The relationship between keto and kidneys is complicated. While keto has been around for a while, there is still a lack of research on the long term effects of the diet.

In this article, you are going to learn whether keto is bad for your kidneys, what happens to your kidneys during ketosis, and if keto can cause kidney stones.

Is Keto Bad for Your Kidneys?

There is no straight answer to whether keto is bad for your kidneys. However, it is generally considered safe for you if your kidneys are in good health. On the other hand, if you have any kidney complications or fully developed kidney disease, you shouldn’t follow the ketogenic diet without consulting your nephrologist.

In general, if your kidneys are functioning normally, you may even experience some health benefits from following a ketogenic diet. These include improved blood sugar control, cardiovascular function, and weight loss (* , *).

A study on 68 obese individuals found no decline in renal function after one year on a very low carbohydrate diet (*). Another meta-analysis on 1000 individuals actually found an improvement in renal function in participants that were on low-carbohydrate diets (*). While these studies possess certain weaknesses, they seem to indicate that there is no direct link between keto and kidney disease.

What Happens to My Kidneys During Ketosis?

You should expect changes in your kidney function on keto due to the increased levels of ketones in your urine.

The first change you can expect to see is due to the negative charge ketones bear. Since ketones are negatively charged, they may result in increased excretion of positively charged ions such as potassium in the urine. This is simply because the negative charge will attract the positive charge during the process of urine filtration (*).

The other change often wrongfully associated with ketosis is increased acidity of urine. This comes from the confusion between ketoacidosis and ketosis.

Ketosis is a natural metabolic state that occurs when the body burns fat for fuel instead of carbohydrates, such as on a ketogenic diet. It is a completely normal physiological response to low blood glucose levels, and it can also occur under certain conditions such as prolonged exercise or pregnancy. In this state, the body produces ketones that can be used for energy in place of glucose. Ketosis is generally considered safe and even beneficial for weight loss and improved insulin sensitivity.

On the other hand, ketoacidosis is a serious medical condition that occurs when the body produces too many ketones, leading to an imbalance in blood pH. This usually occurs in people with uncontrolled diabetes, particularly type 1 diabetes, where insulin levels are low and the body cannot use glucose properly.

Due to the acidic nature of ketones, ketoacidosis has an impact on urine pH due to the high concentration of ketones. Severe ketoacidosis is a life-threatening condition that can lead to coma or death if left untreated.

Can Keto Cause Kidney Stones?

Kidney stones are lumps of minerals and salts found in the kidneys. If treated early, kidney stones often don’t result in any complications. However, if left to grow, they can cause intense pain and sometimes kidney disease.

There is some speculation about whether keto can lead to kidney stones. Those who believe this to be true cite the high protein nature of the ketogenic diet as the reason why it increases kidney stone risk.

However, there are two flaws to this argument. First, keto isn’t a high protein diet but a high-fat diet. The ketogenic diet recommends a protein intake of about 1.2-2 grams per kilogram of body weight which is the same protein content of a typical diet. Furthermore, there is still debate about whether the increased consumption of animal protein is a risk factor for kidney stones. A study that followed 78,293 women for multiple years found that different nutritional factors influenced kidney stone risk but consumption of animal protein wasn’t one of them. The factors that had an impact on kidney stone risk were sodium consumption, calcium consumption, water intake, and body weight (*).

Secondly research currently shows a limited relationship between the ketogenic diet and increased risk of kidney stones. A study on 195 children following a ketogenic diet for five years found that only 6.7% of them developed kidney stones.

No child was taken off the diet due to the stones as there was no statistically significant relationship between kidney stone incidence and the ketogenic diet (*). However, there are a number of studies that suggest a stronger relationship between low-carb diets and kidney stones (*). It should, however, be noted that the majority of these studies were conducted on subjects following very strict versions of the ketogenic diet.

The studies above all found that supplementation with potassium citrate reduced the occurrence of kidney stones suggesting a relationship between mineral salts and kidney stones in people following keto. For this reason, anyone following a ketogenic diet should ensure to optimize electrolyte intake, particularly, positively charged electrolytes like potassium.

Fruits and vegetables are some of the best sources of electrolytes in the diet, however, a high quality electrolyte supplement can also be effective in boosting electrolyte levels in the blood. Electrolyte supplementation should be accompanied by adequate water intake to minimize stress on the kidneys.

In addition to boosting your electrolyte intake, you can also lower your risk for kidney stones by limiting oxalate-rich foods and high sodium foods. Some of the oxalate rich foods to watch out for includes spinach, beets, rhubarb, miso, and sweet potatoes.

Should People At Risk for Kidney Disease Try Keto?

It is not recommended for people with or at risk of kidney disease to try keto without speaking to a qualified health professional.

With recommendation and supervision from your healthcare provider, a ketogenic diet can have a positive effect on kidney disease. In many cases, kidney disease is triggered by conditions such as type 2 diabetes, overweight, and heart disease, all of which have been shown to be positively impacted by following a low-carbohydrate diet (*).

In a case study of an obese man with renal disease triggered by type 2 diabetes, a low-carbohydrate diet resulted in reversal of six year long decline of renal function, weight loss, and improved glycemic control (*). While this study shows great promise in the use of low-carb diets for renal failure, better studies with more participants need to be conducted.

The limited research on the effects of different diets on kidney disease is due to the strict nature of dietary recommendations for patients with kidney disease. Currently, the best diet for an individual living with kidney disease should be personalized to their needs.

The Bottom Line

In conclusion, there appears to be little to no association between keto and kidney disease. In fact, those with healthy kidneys can expect to experience some health benefits such as improved blood sugar control and weight loss. While scientific evidence shows little proof of keto diet side effects on kidney health, individuals with kidney disease shouldn’t start a ketogenic diet without consulting their nephrologist.

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