Long-term effects of prenatal omega-3 fatty acid intake on visual function in school-age children.

Abstract

To assess the long-term effect on visual development of omega-3 polyunsaturated fatty acid (n-3 PUFA) intake during gestation.
Using visual evoked potentials (VEPs), the long-term effects on visual development were evaluated in 136 school-age Inuit children exposed to high levels of n-3 PUFAs during gestation. VEP protocols using color and motion stimuli were used to assess parvocellular and magnocellular responses. Concentrations of the two major n-3 PUFAs (docosahexaenoic acid [DHA] and eicosapentaenoic acid [EPA]) were measured in umbilical cord and child plasma phospholipids, reflecting prenatal and postnatal exposure, respectively.
After adjustment for confounders, cord plasma DHA level was found to be associated with shorter latencies of the N1 and P1 components of the color VEPs. No effects were found for current n-3 PUFA body burden or motion-onset VEPs.
This study demonstrates beneficial effects of DHA intake during gestation on visual system function at school age. DHA is particularly important for the early development and long-term function of the visual parvocellular pathway.

Full text

Page 1

Long-Term Effects of Prenatal Omega-3 Fatty Acid Intake on Visual
Function in School-Age Children
Caroline Jacques, MSc, Emile Levy, MD, PhD, Gina Muckle, PhD, Sandra W. Jacobson, PhD, Ce ´lyne Bastien, PhD,
E´ric Dewailly, MD, PhD, Pierre Ayotte, PhD, Joseph L. Jacobson, PhD, and Dave Saint-Amour, PhD
Objective To assess the long-term effect on visual development of omega-3 polyunsaturated fatty acid (n-3
PUFA) intake during gestation.
Study design Using visual evoked potentials (VEPs), the long-term effects on visual development were evaluated
in 136 school-age Inuit children exposed to high levels of n-3 PUFAs during gestation. VEP protocols using color
and motion stimuli were used to assess parvocellular and magnocellular responses. Concentrations of the two ma-
jorn-3PUFAs(docosahexaenoicacid[DHA]andeicosapentaenoicacid[EPA])weremeasuredinumbilicalcordand
child plasma phospholipids, reflecting prenatal and postnatal exposure, respectively.
Results After adjustment for confounders, cord plasma DHA level was found to be associated with shorter laten-
cies of the N1 and P1 components of the color VEPs. No effects were found for current n-3 PUFA body burden or
motion-onset VEPs.
Conclusion This study demonstrates beneficial effects of DHA intake during gestation on visual system function
at school age. DHA is particularly important for the early development and long-term function of the visual parvo-
cellular pathway. (J Pediatr 2011;158:83-90).
L
and continues throughout the first postnatal year. Adequate intake of essential fatty acids during the prenatal and postnatal
periods is particularly important for optimal fetal and neonatal brain development.2
Eicosapentaenoic acid (EPA) (20:5n-3) and docosahexaenoic acid (DHA) (22:6n-3) are two of the most important omega-3
polyunsaturated fatty acids (n-3 PUFAs). Although EPA and DHA can be synthesized in the liver from their precursor, a-li-
nolenic acid (ALA) (18:3n-3), only small amounts are produced in humans. Thus, intake of large quantities from dietary sour-
ces is needed, particularly from fish, seafood, and sea mammals. DHA is the principal n-3 PUFA found in the brain and is also
highly concentrated in the photoreceptor outer segment membranes of the retina.3DHA plays an important role in sensory,
perceptual, cognitive, and motor function.4In animals, inadequate DHA intake during early visual development leads to de-
creased DHA concentrations in the brain and retina, resulting in impaired neurogenesis, neurotransmitter metabolism, and
visual function.5Inadequate EPA intake has been associated with poorer motor function and mood disorders, but its impor-
tance in visual and brain development is less well understood.4
Previous studies on the effects of dietary n-3 PUFAs on the visual system have focused on postnatal supplementation in term
and preterm infants. Beneficial effects on vision have been demonstrated most
clearly in preterm infants receiving supplementation during the first months of
life.6Furthermore, only visual acuity, measured either behaviorally or, more of-
ten, electrophysiologically using visual evoked potentials (VEPs), has been tested
in these studies. Because VEPs reflect the maturation and the functional integrity
ofthevisualsystem,damagealongvisualpathwaysleadstoabnormalVEPlatency
and/oramplitude.Thevisualsystemcomprisestheparvocellularandthemagno-
cellularpathways,whichcarrydifferenttypesofinformation.7Themagnocellular
pathway is optimally sensitive to low-to-medium spatial frequencies, low achro-
ipids influence neuronal function by modifying characteristics of the membrane, gene expression, and eicosanoı ¨d syn-
thesis, all of which play critical roles in metabolism, growth, and differentiation of cells.1Considerable accumulation of
long-chain polyunsaturated fatty acids occurs in neural and retinal membranes during the third trimester of gestation
From the Sainte-Justine University Hospital Research
Center, Montreal, Quebec, Canada (C.J., E.L., D.S.-A.);
Department of Nutrition, Universite ´ de Montre ´al,
Montreal, Quebec, Canada (C.J., E.L.); School of
Psychology, Universite ´ Laval, Quebec, Canada (G.M.,
C.B.); Research Axis in Population and Environmental
Health, CHUQ Research Center, Quebec, Canada
(G.M., E.D., P.A.); Department of Psychiatry and
Behavioral Neurosciences, Wayne State University
School of Medicine, Detroit, MI (S.J., J.J.); Laboratory of
Human Behavioral Neurosciences, Universite ´ Laval/
Robert-Giffard Research Center, Beauport, Quebec,
Canada (C.B.); Department of Ophtalmology, Universite ´
de Montre ´al, Montreal, Quebec, Canada (D.S.-A.); and
Department of Psychology, Universite ´ du Que ´bec a `
Montre ´al, Montreal, Quebec, Canada (D.S.-A.)
Supported by grants from the National Institute of Envi-
ronmental Health and Sciences/US National Institutes of
Health(R01ES07902,toJ.J.),IndianandNorthernAffairs
Canada-Northern Contaminants Program (to G.M.), the
State of Michigan (Joseph Young Sr Grant, to S.J.), the
Nunavik Regional Board of Health and Social Services,
and the Canadian Institutes of Health Research (to D.S-
A.). The authors declare no conflicts of interest.
0022-3476/$ - see front matter. Copyright ? 2011 Mosby Inc.
All rights reserved. 10.1016/j.jpeds.2010.06.056
DHA
EOG
EPA
FACT
n-3
PCB
PUFA
VEP
Docosahexaenoic acid
Electrooculograms
Eicosapentaenoic acid
Functional Acuity Contrast Test
Omega-3
Polychlorinated biphenyl
Polyunsaturated fatty acid
Visual evoked potential
83

