Are corn, cranberry juice, and Vitamin C good or bad for kidney disease?

The common questions I get asked by my patients are usually about their diet pertaining to their kidney disease. Many of my patients are understandably apprehensive about different food items when it comes to managing their kidney disease.

In this article, I will explain whether some items like corn,cranberry juice and vitamin C are good or bad for kidney disease.  

Is corn good or bad for kidney disease?

Corn can be good in certain kidney diseases but can be bad for certain kidney patients suffering from CKD.

Benefits of eating corn for kidney patients

Corn is rich in many nutrients that can aid people suffering from kidney disease. Corn is rich in fiber which is helpful in reducing LDL cholesterol in the body especially for kidney patients suffering from high cholesterol.

Corn also contains minerals like magnesium which is needed by the body to maintain optimal blood pressure. Magnesium can also improve the quality of sleep.

Therefore, for kidney patients suffering from interrupted sleep, having a sufficient amount of magnesium can be helpful.

Corns are also a rich source of polyphenols, which are compounds found in plant-based foods such as fruits, whole grains, and vegetables.

These polyphenols can help improve the regulation of blood glucose levels of kidney patients suffering from type 2 diabetes.

Concerns while eating corn for kidney patients.

 Kidney patients suffering from CKD who need to cut down on their potassium intake might not benefit from including corn in their diet since corn is rich in potassium.

Hence, it is advisable to consult your nephrologist to properly assess your condition and get an appropriate dietary recommendation.

While corn itself is not harmful to health in general, some of the products derived from corn such as high fructose corn syrup which is sweet syrup extracted from corn can increase the risk of aggravating the condition of a diabetic person.

Is cranberry juice good or bad for kidney disease?

Cranberry juice has beneficial ingredients that are helpful when it comes to certain kidney diseases but drinking cranberry juice for kidney patients may also have its downsides.

Benefits of drinking cranberry juice for kidney patients

Cranberry juice is known to be helpful in treating urinary tract infections. Urinary tract infections often can turn into kidney infections for patients suffering from kidney failure. 

Urinary tract infections are caused by a bacteria known as E.coli which is present in the gut. Drinking cranberry juice has shown to prevent E.coli from causing an infection in the urinary tract.

Although cranberry juice may not be beneficial for treating a kidney infection directly but the antioxidants in cranberry juice can play a protective role when it comes to kidney infections by not allowing the infection to spread from the urinary tract to the kidneys.

Concerns while drinking cranberry juice for kidney patients

Cranberry juice has numerous health benefits because of its antioxidant content. However, for people who are prone to develop kidney stones or for people who are already suffering from kidney stones, drinking cranberry juice might not be a good choice.

Cranberry juice is high in its oxalate content. Cranberry can also reduce the pH in the urine which in turn causes the urine to turn acidic and could lead to the development of kidney stones.

Cranberry juice is naturally low in potassium. However, kidney patients suffering from CKD might need to be watchful about buying their cranberry juice and make sure the juice they are buying does not have any added ingredients to it.

Since some of the packaged juice can have a mixture of other juices in them which may increase the amount of minerals like potassium and phosphorus. Therefore, it is important to read the nutrition labels before buying. 

Is Vitamin C good or bad for kidney disease?

Vitamin C is good for kidney disease as it can help the kidneys in playing a protective role. However, too much vitamin C can be concerning for kidney patients.

Benefits of consuming Vitamin C for kidney patients

Vitamin C is one of the essential vitamins that is needed by the body in sufficient amounts. When it comes to kidney disease, vitamin C may be helpful in playing a protective role for the kidney cells, since vitamin C can act like an antioxidant that protects the cells from oxidative stress.

It has also been indicated in certain studies that consumption of optimal vitamin C might play a role when it comes to kidney cancer. However, further research is needed to conclude the benefits for kidney cancer patients. 

Concerns while consuming Vitamin C for kidney patients

While vitamin C, in general, is not harmful to the body but when vitamin C is consumed in high amounts through supplementation, it can increase the risk of kidney stone formation especially for people who are prone to develop stones. 

Therefore, people who are susceptible to developing kidney stones from calcium oxalate may need to be mindful about not overdoing their vitamin C consumption.

High doses of vitamin C can increase your risk of the most common type of kidney stone, calcium oxalate.


Corn is a nutritious grain rich in fiber and magnesium which can aid kidney patients with high LDL cholesterol. Corn also contains polyphenols that are helpful in increasing glucose uptake in the blood thus helping kidney patients with type 2 diabetes.

However, since corn is also a rich source of potassium, certain CKD patients may need to limit or avoid it depending on their individual condition of the kidneys.

Cranberry juice and Vitamin C are not harmful to kidney patients suffering from diseases like kidney failure or CKD. However, since they are high in their oxalate content, people susceptible to developing kidney stones may need to moderate their consumption.

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