How Plant-Based Diets Can Help Your Kidneys

Plant-based diets have grown in popularity over the recent years. It’s more than just a diet trend if you have chronic kidney disease (CKD). There is lots of science backing its benefits for slowing the progression of kidney disease. In this article I want to teach you some of the amazing ways plant-based diets can help your kidneys!

You may be wondering what exactly is a plant-based diet? Well, there is no formal definition of a “plant-based diet”. It can be described as an eating pattern that emphasizes whole plant-based foods. What do I mean by whole plant-based foods? Think foods found in nature…. vegetables, fruits, nuts, seeds, beans, legumes and whole grains. What is limited in a plant-based diet? Animal products and ultra-processed foods (think sugary drinks, deli meats, packaged snack foods, etc).

You also may be wondering if a plant-based diet is just another name for a vegan diet. Vegan diets do exclude all animal products (meat, poultry, eggs, seafood, dairy) and include plant-based foods… BUT… some vegans may not focus on eating whole plant-based foods. There are plenty of highly processed foods that are considered vegan. Did you know Oreos, Pillsbury crescent rolls and Bac’n Bits are vegan?! Those who follow a plant-based diet may choose to eat some animal products, such as chicken breast, salmon or yogurt in moderation, but the focus of their plate is plants!

Now that we know what a plant-based diet is, let’s dive into how it can help people with CKD.

The picture on the left shows some complications that occur when kidney function declines. Some of these complications are bidirectional, meaning, lack of kidney function can lead to the symptoms but the symptom also leads to worsening of kidney function. Spoiler alert – nutrition has an impact on all of them.

CKD problem: Waste products and toxins build up due to decline in kidney function.

Healthy kidneys filter out waste products/toxins from the blood and excrete them in the urine. Less kidney function = less waste removal. Where does this waste come from? Some is produced from protein metabolism (urea), some is produced by bacteria in our gut. There are other sources of waste products as well.

How plant-based diets help:

Those with CKD wants to avoid too much protein as excess protein hurts the kidneys (they have trouble filtering out urea which is made from protein breakdown). Plant-based protein sources are naturally lower in protein than animal protein sources. For example 100 grams of ground beef = 26.6 g protein, 100 grams of black beans = 8.2 g protein. By switching some meals to plant-based, it will naturally decrease the total protein in your diet.

Another way plant-based diets help reduce waste products in our blood has to do with fiber! Meat and dairy contain no fiber. Plants, however, are full of it! Fiber can help keep our bowels moving. Regular bowel movements are a good thing as that is a way for our bodies to get rid of waste! Fiber also feeds the good bacteria in our gut which helps keep our gastrointestinal tract junctions tighter making it harder for toxins to pass through.

CKD Problem: Metabolic acidosis

Healthy kidneys excrete extra acid in the body and create or reabsorb bicarbonate (which acts as a base). This helps keep the acid/base balance in our body at a healthy level. When there is kidney damage there is a risk of the body becoming too acidic, this condition is called metabolic acidosis.

How plant-based diets help:

Sodium bicarbonate (which is basically baking soda, no pun intended) is a medication that is often used in CKD to treat metabolic acidosis. Studies have shown, plant-based diets can improve metabolic acidosis just as well as medication. When animal products are broken down, they produce acid in the body. This is because animal products have a high amount of sulfate containing amino acids. Plant-proteins have less of these acidic sulfate amino acids and have an alkalizing effect for those with kidney disease – so they improve metabolic acidosis naturally!

CKD Problem: High Blood Pressure

Kidneys help regulate blood pressure. Having high blood pressure also damages kidneys.

How plant-based diets help:

Plant-based diets encourage intake of fruits, vegetables, whole grains, nuts/seeds, legumes and beans. All of these foods are rich in many different vitamins and minerals. One of these minerals, potassium, plays a key role in blood pressure control. Potassium helps relax blood vessels which is how it can help improve blood pressure levels.

Plant-based diets also tend to be lower in sodium which can be a culprit for high blood pressure. In the US, lots of sodium is added to foods during manufacturing – not only for taste, but to make the food last longer on the shelf. By choosing more whole foods, you are naturally reducing your sodium intake. Many people eating a plant-based diet can even add salt to their cooking without exceeding their sodium limit!

CKD problem: Renal bone disease

Bones are constantly changing, they can be built back up or broken down. Along with providing our body structure, they are a reserve for the minerals calcium and phosphorus. Your kidneys help regulate these minerals in the bones and blood. In CKD, extra phosphorus cannot be filtered out into the urine so it builds up in the blood, this can lead to bone and other problems. Kidneys also convert vitamin D to it’s active form (calcitriol) which is needed for healthy bones.

How plant-based diets help:

One of the reasons why beans, legumes, nuts and seeds were restricted in the “old” kidney diet is because they were labeled high in phosphorus. We now know, a good portion of phosphorus in plant foods is bound in the form of phytate. Phytate is not absorbed well in the human body. Phosphorus is easily absorbed in animal products and processed food. Our bodies absorb 90-100% of phosphorus in processed food and only about 30% phosphorus is absorbed in plant-foods. This is why plant-based diets are actually lower in phosphorus! Less phosphorus in your blood is better for your kidneys and bones because there is less risk of phosphorus build up.

Another player in bone health is fibroblast growth factor-23 (FGF23). This is a hormone that regulates phosphorus and vitamin D metabolism. When there is an increase in phosphorus, FGF-23 also increases to try and get rid of the extra phosphorus through the urine. This may sound like a good thing, but it’s not. FGF-23 also hinders the kidney’s ability to make calcitriol (active vitamin D). This causes a chain of reactions which hurts bone health. The good news, plant-based diets are also associated with lower levels of FGF-23, again, due to the lower phosphorus content of the diet.

CKD problem – inflammation

Chronic kidney disease is associated with chronic low-grade inflammation. This is when your body’s immune system goes awry and it can put you at risk for other health conditions.

How plant-based diets help:

Plants-based diets to the rescue again! Plants foods are full of phytochemicals. These amazing compounds do all sorts of good stuff in our bodies. Simply stated, they can sooth our body from the inside and reduce the impact of inflammation. Choosing a wide variety of plant-foods will help you get the most bang for your buck. Different colored fruits and vegetables are associated with different phytochemicals and they benefit us in unique ways! Studies have shown plant-based diets are associated with lower levels of C-reactive protein which is a blood test which measures inflammation in the body.

To summarize....

As you can see, nutrition can be a powerful tool to help manage symptoms of CKD, prevent complications and help prevent progression. The foods you eat affect so many processes in your body. I believe food should be the first line of defense for those diagnosed with CKD. Why let it progress when we can control it from the start? It’s never too early or too late to adopt plant-based eating habits. Small, sustainable changes (like adding one serving of fruit or vegetable to your daily intake) can make a positive impact on your health over time. And remember, a registered dietitian can help guide you to make plant-based eating achievable and delicious!