Is keto bad for kidneys? This is a question that doesn’t receive much attention – which is surprising because nearly 15% of the population struggles with kidney disease.
Normal kidney function is responsible for regulating sodium, calcium, and potassium levels in the body while simultaneously clearing out deadly toxins. The kidneys also help maintain the balance of red blood cells and metabolize vitamin D.
So it comes as no surprise that when our kidneys deteriorate, so too does our health – not to mention the fact that kidney disease is extremely painful. Chronic kidney disease, in particular, will require patients to live on dialysis or worse, require a kidney transplant for survival.
The health of our kidneys can be affected by diet. And the keto diet has come under strong criticism for negatively impacting kidney health.
Important Disclaimer: Before we deep dive into the claims and make sense of the raw data, it is important to note that this article does not constitute medical advice. You should discuss any dietary changes with your doctor. This article is our opinion of the available data.
Understanding the Keto Diet and How it Works
Before we can answer the question, ‘is keto bad for kidneys’, it is important to understand what the keto diet actually entails.
The keto diet redistributes a person’s macronutrient content strongly in favor of fats and leans toward a moderate amount of protein, while attempting to completely minimize carbs (without restricting them entirely).
There is much debate among keto experts with regard to the distribution of fats from protein to carbs. Common ratios include 75% fats, 20% proteins, and 5% carbs and 70% fats, 25% proteins, and 5% carbs. Almost all experts agree that a person on the ketogenic diet should restrict their carbohydrate intake to a maximum of 10% – or 5% for good measure (or less than 50 grams per day).
This high-fat fat diet forces the body to turn to an alternative source of energy, more notably, releasing a ketone called beta-hydroxybutyrate (BHB). The body can use these ketone bodies as a primary energy source during extended periods of glucose deprivation.
It is important to note that there is a large interindividual variability in how people will respond to the ketogenic diet based on various factors such as genetics, age, activity level, state of health, and others. A person’s response to the ketogenic diet is also based on their food choices, such as meal timing, sensitivities, and allergies to various types of foods, and medications.
This is why following a one-size-fits-all approach to the ketogenic diet is not recommended. People should always monitor their body’s response to any changes they make to their diet.
Understanding How Kidneys are Damaged
The kidneys play a central role in regulating our health by removing excess fluids and acids from the body. They remove toxins, waste chemicals, and other drugs while keeping the bones and blood healthy. In other words, the kidneys are the body’s filtration system. As such, our kidneys are the first line of defense against disease, infections, and viruses.
By far, the most common culprits responsible for kidney disease are high blood pressure and kidney disease, both of these can damage the fragile blood vessels and tissues in the kidney.
According to surveys, diabetes accounts for 44% and high blood pressure accounts for 29% of all cases of kidney failure that require a kidney transplant or dialysis.
Risk Factor: Diabetes and Kidney Damage
High blood glucose can trigger a chemical reaction in which sugar adheres to proteins in the bloodstream. This process, known as glycation, leads to the formation of advanced glycation end-products (called AGEs). These AGEs can disrupt the filtering section of the kidney and gradually damage the tissues resulting in kidney damage.
Risk Factor: High Blood Pressure and Kidney Damage
In the case of high blood pressure, there may be too much pressure. They expose the filtration segment of kidneys to blood that is moving at a fast pace and leads to tissue damage. This can affect the healthy functioning of the kidneys and lead to chronic kidney disease.
The root causes of these diseases have not been identified and scientists are still looking for answers. Like most things on social media, skeptics often try to look for scapegoats and the keto diet is often on their radar.
The most realistic way to prevent kidney damage is to treat and prevent high blood pressure and diabetes.
The good news is that both can be greatly improved – and in some cases – reversed with the help of the keto diet.
And the studies are there to back up these claims.
A study published in 2019 examined people with type II diabetes who followed the keto diet over a specific period of time. They managed to improve their blood glucose levels, and most patients managed to reduce their blood sugar to extremely safe levels.
Other health benefits of being on the keto diet included improvements in various health markers including body weight, blood pressure, and other indicators of metabolic syndrome. Most patients needed less medication and almost entirely discontinued the use of injectable insulin.