Page 2

maticcontrasts,andhightemporalfrequencies.Theparvocel-
lular pathway, which mediates visual acuity, is optimally sen-
sitive to medium-to-high spatial frequencies, high contrast,
and low temporal frequencies. As a consequence, the magno-
cellularpathwayismoresensitivetomotionanalysis,whereas
the parvocellular pathway plays a major role in processing
stimulus details and chromatic analysis.8
We assessed the benefits associated with prenatal intake of
n-3 PUFAs in Inuit children living in Nunavik in northern
Que ´bec, Canada. Because fish and marine mammals com-
pose an important part of the Inuit diet, these individuals’
n-3 PUFA intake is substantially greater than that in most in-
dividuals in southern Canada.9However, this population is
also exposed to high levels of several environmental contam-
inants,10including methylmercury, polychlorinated biphe-
nyls, and lead, which were controlled statistically in this
study to isolate the beneficial effects of DHA and EPA. Using
twodifferentVEPparadigms,wemeasuredparvocellularand
magnocellular brain responses in school-age children to test
the hypothesis that the beneficial effects of perinatal n-3
PUFA intake reported during infancy in this population11
wouldcontinuetobeevidentinchildhood.Morespecifically,
we hypothesized that there are significant moderate associa-
tions between n-3 PUFAs and the parvocellular responses
considering that this system mediates visual acuity function,
which is improved by increased perinatal n-3 PUFA intake.
Methods
The sample for this VEP study comprised 171 Inuit children
(mean age, 11.3 years) and their mothers who had previously
participated in the Nunavik Cord Blood Monitoring Pro-
gram. This Canadian project was initiated in the early
1990s to detect environmental contaminants in the food
chain12and measure several toxicants and nutrients in um-
bilical cord blood samples of Inuit newborns from Nunavik.
Information on demographic background; smoking, alcohol,
and drug use during pregnancy; and other maternal charac-
teristics was obtained by maternal interview at the time of
testing. The following inclusion criteria were used: children
aged 10-13 years; no known ophthalmic, neurologic, or de-
velopmental disorder; no medication use; birth weight
$2500 g; and duration of gestation $37 weeks. Although
the duration of gestation was slightly less than 37 weeks for
4 children (2 children born between 36 and 37 weeks and 2
born between 35 and 36 weeks), these children’s VEP re-
sponses did not differ significantly from those of the others
(all P values >.10).
Visualscreeningassessmentsforcolorandacuitywereper-
formed using the Ishihara Test for Color Blindness and the
Snellen E-chart. Visual acuity was considered normal for
scores of 20/20 to 20/30. Visual function also was assessed us-
ing the Functional Acuity Contrast Test (FACT), which pro-
vides a fine measurement of near visual contrast sensitivity.
This test assesses orientation discrimination of high-quality
sine gratings (1.7 degrees of visual angle) at five spatial fre-
quencies (1.5, 3, 6, 12, and 18 cycles/degree) and nine con-
trast levels distributed in 5 rows of increasing contrast. The
contrast step between each grating is 0.15 log units. In each
row, the contrast diminishes from left to right, and the child
is asked to indicate whether the gratings are upright, to the
left, or to the right.
Adequateelectrophysiologicaldatawereobtainedfor136of
the171childrentested.Datawereinadequatebecauseoftech-
nical/computer problems (n =1), lack of cooperation with
visual acuity assessment (n = 6), insufficient signal-to-noise
ratio (n = 5), and poor visual acuity (# 20/40) in one or
both eyes (n = 23). Of the 136 children with adequate electro-
physiologicaldata,134weretestedforcolorVEPsand70were
testedformotion-onsetVEPs.Thestudydesignwasapproved
by the Ethics Committees of Sainte-Justine Hospital, Laval
University, and Wayne State University. Written informed
consent was obtained from a parent of each child and oral as-
sent was obtained from each child.
VEPs
Visual stimuli were generated with Presentation software
(Neurobehavioral Systems, Albany, California). The children
viewed the stimuli binocularly from a distance of 57 cm in
a dimly lit room (24?? 24?of visual field). They were in-
structed to fixate on a small red dot located in the center of
the screen (VP171b LCD monitor; ViewSonic, Walnut, Cal-
ifornia).Wheneverthereflectionofthestimuluswasnotcen-
tered over the child’s pupil, the examiner interrupted the
electrophysiological recording to readjust the child’s head.
Data were recorded with InstEP (InstepEP Systems Inc, Ile
Perrot, Quebec, Canada). Electrooculograms (EOGs) were
recorded from the outer canthus of each eye (horizontal
EOG) and above and below the right eye (vertical EOG).
VEPs were recorded from Oz, T5, and T6 derivations accord-
ing to the international 10-20 system using Ag–AgCl elec-
trodes. The reference and the ground electrodes were
located on the linked ear lobes and the forehead, respectively.
Impedance was kept below 5 kU. The electroencephalogram
signal was amplified and bandpass-filtered at 0.1-100 Hz
(sampling rate, 1000 Hz). One hundred trials were recorded
for each condition (see below). VEPs were time-locked to the
stimulus and averaged. Trials in which the response exceeded
75 mV at any recording site were rejected before averaging, to
eliminate ocular and muscular artifacts.
Parvocellular-related responses were recorded using an
equiluminant color VEP protocol. Chromatic-contrast grat-
ings (95% contrast, 1 cycle/degree) were generated by
superimposing in a counterphased manner red-black and
green-black gratings of identical luminance. At the beginning
of the study, a psychophysical experiment was conducted on
6childrentoassessequiluminanceforthecolorVEPprotocol
using heterochromatic flicker photometry. This method is
based on the observation that although the chromatic system
is generally too slow to follow rapid temporal changes, the
luminancesystemcandetectrapidlychangingluminancedif-
ferences between red and green. Therefore, if the perception
of the flicker is minimized, then the luminance difference is
minimized as well. Mean values obtained in this experiment
THE JOURNAL OF PEDIATRICS
? www.jpeds.com
Vol. 158, No. 1
84
Jacques et al

