The purpose of this post is to sort out several FAQs regarding the VERY LOW PROTEIN DIET and what it means for preserving kidney function.

How “low” is “low”?

People with kidney disease are often told, “Follow a low protein diet to help your kidneys.” This type of vague dietary advice can be confusing for many people. After all, how “low” is “low”? Does that mean eat less meat, no meat, or an actual protein amount, for example 30 grams?

“Low protein” can mean many things. In medical literature, the main low protein diet approaches for reducing protein to preserve kidney function include:

• Vegetarian diet (different variations, but primarily no meat)
• Vegan diet (no animal products)
• Low protein diet (0.6-0.75 gm/kg)
• Very low protein diet (0.3-0.4gm/kg)

Each of these 4 different low protein diet approaches to preserve kidney function have merit, but in different ways and for different stages of kidney disease.

The purpose of this post is to clarify what the VERY LOW protein diet is as opposed to the other types of “low” protein diets.

Important points we will cover:

1. The difference between a low protein and VERY LOW protein diet. This is a very important point to understand because they are not the same and do not have the same outcomes in the medical research.
2. What exactly is a VERY LOW protein diet?
3. What would you expect in this approach?
4. What nutrients you need to balance.

Low protein diet vs. VERY LOW protein diet (VLPD)

As noted previously there are multiple approaches for addressing protein. The difference mainly lies either in the quantity or quality/type of protein. Low protein and very low protein diets end up being almost entirely plant-based (aka no animal products at all) because of the level of protein that needs to reached.

Low protein diet is 0.6-0.8gm/kg of your ideal body weight – ends up being 50-60ish grams of protein/day, depending on the person. Very low protein diets are more along the lines of 0.3-0.4gm/kg per day. This ends up being somewhere around 30-40ish grams/protein/day depending on the person.

So, the difference between a low protein and very low protein diet really is the total quantity of protein allowed in a day. It seems like 20-30 gram protein per day wouldn’t make a difference, but in the research the results are quite different with very low protein diets having some pretty significant, consistent results of helping preserve kidney function and low protein diets having widely variable results.

For the sake of this post, I want to focus on the VERY low protein diet (VLPD) and what you’d expect with that approach. We’ll be writing about the others in the future.

What is a VERY LOW protein diet?

The very low protein diet to preserve kidney function is a very specific dietary approach to preserve kidney function.

In the research you see it referred to as sVLPD for “supplemented very low protein diet.” It is a dietary approach used most often in Europe (Italy specifically) to preserve kidney function for people with late stage 4 or 5 kidney disease. In my opinion it absolutely should and could be used in the United States and Canada (and all over the world) to preserve kidney function and significantly delay the start of dialysis.

Again, the very low protein diet is around 20-30 grams of protein/day. People achieve this level of protein through a high produce, primarily vegan diet. Because this level of protein does not provide enough amino acids for health, people following this approach must take a special supplement called a ketoanalogue. (You can read more about ketoanalogues and kidney disease here). In addition there is special consideration for the protein content of your grains and starch intake and an emphasis on healthy fats to maintain adequate caloric intake.

Just “cutting back” protein intake or cutting out meat is not a very low protein diet.

Who would follow a VERY LOW protein diet?

A LOW PROTEIN diet is generally recommended for people with late stage 4 or 5 chronic kidney disease. For people with earlier stage kidney disease they often have great results in preserving and optimizing their kidney function with other dietary approaches, such as a plant-based diet.

Making a VERY LOW protein diet livable

Reducing your protein intake while getting enough calories is challenging, especially given that most Americans consistently eat way more protein then they generally need. It is absolutely doable and sustainable though with the right education.

The best way to learn how to follow this approach successfully is with the help of a registered dietitian familiar with this dietary approach. I cannot emphasize that enough. However, here are some of the big pieces that should be considered with this approach (and often with any dietary approach):

The BIG pieces of a VERY LOW protein diet

Preserving and optimizing health and kidney function involves considering multiple nutrients, not just protein. When following a very low protein diet we are considering:

• Protein (obviously) – Switching to a plant-based diet and/or getting this low enough to reduce uremic toxins is the goal here.
• Calories: Significant weight loss can be a benefit for some and a huge problem for others with this approach.
• Potassium: People with late stage 4 or 5 kidney disease following this approach may not filter potassium through their kidneys efficiently or may be on medications (for example, losartan) that put them at risk for high-potassium levels in their blood (For example.
• Iron: People with kidney disease are already at risk for anemia because of their decreased ability to make red blood cells. On top of that, making a drastic change in iron intake by cutting out meat can make anemia worse. Anemia can impact your kidney function (hey, kidneys need oxygen too!) so addressing iron intake is important with this diet. Note: meat and animal products are not the only ways to get iron.
• Phosphorus: High phosphorus intake, especially from processed food is linked to progression of kidney disease. Phosphorus naturally occurs in many foods included in the sVLPD (Such as beans) but is not readily absorbed. However, we do watch labs and consider high phos foods as well as teach how to eliminate any chemical phosphate additives.
• Sodium Intake: High-sodium diets impact blood pressure which impacts the kidneys. Taking into account sodium and working on still getting loads of flavor through herbs, vinegars, lemons, limes, etc… is an important part of making the diet palatable and sustainable.
• How to reduce inflammation: Multiple other nutrients play into reducing inflammation. This is a post for another day, but basically in a sVLPD we are making sure that we are considering if dietary habits are providing a full array of nutrients to optimize nutrition.

Is a VERY LOW protein diet right for you?

Research shows that following a very low protein diet for someone with kidney disease may help you preserve kidney function. Because protein is not the only thing that impacts kidney function, there are several pieces that must be considered with a very low protein diet approach. In the VLPD Kidney Program we address several core pieces. Understanding the right amount of protein to aim for:

Understanding the right amount of protein

A VERY low protein diet, often called VLPD, is a diet with a very specific goal level of protein. Generally the goal is about 0.3-0.4 grams of protein per kilogram of a normal body weight. Understanding the right body weight for you to determine your level of protein is something a registered dietitian trained in this approach would help you with. This is a core question we establish in the RenAlign program.

Getting enough calories.

The protein you eat normally contributes significant calories into your diet. Cutting out a large portion of protein from your meals on this program means that you might not be consuming enough calories. This is not always good nor is it safe, particularly in the context of chronic kidney disease.

Not getting enough calories drives the human body into protein catabolism, or a condition where the body starts breaking down protein from your muscles for energy.

On a very low protein diet, even when supplemented with ketoacids, calorie deficits may induce protein-energy wasting or malnutrition (Cupisti et al.). This is counterproductive to our goal to preserve health.

It is important to balance the reduction of protein with an increase in other nutrients in order to ensure consumption of adequate calories to maintain a healthy weight and prevent muscle loss or malnutrition.

One way of adding in calories according to Ko et al., is to include healthy fats.

Healthy fats according to the National Kidney Foundation include: 

• Polyunsaturated vegetable oils: safflower, corn, soybean, cottonseed, sunflower oils
• Monounsaturated oils: olive, canola, peanut, sunflower, coconut oil
• Some high-fat whole foods include avocado, nuts, olives

Fats are great sources of calories on a VLPD because they contain very minimal protein. Being able to incorporate these fats in your diets in healthful proportions and flavorful ways is another part of the puzzle. Our program will provide you with the basics to do just that! 

Another way to add more calories according to Ko et al. is also to include healthy and complex carbohydrates. Some examples include: 

• Whole grains: oats, barley, or brown rice. Wheat may or may not be okay, but we’ll talk about that in the future.
• Starchy vegetables: potatoes, sweet potatoes, winter squash
• Non-starchy vegetables: zucchini, cabbage, carrots, bell peppers
• Fruits: apples, pears, berries, watermelon

Carbohydrates, especially the healthier, more complex carbohydrates, are definitely beneficial not only to add extra calories, but also to add more fiber, vitamins, and minerals to your diet. However, when following a very low protein diet even the protein in carboydrate choices can make a difference. In the RenAlign program we teach which grains are lowest in protein and how certain low protein grain products are very helpful tools to reach the correct protein level.

Balancing potassium.

Following a very low protein diet for kidney disease will automatically result in a significant reduction in your consumption of protein-dense animal products, which includes meat, fish, poultry, dairy, and dairy products. Consequently, your diet will mainly be plant-focused, including healthy and complex carbohydrates as outlined above.

Because plant-based diets are generally high in potassium this can be a concern for people in late stage kidney disease.

