Sodium is the most abundant extracellular cation and therefore pivotal in determining fluid balance. At the beginning of life, a positive sodium balance is needed to grow. Newborns and preterm infants tend to lose sodium via their kidneys and therefore need adequate sodium intake. Among older children and adults, however, excessive salt intake leads to volume expansion and arterial hypertension. Children who are overweight, born preterm, or small for gestational age and African American children are at increased risk of developing high blood pressure due to a high salt intake because they are more likely to be salt sensitive. In the developed world, salt intake is generally above the recommended intake also among children. Although a positive sodium balance is needed for growth during the first year of life, in older children, a sodium- poor diet seems to have the same cardiovascular protective effects as among adults. This is relevant, since 1): a blood pressure tracking phenomenon was recognized 2); the development of taste preferences is important during childhood; and 3) salt intake is often associated with the consumption of sugar-sweetened beverages (predisposing children to weight gain).
22
Abstract
Sodium is the most abundant extracellular
cation and therefore pivotal in determining
fluid balance. At the beginning of life, a po-
sitive sodium balance is needed to grow.
Newborns and preterm infants tend to lose
sodium via their kidneys and therefore need
adequate sodium intake. Among older child –
ren and adults, however, excessive salt in –
take leads to volume expansion and arterial
hypertension. Children who are overweight,
born preterm, or small for gestational age
and African American children are at incre –
ased risk of developing high blood pressure
due to a high salt intake because they are
more likely to be salt sensitive. In the deve –
loped world, salt intake is generally above
the recommended intake also among child –
ren. Although a positive sodium balance is
needed for growth during the first year of
life, in older children, a sodium- poor diet
seems to have the same cardiovascular
protective effects as among adults. This is
relevant, since 1): a blood pressure tracking
phenomenon was recognized 2);
the
development of taste preferences is impor –
tant during childhood; and 3) salt intake is
often associated with the consumption of
sugar-sweetened beverages (predisposing
children to weight gain).
Introduction
The words salus (Latin for health) and salub-
ris (healthy) underscore the role of salt in
ancient Rome, where salt was regarded as a
symbol of health and prosperity, likely becau –
se of it s role in foo d pr eser vation
1). In the eyes
of Homer, salt represented a divine subs-
tance
2), whereas it was a cornerstone of daily
life in the Jewish–Christian tradition (Esdra
6,9; Esdra 7,22; Gb 6,6; Lv 2, 13; 2Re 2,21; Mt
5,13). Historically, salt was a precursor of
coins (e.g., salt tax, 1Mac 10,29), and it led to
the discovery of shipways and adventurous
trips. In ancient Rome, soldiers were paid a specific quantity of salt
(salarium) rather than
gold or coins. Thus, salt was an important
currency. The relevance of salt is also reflec –
ted in the name of numerous cities including
Salzburg (Austria), Langensalza (Germany),
Sandwich (England), and Saltcoats (Scot –
land). At the beginning of the late modern
p er io d , the s alt t a x was imp or t ant ; in f act , s alt
tax officers were decapitated during the
French Revolution
3). In several cultures
around the world, salt (a white substance) is
a symbol of the imperishable; it was an emb –
lem of immortality and loyalty, which is reflec –
ted by the sharing of bread and salt with a guest, a tradition that remains alive in Slavic
countries
3). Salt is the spice
par excellence
because it provides taste and flavor to food.
Finally, consider the Latin expression cum
grano salis (literally, with a grain of salt),
which means with common sense. An abun-
dance of literature has appeared about the
role of salt on bloo d pr es sur e, throughout this
review we consider and highlight some key
papers focusing on this problem in childhood.
Physiological aspects
Sodium, the most abundant extracellular ca-
tion, is pivotal in determining fluid balance 4).