Page 3

were used to generate the color stimuli used for the entire
sample. The equiluminant gratingswere presented in a rever-
sal mode (2 reversals/second), which typically produces
a dominant negative component at ?100 ms after stimulus
onset, followed by a positive component.13
Magnocellular-related VEP responses were recorded using
a motion-onset paradigm that is optimal for eliciting robust
VEP responses with low intersubject variability.14Achro-
matic motion-onset detection was elicited by the presenta-
tion of initial stationary concentric gratings for a 1120-ms
period, followed by an abrupt onset (160 ms) of radial mo-
tion alternating at random intervals between expanding mo-
tion and contraction motion. In adults, such an onset/offset
duty cycle(13%,ie,160/160 +1120)producesatypicalP100/
N180 complex, in which N180 is the dominant motion-
related component.15In children, however, the negative
component is manifested only after 200 ms.16Spatial fre-
quency was decreased (1-0.2 cycle/degree), and motion ve-
locity was increased (by 5-25 degrees/second) toward the
periphery to account for different motion sensitivities in
the centerversus the periphery of the visual field.The tempo-
ral frequency (5 cycles/second) was thus kept constant over
the whole stimulus field. Sinusoidal modulation of lumi-
nance and low contrast stimuli (10%) were used to eliminate
high spatial frequencies and selectively target the magnocel-
lular processing.17
Biological Samples
Umbilical cord and child blood samples were analyzed for
concentrations of n-3 PUFAs (DHA andEPA), as well as total
mercury (Hg), polychlorinated biphenyls (PCBs), lead (Pb),
and selenium (Se). A 30-mL blood sample obtained from
the umbilical cord was used as an indicator of prenatal expo-
sure;a20-mLvenousbloodsampleobtainedfromeachpartic-
ipant was used to document body burden at time of testing.
Contaminant analyses were performed at the Centre de Toxi-
cologieduQue ´bec,whichisaccreditedbytheCanadianAsso-
ciation for Environmental Analytical Laboratories. Fatty acid
compositions of plasma phospholipids were measured at the
University of Guelph Lipid Analytical Laboratory using capil-
lary gas-liquid chromatography. A 200-mL aliquot of plasma
was extracted after the addition of chloroform:methanol (2:1
vol/vol) in the presence of a known amount of internal stan-
dard (diheptadecanoyl phospholipid). Total phospholipids
were isolated from the lipid extract by thin-layer chromatog-
raphy using heptane:isopropyl ether:acetic acid (60:40:3 by
vol) as the developing solvent. After transmethylation with
BF3/methanol, the fatty acid profile was determined by capil-
lary gas-liquid chromatography. Concentrations of DHA and
EPA were expressed as percentages of the total area of all fatty
acidpeaksfromC14:0toC24:1(%weight).Concentrationsof
the 14 most prevalent PCB congeners (IUPAC nos. 28, 52, 99,
101,105, 118, 128, 138, 153, 156, 170, 180, 183, and 187)were
measured in purified plasma extracts using a high-resolution
gas chromatograph (HP 5890 Series II Plus; Hewlett-
Packard, Palo Alto, California) equipped with a 30-m J&W
DB-5 column and an HP 5890B mass spectrometer (Agilent,
Santa Clara, California) according to the method described
by Dallaire et al.18Compounds are automatically extracted
from the aqueous matrix using solid-phase extraction. The
limitofdetection(LOD)was<0.05mg/LforallPCBcongeners
except PCB-52 (LOD = 0.15 mg/L). Total Hg, Pb, and Se con-
centrations were measured in whole blood samples by induc-
tivelycoupled plasmamassspectroscopy(using a Sciex ELAN
6000 instrument for Pb and Se and an ELAN DRC II instru-
ment for Hg; PerkinElmer, Waltham, Massachusetts). The
LODs were 0.002 mg/dL for Pb, 0.10 mg/L for Hg, and 0.09
mmol/L for Se. DHA was measured in plasma phospholipids
using the same procedure as for cord blood. For the present
study, PCB congener 153, expressed on a lipid basis, was
used as a marker of total PCB exposure, because it is highly
correlated with other PCBcongeners andis consideredan ad-
equatemarkerof exposuretoenvironmentalPCBmixtures in
the Arctic region.19
TableI. Descriptive statisticsof color andmotion VEPs,
n-3 PUFAs, and potential confounding variables
NMeanSDInterquartile range
Color VEPs
N1 latency, ms
P1 latency, ms
N1-P1 amplitude, mv
Motion VEPs
N2 latency, ms
N2 amplitude, mv
N-3 PUFAs*
DHA child, % phospholipids
EPA cord, % phospholipids
EPA child, % phospholipids
Potential confounding variables
Hg cord, nmol/L
Hg child, nmol/L
PCB 153 cord, mg/kg of lipids) 132 128.18 97.55
PCB153child,mg/kgoflipids) 132
Pb cord, mg/dL
Pb child, mg/dL
Nutrients*
Se cord, mmol/L
Se child, mmol/L
Others
Age
Parity
Socioeconomic status†
Breast-feeding, monthsz
Sex, % female
Marijuana use during
pregnancy, % yes
Smoking during pregnancy,
% >10 cigarettes/dayx
Binge drinking during
pregnancy, % $5
standard drinks of
alcohol per occasion
Testing time, % a.m.
Airplane transportation on
testing day, % yes
134 104.2
134 138.9
134
9.0
19.4
6.8
80-154
101.6-212.9
0.3-36.410.3
70 237.5
70
25.3
3.5
179.7-296.9
-18.0 to -0.4-7.0
132
131
132
2.30
0.45
0.60
0.93
0.43
0.50
0.60-5.51
0.00-2.89
0.04-2.96
133 106.68 81.44
13321.51 25.32
9-442
0.2-170.0
21.61-653.60
6.82-809.52
0.83-19.48
0.83-26.52
79.08 94.61
4.77
5.39
133
133
3.32
4.97
123
133
4.56
2.46
2.54
1.22
1.93-20
0.86-12
117
136
136
55
136
117
11.3
2.07
29.69 12.75
13.3
52
21.4
0.64
1.83
9.80-12.95
0-8
8-66
1-60 15.95
12244.3
11929.4
136
136
58.8
44.1
DHA, EPA, environmental contaminant (PCB, Hg, and Pb), and Se concentrations were mea-
sured in umbilical cord and child blood samples. DHA and EPA concentrations are expressed
in percentage according to plasma phospholipids.
*Child blood concentrations were measured at 11 years of age.
†Hollingshead index22for the mother and her partner or, if she was not self-supporting, for her
primary source of support.
z40% of the children were breast-fed.
x82.8% of the mothers smoked during pregnancy.
January 2011
ORIGINAL ARTICLES
Long-Term Effects of Prenatal Omega-3 Fatty Acid Intake on Visual Function in School-Age Children
85

