YMCA Healthy Living Magazine, powered by n4 food and health SPRING 2019 | Page 5

The link between salt,
hypertension and kidney
disease
High salt intake over a long period of time
can certainly have a detrimental effect on
our bodies. Excessive intake of salt
increases our risk of developing
hypertension (high blood pressure).
While it is normal for our blood pressure
to rise and fall during the day – such as
when we sit versus stand, or when we
experience a stressful situation -
hypertension is when our blood pressure
is persistently higher than normal. The
problem is, we usually can’t feel high
blood pressure, and this is why it is often
called a ‘silent killer’.
According to the WHO, hypertension is
the number one risk factor for mortality
(early death) worldwide. A high salt
intake puts a lot of pressure on kidneys
- which are working overtime to remove
the excess sodium in our blood. Our
bodies try to fix the problem by diluting
the sodium in our blood with extra fluid.
This increases the overall blood volume,
placing more strain on the heart, blood
vessels and the kidneys. Over time, the
extra strain on the kidneys can cause
irreversible damage and eventually lead
to kidney failure (when the kidneys are
no longer able to filter the blood
adequately and keep us healthy).
Salt, heart disease and stroke
Another health concern associated with
excessive salt intake is that chronic
hypertension increases our risk of
cardiovascular disease (both heart
attack and stroke). The extra blood
GENETICS MAY PLAY A
ROLE IN OUR BODY’S
RESPONSE TO SALT
SALT INTAKE OVER TIME
In paleolithic times, salt intake was estimated to be
less than 1g/day – which came from natural sources
(predominantly meat). The earliest evidence of salt
processing dates back to around 6,000 years ago,
and it has now been used to preserve and flavour
food for thousands of years. With the spread of
civilisation, salt became a major trading commodity.
These days, our heavy reliance on processed foods
(which are often deceptively high in salt) has seen
our intake skyrocketing – back toward levels in the
19th century before refrigeration was invented!
volume and pressure caused by hypertension causes the tiny
muscles in our artery walls to become stronger and thicker,
which means they become less elastic and more narrowed
over time.
This narrowing of blood vessels further increases hypertension
and puts extra pressure on our heart (which now has to work
harder to pump blood around our bodies). Heart disease and
heart attacks can be due to the heart muscles or valves
becoming stiff, or due to blockages in major coronary arteries.
Strokes happen when major blood vessels to the brain are
either blocked or burst, causing what can be irreversible
damage to the brain.
Is salt a problem for everyone?
Recent research suggests genetics may play a role in our
body’s response to salt. This essentially means that people
respond differently to salt intake. Those who are ‘salt sensitive’
will experience great reductions in blood pressure after
following a low sodium diet, while those who are ‘salt resistant’
may not find that increasing or reducing salt affects their blood
pressure much at all.
However, there is not enough evidence yet to make strong
conclusions about specific groups, and to know who is salt
sensitive and who is not. Therefore, the current evidence
‘supports’ the benefits of limiting salt intake for everyone.
You’ll find more information on salt and how to reduce your
intake throughout this edition, and you can also head to
heartfoundation.org.au for fact sheets, recipes and tips.
SPRING 2019 YMCA HEALTHY LIVING MAGAZINE
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