Dr Sarah Jarvis
My Weekly’s favourite GP from TV and radio writes for you
Forget trendy detox diets. Your kidneys are hard at work 24 hours a day filtering out waste and toxins. Along with your liver, they’re inbuilt detox machines. But as you get older, it’s natural for your kidneys to be less efficient. They need a little care to help them look after you.
Along with getting rid of products made by your body that you no longer need, your kidneys keep the level of salts in your body stable. If the sodium and potassium levels in your blood aren’t within a certain narrow range, it can have effects on parts of your body like your muscles and heart. When your doctor measures your kidney function, they’re looking at levels of sodium and potassium but also at your eGFR – the rate at which your kidneys filter fluids. The lower this glomerular filtration rate, the slower your kidneys remove waste products.
Definitions of chronic kidney disease (CKD) are based on eGFR levels. A reading of over 60 is normal; 30-59 is stage 3 CKD; 15-29 is stage 4; and under 15 is stage 5. At stage 5, most people will be considered for dialysis or a kidney transplant.
But it’s more complicated than that. With age, your eGFR naturally drops off – and if this is a gradual decline, you’re unlikely to feel unwell. It usually won’t do any harm as long as you take care of your kidneys. Many of my patients are very worried at the idea that they have “disease” of their kidneys. But for many it’s a natural sign of ageing that they’d never know about if they didn’t have their kidneys
CUTTING YOUR SALT INTAKE PROTECTS YOUR KIDNEYS AND HEART. COOKING FROM SCRATCH MAKES IT EASIER TO CONTROL YOUR SALT INTAKE.
checked. Most of the steps to protect your kidneys if you have mild or moderate CKD are the common sense things I advise all my patients to do.
Drinking enough fluid to keep your urine pale straw coloured is an important one for kidneys.
Having CKD is also a warning sign that you need to take extra care of your heart – many risk factors for kidney decline are the same as for heart attack and stroke. So “know your numbers” on blood pressure and cholesterol.
If you’re 40-75, you’re entitled to a free NHS health check every 5 years, where you’ll have your blood pressure, cholesterol and other measurements taken.
These are all entered into a computer which calculates your 10-year risk of having a heart attack or stroke. This helps the GP decide if you need a statin tablet, which can protect your kidneys as well as reducing your risk of heart attack. If your blood pressure is consistently high, your doctor would recommend blood pressure tablets regardless.
If you have CKD, your GP is likely to suggest extra precautions. They’ll probably recommend a medicine called an ACE inhibitor (their names end in “-pril”, like ramipril and lisinopril). Widely used for high blood pressure, they also protect kidneys by reducing pressure on them. Very occasionally ACE inhibitors (and their cousins the “-sartans” like valsartan or candesartan, which protect kidneys) can do kidneys more harm than good. Blood tests are essential to keep an eye on your kidney function (before you start the medicine, a month later and at least every year after that).
If you have diabetes, you should have a urine test at least yearly to check the level of protein in your kidneys. Keeping your blood sugar well controlled will help your kidneys too. Next issue: The resolutions your GP wants you to make
DEPENDING ON YOUR STAGE OF CKD, IT’S IMPORTANT TO HAVE YOUR KIDNEY FUNCTION CHECKED EVERY 3-12 MONTHS – DO ATTEND WHEN INVITED!