Page 4

Statistical Analyses
BecausePCB153,Hg,Pb,andSeconcentrationsfollowedlog-
normaldistributions,allanalyseswereconductedwithnatural
log-transformedvaluesforthesevariables.Hierarchicalmulti-
ple regression analyses were conducted to assess the relation-
ship between each DHA and EPA variable and each VEP
measure when controlling for confounders. The control vari-
ables assessed in this study are listed in Table I. Confounders
were selected using a hybrid strategy combining significance
test and change-in-estimate procedures: (1) among the set
of control variables, each variable related to the VEP
measure in question at P < .20 was selected; (2) the n-3
PUFA variable was entered in the first step of the regression
analysis, each potential confounder meeting the P < .20
criterion was then entered hierarchically, starting with the
one showing the highest correlation with the outcome,
continuing with the one showing the next highest correlation
with the outcome, and so on; and (3) a confounder was
retained in the model if its inclusion changed the association
(standardized b coefficient) between the n-3 PUFA variable
and the outcome at step of entry by at least 10%.
The 0.20 a level and 10% change value criteria were based
on the work of Greenland and Rothman20and Maldonado
and Greenland.21All statistical analyses were performed us-
ing SPSS 16.0 (SPSS Inc., Chicago, Illinois).
Results
Descriptive data for the n-3 PUFAs, color and motion-onset
VEPs, and control variables are given in Table I. The
following potential confounding variables were examined:
child’s sex, age at time of testing, time of day when testing
occurred (a.m. or p.m.), parity, socioeconomic status
(Hollingshead Index),22mother’s education, transportation
by airplane from a more remote village for testing (yes/no),
duration of breast-feeding, and exposure to maternal
alcohol, marijuana use, or cigarette smoking during
gestation. The rate of maternal smoking is about 4-5 times
higher in this community compared with that in the
general population of the United States and southern
Canada23(Table I). Comparing the 134 children with valid
VEP data and the 37 whose data were discarded revealed
no differences in terms of the data on n-3 PUFAs and
contaminants collected at birth and at the time of testing
or for any of the other control variables assessed (all P > .10).
The color VEPsrecordedfromOzeliciteda major negative
waveatapproximately104ms(N1),followedbyamajorpos-
itive wave at approximately 139 ms (P1) (Table I). The N1-
to-P1 amplitude averaged 10.3 mv, which is consistent with
a report by Crognale.13For motion VEPs, N2 was the
major component recorded at electrode sites T5 and T6.
The mean latency was 237 ms, with an amplitude of -7.0
mv. Although these latter values are slightly different than
those found in adults, in whom latency is typically shorter
and amplitude is typically lower, similar results have been
observed in children,16suggesting that motion-onset VEP
is not yet mature at school age. Grand average waveforms
for motion and color VEPs are presented in the Figure.
Intercorrelation and Multiple Regression Analyses
Pearson correlations were conducted to examine the rela-
tionships among DHA, EPA, and environmental contami-
nants. Cord DHA was strongly associated with cord EPA,
moderately associated with child DHA, and weakly associ-
ated with child EPA and Hg as well as with cord and adult
PCB 153. No significant correlation (P > .05) was found
Figure. A, Color (Oz site) and motion (T5-T6 sites) VEP grand mean average from valid subjects for 134 and 70 children, re-
spectively. B, Color VEP N1 and P1 latency as a function of cord plasma phospholipid DHA concentration.
THE JOURNAL OF PEDIATRICS
? www.jpeds.com
Vol. 158, No. 1
86
Jacques et al

