Most people don’t know they’re affected with chronic kidney disease (CKD) until the condition is already advanced. Because late-stage kidney disease can cause a build-up of waste in your body and lead to a number of other health conditions – including gout, bone disease, and heart disease – it’s a good idea to protect your kidney health even if you haven’t been diagnosed with CKD.
Watching your diet is one of the most important ways you can do to help keep your kidneys healthy and to prevent or manage CKD.
How Diet Can Impact Kidney Health
The kidneys are filled with tiny blood vessels that help filter waste and extra water from your blood and remove them from your body. If you have CKD, your kidneys can’t filter blood as well as they should, causing excess waste to build up in your body.
Diabetes and hypertension (high blood pressure) are the two leading causes of kidney disease. High blood sugar levels in uncontrolled diabetes and high blood pressure can damage the kidney’s blood vessels, leaving them unable do their job properly, says Krista Maruschak, RD, a registered dietitian at the Cleveland Clinic.
“Untreated or uncontrolled diabetes and high blood pressure can have a significant effect on the development of CKD over time,” says Maruschak.
A healthy diet can help you prevent or manage conditions like diabetes and high blood pressure, in part by helping you to maintain a healthy weight, says Maruschak. In turn, this supports your kidney health.
As part of a kidney-friendly diet, you may also need to limit certain foods to help prevent further kidney damage.
Diet Tips for Kidney Health
A kidney-friendly diet should limit sodium, cholesterol, and fat, and instead focus on fruit, vegetables, whole grains, low-fat dairy, and lean meats (seafood, poultry, eggs, legumes, nuts, seeds, and soy products), says Maruschak. People who have already been diagnosed with CKD may also need to limit certain other nutrients, she adds.
Here are eight ways to upgrade your diet to maintain kidney health:
1. Portion Your Plate
As a general rule of thumb, Maruschak suggests filling roughly half of your plate with vegetables and fruit, one-quarter with lean protein, and one-quarter with whole grains.
2. Limit Your Salt Intake
Sodium sneaks its way into all sorts of places you wouldn’t imagine, especially packaged foods such as soup and bread. Limiting your sodium intake helps keep your blood pressure under control. Aim for 2,300 milligrams per day – that’s about 1 teaspoon of table salt – according to the Dietary Guidelines for Americans, 2020–2025, published by the U.S. Department of Agriculture (USDA).
If you’re at risk of or already have high blood pressure, Maruschak suggests following a low-sodium diet, and specifically the Dietary Approaches to Stop Hypertension (DASH) eating plan.
Cook At Home Using Whole, Unprocessed Food
When you prepare meals at home using fresh ingredients, you control exactly how much sodium (and fat) goes into it.
Get Creative With Seasonings
Maruschak suggests avoiding salt when cooking or at the table. Instead, use spices, herbs, lemon, and other sodium-free seasonings.
3.Be Mindful of Protein
When you eat protein, your body produces waste that’s filtered through your kidneys. While protein is an important part of a healthy diet, eating more protein than you need may cause your kidneys to work harder. While research on the effects of a high-protein diet on overall kidney health is still evolving, as noted in a study from 2020, your doctor will likely recommend a lower-protein diet if you already have CKD. “Having too much protein can cause waste to build up in your blood, and your kidneys may not be able to remove it,” Maruschak says.
People with any stage of CKD who aren’t on dialysis should limit their protein intake to 0.6 to 0.8 grams per kilogram of body weight to reduce kidney disease progression, Maruschak says. For example, a person who weighs 150 pounds (68kg) would need 40 to 54 grams of protein per day, which is about 4 to 6 ounces of protein from animal or plant sources, according to the National Kidney Foundation of Hawaii. Be sure to speak with a registered dietitian to determine the right amount of protein for you.
Whether or not you’ve been diagnosed with CKD, it can help to opt for healthier protein sources and watch your portion sizes. Good sources of protein include:
- Lean meat, fish, or skinless poultry (one portion size is 2 to 3 ounces, or about the size of a deck of cards)
- Dairy (one portion size of yogurt and milk is ½ cup, while one portion of cheese is 1 ounce — about the size of your two thumbs together)
- Beans, chickpeas, lentils, peas (one portion is ½ cup)
- Nuts (one portion is ¼ cup)
4. Choose Complex Carbs Over Simple Carbs
Carbohydrates are your body’s main source of energy, and those that occur naturally in fresh foods are filled with fibre to support heart and gut health and keep your blood sugar levels steady. However, simple carbs – such as added sugar in desserts, sweetened beverages, and many packaged foods – can spike blood sugar and increase the risk of obesity, type 2 diabetes, and heart disease.
As part of an overall healthy diet, you should limit sweets and foods with added sugars. Check food labels closely – added sugars are found in many surprising places, like fruit yogurt, says Maruschak.
Healthier carbohydrate choices include whole grains, fruits, vegetables, beans, and lentils.
If you have diabetes and are on insulin, you may need to be even more careful about your carbohydrate intake. “It is likely that people will need to count carbohydrates at meal times so they can dose their insulin correctly,” says Maruschak.
5. Limit Saturated Fats and Avoid Trans Fat
Diets that are high in saturated and trans fats increase the risk of heart disease – and what’s bad for your heart is bad for your kidneys. “Heart health and kidney health are interconnected, as the heart constantly pumps blood throughout the body and the kidneys continuously filter the blood in order to remove waste products and excess fluid from the body,” Maruschak says.
The USDA’s dietary guidelines recommend limiting saturated fats to less than 10 percent of your total daily calories. Main sources include meats, full-fat dairy products, butter, lard, coconut oil, and palm oil, says Maruschak. And try to avoid trans fats, found in baked goods and fried foods. Instead, fill up on heart-healthy unsaturated fats, found in fatty fish, avocadoes, olives, and walnuts.
6. Watch Your Alcohol Intake
Alcohol harms your kidneys in several ways, explains Maruschak. It’s a waste product that your kidneys have to filter out of your blood – and it makes your kidneys less efficient. It’s dehydrating, which can affect the kidneys’ ability to regulate your body’s water levels. It can affect your liver function, which in turn can impact blood flow to the kidneys and lead to CKD over time. And a high alcohol intake has been linked to an increased risk of high blood pressure, which can lead to kidney disease.
Maruschak says both men and women should drink no more than one alcoholic beverage per day. That’s 12 ounces of regular beer, 5 ounces of wine, or 1.5 ounces (one shot glass) of distilled spirits, according to the National Institute on Alcohol Abuse and Alcoholism. “It’s always best to speak with your physician about your alcohol intake, as some people should not be consuming any alcohol at all,” she says.
7. Talk to Your Doctor About Whether You Need to Limit Phosphorus and Potassium
Phosphorus and potassium are minerals that your body needs for certain processes. Phosphorus helps build strong bones, while potassium helps regulate your heartbeat and keeps your muscles working properly.
If you have CKD, however, these minerals can build up in your blood, causing problems throughout your body. High levels of phosphorus can pull calcium from your bones, making bones weak and more likely to break, and may cause itchy skin and bone and joint pain. You may need to limit foods high in phosphorus, such as animal protein, dairy, and some soda drinks. High levels of potassium (found in certain fruit and vegetables, as well as dairy) can cause heart problems. Your doctor will run blood tests to check your potassium and phosphorus levels. Be sure to ask if you’re not sure whether you need to keep tabs on your intake of these minerals.