The total sodium content of the adult human
body is ~
80 m
mol/kg of fat-free body
weight
5); this proportion is higher in new –
borns, infants, and children 6) , 7) . Fluid and so –
dium balances play a central role in regulating
blood pressure and, potentially, in the deve-
lopment of arterial hypertension. Several
factors modulate salt handling, such as –
among others – acti
vati
on of the sympathetic
nervous system, hyperinsulinemia, hypercal –
Salt intake in children and its
consequences on blood pressure
Sebastiano A. G. Lava, Mario G. \bianchetti, Giacomo D. SimonettiReceived: 29 March 2014/Revised: 23 July 2014/Accepted: 24 July 2014 © IPNA2014
Reproduced from Pediatr Nephrol, 2014 Aug 17 ISSN 0931- 041X
With kind permission of Springer Science + \business media
Fig 1: Excess sodium modulates lymphangiogenesis, and osmotically inactive sodium accumu –
lates in the skin interstitium, binding proteoglycans. Excess sodium recruits macrophages, and
subsequently activates within subcutaneous macrophages (cells with blue nucleus) a transcrip-
tion factor, tonicity-enhanced binding protein, which in turn induces the production of the an –
giogenic protein vascular endothelial growth factor-C. Vascular endothelial growth factor-C
stimulates lymphatic vessel (red) growth and creates a new fluid compartment, which buffers
the increased body sodium (yellow) and ameliorates the tendency to excess body fluid linked
with excess salt intake. Adapted with permission from15).
1Prof. ffRTofaff.bai
1Prof. RTab
23
cemia, acid-base balance 8), hyperaldostero-
nism 8) , 9) , leptin 10 ), genetic background, and
maybe also circulating cardioglycosides 11 ).
Most of these systems ultimately work
through the kidney, with the renin-aldostero –
ne-angiotensin system playing a pivotal role
in fluid and sodium homeostasis. This impor –
tance is suggested by several monogenetic
hypertensive diseases
12 ). Furthermore, it was
demonstrated via transplantation experi –
ments in both rats and humans that essential
hypertension resolved after bilateral nephrec –
tomy and kidney transplantation
13 ).
Newer data suggest that an extrarenal system
may play a role in sodium handling. Elegant
experiments by Titze and coworkers propose
that so dium can b e stor ed on negati vely char -ged glycosaminoglycans in the skin interstiti
–
um, where it becomes osmotically inactive
14 ).
Thus, the skin interstitium might act as a ne –
gatively charged capacitor and fluid-buffering
sys tem ab l e to s tor e s o dium w ithout comm en –
surate water retention. In this way, it could
blunt accumulation of excess body fluid (and
the resultant high blood pressure) following
high salt intake
14 ). Actually, sensing the accu –
mulation of sodium cations, macrophages
might be recruited and subsequently release
vascular endothelial growth factor C (VEGF-
C), which stimulates hyperplasia of the cuta –
neous lymph capillary network, inducing local
clearance of skin electrolytes ( F i g . 1)
14 ) , 15 ) .
These mechanisms might be impaired or
overwhelmed in salt-sensitive hypertensive
individuals. At this time, it is not known which pathways may be involved. Furthermore,
nothing is known about these proposed pa-
thways in children or about possible develop
–
mental expression of such mechanisms.
Electrolytes and fluid balance
among newborns and in\bants
A p ositi ve so dium balance is ne ces s ar y at the
beginning of life. Although ~
30–
50
% of
the
adult body sodium content resides in the
skeleton, this proportion is much smaller
among infants and small children. Thus, a
positive sodium balance is needed during
development to build the skeleton and p er mit
growth. Since infancy constitutes the most
important and rapid growth period of life, in –
fants need ~
95–
115 mmol sodium per kilo –
gram of weight gain
6). While urine production
begins at ~
9–1
2 gestational weeks, nephro –
genesis is not complete until 35–36 gestatio –
nal weeks
16 ) , 17 ) . Glomerular filtration rate
(GFR) doubles during the first 2 weeks of
life
17 ), and several tubular transport mechanis –
ms mature after birth 18 ).
The concentration ability of term neonates is
limited, with a maximal urine osmolality of
~
700
–800 mOsm/kg H
2O16 ). Preterm new-
borns show lower concentration abilities
( 60 0 –70 0 m Osm/k g H
2O ) . O n the other hand ,
they also have a lower GFR and therefore a
reduced ability to excrete water.
