CateringGCSERevisionGuide:Salt
Notonlydoessalthelpcontrolyourfluidbalance,italsocontrolsthewayyourmusclesand
nerveswork.Ourbodiesautomaticallyregulatehowmuchsalt,orsodium,thereispresent.If
levelsaretoohighwegetthirstyanddrink-thisspeedsuptheeliminationofsaltthroughour
kidneys.
AccordingtotheFoodStandardsAgency(UK)3,thehumanGuidelineDailyAmount(GDA)
shouldbe:
§
Age11yearsandover,6gperday(2300mgsodium)
§
Age7-10years,5gperday
§
Age4-6years,3gperday
§
Age1-3years,2gperday.
Infantsunder1yearshouldnotbegivensaltbecausetheirkidneysarenotmatured
Thedifferencebetweensaltandsodium
Saltissodiumchloride(sodiumpluschlorine).Thesodiuminthesaltiswhatyouhavetolook
outfor.40%ofsaltissodium.
Ifsodiumislistedonthelabel'snutritionalinformationinsteadofsaltyouhavetomultiplythe
amountby2.5togettheequivalentsaltcontent.Forexample,ifaportionoffoodcontains1g
ofsodiumper100g,youwillknowitcontains2.5gofsaltper100g.
Howsaltcanaffecthealth
Studieshaveindicatedthattoomuchsaltconsumptionislinkedtohealthproblems,suchas
hypertension(highbloodpressure)andosteoporosis.Ifyousufferfromhypertensionyou
wouldbenefitfromconsuminglesssalt.Ifyouhaveit,youaremorelikelytodevelopheart
diseaseorhaveastroke
Veryyoungchildren,veryelderlypeople,aswellaspeoplewithkidneydiseasecannotexcrete
sodiumandregulatebodyfluidefficiently.
CateringRevision
Whydoesthebodyneedsaltandwhathappensifyouhavelow
saltlevels?
Thereasonthebodyneedssaltisbecauseeverysingleoneofourcellscontainslargeamounts
ofsaltand,saltisthegenerictermforions,chargedparticles,andmostofthecellsinour
bodyinfact,allofthecellsinourbodyareelectrical.Inotherwordstheypumptheseions
fromonesideoftheircellmembranewhichisalipidoroilysubstanceandthereforean
insulatorsotheypumpionsfromonesideofthatmembranetotheotherandthismeans
thereisanelectricalpotentialdifferenceacrossthemembraneofacellandthismeansthat
thisgradientthiselectricaldifferencecanbeusedbythecelltodoothersortsofwork.So
cellsforinstancedohavechannelsthatsodiumcanflowintothecellanditcomesdownits
potentialdifferenceinconcentrationgradientandtheresultisthatitcanbeusedtopullin
glucoseatthesametime.Sosugarscangetintocells.
Soweneedsaltsinourcells-that’showtheyregulatetheirsizebybringingwaterinby
osmosis.That’showtheyregulateelectricalactivity.Nervecellsforinstancecouldn’tcarry
informationwithoutactuallyhavingthiselectricalgradientacrossthemembranebecauseall
that’shappeningwhenanervecellsfiresoffanimpulseisthatyougetasuddenfloodof
sodiumintoonepatchofanervecell.Thisbringsinlotsofplusintothatpartofthecelland
thereforeanelectricalsignalgoeswhizzinggoesdownthenerveandgetsbuiltupand
regeneratedasitgoesdownthenerveandittravelsatabout50toa100metersasecondso
veryrapidtransmissionofinformation.
Soweneedsaltsinourbody,wetakeinsaltinourdiet,weabsorbsaltsandthosesaltsare
alsoincludeimportantthingslikecalciumtomakeyourbonestrongbutyou’realsolosing
saltsallthetimewhenyougotothetoiletforexampleyoulosecalcium,youlose
phosphates.Thisisbothinurineandfaecessoyouhavetocontinuouslytopupthenumber
ofsaltsthatyouhaveinyourbodybecauseyouhaveobligateorinsensiblelosses.
Wehearsomuchaboutsaltbeingreallybadforyouinyourdietgivingyouhighblood
pressure.Thebodyisverygoodatscavengingsaltfromwhatyoueatandwhatyoudrinkso
it’sveryrareforpeopletogettoolowerlevelsofsaltinthebodybasedondietalone.Usually
there’ssomethingpathologicalgoingon.Sometimeswhathappensisthatpeoplehavea
problemcalledsyndromeofinappropriateADH.Thisisanti-diuretichormoneandthebody
savestoomuchwatersoitscavengesbackwaterandasaresultyourbloodcanbecometoo
diluteandyouhaveverylowsodiumlevelsandthiscancauseproblemswithyourbrain
swelling.Itcanalsocausetheaccumulationofwaterelsewherearoundthebodyanditcan
causeheartfailuresoabadthingtohave.Butthatcancauselowsaltlevelsthatcanmake
peoplefeeldizzy.