Page 5

between cord DHA and cord or child Pb. On the other hand,
cord EPA was moderately associated with cord and child Hg
and child PCB 153 and weakly associated with cord PCB 153
and child Pb. Cord EPA was not significantly correlated with
child EPA or cord Pb (Table II).
Table III shows Pearson correlations and regression
coefficients relating the n-3 PUFAs and the VEPs. Table III
presents raw regression coefficients both before and after
adjustment for covariates and standardized regression
coefficientsafteradjustment
adjustment for potential confounders, no significant
relationship was found between cord or child n-3 PUFAs
and motion-onset VEPs. However, as predicted, cord DHA
was associated with shorter latencies of the early N1 (b =
-.28; P < .01) and P1 (b = -.22; P < .05) components of the
color VEPs. No potential confounders were associated with
either of these effects.
To further study these effects, we divided cord DHA con-
centration into quartiles. Dose-response relationships were
examined by analyses of covariance (ANCOVA), in which
each VEP component found to be associated with prenatal
DHA intake in the regression analyses was analyzed in rela-
tion to DHA group, after adjustment for the potential con-
founders used in the regression analyses (Figure, B). As
expected, a main effect of DHA quartiles was found for
both N1 latency [F(3, 1160)= 5.17; P = .002] and P1 latency
[F(3, 3474)= 3.23; P = .025]. Post hoc analyses for the N1
ANCOVA revealeda threshold
a significant (P < .05) shortening of latency between the
two lowest quartiles and the two highest quartiles
(Figure, B), suggesting beneficial effects in children whose
cord DHA concentrations exceeded at least 3.6% of plasma
phospholipids, but no significant differences between the
first two quartiles or between the two last quartiles (both
P > .10). In contrast, the relationship of cord DHA to P1
for covariates.After
effect. Therewas
latency was dose-dependent, with no significant differences
between the adjacent groups (P > .05). The difference in
latency between the lowest quartile and the highest quartile
was 7 ms for N1 latency (P = .014) and 14 ms for P1
latency (P = .011), both of which were equivalent to 0.7
standard deviation (SD).
Snellen visual acuity score and contrast sensitivity scores,
asassessedbytheFACT,werealsoanalyzedtoexplorethehy-
pothesis that beneficial effects of DHA on VEPs can be de-
tected with behavioral testing. The prenatal n-3 PUFA
indicators (DHA and EPA) were not correlated with visual
acuity or with any of the 5 FACT scores (P > .10). This ab-
sence of associations was corroborated in multiple regression
analysis controlling for potential confounders.
Discussion
The timing and shape of the VEP responses in our cohort
were similar to those found in the general population.13,16
We assessed the impact of prenatal exposure to n-3 PUFAs
onVEPsinschool-agechildren.Inapreviousstudyofinfants
fromthissamepopulation,wereportedthatcordDHAphos-
pholipids were associated with better visual acuity as mea-
sured behaviorally using the Teller Acuity Card test.11The
results of the present study confirm and extend those previ-
ous findings by showing that the beneficial fetal DHA intake
on visual development persists into late childhood, and sug-
gestthat this effectis specific toparvocellularfunction,which
is known to mediate visual acuity and color processing. Al-
though this effect appears to be subtle and subclinical (being
not significantly related to our behavioral measurements of
visual acuity), this finding is of scientific and public health
importance, in that it demonstrates a beneficial role of n-3
PUFA exposure during pregnancy on visual processing
Table II. Intercorrelations among DHA, EPA, Hg (log), PCB 153 (log), and Pb (log) concentrations sampled from cord
and child blood
DHAEPAHgPCB 153Pb
CordChildCordChildCordChild CordChildCordChild
DHA
Cord
Child
10.38***
1
0.61***
0.30***
0.20*
0.68***
0.20*
0.00
0.17*
0.34***
0.19*
0.11
0.20*
0.21*
0.16
?0.05
0.14
0.02
EPA
Cord
Child
10.15
1
0.33***
0.07
0.33***
0.30***
0.21*
0.18*
0.31***
0.18*
0.16
?0.02
0.19*
0.09
Hg
Cord
Child
10.51***
1
0.44***
0.35***
0.40***
0.56***
0.31***
0.19*
0.14
0.23**
PCB 153
Cord
Child
Pb
Cord
Child
10.48***
1
0.27**
0.26**
0.10
0.29**
10.17
1
Child blood concentrations were measured at age 11 years.
*P #.05.
**P #.01.
***P #.001.
January 2011
ORIGINAL ARTICLES
Long-Term Effects of Prenatal Omega-3 Fatty Acid Intake on Visual Function in School-Age Children
87