Due to tubular immaturity, sodium is often
lost during the first 2–3 weeks of life, thereby
leading to a negative sodium balance (i.e., the
physiological contraction of extracellular vo –
lume after birth and compensation for the
transepithelial hypotonic water lost)
17 ). Never –
theless, the sodium balance is generally
maintained in term newborns because the
fractional sodium excretion (FE
Na) stabilizes
at ~
1 % (o
r even lower) near the third day of
life. In addition, plasma concentrations of
renin, angiotensin, and aldosterone are high
in newborns, thereby shifting the sodium ba-
lance in a positive direction. Plasma concen –
trations of these mediators decrease during
the first weeks of life, in parallel with the
maturation of several tubular transporters
16 ).
Experimental data have shown that sodium
plays a role in stimulating growth. The side
effects of sodium deprivation were shown at
a cell proliferation level in bones and nerves.
Chronic sodium depletion retards growth in
both experimental rats and humans
17 ); thus,
due to the increased losses, preterm infants
Fig 2: Sodium balance among preter m infants bor n at 27–34 gestational weeks. The red histo –
g r ams show the sp ont aneous cour se of so dium balance among nor mally fed , other w ise healthy,
preterm infants. The green histograms depict the course of sodium balance among preterm
infants who received a sodium supplementation of 4–5 mmol/kg/day. Adapted with permissi –
on from19).
Age
(years) Mean daily salt
i n t a k e ( g /d a y )Range
( g /d a y )Recommended
daily salt intake
( g /d a y )
< 1 0.50 . 4 –1 . 3< 1
1–5 43.3 – 4.92
5 –1 0 63 . 7– 8 .14
10 –20 86 . 7–11 . 05
Table 1: Mean and recommended salt intake at different ages.
To convert a gram of salt to a millimol of sodium, divide by 0.058 g/mmol.
To convert from a gram of salt to a gram of sodium, multiply by 0.3972), 18), 20).
1Prof. ffRTofaff.bai
1Prof. RTab
24
should be supplemented with sodium. In fact,
salt lost is greater among preterm and low-
birth-weight (L\bW) infants
16 ) , 17 ) , placing these
child
ren
at risk of developing associated
neg
ative salt balances and hyponatremia
(Fi
g. 2) .
A seminal study demonstrated that preterm
infants supplemented with 4–5 mmol/kg per
day of sodium during the first 2 weeks of life
reached a positive sodium balance more ra-
pidly, lost less weight postnatally, and regai-
ned birthweight more quickly compared with
a control group of nonsupplemented infants
(Fig. 2) . Interestingly, the effect of this inter-
vention on infant weight remained significant
after supplementation ceased
19 ). In contrast,
full-term infants fed breast milk receive
~
1 mm
ol/kg per day of sodium, which is
enough for an equilibrated growth
6). Sodium
intake < 1 mmol/kg per day might lead to
hyponatremia and growth retardation and
should therefore be avoided.
Salt intake during childhood
Due to regulation mechanisms, the minimal
sodium requirement under constant condi -
tions (i.e., after development) is low: in fact,
~
0.1
mmol Na
+/10 0 kcal might b e enough. At
the other extreme, humans can tolerate up to
10 mmol Na
+/100 kcal without experiencing problems
6). Upper limits for the recommen
-
ded daily salt intake are given in Ta b l e 1 .
According to data from 1997, 4-year-olds in
the UK consumed 4.7 g/day of salt (i.e., 81.0
mmol/day), whereas 18-year-olds ingested
6.8 g/day (i.e., 117 mmol/day)
21 ). Similar data
were recently published regarding the US:
8- to 18-year-olds had a mean intake of 8.6
g/day (i.e., 148 mmol/day). In addition, that
study noted that salt intake increased with
age
22). Furthermore, salt intake was higher
among boys than girls, among normal-weight
than over weight par ticipant s , and among non -
Hispanic white than Hispanic-white and dark-
skinned participants.
