Even when many of their cells are damaged, kidneys still carry out their work without the body feeling any symptoms. As a result, kidney disease often goes unnoticed. However, if you have diabetes, you need to start caring for your kidneys. Chronic kidney disease affects an estimated two million people across Canada, and diabetes is the leading cause.

What is chronic kidney disease?

Chronic kidney disease (CKD) occurs when delicate blood vessels in the kidneys become damaged. Most often, uncontrolled high blood glucose levels causes damage in people with diabetes. The second most common cause is high blood pressure.

CKD is divided into five stages, based on the level of kidney function. Stage 1 is very mild kidney damage, while Stage 5 requires treatment such as dialysis or a transplant to sustain life.

Testing for CKD

A simple blood test, called the GFR (glomerular filtration rate), can tell how well your kidneys are working. It measures the amount of blood that filters across small blood vessels in the kidneys in a certain time.

Protein leaking into urine is an early warning sign. Normally, there is very little protein in urine as the kidneys filter it back into the blood. Protein in a urine sample indicates some kidney damage.

Take control of your health by asking your family doctor about these tests and the numbers you have scored.

One diet does not fit all

Nutrition recommendations vary depending on the severity of the kidney disease. In very early stages, controlling problems such as high blood pressure or diabetes that threaten the kidneys is key. Keep your blood glucose levels and blood pressure in the target range determined by you and your doctor.

In the middle stage (3), reducing sodium and protein can slow down progression of the disease. In later stages (4 and 5), the kidneys may be unable to remove excess minerals from the body, allowing potassium and phosphorus to build up in the blood. At this time, a diet restricting potassium and phosphorus, in addition to sodium and protein, may be needed. Of course, continuing to control underlying problems is important at any stage.

	Stage 1	Stage 2	Stage 3	Stage 4	Stage 5
GFR (mL/min)	Greater than 90 At risk of developing CKD	60 to 89 Mild CKD	30 to 59 Moderate CKD	15 to 29 Severe CKD	15 or less Severe CKD needing treatment
General diet recommendations	Control underlying problems, such as diabetes, high blood pressure, or heart disease damaging the kidneys
General diet recommendations			Reduce sodium and protein intake	Reduce protein and sodium intake; some may also need to restrict potassium and phosphorus

Prevention – the best strategy

If you have diabetes, the best way to prevent kidney problems and many dietary restrictions is by keeping your diabetes under control. Limit sweets and control the amount of carbohydrate (grains, fruits, some vegetables and milk) at each meal. Regular physical activity helps keep blood glucose levels under control. It also helps control blood pressure, manage stress and improve cholesterol levels.

Keep your kidneys healthy by using the following strategies.

Take your medication as prescribed.
Keep blood glucose in good control. Aim for an A1C level (which indicates blood glucose control over a three month period) of less than 7.0 per cent.
Stay active and maintain a healthy weight.
Control blood pressure. The target for healthy kidneys is 130/80 or below.
Make sure cholesterol is in the normal range.
Reduce or stop smoking.
Learn how to manage stress in your life.

Sodium – more than just the salt shaker

Salt in food

77 per cent from processed foods
12 per cent naturally occurring
6 per cent added in cooking
5 per cent added at the table

Salt, or sodium, has become a major part of our diets in Canada since processed foods appeared. It is an issue for those with high blood pressure, as salt acts like a sponge and makes the body retain water. This extra fluid can lead to high blood pressure, swelling in the legs, ankles and other parts of the body, and difficulty breathing. For those with kidney disease it is even more of a concern, since the kidneys must process all of the sodium. Some research shows that eating too much sodium may speed up kidney disease.

Think you are limiting sodium by avoiding the salt shaker? Think again. Most of the sodium in our diets (77 per cent) comes from hidden salt in processed food.

When food is processed the sodium content multiplies:
Cucumber 7 slices = 2 mg	Cucumber with salad dressing = 234 mg	Dill pickle, 1 medium = 928 mg
Pork, 3 ounces = 59 mg	Bacon, 4 slices = 548 mg	Ham, 3 ounces = 1,114 mg
Tomato, 1 small = 14 mg	Tomato juice, 1 cup = 691 mg	Tomato sauce, ¾ cup = 979 mg
Chicken, half breast = 69 mg	Chicken noodle soup, half can = 902 mg	Chicken dinner, fast food = 2,234 mg

Tricks for limiting sodium

Aim to eat less than 2300 milligrams of sodium per day. As you can see from the processed food table, it does not take long to pass that target! To eat less sodium, follow these guidelines.

Fresh is best! Whenever possible, use fresh vegetables, meats and grains instead of canned, processed or packaged versions.
Take the salt shaker off the table and limit the amount added in cooking. Season foods with fresh or dried herbs, spice blends like Mrs Dash™, vinegars, lemon juice, garlic and ginger.
When dining out, ask for sauces and dressings on the side. Ask that no salt be added to your meal.
Avoid deli meats and bacon. Use leftover roast beef, chicken or turkey in sandwiches instead.
Avoid canned soups. Make your own with low-sodium or homemade broth.
When buying packaged food, look for low-sodium options. Learn how to read and interpret the nutrition information on food labels.

Protein – a balancing act

Protein, found in foods like meat, poultry, fish, dairy, beans and nuts, is a very important nutrient. Your body needs protein every day to build muscles and repair tissue. Including protein with your meals can help stabilize blood glucose and make you feel full and satisfied.

The problem, as with sodium, is that most people eat far more protein than they need. For those with moderate to severe kidney disease, this can harm the kidneys. Too much protein stresses the kidneys and may speed the progression of the disease.

You can avoid getting too little or too much protein by eating small amounts daily. Ideally, split these foods between your meals. A good guide is to keep your meat portions the size of the palm of your hand. Alternatively, have protein take up one quarter of your plate and starch another quarter. Fill the remaining half with vegetables.

Potassium and phosphorus

Potassium and phosphorus are minerals that play important roles in the body and are found in many foods we eat. With kidney disease, the levels in your blood can become too high or low because your kidneys have trouble filtering them out. Although this is not usually an issue until the moderate to severe (3 to 5) stages, it varies between individuals. Knowing your levels will help you to do what is best for your body.

Potassium is found in many fruits and vegetables, including bananas, orange juice and potatoes. If the level in the blood is too high or low, it can affect the heart. An extremely high level can even cause the heart to stop beating.

Those who do not need to limit potassium can enjoy plenty of vegetables and fruits every day. A diet high in potassium can help lower blood pressure, which is another risk factor for kidney disease.

Phosphorus is found in dairy products, legumes, bran, nuts and meat. An overly high level of phosphorus in the blood can make calcium leave your bones. Weak bones and hardened arteries can result. Those with stage 3 to 5 kidney disease may want to limit high-phosphorus foods. For instance, limit milk products to one cup (250 mL) per day and cheese to one ounce (30 grams) three times per week.

Making it work for you

Adjusting your diet to help protect your kidneys does take effort, but is well worth it! Ask for a referral to a dietitian who can assist you. A healthy diet for your kidneys takes your other illnesses and your quality of life into consideration. Working to find this balance can help keep you – and your kidneys – happy and healthy.

Eating to Protect Your Kidneys Slowing chronic kidney disease