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 5