As CKD progresses, the kidney gradually loses its function to filter out potassium from the blood. Too much potassium may result in muscle weakness, irregular heartbeat, and even a heart attack. 

In the RenAlign program we talk about how to balance potassium including how to include some important high potassium foods in the diet.

According to the “Nutritional Treatment of Advanced CKD” consensus statement by Cupisti et al., patients with advanced stages of chronic kidney disease, especially stages 4 and 5, should monitor their blood potassium level. This requires close monitoring by a renal dietitian because balancing blood potassium includes management of drug regiments as well as intake of potassium from the diet.

One basic skill that will be covered in our program includes how to choose lower potassium fruits and vegetables and incorporate them in variable and flavorful ways into your everyday meals.

Getting enough iron.

Another consideration in switching to a very low protein diet is making sure you get enough iron. By being on a plant-focused diet, you will be eliminating good sources of readily absorbable iron, which would otherwise be found in a lot of animal products.

This is especially a concern because anemia is very prevalent in patients with CKD. According to NHANES III 1999-2004, prevalence of anemia increases with stages of CKD, with 8.4% at CKD stage 1, up to 53.4% at CKD stage 5. 

Anemia describes a condition with reduced number of circulating red blood cells or hemoglobin, which are the oxygen carriers in blood. Without enough oxygen being transported throughout the body, one can experience fatigue, reduced productivity and ability to learn, and thus, reduced quality of life.

With CKD, anemia can bring more dire consequences including sleep disturbances, CKD progression, cardiovascular comorbidities, and higher direct healthcare costs when compared with healthcare of CKD without anemia (Stauffer et al.).

Anemia with CKD also increases the 2-year mortality risk from 100% increase with just CKD to 270% increase with anemia in the picture.

Some potential causes for anemia in patients with CKD include iron deficiency, inflammation, accumulation of uremic toxin, and the kidney failing to produce enough erythropoietin, a hormone required for red blood cell production.

Some of these factors must be medically managed, but we can definitely prevent iron deficiency and accumulation of uremic toxin, especially through our RenAlign very low protein diet program.

The RenAlign program includes iron-rich, low protein foods and strategies and other methods of increasing iron into your diet. For example, we emphasize the use of cast iron skillets when cooking and consuming acidic foods with iron-rich foods to enhance absorption.

The meal plan provided with our program also ensures adequate iron every day, so you won’t have to think about your iron intake while you learn the ropes of this new program.

Phosphorus and Sodium Considerations

Following a low-sodium diet with minimal chemical phosphates is  a core piece of slowing progression of kidney disease and preventing complications.  We discuss more about sodium and a very low protein diet here, and phosphorus and a very low protein diet here.

The RenAlign program addresses each of these by teaching you how to identify phosphates in the food supply – especially chemical phosphates that could contribute to bone disease.  We also have worked hard to curate some simple, whole food recipes that are low in sodium, but loaded with flavor. We walk through how to construct each of your meals in the program and how to flavor.

Supplements for a very low protein diet expensive?

Very low protein diets are always coupled with ketoanalogue supplements and B vitamins. I wrote a post on ketoanalogues here to understand more why they are used with kidney disease.

Is a Very Low Protein Diet right for you?

People wanting to follow a supplemented very low protein diet should talk with their dietitian and doctor about this approach. For people with stage 4 or 5 kidney disease and/or a high level of proteinuria this approach could help delay dialysis for a significant amount of time. Professional guidance in following this type of diet avoids many of the pitfalls such as staying consistent, avoiding malnutrition and excessive weight loss, and finding foods you can love.

Authors:

Jessianna Saville, MS, RDN, LD, CSR, LD

Clarissa Paimanta, RDN, LD

References:

Cupisti A, Brunori G, Di Lori BR, D’Alessandro C, Pasticci F, et al. Nutritional treatment of advanced CKD: twenty consensus statements. J Nephrol. 2018; 31(4): 457–473.

Ko GJ, Obi Y, Tortoricci A, Kalantar-Zadeh Kamyar. Dietary protein intake and chronic kidney disease. Curr Opin Clin Nutr Metab Care. 2017; 20(1): 77-85.

Stauffer ME, Fan T. Prevalence of anemia in chronic kidney disease in the United States. PLoS ONE. 2014; 9(1): e84943.