Ta b l e 1 summarizes data from several sour -
ces regarding actual salt int ake among child -
ren and compares it with agerecommended
salt intakes. The variability among age, sex,
and the single studies is considerable. Salt
intake increases with age due to differences
in total food consumption and food cho -
ices
23 ). In summary, salt intake is generally
≥
5.8
g/day (i.e., 100 mmol/day) starting at
~
5 ye
ars of age and increases by ~
250
mg/
day per year (i.e., 4.3 mmol a day per year)
23 ).
Very recent data appear to confirm these
results
20 ). Salt intake studies are difficult to conduct.
Food diaries, 24-h urinary sodium, overnight
urinary sodium, and spot urinary sodium/
creatinine ratio, while being adequate assess-
ment s of compliance w ith dif fer ent salt- int ake
regimens, are unreliable in accurately asses-
sing absolute dietary salt intakes
24 ). In parti-
cular, food diaries and urine measurements
tend to under estimate salt int ake
23 ). Available
data must therefore be interpreted with cau -
tion. Importantly, a tracking phenomenon was
identified with respect to salt intake; in other
words, a taste habituation is present that
generates dietary routines
25 ) , 26 ) . Interestingly,
boys eat ~
20 mm
ol/day more salt than girls,
and dark-skinned children eat ~
15 m
mol/day
more salt than white children
23 ). Adults con-
sume ~
70–
80
% of
their salt intake from ma-
nufactured foods, snacks, and restaurant and
fast-food meals, whereas only ~
10 %
occurs
naturally in foods and another 10
% co
mes
from discretionary use at home (added at the
table or during cooking )
23 ) , 27 ) . Childhood data
are limited; however, they seem to globally
reflect the adult data
23 ). Interestingly, cereals
are the largest contributor to dietary salt in-
take ( ~
40 %),
followed by meat products
( ~
20 %) an
d milk products ( ~
1 0 % )20 ) , 23 ) .
E\b\bects o\b salt on blood pressure
among children and adolescents
Among older children, excessive salt intake
leads to the same complications that are
known among adults: volume expansion and
arterial hypertension. Several epidemiologi -
cal, observational and population studies
suggest that salt intake is associated with
hypertension in children
24) , 28 ) . As stated abo -
ve, salt- int ake studies ar e dif ficult to conduct .
Nevertheless it is possible to analyze the re -
lative changes in salt intake among children
(using any of the methods listed above) in
interventional studies
24 ).
T he pioneer ing study of a salt int ake r e duction
campaign was performed in Japan in the
1950 s
24 ) , 29 ) . T his campaig n was able to r e duce
mean salt intake by ~
1.5
g/day (i.e., 26
mmol/day). The effects of this intake reduc-
tion were noted among school children over
more than 15 years. Several observational
studies have not found a significant associa-
tion between salt and blood pressure; howe -
ver, they present various methodological
problems
24 ). In fact, most high-quality studies
have demonstrated a significant association
between salt intake and hypertension among
Fig 3:
Odds ratios (ORs) for developing high blood pressure among 6,235 US children 8–18
years old. Children were divided into quartiles based on their sodium intake. The Y-axis shows
ORs for developing high bloo d pr es sur e ( pr ehy p er tension or hy p er tension ) . T he blue bar s depict
ORs for all studied participants, and the red bars show the ORs for the subgroup (37.1
%) o
f
overweight and obese children. This graph was developed based on data from Yang et al.22).
