was
determined
spectrophotometrically
(Johnston
&
Jones,
1966).
Samples
of
Brussels
sprouts
were
ana-
lysed
for
myrosinase
content
by
a
method
as
described
by
Wilkinson
et
al.
(1984).
Results
The
fresh
Brussels
sprouts
contained
a
total
of
247
mg
of
glucosinolates/100
g
of
which
progoitrin
and
glucobrassicin
comprised
66
and
70
mg/100
g
re-
spectively.
After
cooking,
these
glucosinolate
con-
centrations
had
fallen
to
124-165
mg
(mean
148
mg)/
100
g;
40-53
mg
(mean
46
mg)/100
g
and
23-28
mg
(mean
26
mg)/100
g
respectively,
a
finding
broadly
in
agreement
with
that
reported
by
Sones et
al.
(1984b).
These
values
are
consistent
with
the
cooked
sprouts
being
a
major
dietary
source
of
progoitrin.
The
serum
thyroid
hormone
values
for
all
subjects
throughout
the
8
or
9
weeks
of
the
study
are
available
from
the
authors
on
request.
All
values of
total
T4
4
(60-160
nmol/1)
and
total
T3
(1.2-3.5
nmol/I
were
within the
respective
reference
ranges
and
there
were
no
significant
departures
from
the
reference
ranges
for
TSH
(0.2-7.0
milli-units)
and
free
T4
(8.8-23.0
pmol/1).
Small
daily
fluctuations
occurred
in
the
sub-
jects
as
well
as
in
two
additional
female
subjects
who
were
observed
during
the
first
phase
of
the
study
only.
Thcrc
were
no
consistent
changes
in
any
of
the
parameters
studied
in
either
phase
B
(with
sprouts)
or
in
phase
C
(excluding
all
brassicas)
(Table
1).
This
was
true
for
the
group
of
volunteer
subjects
as
a
whole
and
for
each
individual
within
it.
An
increase
in
secretion
of
TSH
is
recognized
as
the
earliest
indi-
cation
of
hypothyroidism
when
the
thyrotrophic
con-
trol
mechanism
is
intact.
Although
serum
TSH
con-
centrations
were
measured
with
sufficient
sensitivity
to
allow
detection
of
even
minimal
differences,
no
significant
increase
was
observed.
In
conditions
of
continued
dietary
iodine
deficiency
it
is
known
that
17
Table
1
Mean
serum
thyroid
hormone
concentrations
of
10
volunteer
subjects
TSH
=
thyrotrophic
hormone;
T4
=
thyroxine;
T3
=
tri-
iodothyronine
a
= see
Armitage
(1971)
T3
may
be
synthesized
preferentially
(Beckers
&
Delange,
1980).
Goitrin
is
believed
to
impede
cova-
lent
binding
of
iodine
to
thyroglobulin
and
prevent
the
oxidation
of
iodide
by
thyroid
iodide
peroxidase
(Gaitan,
1980).
In
any
event,
in
the
present
short-
term
study,
the
ratios
of
T3/F4
remained
unaltered.
Total
T4
remained
unchanged
and
there
was
a
posi-
tive
correlation
between
total
T4
and
free
T4
in
the
group
as
well
as
individuals,
indicating
that
brassica
ingestion
had
not
affected
the
amount
of
binding
protein
or
the
extent
of
binding.
It
appears
therefore
that
under
the
conditions
of
the
present
study
no
general
tendency
toward
alteration
in
thyroid
function
has
been
demonstrable.
Discussion
During
the
4-week
period
when
sprouts
were
con-
sumed
the
subjects
had
a
mean
daily
intake
of 222
mg
of
total
glucosinolates,
corresponding
to
69
mg
of
progoitrin
and
39
mg
of
glucobrassicin
respectively.
From
the
data
obtained
by
Sones et
al.
(1984b)
it
is
possible
to
estimate
that
5%
of
the
population
of
the
UK
have
a
daily
intake
of
glucosinolates
in
excess
of
200
mg
during
the
winter
months,
including
50
and
60
mg
of
progoitrin
and
glucobrassicin
respectively.
This
calculation
takes
account
of
environmental
and
agronomical
factors
and
of
the
fact
that,
due
to
the
autumn
and
winter
harvesting
of
glucosinolate-rich
Brussels
sprouts,
total
intake
during
the
winter
period
is
double,
and
that
of
progoitrin
five
times
greater
than,
that
in
the
summer.
