Kidney Disease Diet: 8 Foods That May Be Beneficial, According to Experts
If you have chronic kidney disease, one of the most important things you'll do is meet with a renal nutritionist, aka a nutritionist who specializes in kidney function. Certain foods, even some good for you foods like fruits and veggies, may have to be restricted or even off limits when you have kidney disease.
"At first, a kidney-friendly diet can seem overwhelming to my patients with CKD, but over time, it becomes something that's much more manageable," says Melissa Ann Prest, DCN, RDN, a renal nutritionist in Chicago and a spokesperson for the Academy of Nutrition and Dietetics.
What can I eat with chronic kidney disease?
Your dietary restrictions depend on what stage of kidney disease you're at, says Prest. "In the early stages, it's all about following an overall healthy low-sodium diet, especially if you have other conditions like type 2 diabetes or high blood pressure," she tells Health. "But as the disease progresses, you'll find that you also need to start restricting protein, as well as foods high in the minerals potassium and phosphorus."
Here are eight foods that are good to include as part of your regular diet, no matter your stage of CKD.
All patients with CKD need to watch their salt intake. "When your kidneys are damaged, they can't control how much sodium is in your body, which can cause your blood pressure to rise," explains Staci Leisman, MD, a kidney specialist at Mount Sinai Hospital in New York City. This in turn worsens kidney damage, and also raises your risk of heart disease.
If you have kidney disease, it's very important that you follow the recommendation of groups like the American Heart Association and National Kidney Foundation (NKF) and consume under 2,300 milligrams a day. People in the later stages of kidney disease may need to go even lower, adds Dr. Leisman.
One great way to slash sodium from your diet is to reach for your spice rack instead of the salt shaker, says Erin Rossi, RD, a nutritionist who specializes in kidney disease at the Cleveland Clinic.
Spices like basil, curry, dill, ginger, and rosemary can add flavor to any dish, whether it's meat or a vegetable. NKF suggests that you purchase them in small amounts, because they lose flavor over time. Add ground spices to foods about 15 minutes before you finish cooking them, and add whole spices to food at least one hour before, the kidney foundation advises. If you're using fresh herbs, combine them with oil or butter, let them sit for 30 minutes, then brush them on meat or veggies as they cook.
While you may be tempted to use a salt substitute, Rossi doesn't recommend it. "They often contain potassium, which many patients, particularly those with late-stage disease, need to limit," she explains.
There's no doubt that all types of berries are nutritional powerhouses: they're rich in heart-healthy antioxidants, including vitamin C, states the Academy of Nutrition and Dietetics. But they also have another benefit: they're low in potassium. "When people get into very late-stage kidney disease, certain foods, even nutritious ones like fruits and vegetables, can increase the potassium in your blood to a dangerous level," says Prest. This can cause symptoms like weakness, numbness, and tingling, or even trigger heart palpitations or a heart attack.
Berries have an additional benefit: they help reduce blood pressure, which is another risk factor for kidney disease. A 2011 study published in the American Journal of Clinical Nutrition found that people with the highest intake of the antioxidant anthocyanin—mainly from blueberries and strawberries—had an 8% reduction in the risk of high blood pressure, compared to those with the lowest. Other fruits low in potassium include apples, cherries, peaches, plums, pears and grapes.
Fruits higher in potassium include bananas, avocados, melons, oranges, prunes and raisins. But always check with your nutritionist before cutting out those foods, stresses Prest. "If your potassium levels are normal, then there's no reason why you can't safely eat these fruits, which are all good for you," says Prest.
"We're more concerned about patients avoiding processed foods that have phosphorous added to them to make them shelf stable, like pancake mixes, chicken patties, and macaroni and cheese," adds Prest. So what should you look for when you're shopping? NKF suggests checking labels for additives that include "phos"—for example, dicalcium phosphate, disodium phosphate, monosodium phosphate, or phosphoric acid.
People with kidney disease need to limit the amount of protein they eat. "Having too much protein can cause waste to build up in your blood, and your kidneys may not be able to remove all the extra waste," explains Rossi. But you still need enough protein to maintain muscle mass, and help your body fight off infection.
"When it comes to protein, it's also not just about how much you eat—it's about eating higher quality proteins," she adds. Animal proteins like meat, poultry, fish, and eggs are the easiest proteins for your body to break down and use, compared to plant based proteins. But eggs are a particularly good source of protein because they're also low in phosphorus, which is another mineral you need to limit when you have chronic kidney disease, Rossi notes.