1Prof. ffRTofaff.bai
1Prof. RTab
25
children 24 ). An interesting study was perfor-
med based on the National Diet and Nutrition
Survey for Young People program undertaken
in 1997 in the UK. This study showed that an
increase in salt intake of 1 g/day (i.e., 17.2
mmol/day) increased systolic blood pressure
(S\bP) by 0.4 mmHg
21 ) among 4- to 18-year-
olds. A meta-analysis by He and McGregor
reviewed ten controlled studies (nine of which
were randomized) among children and adole -
scents and three controlled studies among
infants
24 ). It is interesting to note that alt-
hough many studies have been conducted on
this topic, the authors of that study found only
13 controlled trials. Furthermore, in several
studies, there were important flaws limiting
their credibility. The authors calculated the
percentage change in salt intake using the
qualitatively best available technique: 24-h
urinary sodium, overnight urinary sodium,
spot urinary sodium/creatinine ratio, or food
diary. These measures were used to index
salt-intake reduction. The child and adole -
scent studies included in the meta-analysis
comprised a total of 966 participants, with a
median age of 13 years (range 8–16 years)
and a median salt-intake reduction duration 4
of weeks (range 2 weeks to 3 years). Median
salt intake reduction was 42
% (
interquartile
range (IQR) 7–58
%);
this reduction was ac-
companied by reductions in systolic blood
pressure (S\bP (−1.17 mmHg, 95
% co
nfidence
interval (CI) −1.78 to −0.56 mmHg, p < 0.001)]
and diastolic blood pressure (D\bP) (−1.29
mmHg, 95
% CI
−1.94 to −0.65 mmHg,
p< 0.0001). After excluding the only nonran-
domized study, results were similar, and sig-
nificance was maintained: S\bP −0.93 mmHg
(95
% CI
−1.66 to −0.20, p=0.01), D\bP −1.07
mmHg (95
% CI
−2.00 to −0.14 mmHg,
p= 0.02). Diet adherence was low in two stu -
dies (< 5
% di
fference between two diet
groups); thus, the authors performed a suba -
nalysis of the studies with relevant adherence.
Results were in the same range, and the sig-
nificance wassimilar (S\bP −1.18 mmHg, 95 %
CI −1.82 to −0.55 mmHg, p=0 .0003; D\bP
−1.20 mmHg, 95
% C I
−1.86 to −0.54 mmHg,
p= 0.0003 ) . Study heterogeneit y was not sig -
nificant, and no evidence of publication bias
was detected
24 ).
The three infant studies comprised 551 parti -
cipants. Due to the low reliability of D\bP mea -
surements during infancy, the authors only
examined S\bP. Median duration of reduced salt
intake was 20 weeks (range 8 weeks to 6 mon -
ths), and median salt intake reduction was 54
% (I
QR 51–79
%).
These results were accompa
-
nied by an S\bP reduction of −2.47 mmHg (95
%
CI −
4.00 to −0.94 mmHg, p<
0 . 01 ) .
Role o\b potassium
T he daily so dium int ake of hy p er tensi ve child -
r en should b e decr eased , and their p ot as sium
intake should be adequate
28 ) , 30 ) . Evidence
suggests that this dietary intervention has
positive short- and long-term effects on blood
pressure. In fact, there is a substantial body
of literature discussing various dietary and
lifestyle interventions possibly capable of
reducing blood pressure independently of salt
restriction
10 ). In particular, a diet rich in fruits
and vegetables, low-fat dairy products, and
low saturated and total fat (the so - called
Dietary Approaches to Stop Hypertension,
DASH, diet) was able to decrease blood pres -
sur e by 5.5/3.0 mmHg
31 ). Interestingly, reduc-
tion in salt intake and the DASH diet lowered
blood pressure significantly, with greater ef-
fects in combination than singly
32).
T he ef fect of maint aining su f ficient p ot as sium
intake is
mos
t likely smaller than that of
maintaining a lower sodium intake
28 ). A high
potassium intake and a low Na +/K + ratio ap -
pears to positively affect the physiological
rise of blood pressure in childhood, resulting
in smaller blood pressure slopes
33). Finally, a
study among normotensive African American
adolescents showed that potassium supple -
mentation reversed nondipper patients into
physiological dipper behavior
34).