It
should,
however,
be
emphasized
that
these
values
may
still
be
a
con-
siderable
underestimate
since
the
calculation
takes
no
account
of
the
intake of
processed
vegetables
or
of
those
grown
domestically
neither
of
which
sources
were
included
in
the
MAFF
intake
values
(Sones et
al.,
1984b).
The
levels
of
intake
therefore
in
the
present
study
may
be
seen
as
realistic.
The
great
proportion
of
brassicas
are
consumed
in
the
UK
after
cooking
or
processing,
during
which
the
myrosinase
would
be
expected
to
be
partly
or
totally
inactivated.
We
have
demonstrated,
in
the
course
of
other
work,
that
residual
myrosinase
can
be
detected
in
Brussels
sprouts
which
have
been
boiled
for
6-7
mins
(E.
A.
Spinks,
K.
Sones
&
G.
R.
Fenwick,
unpublished
work).
In
the
present
study
only
five
of
the
eight
cooked
sprout
samples
examined
possessed
detectable
myrosinase
activity,
ranging
from
1
to
4%
(mean
2.4%)
of
that
originally
present.
Subsequent
analysis
of
the
cooked
sprout
samples
failed
to
detect
any
free
5-vinyloxazolidine-2-thione
or
thiocyanate
ion;
thus
the
effect,
if
any,
of
the
sprouts
on
the
thyroid
function
may
be
supposed
to
be
a
result
of
the
intact
glucosinolates
or
of
any
metabolites
produced
therefrom
in
vivo.
Little
is
known
about
such
metabolism,
although
there
is
some
evidence
to
indicate
that
at
least
partial
breakdown
of
glucosinolates
does
occur
when
animals
and
poultry
consume
rapeseed
meal
in
which
the
endogenous
myrosinase
has
been
inactivated
(Greer,
1962;
Pearson et
al.,
1983).
In
man
it
has
been
ob-
served
(Oginsky et
al.,
1965)
that
glucosinolates
may
be
degraded
by
Paracolobactrum
and
Greer
&
Deeney
(1959)
have
reported
that
5-vinyloxazolidine-2-
thione
may
be
formed from
progoitrin
in
vivo
with-
out
the
necessity
of
a
source
of
exogenous
myrosinase.
It
would,
however,
seem
desirable
to
re-examine
this
report
by
using
modern
methods
of
analysis.
If
it
were
to
be
assumed
that
the
appropriate
precursors
yielded
5-vinyloxazolidine-2-thione
and
thiocyanate
ion
quantitatively
in
the
body,
then
daily
intakes
of
14
and
3
mg
respectively
would
result.
Moreover,
ad-
ditional
thiocyanate
ion
would
be
expected
to
result
from
the
metabolism
of
other
glucosinolate-derived
products;
for
example
nitriles
(via
the
effect
of
rho-
danase)
and
isothiocyanates
(Langer
&
Stolc,
1965).
Even
if
these
latter
processes
occurred
it
would
be
unlikely
that
the
level
of
thiocyanate
ion
would
reach
that
required
to
produce
an
effect
on
thyroid
function
since
it
has
been
reported
that
a
single
dose
of
250-
1000
mg
was
necessary
to
produce
a
significant
re-
duction
in
radioactive
iodine
uptake
(Vilkki et
al.,
1962).
More
recently,
Dahlberg et
al.
(1984)
have
shown
that
a
daily
intake
of
8
mg
of
thiocyanate
ion
(via
milk
containing
20
mg
of
thiocyanate/1)
for
12
weeks
had
no
observable
effect
on
thyroid
function.
The
situation
for
5-vinyloxazolidine-2-thione
is
rather
different,
since
the
potential
intake
in
the
present
study
(14
mg/day)
is
comparable
with
single
doses
(25-50
mg)
found
by
Vilkki et
al.
(1962)
and
Langer et
al.
(1971)
to
reduce
significantly
radio-
active
iodine
uptake
by
the
thyroid.
Peltola
&
Krusius
(1971)
have
also
shown
that
a
daily
dose
of
100-
400
wg
for
5-6
months
reduced
the
radioactive
iodine
uptake
of
patients
suffering
from
mild
thyrotoxicosis.
On
the
basis
of
these
results,
it
would
seem
unlikely
that
the
5-vinyloxazolidine-2-thione
would
not
have
shown
an
effect,
bearing
in
mind
the
sensitivity
of the
methods
used
in
the
present
study
to
monitor
thyroid
function.
