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The kidneys are extremely important for your overall health. They are the body’s waste filtration system, as they remove the waste, toxins, and extra fluid from the blood, which are then excreted out of the body in the form of urine. (1)
If your kidneys don’t function properly, these impurities will start building up in your blood, damaging various organs and triggering various ailments.
If left untreated, kidney damage or dysfunction becomes worse with time and eventually advances to complete kidney failure, which can be quite fatal.
The foods you eat have a significant bearing on your renal health. And even if you do develop kidney disease, eating right can help manage it so that it does not advance to a more serious stage. (2)
This article presents some ways that you can prevent kidney damage by eating healthily!
Foods That Are Good for the Kidneys
The following foods can help prevent and manage kidney disease:
Cauliflower contains many essential nutrients and is fairly low in potassium and phosphorus, which are to be limited when suffering from kidney disease. (3) Cauliflower contains the antioxidant sulforaphane, (4) which has been shown to improve cardiovascular health in some studies.
The better your cardiovascular health, the lesser your risk of developing kidney disease.
Blueberries are fairly low in potassium, sodium, and phosphorus again. They contain anthocyanins, (5) the antioxidant class that helps with inflammation and related conditions, such as diabetes and cardiovascular disease (CVD). (6)
3. Sea bass
Sea bass is a low-fat food and most of that fat is omega-3 and omega-6 fats. (7)
Eggs are low in key vitamins and minerals, including potassium, sodium, and phosphorus. In addition, some eggs are high in omega-3 fats, depending on the type of egg. (9)
Garlic was used in ancient times as medicine. It has very low calories and contains a little of everything.
Garlic has also been shown in a recent controlled clinical trial to have an effect on lowering blood pressure, (11) another risk factor for kidney disease, even more so than a prescription blood pressure medication! (12)
6. Olive oil
Olive oil contains 14% omega-3 fatty acids and 73% monounsaturated fats. Monounsaturated fats are good for heart health as well.
Olive oil has powerful anti-inflammatory properties, which come from oleic acid, one of the monounsaturated fats. It is the main fat in the Mediterranean diet, which is shown to protect against heart disease and is recommended for kidney health as well. (13)
Cabbage is high in nutrients and low in calories. It contains the same classes of antioxidants as cauliflower and blueberries (if it is red cabbage) and also contains polyphenols. (14) All of these together have some powerful anti-inflammatory benefits.
8. Bell peppers
Bell peppers contain different antioxidants depending on the color of the pepper. One of these is quercetin, which has been shown to have an effect on both CVD and hypertension in more recent studies. (15) This effect has been demonstrated in both animal and human studies.
Radishes have some powerful compounds in them! These include compounds that help reduce diabetes risk (16) and improve blood flow. Moreover, radishes contain compounds that help the kidneys flush out toxins.
Pineapple is a powerhouse of vitamin C and antioxidants. Oxidative stress can cause chronic inflammation, and this can lead to health problems. (17) Interestingly, the types of antioxidants in pineapple are bound, meaning they produce longer-lasting effects in the body.
Importance of Healthy Eating for Healthy Kidneys
Healthy eating plays a big role in healthy kidneys. If a person’s diet is high in fat, salt, sugar, that person is at risk for obesity and related problems, such as high blood pressure and diabetes. People with these conditions become at risk of kidney disease as well, due to the increased inflammation in their blood vessels. (18)
Consistently eating a healthy diet may prevent this strain and damage on the kidneys.
Importance of eating kidney-friendly foods for people with kidney disease
In people with chronic kidney disease, there are many ways that nutrition can affect the outcome, again depending on the stage of the disease and cause.
In late-stage kidney disease, many nutrition-related factors and malnutrition come into play and these are extremely significant. (19) In general, the renal diet is designed to reduce the amount of waste the kidney is required to filter and prevent further damage and strain to the kidneys.
What Is a Renal Diet?
A renal diet is specifically designed to reduce the toxic load on the failing kidneys to save them from further damage. It basically limits the consumption of certain minerals and fluids that contribute to waste and water buildup in the blood.