Page 6

through late childhood. The DHA-related improvement in
latency between the lowest and highest cord DHA quartiles
averaged 0.7 SD for both latency measures. Again, these dif-
ferences are difficult to interpret in terms of clinical signifi-
cance, but they clearly are not negligible in terms of
optimal visual function. Although DHA concentrations in
cord plasma phospholipidsare?3-foldhigher inArctic Que-
bec than in southern Quebec,9it is noteworthy that cord
DHA levels in Nunavik are similar to those reported in sev-
eral other Western regions, notably Europe24,25and Massa-
chusettsinthe United
heterogeneity of laboratory analysis and quantification
methods, direct cross-national comparisons are difficult.
The beneficial effects can be seen with relatively modest in-
creases in DHA, that is, $3.6% of fatty acids (Figure 1, B).
The effects on color VEPs were specific to DHA and were
notrelated toHg, Pb,orPCBs,whichoften co-occurwithex-
posure to PUFAs. Prenatal exposure to these contaminants
was measured in umbilical cord blood, and postnatal expo-
sure was measured at the time of testing. Although assessing
postnatal exposure at more than one time point would have
been preferable, PCBs, which have a long half-life in biolog-
States.26
Because ofthe
ical tissue,19are likely to reflect exposure during an extended
period. The 11-year blood Hg concentration will represent
long-term exposure if the child’s fish intake is relatively sta-
ble, and the 11-year Pb body burden is likely to reflect post-
natal exposure from the toddler period, when the majority of
Pb exposure occurs.27
Other studies in fish-eating populations, such as in the
Seychelles Islands, have suggested that the benefits from in-
creased intake of nutrients from fish can outweigh the risks
of increased Hg exposure.28Similarly, data from question-
naire reports from the Avon Longitudinal Study of Parents
and Children (ALSPAC) suggest that the risks to a child’s
neurodevelopment from a deficiency from maternal seafood
nutrients during pregnancy exceed the risks of harm from
contaminants.29Our results do not indicate that PUFAs
can protect against adverse effects of Hg or other contami-
nants; however, it is clear that increased prenatal DHA intake
is beneficial for childhood visual processing even in the pres-
ence of contaminants, at least for the endpoints investigated
here. In contrast, other endpoints that were examined in this
cohort were vulnerable to contaminant toxicity even after
controlling for the beneficial effects of DHA.30,31
Table III. Relationships among DHA and EPA at birth and during childhood and VEP outcomes
B ± (SE)†
VariableN Confounders*BeforeAfterrßz
Color VEPs
N1 latency
Cord DHA
Child DHA
Cord EPA
Child EPA
P1 latency
Cord DHA
Child DHA
Cord EPA
Child EPA
N1-P1 amplitude
Cord DHA
Child DHA
Cord EPA
Child EPA
Motion VEPs
N2 latency
Cord DHA
Child DHA
Cord EPA
Child EPA
N2 amplitude
Cord DHA
Child DHA
Cord EPA
Child EPA
96
96
96
96
None
Cord DHA, cord Se, cord EPA
Cord DHA
Cord DHA, child DHA, cord Se, cord EPA
-1.5 (0.5)
-1.2 (0.8)
-1.0 (1.5)
-0.9 (1.3)
-1.5 (0.5)
-0.8 (0.8)
2.6 (1.9)
0.2 (1.8)
-0.28**
-0.15x
-0.06
-0.07
-0.28**
-0.1
0.18
0.02
97
97
97
97
None
Cord DHA, cord Se
Cord DHA, cord Se
Cord DHA, cord Se
-3.2 (1.4)
-0.5 (2.1)
-4.4 (4.0)
5.4 (3.6)
-3.2 (1.4)
0.5 (2.0)
-0.9 (4.7)
5.6 (3.3)
-0.22{
-0.02
-0.11
0.16x
-0.22{
0.03
-0.02
0.16x
81
81
81
81
None
Child Se, cigarette
Child Se, cigarette, cord Se
Child Se, cigarette
-0.8 (0.7)
1.4 (0.9)
0.9 (1.8)
1.8 (1.5)
-0.8 (0.7)
1.0 (0.9)
1.1 (1.8)
1.1 (1.4)
-0.14
0.17x
0.05
0.14{
-0.14
0.12
0.07
0.08
45
47
45
47
Cigarette, cord Hg, child DHA, child EPA
Cigarette
Cigarette, cord Hg, child DHA, child EPA
Cigarette
0.7 (3.3)
7.6 (4.0)
-3.0 (8.3)
19.8(9.7)
-0.8 (3.7)
5.9 (4.0)
-3.9 (8.6)
16.6 (9.6)
0.03
0.28{
-0.55
0.29{
-0.04
0.21
-0.07
0.24x
57
57
57
57
Sex, cord Pb
Sex, cord Pb, child Pb, cord Se
Sex, cord Pb
Sex
0.1 (0.4)
-0.4 (0.6)
-0.0 (1.0)
-0.6 (1.5)
-0.1 (0.4)
0.0 (0.6)
-0.7 (1.1)
-0.3 (1.4)
0.04
-0.09
-0.00
-0.06
-0.37
0.00
-0.09
-0.02
Raw regression coefficients were measured before and after adjustment for confounders, and standardized regression coefficients were measured after adjustment for confounders. The following
control variables were considered for inclusion in the regression models: child sex, age, hemoglobin concentrations at time of testing, time of day of testing (a.m. or p.m.), parity, socioeconomic
status, mother’s education, airplane transportation (if travel by plane was required), breast-feeding duration, and mother’s cigarette smoking, alcohol consumption, and marijuana use during preg-
nancy. Each row presents the findings from one multiple regression analysis. The first line shows the dependent variable; subsequent lines show the n-3 PUFA predictor that was entered in the first
step of the regression analysis. Child blood concentrations were measured at age 11 years.
*Listed in order of entry into the model.
†Raw regression coefficient ? standard error.
zStandardized regression coefficient.
xP #.10.
{P #.05.
**P #.01.
THE JOURNAL OF PEDIATRICS
? www.jpeds.com
Vol. 158, No. 1
88
Jacques et al