It
is
considered
more
likely
that
the
lack
of
18
observed
effect
is
a
result
of the
absence
of
5-vinyl-
oxazolidine-2-thione
from
the
system,
either
because
the
parent
glucosinolates
are
not
being
broken
down
in
vivo,
or
because
such
breakdown
does
occur
but
does
not. yield
the
same
(goitrogenic)
product
as
is
produced
by
plant
myrosinase.
An
additional
possi-
bility
that
cannot
be
excluded
is
that
breakdown
to
5-vinyloxazolidine-2-thione
does
occur in
vivo
(as
reported
by
Greer
&
Deeney,
1959),
but
that
this
compound
is
subsequently
further
metabolized
to
non-goitrogenically
active
products.
Further
work
is
needed
to
distinguish
between
these
possibilities.
Langer
&
Michajlovskij
(1969)
and
Elfving
(1980)
have
observed
the
formation
of
4-hydroxy-5-vinyl-
oxazolidine-2-thione
(IV)
(Figure
1)
after
the
in-
jection
of
35S-labelled
goitrin
into
the
rat;
however,
according
to
the
former
workers,
this
metabolite
also
possessed
antithyroid
activity.
Other
chemical
changes
in
the
structure
of
oxazolidinethiones,
involving
ring
opening
and
polymerization,
have
been
observed
in
ruminants
(Lanzani et
al.,
1974).
While
these
might
be
expected
to
produce
changes
in
the
antithyroid
effects,
the
situation
in
man
is
unknown.
Further
work
is
clearly
necessary
to
elucidate
the
fate
of
dietary
glucosinolates
in
man.
Such
studies
would
also
be
relevant
to
the
reported
anticarcino-
References
genic
effects
of
a
variety
of
other
breakdown
products
of
indole
glucosinolates
(Fenwick et
al.,
1983a).
However,
on
the
basis
of
the
present
limited
study,
it
is
considered
that
concern
over
the
intake
of
signifi-
cant
amounts
of
goitrogens
via
the
consumption
of
boiled
green
vegetables
may
have
been
overstated.
The
vegetables
considered
here
have
been
cooked,
thus
inactivating
the
enzyme
responsible
for
forma-
tion
of
the
goitrogens.
Consumption
of
uncooked
(e.g.
coleslaw,
pickled
and
fermented
cabbage)
or
partially
cooked
brassicas
might
be
expected
to
lead
to
a
larger
intake
of
goitrogens
and
these
also
enter
the
body
via
milk
or
dairy
products
after
the
feeding
of
cattle
on
rapeseed,
brassica
forages
or
fodders.
Under
these
circumstances,
an
effect
on
normal
thyroid
function
may
be
observed,
particularly
among
selected
’at-risk’
groups,
e.g.
children
and
pregnant
women.
Studies
are
in
progress
to
examine
such
possibilities.
The
authors
are
grateful
to
Mr
R.
K.
Heaney,
Mr.
J.
Franklin
and
Dr
R.
Shepherd,
AFRC
Food
Research
Insti-
tute,
Norwich,
and
to
Dr
J.
G.
Vaughan,
Queen
Elizabeth
College,
London,
for
assistance
in
the
work
presented
here.
Thanks
are
also
due
to
Dr
D.
G.
Lindsay,
MAFF
Food
Science
Division,
for
originally
suggesting
this
study.
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... No human studies with the NF were provided by the applicant. The applicant addressed concerns related to glucosinolates by providing intakes of glucosinolates from the background diet and from the NF, and by referring to the scientific publications that reported on effects of glucosinolate intakes in various clinical trials (Langer et al., 1971;McMillan et al., 1986;Kensler et al., 2005;Shapiro et al., 2006). The applicant argues that based on these studies, so-called 'safe levels' for total and/or individual glucosinolates can be assumed. ...
... thiocyanate and isothiocyanates), which may add to the effect of goitrin on the iodine uptake. McMillan et al. (1986) examined the effect of 150 g cooked Brussels sprouts, given as part of a normal diet to 10 healthy volunteers over a period of 4 weeks, on thyroid function. The consumption of cooked Brussels sprouts had no effect on thyroid function as determined by measurement of TSH, thyroxine and triiodothyronine. ...