Kidney disease is defined in 5 stages. The diet is dependent on what stage of the disease a person is in. The stage is determined by how many milliliters of blood per minute the kidneys can filter, known as the glomerular filtration rate (GFR). (20)
A GFR of 90–130ml/min is normal function, which does not call for any major dietary restrictions, but healthy eating must be continued to keep the kidneys in the best condition. A GFR below the normal range indicates renal disease.
Dietary measures for every stage of kidney disease are as follows:
- The first two stages of kidney disease require minimal to no changes in the diet.
- At stage 3, with a GFR of 30–59ml/min, a person should restrict proteins to 0.8 grams/kilogram of weight.
- At stage 4, with a GFR of 15–29ml/min, protein consumption should be 0.6grams/kilogram.
- Stage 5, a GFR of under 15ml/min, is considered end stage, and a person must be on dialysis and follow a specialized diet, usually high calorie, high protein, and fluid restricted. (21)
Some minerals must be avoided when suffering from kidney disease.
Phosphorus, sodium, and potassium should be limited because of the strain they place on the kidney through the following:
- Sodium causes water retention, which means your failing kidneys have to work extra hard to filter out the excess fluid from the blood. This leads to further kidney damage.
- Phosphorous in the right amounts is good for your bones, but too much of it can be counterproductive and make them weaker. You need properly functioning kidneys to maintain optimum phosphorous levels in the body. However, if your kidneys fail to filter out the excess phosphorous, it builds up in your blood and starts damaging your bones. Thus, people with late-stage renal disease have no choice but to control their phosphorous intake.
- Foods that are rich in potassium react negatively with the excess sodium and phosphorous in the blood, causing health issues.
Other Dietary Modifications for a Healthy Kidney
It is suggested that a Mediterranean diet pattern can be beneficial for reducing high blood pressure, risk of diabetes, and CVD. This basically entails eating more of healthy fats, whole grains, nuts and seeds, lean meats, low-fat dairy, beans and legumes, and plenty of fruits and vegetables, while simultaneously limiting your intake of salt, sugar, and unhealthy fats (saturated and trans fat).
Always prefer fresh foods over processed ones as the latter are full of sodium, unhealthy fats, and sugar that harm not just your kidneys but overall health. Minimize your intake of carbonated beverages as well. (22)
High sodium foods are recommended to be avoided, because sodium can contribute to water retention, which is important for late-stage kidney disease. High-potassium foods are also problematic because of the interaction with phosphorus and sodium.
Vitamins That Benefit the Kidneys
People with kidney disease have higher needs for water-soluble vitamins, which are the B vitamin family and vitamin C. This is potentially due to dialysis. (23) B vitamins play a role in many important functions in your body.
Your doctor may prescribe special renal vitamins that include these vitamins.
Should people suffering from kidney diseases consume a nonvegetarian diet?
It has been thought that it is too difficult to get enough protein on a vegetarian diet, something that is very important in dialysis. Whole grains and other vegetarian products potentially contain too much potassium or phosphorus.
However, some recent reviews and advice have deemed it acceptable and possible to follow a vegetarian pattern and still obtain the proper nutrients. This is more difficult to do with a vegan diet, however. (24)
Should water be consumed in moderation by people suffering from kidney disease?
The answer depends on which stage of disease a person is in. The kidneys filter blood, not just fluids, and send the waste products to be excreted by the bladder. Dehydration, if severe, can cause acute kidney problems.
Thus, in the early stages, 1–3, limiting fluids should not be deemed necessary by your doctor. In stages 4–5, and especially stage 5, the kidneys filter so little that fluid may build up in the body cavity, called edema. This is when fluid restriction becomes needed. (25)
A healthy diet and exercise are important parts of living well with kidney disease. Hypertension, diabetes, and CVD all raise your risk for kidney disease. You can help reduce this risk by following a healthy diet pattern that reduces inflammation.
Should you develop kidney disease, the renal diet is designed to slow the progression and make the kidneys’ job easier. Your doctor and dietitian will determine the best diet and treatment plan for you.