Page 7

No significant association was found between cord DHA
and motion-onset VEPs. This finding needs to be interpreted
with caution, however, given the smaller sample for the
motion-onset protocol. But considering that the magnitude
of the association between cord DHA and motion-onset N2
was close to 0, it seems unlikely that a significant effect would
have emerged for this outcome with a larger sample. Our
findings add to the growing body of evidence suggesting
that increasedDHAlevelsduring fetal developmentandearly
life are associated with more optimal perceptual and cogni-
tive function, particularly vision.32Most of the previous
studies in this field have focused on postnatal n-3 PUFA
supplementation during the first months of life, providing
evidence that such supplementation can enhance visual
acuityduringthefirstmonthsoflife.33However,theseresults
have been observed primarily in preterm infants, and the
picture is much less clear in healthy term infants.34Of
particular interest is a recent study reporting that beneficial
effectsonvisualacuity continuetobeevidentthrough4years
of age inbreast-fed or DHA-supplementedhealthyterm chil-
dren compared with children receiving n-3 PUFA-free for-
mula.35
The finding that the beneficial effects on parvocellular
function were seen in relation to cord DHA but not to child
plasma DHA suggests that DHA intake during the prenatal
period plays a critical role in the early development of the vi-
sual system, and that the beneficial effects are detectable well
into the school age years. The maternal-to-fetal transfer of
DHA during gestation is heavily influenced by maternal cir-
culating DHA and dietary DHA intake.36Because placental
fatty acid transfer involves diffusion as well as membrane
and systolic fatty acid binding proteins, genetic factors also
presumably affect the fetal supply. However, maternal intake
of essential fatty acids during pregnancy is clearly a critical
factor. We found a strong correlation between the DHA con-
centrations in maternal and cord plasma phospholipids of
Inuit newborns.11The mean cord plasma DHA concentra-
tion was significantly higher than the mean maternal plasma
DHA concentration, indicating that the mother transmits
a significant proportion of her DHA to the fetus.
MaternalDHAsupplementationfromfishoilduringpreg-
nancy is known to affect the visual development of their off-
spring. Judge et al37found that infants whose mothers
received DHA supplementation during gestation performed
significantlybetterontheTellerAcuityCardTestat4months
postpartum. An earlier study evaluated the effects of mater-
nal DHA supplementation on healthy term infants using
VEPs.38One hundred women received supplementation
with either fish oil capsules rich in DHA or placebo from
week 15 of pregnancy until delivery. No significant differ-
ences in any VEP measure were seen between the groups
with and without supplementation, possibly due to the low
DHA level in the blended fish oil supplements (about 7 times
lower than that in the supplements used by Judge et al37).
Nonetheless, it is of particular interest that, regardless of
the supplementation, an infant’s DHA status at birth was as-
sociated with shorter P100 peak latencies as tested with
pattern-reversal VEPs at 12.5 and 16.5 months postconcep-
tional age.38
In conclusion, the present study provides new evidence for
the importance of in utero DHA for development of the vi-
sual system, particularly for parvocellular function. n
Acknowledgment information is available at www.jpeds.com.
Submitted for publication Feb 3, 2010; last revision received May 26, 2010;
accepted Jun 29, 2010.
Reprint requests: Dave Saint-Amour, PhD, Universite ´ du Que ´bec a ` Montre ´al,
Case postale 8888, succursale Centre-ville, Montre ´al (Que ´bec) H3C 3P8,
Canada. E-mail: saint-amour.dave@uqam.ca.
References
1. Jump DB, Clarke SD. Regulation of gene expression by dietary fat. Annu
Rev Nutr 1999;19:63-90.
2. McNamara RK, Carlson SE. Role of omega-3 fatty acids in brain devel-
opment and function: potential implications for the pathogenesis and
prevention of psychopathology. Prostaglandins Leukot Essent Fatty
Acids 2006;75:329-49.
3. Fliesler SJ, Anderson RE. Chemistry and metabolism of lipids in the ver-
tebrate retina. Prog Lipid Res 1983;22:79-131.
4. Kidd PM. Omega-3 DHA and EPA for cognition, behavior, and mood:
clinical findings and structural-functional synergies with cell membrane
phospholipids. Altern Med Rev 2007;12:207-27.
5. AndersonGJ, Neuringer M, Lin DS, Connor WE. Can prenatal N-3 fatty
acid deficiency be completely reversed after birth? Effects on retinal and
brain biochemistry and visual function in rhesus monkeys. Pediatr Res
2005;58:865-72.
6. SanGiovanni JP, Parra-Cabrera S, Colditz GA, Berkey CS, Dwyer JT.
Meta-analysis of dietary essential fatty acids and long-chain polyunsatu-
rated fatty acids as they relate to visual resolution acuity in healthy pre-
term infants. Pediatrics 2000;105:1292-8.
7. Shapley R. Visual sensitivity and parallel retinocortical channels. Annu
Rev Psychol 1990;41:635-58.
8. Livingstone MS, Hubel DH. Psychophysical evidence for separate chan-
nels for the perception of form, color, movement, and depth. J Neurosci
1987;7:3416-68.
9. Lucas M, Dewailly E, Muckle G, Ayotte P, Bruneau S, Gingras S, et al.
Gestational age and birth weight in relation to n-3 fatty acids among In-
uit (Canada). Lipids 2004;39:617-26.
10. MuckleG,AyotteP,DewaillyE,JacobsonSW,JacobsonJL.Determinants
of polychlorinated biphenyls and methylmercury exposure in inuit
women of childbearing age. Environ Health Perspect 2001;109:957-63.
11. Jacobson JL, Jacobson SW, Muckle G, Kaplan-Estrin M, Ayotte P,
DewaillyE.Beneficialeffectsofapolyunsaturatedfattyacidoninfantde-
velopment: evidence from the inuit of arctic Quebec. J Pediatr 2008;152:
356-64.
12. Muckle G, Dewailly E, Ayotte P. Prenatal exposure of Canadian children
to polychlorinated biphenyls and mercury. Can J Public Health 1998;
89(Suppl 1):S20-7.
13. Crognale MA. Development, maturation, and aging of chromatic visual
pathways: VEP results. J Vis 2002;2:438-50.
14. Kuba M, Kubova Z, Kremlacek J, Langrova J. Motion-onset VEPs: char-
acteristics, methods, and diagnostic use. Vis Res 2007;47:189-202.
15. Bach M, Ullrich D. Motion adaptation governs the shape of motion-
evoked cortical potentials. Vis Res 1994;34:1541-7.
16. Langrova J, Kuba M, Kremlacek J, Kubova Z, Vit F. Motion-onset VEPs
reflect long maturation and early aging of visual motion-processing sys-
tem. Vis Res 2006;46:536-44.
17. Kaplan E, Shapley RM. The primate retina contains two types of gan-
glion cells, with high and low contrast sensitivity. Proc Natl Acad Sci
USA 1986;83:2755-7.
January 2011
ORIGINAL ARTICLES
Long-Term Effects of Prenatal Omega-3 Fatty Acid Intake on Visual Function in School-Age Children
89