Safety of whole seeds of oilseed rape (Brassica napus L emend. Metzg.) as a novel food pursuant to Regulation (EU) 2015/2283
Article
Full-text available
  • Jan 2023
Following a request from the European Commission, the EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA) was asked to deliver an opinion on whole seeds of oilseed rape as a novel food (NF) pursuant to Regulation (EU) 2015/2283. The NF consists of seeds of oilseed rape, in particular double low white flowering varieties of Brassica napus (oilseed rape Brassica napus L. emend. Metzg). The NF's oilseed rape is produced following drying, cleaning and storage procedures traditionally used for oilseed rape in oil production. The NF is proposed to be used as an ingredient in 'Bread and rolls with special ingredients added' and 'Gluten free bread'. The target population is the general population. The highest daily intake of the NF was estimated for young children as 92.6 mg/kg body weight (bw) per day. The Panel notes that intakes of the NF can result in considerably increased levels of glucosinolates consumption as compared to intakes of glucosinolates from background diets. The Panel asked the applicant for additional studies to support the safety of the NF, but these were not provided. The Panel concludes that the safety of whole seeds of oilseed rape under the proposed conditions of use has not been established.
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... The hydrolysis of another class of glucosinolates, known as indole glucosinolates, leads to the release of thiocyanate ions that can rival with iodine for uptake by the thyroid gland. (23) One study in humans concluded that the uptake of 150 g/day of cooked Brussels sprouts for a span of four weeks had no negative influences on thyroid function (24) . This was linked with the fact that heating cruciferous vegetables denatures much or all of this probable goitrogenic effect. ...
... (23) Jagminder K. et al found that the goitrogenic potential of a plant or food depends upon the amount of active goitrogen present in it. Various procedures like soaking, washing, boiling and cooking can help in reducing the goitrogenic potency of these foods (34) On the other hand, McMillan M et al concluded that the consumption of 150 g/day of cooked cyanogenic plant food for four weeks had no effects on thyroid function (24) CONCLUSION Amiodarone drug induced the hyperthyroidism in rats treated for 13 weeks. The use of un cooked cabbage decrease the changes in the bone in both histological and radiographic evaluations ...
Effect of Amindarone induced hyper thyriodism on bone remodeling process: histological and radiodensitometric analysis. (Experimental study in rats)
Article
Full-text available
  • Apr 2019
ABSTRACT Objectives: The aim of the study was to evaluate the effect of Amindarone drug alone and in combination with cabbige on bone methabolism on both histological and radiographical . Subjects& Methods: 15 rats were allocated in three groups, in group (I) the rats received the amiodarone, group (II) rats received aminodarone and uncooked cabbage while group(III) serve as a control group, by the end of 13th week the rats were sacrified using an overdose of I.V. Phenobarbital.mandibles of the rats were subjected to histological and radiograghic examination . Results: on the radiographic examination of the rats’ mandible in group I that received the Amiodaron the bone density showed decrease with average of( 601 ± 203) while in group II that received the Amiodaron and cabbages showed less decrease in bone density with average of (730 ± 160.4) than the control group (group III) that showed average of bone density of (830 ± 139.5) there is a significant difference among the groups P<0.001. Conclusion: Amiodarone drug induced the hyperthyroidism in rats treated for 13 weeks. The use of un cooked cabbage decrease the changes in the bone in both histological and radiographic evaluations Key words: Amindarone, hyper thyriodism, Computed tomography, CT Bone density.
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... The results showed no significant changes in serum TSH, T4, or T3 levels, irrespective of the presence of Brussels sprouts in the diet. The authors suggested that goitrin, present in Brussels sprouts, was deactivated due to the cooking process, and therefore, a diet rich in Brussels sprouts did not affect the thyroid [46]. ...
Do Brassica Vegetables Affect Thyroid Function?—A Comprehensive Systematic Review
Article
Full-text available
Brassica vegetables are widely consumed all over the world, especially in North America, Asia, and Europe. They are a rich source of sulfur compounds, such as glucosinolates (GLSs) and isothiocyanates (ITCs), which provide health benefits but are also suspected of having a goitrogenic effect. Adhering to PRISMA guidelines, we conducted a systematic review to assess the impact of dietary interventions on thyroid function, in terms of the potential risk for people with thyroid dysfunctions. We analyzed the results of 123 articles of in vitro, animal, and human studies, describing the impact of brassica plants and extracts on thyroid mass and histology, blood levels of TSH, T3, T4, iodine uptake, and the effect on thyroid cancer cells. We also presented the mechanisms of the goitrogenic potential of GLSs and ITCs, the limitations of the studies included, as well as further research directions. The vast majority of the results cast doubt on previous assumptions claiming that brassica plants have antithyroid effects in humans. Instead, they indicate that including brassica vegetables in the daily diet, particularly when accompanied by adequate iodine intake, poses no adverse effects on thyroid function.
