Eating for improved kidney function is extremely important for those whose kidneys are not in optimal health. But, even if your kidneys are healthy, eating to improve their function can still be beneficial. Anything and everything that makes it into our blood will affect our kidneys, one way or the other. This means what we consume matters, even if our kidneys are in perfect working order. Diet matters more so if your kidneys are in any way compromised, and especially if you suffer from Chronic Kidney Disease (CKD).
The kidneys are essential to our health and longevity. They are also one of only a few twinned internal organs in the human body. They’re basically trash collectors, and each day they process 200 quarts of blood and sift out approximately 2 quarts of waste products and excess water, which then becomes urine, travels from the kidneys through the ureters to the bladder, where it is stored until … Well, you know the rest.
But kidneys don’t just remove waste from the blood, they also remove drugs and toxins. And depending on the nature of these last, one’s kidneys could lose their filter function and fail. If that happens, they will no longer be able to handle their other jobs, such as controlling the body’s chemical balance, making red blood cells, keeping the bones healthy, and controlling blood pressure. Below, I’ve compiled a list of foods that are considered among the most helpful for people suffering from CKD and dialysis patients, but also for those who wish to protect the health of their kidneys.
Best Foods for Kidney Health
- Cabbage – is high in vitamins K and C, fiber, phytochemicals / anti-oxidants, and is a great source of vitamin B6 and folic acid (folate).
- Red Bell Pepper – are an excellent source of vitamins B6, A and C, folic acid and fiber. They also contain the antioxidant lycopene, which has been proven to be protective against certain types of cancers.
- Cauliflower – is rich in vitamin C, folic acid and fiber. It’s also a great source of indoles, glucosinolates, and thiocyanates — compounds that have been shown to help neutralize toxic substances and prevent cellular mutations.
- Garlic – reduces inflammation, prevents plaque formation on teeth, and helps to normalize “bad” cholesterol levels.
- Onions – are rich in flavonoids, particularly quercetin, a powerful antioxidant with many protective benefits. Onions are also a good source of the mineral chromium, which helps fat, carbohydrate and potassium metabolism.
- Apples – are high in fiber and anti-inflammatory compounds that benefit the entire body.
- Cranberries – contain a compound that prevents bacteria from sticking the wall of the bladder and the lining of the GI tract and stomach, thus preventing bladder infections and bacterial-induced ulcers.
- Blueberries – are high in antioxidant phytonutrients called anthocyanidins, as well as natural compounds that reduce inflammation; they are also a good source of vitamin C and the vital mineral manganese.
- Raspberries – contain a phytonutrient called ellagic acid which acts as an antioxidant, neutralizing free radicals and preventing cell damage, as well as anthocyanins, which give them their red color. They are also a superb source of manganese, vitamin C, fiber and folic acid and B vitamins.
- Strawberries – are rich in two phenols: anthocyanins and ellagitannins. Anthocyanins give them their red color and both are powerful antioxidants that help protect the cells from free radical damage. They are also an excellent source of vitamin C, manganese and fiber.
- Cherries – have been shown to reduce inflammation when eaten daily. They are also loaded with antioxidants and phytochemicals that protect against free radical damage.
- Red Grapes – contain several flavonoids that give them their reddish color. These flavonoids not only fight free radicals but also reduce the formation of blood clots. Resveratrol, a flavonoid found in grapes, is thought to stimulate the production of nitric oxide – which helps relax muscle cells in the blood vessels, increasing blood flow. These flavonoids have also been shown to provide protection against inflammation and cellular mutation.
What do all of these fruits and vegetables have in common, besides being rich in healing, protective antioxidants? All of these foods are low in potassium, even lower in phosphorus, easy to find and relatively inexpensive. This is extremely important for those who suffer from CKD and/or undergoing dialysis because it is the kidneys’ job to filter excess phosphorus and potassium from the body, but if your kidneys are compromised they won’t be able to do their job efficiently.
Phosphorus, Potassium and Kidney Disease
Phosphorus is a mineral that is essential to bone health, but high phosphorus levels in the blood (hyperphosphatemia) can weaken bones – by leeching calcium from them, and lead to dangerous calcium deposits in the blood vessels, eyes, lungs and heart. Dialysis can remove some phosphorus from the blood, but anyone undergoing dialysis treatments must take steps to limit phosphorus build up between treatments. And this precaution doesn’t just apply to people with severe kidney issues, anyone who suspects that their kidneys are not functioning at optimal levels would be wise to eat a low phosphorus diet. The same goes for potassium.
The mineral Potassium is a necessity for overall health, especially heart health – potassium keeps the heartbeat regular and the muscles functioning properly, but if the kidneys are not functioning normally excess potassium will not be excreted from the body. A build up of potassium in the blood (hyperkalemia) is very dangerous, as it can lead to potentially fatal irregular heart rhythms and heart attack, so you can see how supporting the health and function of the kidneys is important to one’s overall health and survival.
Phosphorus and Potassium Needs for Kidney Patients
Most foods contain phosphorus, especially foods rich in complete protein – meat, fish, nuts and seeds, but if you overindulge in low phosphorus foods you can get high doses of the mineral as well. The same goes for potassium. For those with CKD, it’s important to be mindful of how much of both minerals you are consuming. Your phosphorus and potassium needs will vary, depending on the state of your kidneys, but (generally) adults with CKD should try to limit their phosphorus intake to 800-1,000 milligrams of phosphorus per day. The American Association of Kidney Patients recommends 2,000 to 3,000 milligrams of potassium per day, for dialysis patients. Those receiving daily dialysis can consume more – 3,000 to 4,000 milligrams. However, you should discuss how much or how little of both minerals you need with your physician, before making any drastic changes to your diet.
Causes of Kidney Failure
Two major causes of kidney failure are diabetes and hypertension. What makes these conditions a danger to the health of your kidneys?
- High blood pressure (hypertension) damages the small blood vessels in the kidneys, and
- Too much glucose in the blood poisons the kidneys
Both of these conditions can cause the kidneys to lose their filtering ability over time. Fortunately, the foods that improve kidney function also benefit hypertension and diabetes. A plant-based, whole food diet has been shown to help reverse both of these conditions. A perfect example would be Dr. Gabriel Cousens’ documentary, Simply Raw: Reversing Diabetes in 30 Days, which is available for free on YouTube.
Controlling phosphorus and potassium consumption is, obviously, very important for those with kidney issues. But even those with healthy kidneys can benefit from the occasional relief such a nutrient-dense diet would provide, as it can heal the body and lighten the kidneys’ load. To quote Benjamin Franklin, “An ounce of prevention is worth a pound of cure.”
“Potassium and Your CKD Diet”. National Kidney Foundation, n.d. Web. October 2016
“Stage 4 Kidney Disease”. Physicians Committee, n.d. Web. October 2016
“Phosphate Intake in Chronic Kidney Disease (Predialysis and Dialysis)”. Diet in Chronic Kidney Disease, n.d. Web. October 2016
“Potsassium Intake in Chronic Kidney Disease (Predialysis and Dialysis)”. Diet in Chronic Kidney Disease, n.d. Web. October 2016
“Nutrition and Renal Disease”. Physicians Committee, n.d. Web. October 2016