Page 8

18. Dallaire R, Dewailly E, Pereg D, Dery S, Ayotte P. Thyroid function and
plasma concentrations of polyhalogenated compounds in Inuit adults.
Environ Health Perspect 2009;117:1380-6.
19. Ayotte P, Muckle G, Jacobson JL, Jacobson SW, Dewailly E, Inuit
Cohort S. Assessment of pre- and postnatal exposure to polychlorinated
biphenyls: lessonsfromtheInuit CohortStudy.EnvironHealthPerspect
2003;111:1253-8.
20. Greenland S, Rothman KJ. Introduction to stratified analysis. In:
Rothman KJ, Greenland S, eds. Modern Epidemiology. Philadelphia:
Lippincott Williams & Wilkins; 1998. p. 253-79.
21. Maldonado G, Greenland S. Simulation study of confounder-selection
strategies. Am J Epidemiol 1993;138:923-36.
22. Hollingshead AB, Four factor index of social status, New Haven, CT:
Yale University; 1975.
23. Andres RL, Day MC. Perinatal complications associated with maternal
tobacco use. Semin Neonatol 2000;5:231-41.
24. Rump P, Mensink RP, Kester AD, Hornstra G. Essential fatty acid com-
position of plasma phospholipids and birth weight: a study in term ne-
onates. Am J Clin Nutr 2001;73:797-806.
25. Krauss-Etschmann S, Shadid R, Campoy C, Hoster E, Demmelmair H,
Jimenez M, et al. Effects of fish oil and folate supplementation of preg-
nant women on maternal and fetal plasma concentrations of docosahex-
aenoic acid and eicosapentaenoic acid: a European randomized
multicenter trial. Am J Clin Nutr 2007;85:1392-400.
26. Donahue SM, Rifas-Shiman SL, Olsen SF, Gold DR, Gillman MW,
Oken E. Associations of maternal prenatal dietary intake of n-3 and n-6
fatty acids with maternal and umbilical cord blood levels. Prostaglandins
Leukot Essent Fatty Acids 2009;80:289-96.
27. Chiodo L, Jacobson S, Jacobson J. Neurodevelopmental effects of
postnatal lead exposure at very low levels. Neurotoxicol Teratol 2004;
26:359-71.
28. Myers G, Davidson P, Strain J. Nutrient and methyl mercury exposure
from consuming fish. J Nutr 2007;137:2805-8.
29. Hibbeln JR, Davis JM, Steer C, Emmett P, Rogers I, Williams C, et al.
Maternal seafood consumption in pregnancy and neurodevelopmental
outcomes in childhood (ALSPAC study): an observational cohort study.
Lancet 2007;369:578-85.
30. Plusquellec P, Muckle G, Dewailly E, Ayotte P, Begin G, Desrosiers C,
et al. The relation of environmental contaminants exposure to behav-
ioral indicators in Inuit preschoolers in Arctic Quebec. Neurotoxicology
2010;31:17-25.
31. Boucher O, Bastien C, Saint-Amour D, Dewailly E, Ayotte P, Jacobson J,
et al. Prenatal exposure to methylmercury and PCBs affects distinct
stages of information processing: an event-related potential study with
Inuit children. Neurotoxicology 2010;31:373-84.
32. Innis SM. The role of dietary n-6 and n-3 fatty acids in the developing
brain. Dev Neurosci 2000;22:474-80.
33. BirchEE,BirchDG,HoffmanDR,UauyR.Dietaryessentialfattyacidsup-
ply and visual acuity development. Invest Ophthalmol Vis Sci 1992;33:
3242-53.
34. Gibson RA, Makrides M. Polyunsaturated fatty acids and infant visual
development: a critical appraisal of randomized clinical trials. Lipids
1999;34:179-84.
35. Birch EE, Garfield S, Castaneda Y, Hughbanks-Wheaton D, Uauy R,
Hoffman D. Visual acuity and cognitive outcomes at 4 years of age in
a double-blind, randomized trial of long-chain polyunsaturated fatty
acid-supplemented infant formula. Early Hum Dev 2007;83:279-84.
36. Innis SM. Essential fatty acid transfer and fetal development. Placenta
2005;26(Suppl A):S70-5.
37. Judge MP, Harel O, Lammi-Keefe CJ. A docosahexaenoic acid-
functional food during pregnancy benefits infant visual acuity at four
but not six months of age. Lipids 2007;42:117-22.
38. Malcolm CA, McCulloch DL, Montgomery C, Shepherd A, Weaver LT.
Maternaldocosahexaenoicacidsupplementationduringpregnancyandvi-
sualevokedpotentialdevelopmentinterminfants:adouble-blind,prospec-
tive, randomised trial. Arch Dis Child Fetal Neonatal Ed 2003;88:F383-90.
THE JOURNAL OF PEDIATRICS
? www.jpeds.com
Vol. 158, No. 1
90
Jacques et al

Page 9

Acknowledgments
We are grateful to the Nunavik population for their participation in
this study and to the medical and health care professionals from the
health centers and the nursing stations involved for their assistance.
We acknowledge the long time support of the Nunavik Nutrition and
HealthCommittee,thePublicHealthDirectoroftheNunavikRegional
Board of Health and Social Services, the Municipal Councils of Puvir-
nituq, Inukjuak, Kuujjuaq and Kuujjuarapik, Inuit Tapiriit Kana-
tami, Pauktuutit Inuit Women’s Association, and Nunalituqait
Ikaluqatigiitut Association and of the professionals from the Centre
de Toxicologie du Que ´bec. We would like to thank Renee Sun, Alacie
Puv, Line Roy and Brenda Tuttle for participant recruitment and
data collection, Jocelyne Gagnon and Neil Dodge for assembling the
dataset,andDr.JanKremla ´cekforprovidinguswiththemotionvisual
stimuli.
January 2011
ORIGINAL ARTICLES
Long-Term Effects of Prenatal Omega-3 Fatty Acid Intake on Visual Function in School-Age Children
90.e1