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... This observation agrees with others who did not note any harmful effects of different brassica vegetables on thyroid function in humans. The first published study of McMillan et al. (19) showed that the inclusion of cooked Brussels sprouts (150 g daily for four weeks) into a normal diet had no effect on their thyroid function, as determined by thyroid-stimulating hormone (TSH), T3, and T4 measurement, even though Brussels sprouts contain high amounts (220 mg/100 g) of glucosinolates. Shapiro et al. (20) did not observe any significant changes in TSH, T3, and T4 levels, or even consistent thyroidal toxicities, when broccoli sprouts were consumed for seven days (25 μmoL isothiocyanate; or 25 μmoL glucosinolate; or 100 μmoL glucosinolate per day). ...
Evaluation of the consumption of potentially goitrogenic food products in various models of plant-based diets in Poland
Article
Full-text available
  • Feb 2024
  • ACTA POL PHARM
The aim of this study was to evaluate the consumption frequency of the selected examples of goitrogenic foods in four different groups of people in Poland, who used traditional, vegetarian, vegan and pescovegetarian diets. The validated consumption frequency questionnaire of the examples of goitrogenic foods in four groups of people (n=365) on afore-mentioned diets, was performed in Poland in 2022. The statistical correspondence analysis model (CAM) was used to quantify and reveal potential relations between dietary habits and thyroid dysfunction, family history of thyroid disease, use of thyroid drugs (L-thyroxine, propylthiouracil, thiamazole), or iodine dietary supplements/drugs. Statistical analyses revealed an increased odds ratio more than 3, 8, and 6 times higher for tofu; plant-based meat; and soy beverages, respectively, by vegetarian’s vs traditional diet. Respondents with diagnosed hypothyroidism consumed soy, flax products, but avoided iodine-rich products. All respondents on traditional diet used iodine-rich products while 22% vegetarian and 23% vegan excluded them. CAM analysis did not show any relation between brassica vegetables and thyroid dysfunction. Despite the results obtained using food questionnaire were not combined with biochemicals data, some tendencies in food behavior among Polish vegans, vegetarians, and pescovegetarians appeared. Apart from some interesting correlations and tendencies, revealed in our study, further in-depth research, combined with biochemical analysis, will allow to better understand, and explain these observations. Still, the effort should be made in the future in equalizing the proportions of female and male participants of such studies, what should bring some additional data on the gender influence.
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... As far as the time of hypothyroidism induction is concerned, 5 weeks of experiment caused significant increase in TSH level and the decrease in T4 level, with no effect in T3, but for 10 weeks of experiment, no differences in TSH and T3 levels, and only significant decrease in T4 was noted in the iodine deficiency model [11,13]. The compensatory increase of TSH is recognized as the earliest indicator of hypothyroidism [19], according to the negative feedback between TSH and thyroid hormones. It was previously suggested that in case of the iodine deficiency, lack of changes in TSH levels may result from the effect of the adaptation of the animals, observed in the experiments lasting 8 weeks or longer [4,11]. ...
The Impact of Kohlrabi Sprouts on Various Thyroid Parameters in Iodine Deficiency- and Sulfadimethoxine-Induced Hypothyroid Rats
Article
Full-text available
  • Jul 2022
Brassica sprouts, as the rich source of dietary glucosinolates, may have a negative effect on thyroid function. In this study, kohlrabi sprouts diet, combined with two models of rat hypothyroidism, was tested. TSH, thyroid hormones and histopathology analysis were completed with the evaluation of immunological, biochemical, haematological parameters, cytosolic glutathione peroxidase, thioredoxin reductase in the thyroid, and plasma glutathione peroxidase. A thermographic analysis was also adapted to confirm thyroid dysfunction. The levels of TSH, fT3 and fT4, antioxidant enzyme (GPX) as well as histopathology parameters remained unchanged following kohlrabi sprouts ingestion, only TR activity significantly increased in response to the sprouts. In hypothyroid animals, sprouts diet did not prevent thyroid damage. In comparison with the rats with iodine deficiency, kohlrabi sprouts diet decreased TNF-α level. Neither addition of the sprouts to the diet, nor sulfadimethoxine and iodine deficiency, caused negative changes in red blood cell parameters, glucose and uric acid concentrations, or kidney function. However, such a dietary intervention resulted in reduced WBC levels, and adversely interfered with liver function in rats, most likely due to a higher dietary intake of glucosinolates. Moreover, the possible impact of the breed of the rats on the evaluated parameters was indicated.