Children at increased
risk \bor salt sensitivity
Sal
t sensitivity is defined as the significant
aug ment ation of ar ter ial bloo d pr es sur e follo -
wing increased salt intake. Overweight child-
ren
9 ) , 22 ) , 28 ) , 3 5 ) , childr en w ho wer e b or n pr eter m
or small for gestational age (SGA) 36), and
African American children 28 ) are at an incre -
ased risk of developing high blood pressure
when exposed to high salt intake, because
these groups present higher prevalence of
salt sensitivity. Overweight children are the
most relevant risk group because they re-
present an intervention population (e.g., via
weight-reduction campaigns). Furthermore,
the prevalence of childhood obesity has inc-
reased
35) , 37) . A recent study performed in the
USA evaluated the effect of salt on blood
pressure among 8- to 18-year-olds, distingu -
ishing b et ween nor mal - weight and over weight participants
22). The prevalence of overweight
and obesity (37.1
%) a
nd the prevalence of
prehypertension or hypertension (14.9
%)
w
ere high. The authors of that study calcula -
ted that participants’ S\bP increased by ~
1
mmH
g for each gram of increased sodium
intake per day (i.e., 43.5 mmol/day), and this
increase was ~
1.3
mmHg g r eater among over-
weight and obese participants (1.5 mmHg)
compared with normal-weight participants
( ~
0.2
mmHg)
22). However, D\b P was not sig ni -
ficantly associated with sodium intake. The
authors subdivided participants into salt-in -
take quartiles, and comparison between the
lowest and highest quartiles revealed an ad -
justed hypertension risk of 1.98. Results of
the subanalysis compared normal-weight and
over weight childr en and wer e even mor e inte -
resting: the adjusted risk among normal-
weight participants was 1.15, whereas it was
3.51 among overweight and obese children
(Fig. 3) . The risk for (pre- ) hypertension incre -
ased by 35
% fo
r each additional gram of sodi -
um per day among normal-weight participants
and by 74
% am
ong overweight and obese
children. Finally, a relative excess risk due to
interaction (RERI) was identified, which me -
ans that these risk factors were synergistic.
Sp e ci fically, they not only incr ease d the global
risk by their respective factors but also led to
an even greater risk due to their concomitant
presence and interaction. The pathophysiolo -
gical mechanism that develops salt sensitivity
in obese children is likely due (among other
possibilities) to insulin resistance and hy -
perinsulinemia, which activate the renal sym -
pathetic nervous system that causes vaso -
constriction and reduces renal blood flow,
thereby activating the renin-angiotensin-
aldos
terone system and inducing salt sensiti -
vity
9) , 38) , 39) .
The second risk group comprises children
born preterm or with low birth weight (L\bW).
One study found an increased salt-sensitivity
risk among children who were of low birth
weight (L\bW) or small for gestational age
(SGA)
36). The salt-sensitivity prevalence at
7–15 years of age was 37
% am
ong L\bW and
47
% am
ong SGA children. These rates were
much greater than one might expect in the
general adult population. Similar results were
found among adults
40).
People at increased cardiovascular risk (e.g.,
African Americans, patients with hypertensi -
on, and people with family history of hyper-
tension ) are more likely to have a salt sensiti -
1Prof. ffRTofaff.bai
1Prof. RTab
26
vit y than control people 28 ). In a well- designed
study, sodium retention among African Ame -
rican and white adolescent girls fed low- and
high-sodium diets was compared. African
American adolescent girls showed a higher
retention of sodium compared with Caucasian
gir ls. T hus , a dif fer ent t y p e of so dium handling
might be (partially) responsible for the greater
salt-sensitivity prevalence among African
Americans
41 ). In fact, despite the sodium re-
tention, neither blood pressure nor weight
increased, so that the retained sodium had to
reside in a nonextracellular compartment
41 ).
The authors speculated that this compart -
ment is the skeleton
41 ), but in light of the ne-
wer findings from Titze and colleagues, it is
tempting to assume that this might have been
the skin interstitium
14 ).
Tracking and programming
The deleterious effect of a high salt intake is
not limited to childhood; rather, it has long-
lasting effects on blood pressure
26). High
blood pressure in childhood predisposes to
hypertension in adulthood and increases the
risk of developing cardiovascular disease and
premature death
22), 42) . Animal models suggest
that salt intake during the first years of life
might have a programming effect on blood
pressure
24 ) , 43 ) . In other words, transitory salt
exposure during the first years of life might
lead to a permanent increase in blood pressu -
re, even when salt intake decreases later in
life. In a double-blind randomized trial perfor -
med almost 30 years ago among 476 newborn
infants divided into low-sodium-diet ( n=231 )
and normal-sodium-diet ( n=245) groups, an
association was found between salt intake
and blood pressure during the first 6 months
of life; specifically, a progressive increase in
bloo d pr es sur e was obser ved among b oth diet
groups across each month of observation
44).