A 2009 meta analysis of various randomized controlled trials found that low carb diets (like the keto diet) were effective at reducing blood pressure and lowered the risk of cardiovascular diseases, over the course of 12 months.
By managing high blood pressure and diabetes, patients can minimize the damage done to their kidneys (and in some cases, slow them down entirely).
Busting the “Protein is Bad for Your Kidneys’ Myth
Dietary protein has commonly been identified as a major risk factor for kidney damage. It is important to understand why this concern is not grounded in reality. One of the first indicators of protein damage is proteinuria. It’s when proteins appear in urine.
This leads many people to believe that a high protein diet leads to kidney damage. It should be noted that a properly designed ketogenic diet only contains moderate amounts of protein – to the tune of 75 grams of protein in a 2000 calorie diet. The average person has no reason to worry about the kidney when switching to a keto diet or due to their protein intake.
Several meta-analyses here and here have found no evidence that low-carb diets lead to kidney health.
Keto Diet and Kidney Stone Risk
Kidney stones are hard, irregularly shaped objects that form inside the kidneys. They usually vary in size and can be as small as grains of sand to as large as a golf ball, in severe cases. Most kidney stones are made of calcium phosphate or calcium oxalate. Common risk factors for kidney stones include type II diabetes, high blood pressure, and obesity – which, in turn, are risk factors for kidney disease.
No research – aside from anecdotal reports – has found any link between kidney stone formation among individuals who follow the ketogenic diet. Some people conclude that they developed kidney stones after jumping on a low carb diet. Their observations can be easily explained by a range of various factors including genetics and lifestyle choices. The timing of a stone’s formation has nothing to do with the keto diet.
In fact, one research found that a low carb diet, like keto, can improve renal function in people because of the rapid weight loss. In other words, keto can lead to healthy kidneys.
Does Ketosis Overwork the Kidneys Due to High Acidity?
Another common misconception is that the keto diet can alter the acidity of the body from neutral to dangerously low levels of pH. This change in acidity can damage the kidneys.
However, it is important to understand that this life-threatening condition is a result of diabetic ketoacidosis (DKA), not to be confused with ketosis.
DKA is a debilitating condition that occurs due to excessive buildup of ketones, most commonly in people with diabetes. The acidity can damage the kidney and liver. The biggest risk factor for DKA is type I diabetes.
Ketosis due to the keto diet, on the other hand, is a condition where the buildup of ketones is within a safe range that does not lead to DKA. You can test for the levels of ketones in your body using a urine test. Check out our in-depth article on using keto urine strips.
The Benefits of the Keto Diet on Kidneys
Now that we have refuted some of the skepticism surrounding the keto diet, it’s time to discuss some of the benefits of the keto diet on the kidneys.
Diabetic nephropathy is a serious complication that damages the glomeruli, these are a cluster of nerve endings in the kidney responsible for filtering the blood. Studies show that a ketogenic diet can reverse diabetic nephropathy due to improved blood sugar control and positively alter genetic expression in the kidneys. One study on mice on a ketogenic diet found that diabetic nephropathy was reversed in just two months.
Chronic kidney disease is linked to a risk of heart diseases. However, the keto diet can reduce the risk of cardiovascular disease because the keto diet lowers the body’s levels of LDL cholesterol – which is good for the kidneys. This is confirmed by various studies here, here, and here.
Is Keto Bad for Kidneys?
So what’s the takeaway? Is keto bad for kidneys?
It is common for people to think in black and white or good and bad terms. This is very common on social media where you see the target shifting from fats being bad to carbs being bad or carbs being good again to sugar being the internet’s new punching bag.
The truth is, there are many grains of truth to these blanket statements and all macronutrients can be bad for the body if they are consumed in excess or if they displace other nutrients from the diet. But none of them are bad when taken in moderation. You need to look at the keto diet as a whole based on your individuality and find your perfect ratio of macronutrients.
And as always, you should always consult with a medical doctor or your dietician before starting any type of diet, keto included. This is especially important for people with kidney disease.
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