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... Therefore, augmented consumption of broccoli in the present study may have compromised the thyroid gland's function and subsequently elicited a negative effect on the liver (27). However, it is important to emphasize that broccoli, particularly if cooked, does not constitute much of a threat to thyroid hormones synthesis in humans (28). ...
Broccoli consumption attenuates inflammation and modulates gut microbiome composition and gut integrity-related factors in mice fed with a high-fat high-cholesterol diet
Article
Full-text available
  • Sep 2021
Background: Nonalcoholic fatty-liver disease (NAFLD) is a global health problem associated with gut dysbiosis and intestinal permeability. Broccoli is a natural source of bioactive phytochemicals, characterized by health-promoting properties. Objective: This study evaluated the effect of broccoli florets and stalks on liver fat accumulation, inflammation, gut microbiome, and intestinal barrier integrity. Design: Male C57BL/6J mice (n = 32, 8-week-old) were fed with a high-fat high-cholesterol diet (HFCD) with/without 15% broccoli (florets or stalks) for 7 weeks. Liver damage was evaluated by changes in glucose response and histological and biochemical parameters. Protein and gene expressions related to liver inflammation were examined. The effect of broccoli on microbiota population together with genes related to barrier integrity in the gut was investigated. Results: Dietary broccoli improved the glycemic response assessed by oral glucose tolerance test (OGTT). Histological evaluation showed no change in hepatic steatosis. Broccoli consumption also attenuated inflammation as revealed by lower inducible nitric oxide synthase (iNOS) and serum amyloid A1 (SAA1) expression levels in broccoli-supplemented groups. Gut microbiota analysis demonstrated elevated Acidifaciens and reduced Mucispirillum schaedleri abundance in the stalks group, whereas Proteobacteria strains abundance was increased in the florets group. Gut integrity remained unchanged. Conclusion: Broccoli supplementation improves glucose tolerance, attenuates liver inflammation, and alters microbial composition, but does not affect gut integrity. This research provides new evidence on the effects of dietary broccoli under HFCD.
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Brassica Vegetables and Hypothyroidism
Chapter
  • Oct 2024
Consuming vegetables from the Brassica genus is not just a dietary choice but a health-conscious decision. The vegetables, rich in over 100 diverse β-thioglucoside-N-hydroxysulfates, known as glucosinolates, have been linked to myriad health benefits. When the glucosinolates interact with the enzyme myrosinase, typically after chewing, they form isothiocyanates, some immediately broken down to release a permanently charged thiocyanate ion. Glucosinolates’ enzymatic and non-enzymatic breakdown produces major isothiocyanates, thiocyanates, nitriles, indole-3-carbinol, and diindolylmethane dimers.
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Comprehensive overview of glucosinolates in crucifers: occurrence, roles, metabolism, and transport mechanisms—a review
Article
Full-text available
Plants of the Brassicaceae family exhibit a sophisticated defense mechanism against plant pathogens and insect herbivores, leading to the production of diverse hydrolytic derivatives such as thiocyanates, isothiocyanates, nitriles, and epithionitriles. These chemical transformations are catalyzed through the enzymatic action of myrosinase on glucosinolates (GSLs), which are otherwise inactive in the intact plant. The hydrolytic products of GSLs are incredibly effective at protecting plants from pests, weeds, herbivores, bacterial and fungal attack. The impact of GSLs on animal health is multifaceted, with nutritional attributes varying based on chemical structure and concentration. While certain GSLs and their derivatives in Brassica plants are associated with health benefits and cancer prevention, others have been linked to goitrogenic effects in ruminants, with concentrations ranging from 50 to 120 μmol g⁻¹. This variability has implications for the use of rapeseed–mustard meal in food and feed. Despite considerable efforts to modify the chemical profile of GSLs in Brassica species, a comprehensive understanding of their composition and metabolism is still essential for achieving effective and targeted manipulation. This review aims to consolidate both foundational and recent advancements in GSLs research, with a focus on their biological properties, role in plant-pathogen interactions, transport and strategies for managing their accumulation in Brassica seeds. Our goal is to enhance the utilization of this crop by maximizing its potential benefits. This information could be pivotal in developing new varieties with tailored GSLs content and profile, resulting in improved crop yields, enhanced nutritional quality, and greater biofumigation efficacy, thereby benefiting both agriculture and human health.