"When your kidneys are not working well, phosphorus builds up in your blood, which can leach calcium from your bones and raise your risk of developing osteoporosis," she explains. While foods like nuts, seeds, peanut butter, and beans are all good sources of protein and part of a heart heathy diet, they're also high in phosphorus. Talk to your dietitian about how much of these foods you can safely eat.
A kidney-friendly diet should be low in saturated fat, which raises your risk of heart disease, says Rossi. That makes healthy fats like olive oil the best choice for cooking and baking, and you can also use it in place of high-fat salad dressings, she notes.
A Mediterranean style diet—an eating pattern rich in fruits, veggies, fish, and heart-heathy fats like olive oil—is linked to a 50% reduced risk of developing chronic kidney disease and a 42% reduced risk of experiencing rapid kidney function decline, according to a 2014 study published in the Clinical Journal of the American Society of Nephrology. It's also sodium-, potassium-, and phosphate-free, making it an excellent choice for people with kidney disease.
Cauliflower and other cruciferous veggies
Got a craving for potassium-rich potatoes? Munch on mashed cauliflower instead. It's high in fiber but low in both potassium and phosphorus, making it a healthy choice for people with kidney disease, says Prest.
Some tasty ways to eat it: puree it as a cream sauce, mash it into a pizza crust, grate it into a substitute for rice or pickle it for a low-calorie salty, crunchy satisfying snack. Other cruciferous veggies, like cabbage or kale, are good choices too. (Broccoli is also fine, but eat it raw, as cooked broccoli contains more potassium, the NKF points out.)
You can also leach high potassium veggies like potatoes, sweet potatoes, carrots, beets, and winter squash to pull some of the potassium out, NKF explains. Slice them 1/8-inch thick, rinse them, and then soak them for at least two hours in warm water using a 10-to-1 water-to-veggie ratio. Then cook them with five times the amount of water to the amount of vegetable.
You may have heard that you need to restrict fluid intake if you have kidney disease, but that's really only true in late stages of disease when you require dialysis. "If you're not at that point, and you don't have swelling in your legs, feet, or ankles, or around your eyes, it's usually not necessary," says Prest.
Water itself helps your kidneys remove wastes from your blood, and helps keep your blood vessels open so that blood reaches your kidneys, says NKF. If you're parched, it's harder for this delivery system to work and can even lead to more kidney damage. It also reduces your chance of developing kidney stones or urinary tract infections, both of which can harm kidneys. Coffee and tea are also fine and may even be protective: a 2018 study published in Nephrology Dialysis Transplantation found that the more caffeine people with chronic kidney disease consumed, the lower their chances of dying from any cause. Try to drink it black, or with as little milk or cream as possible, since dairy itself is high in phosphorus.
If you're in the later stages of kidney disease, your doctor may tell you to limit all fluids, including water. The first step is to cut back on foods that contain a lot of water, like soup, ice, and gelatin, as well as certain fruits and veggies, says Prest. (NKF says most dialysis patients will have to cap fluid consumption at about 32 ounces a day.)
Surprisingly, you don't have to shun white breads, pastas, rice, and other refined grains. In fact, these foods may be beneficial for people with very advanced CKD who need to limit their phosphorus and/or potassium content, says the NKF. That's because these minerals can build up in the blood of people whose kidneys no longer function properly, wreaking havoc on their bones and heart, says the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK).
Turns out the more bran and whole grains in bread, the higher their phosphorus and potassium content.
"Whole grain products are higher in phosphorus and potassium, so they need to be limited if you have kidney disease," says Rossi. Just don't overdo it on the starchy stuff, as they can cause you to gain weight and raise risk of developing type 2 diabetes, the leading cause of kidney disease, says NIDDK.
Garlic and onions
Garlic and onions, including shallots, chives, and leeks, are part of same family, says the National Center for Complementary and Alternative Health. And they're a great options for seasoning food if you have chronic kidney disease, since they provide a robust, savory flavor that will prevent you from reaching for the salt shaker or seasonings with added phosphorus, says Prest.
They also may be protective against CKD. Why? They contain allicin, a substance that appears to lower blood pressure and improve kidney dysfunction. A 2017 study published in the International Journal of Molecular Science found that high doses of allicin were just as effective as the high blood pressure and kidney disease drug losartan. A 2016 study in another journal concluded that allicin can help reduce high blood pressure in people with CKD.
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