Of the 476 children studied, 167 were recrui -
te d for a follow - up as ses sment 15 year s later.
S\bPs of those fed low-salt diets during their
first 6 months of life were significantly lower
(−3.6 mmHg, 95
% CI
−6.6 to −0.5 mmHg,
p= 0.02), although the dietary salt intake did
not significantly differ between groups at 15
year s of age
45). T his is sue, however, is contr o -
ver sial, since the liter atur e of fer s var iable and
limited results
46) , 47) . In particular, studies de -
nying an association are problematic because
they present several flaws limiting their inter -
pretation.
Relevance \bor public health
Data regarding salt intake in childhood are
relevant, particularly from a public health
perspective. First, high blood pressure is an
important cause of disease burden measured
as Disability Adjusted Life Years (DALY)
48).
Second, a blood-pressure-tracking effect was
documented: children with hypertension of -
ten mature into adults with hypertension.
Third, risk of hyper tension appears to be inc -
reased with higher sodium intake in child-
hood. Fourth, taste preferences are imprinted
during childhood: children who typically con -
sume a significant amount of salt are likely to
prefer salty meals as adults
25). In fact, salty
snacks consumed during childhood might
suppress the ability to taste salt, thereby
programming salty meal consumption during
adulthood
24 ).
Among Australian children, salt intake led to
an increased fluid intake ( r=0.42, p<0 . 0 01 ) :
each additional gram of salt consumed was
associated with an additional 46-g intake of
fluids per day. \because two thirds of these
children drank sugar-sweetened beverages,
their sugar intake increased with their salt
intake ( r=0.35, p<0.001): each additional
gram of salt was associated with an additional
17- g int ake of sugar- sweetene d b ever ages p er
day
49). In other words, adolescents who con-
sume a significant amount of salt also tend to
be overweight. Similar results were found in
Great \britain (each additional gram of salt
consumed was associated with an additional
27-g intake of sweetened beverages per
day)
35). \based on these data, reducing one’s
daily salt intake might also contribute to the
prevention of obesity and overweight among
children
35) , 49) .
Conclusions
Evidence indicates that reduced salt intake
benefits children. Although at the beginning
of life a positive sodium balance is required
for growth, during the first year of life, a low-
salt diet among older children seems to have
the same cardiovascularprotective effects
known among adults, particularly with re-
spect to blood pressure reduction. Whether
salt-intake reduction affects cardiovascular
outcomes remains controversial; however,
most of the literature currently suggests that
a restricted salt intake plays a preventive
role
50) –53) . A low-salt diet is especially impor -
tant for overweight children, those born pre -term, those born SGA, and those who have
hypertension or present nonpreventable car
-
diovascular risk factors (e.g., family history of
hypertension, African American heritage).
Salt intake during childhood is relevant for
public health: first, elevated blood pressure
during childhood predicts elevated blood
pressure during adulthood; second, salt in-
take increases hypertension risk in childhood;
third, taste preferences are developed during
childhood; fourth, salt intake is often associ -
ated with consumption of sugar-sweetened
beverages. Further research is needed to
identify and evaluate possible preventive in-
terventions on individual and systemic bases
during childhood.
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Korrespondenzadresse
G. D. Simonetti
Pediatric Department of Southem
Switzerland
6500 \bellinzona, Switzerland
giacomo.simonetti @ eoc.ch
No Conflict of interest.
fl
fl
Weitere Informationen
Autoren/Autorinnen
A. G. Sebastiano Mario G. Bianchetti Prof. Dr. med. Giacomo D. Simonetti , Istituto pediatrico della Svizzera Italiana, Ente Ospedaliero Cantonale, Bellinzona & Università della Svizzera Italiana, Lugano, Andreas Nydegger