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Environmental Factors Affecting Thyroid-Stimulating Hormone and Thyroid Hormone Levels
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Thyroid hormones are necessary for the normal functioning of physiological systems. Therefore, knowledge of any factor (whether genetic, environmental or intrinsic) that alters the levels of thyroid-stimulating hormone (TSH) and thyroid hormones is crucial. Genetic factors contribute up to 65% of interindividual variations in TSH and thyroid hormone levels, but many environmental factors can also affect thyroid function. This review discusses studies that have analyzed the impact of environmental factors on TSH and thyroid hormone levels in healthy adults. We included lifestyle factors (smoking, alcohol consumption, diet and exercise) and pollutants (chemicals and heavy metals). Many inconsistencies in the results have been observed between studies, making it difficult to draw a general conclusion about how a particular environmental factor influences TSH and thyroid hormone levels. However, lifestyle factors that showed the clearest association with TSH and thyroid hormones were smoking, body mass index (BMI) and iodine (micronutrient taken from the diet). Smoking mainly led to a decrease in TSH levels and an increase in triiodothyronine (T3) and thyroxine (T4) levels, while BMI levels were positively correlated with TSH and free T3 levels. Excess iodine led to an increase in TSH levels and a decrease in thyroid hormone levels. Among the pollutants analyzed, most studies observed a decrease in thyroid hormone levels after exposure to perchlorate. Future studies should continue to analyze the impact of environmental factors on thyroid function as they could contribute to understanding the complex background of gene–environment interactions underlying the pathology of thyroid diseases.
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The Quantitative Analysis of Glucosinolates in Cruciferous Vegetables, Oilseeds and Forage Crops Using High Performance Liquid Chromatography
Article
  • Jan 1984
An hplc method of glucosinolate analysis is described which allows the quantitative determination of these compounds in cruciferous oilseeds, vegetables and forage crops. The method compares favourably with a gas chromatographic technique for individual glucosinolate analysis and has several advantages which are particularly useful for the analysis of seed and leaf material. Whilst no attempt has been made to optimise the analytical procedures to allow the rapid screening of breeding programmes, this would not appear to be limiting.Die quantitative Analyse von Glucosinolaten in Cruciferen-Gemüse, -Ölsaaten und -Futterpflanzen mittels Hochleistungs-Flüssigkeits-ChromatographieDas HPLC-Verfahren der Glucosinolatanalyse wird beschrieben, mit dem man diese Verbindungen in Ölsamen, Gemüse und Futterpflanzen von Kreuzblütlern quantitativ bestimmen kann. Im Vergleich zu der Gaschromatographiemethode für die individuelle Glucosinolatanalyse hat das HPLC-Verfahren mehrere Vorteile, die besonders zweckdienlich bei der Analyse von Samen- und Blattmaterial sind. Es wurde nicht versucht, das analytische Verfahren so zu optimieren, daß es in Züchtungsprogrammen für eine erste schnelle Auslese in großen Analysenserien bereits anwendbar ist; aber es scheint, daß dieses durchaus möglich ist.
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Variations in the thiocyanate content of kale varieties
Article
Thiocyanate is widely distributed in Brassica crops. It has been frequently reported that these crops show goitrogenic activity and lead to reduced fertility in livestock. A simple colorimetric method for the determination of the thiocyanate in freeze-dried samples of Brassica plants has been used to study variations within the plants and among varieties. Intra-plant variation was found to be large with the highest concentrations in young leaves, necessitating the use of a carefully controlled sampling technique. Significant inter-varietal differences were found which indicate that it may be possible to breed new kale varieties with a lower thiocyanate content than that present in current varieties grown as food for livestock.
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Bitterness in Brussels-sprouts (Brassica-Oleraceal Var Gemmifera) – the role of glucosinolates and their breakdown products
Article
The bitterness associated with certain cultivars of Brussels sprouts has been shown to be linked to the presence of the glucosinolates, sinigrin and progoitrin. Whereas the former compound is bitter per se, the bitterness associated with the latter compound is due to its decomposition product, the goitrogen (-)5-vinyloxazolidine-2-thione. A method is described for the screening of cultivars of this, and other, Brassica vegetables for potential bitterness.
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An estimate of the mean daily intake of glucosinolates from cruciferous vegetables in the UK
Article
Samples (174) of cabbage, Brussels sprouts, cauliflower and swede-turnip have been analysed for total and individual glucosinolate content in both the fresh and cooked form. Using data from the 1980 National Food Survey, the national mean daily intake is calculated to be 46.1 mg in fresh material, and 29.4 mg in cooked. There are large variations within the UK (for example in Scotland it is less than half that in south-west of England), between income groups and over the year. National mean daily intake figures for the glucosinolates yielding goitrogenic products such as oxazolidine-2-thiones and thiocyanate ion are 6.7 and 14.7 mg respectively; the former figure is approximately doubled in the winter months. Based upon the above variations, arising from eating habits in the UK, together with the known large variation in glucosinolate content in cruciferous plants because of agronomic and environmental effects, it is likely that certain individuals will consume more than 300 mg total glucosinolates per day. The nutritional and toxicological consequences of such an intake are unknown at present.
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Rapeseed meal and egg taint: Effects of B. campestris meals, progoitrin and potassium thiocyanate on trimethylamine oxidation
Article
The inclusion of Candle (low glucosinolate) and Yellow Sarson (high glucosinolate) rapeseed meals in the diet of laying hens (100 g kg−1 for 14 days) depressed the oxidation of trimethylamine (TMA) by about 34% and 77% respectively and raised the mean TMA content of their eggs to 0.56 and 1.47 μg g−1. A dehulled, extracted Yellow Sarson meal had only a slight effect. A high glucosinolate B. napus meal suppressed TMA oxidation almost completely when fed for only 4 days. Differences in the tainting potential of the meals were related to their progoitrin contents. When fed alone this substance had a comparable effect on TMA oxidation which was due to the formation of goitrin in the gastrointestinal tract and its inhibition of TMA oxidase. Potassium thiocyanate (250 and 1000 mg kg−1 diet for 14 days) had no effect on TMA oxidation. It is concluded that neither the breeding of low glucosinolate cultivars of rapeseed nor treatment of the meal is likely to provide a practicable solution to the taint problem and that the elimination of the tainting defect from commercial stock by selective breeding would be more effective.
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Glucosinolates in Brassica vegetables. Analysis of 27 cauliflower cultivars (Brassica oleracea L. var botrytis subvar cauliflora DC)
Article
The glucosinolate content of 27 cultivars of commercially grown cauliflower have been determined. The levels of total glucosinolates (<120 mg 100 g−1 fresh wt) were comparable with those previously reported for cabbage, but much lower than those found in Brussels sprouts. The major individual glucosinolates were identified as those possessing prop-2-enyl-, 3-methylsulphinylpropyl-, 3-indolylmethyl- and 1-methoxy-3-indolylmethyl- side chains. Smaller amounts of but-3-enyl-, 2-hydroxybut-3-enyl-, 3-methylthiopropyl-, 4-methylthiobutyl-, 2-phenylethyl-, pent-4-enyl-, 2-hydroxypent-4-enyl- and 5-methylthiopentyl-glucosinolates were also measured in some cultivars, the last three compounds not previously having been reported in cauliflower. Environmental effects, determined for the cultivars Wallaby, Coolabah, Barrier Reef and Snowy River were much less than previously found in Brussels sprouts.
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Glucosinolates in Brassica vegetables. Analysis of 22 varieties of Brussels sprout (Brassica oleracea var. gemmifera)
Article
The glucosinolate content of 22 cultivars of Brussels sprout have been determined. The levels of total glucosinolates, determined by methods based on glucose release and gas chromatography, were substantially higher than those reported by other workers for cabbage and Chinese cabbage. The major glucosinolates in Brussels sprout leaf material were identified as gluconapin, progoitrin, sinigrin and glucobrassicin, with the latter two generally predominating. Detailed analysis of the material from five different growing sites has shown considerable variation in the total content but surprisingly little difference in the relative proportions of the individual glucosinolates within each cultivar. The glucosinolates of the corresponding seed material differ significantly from that in leaf; in particular glucobrassicin is found in trace amounts only, and glucoerucin, glucotropaeolin and neoglucobrassicin are all present, in addition to sinigrin, progoitrin and gluconapin.
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