The term plant-based eating was said to be coined in 1980 by Dr. T Collin Campbell who has done extensive research over the years focusing on diet and disease. 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 post I’ll go over what a plant-based diet is and how it benefits your kidney health.
Definition of a plant-based diet
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.
Plant-based diets encourage foods found in nature…. vegetables, fruits, nuts, seeds, beans, legumes and whole grains. Plant-based diets are lower in animal products and ultra-processed foods (think sugary drinks, deli meats, packaged snack foods, etc).
Plant based diets vs. vegetarian diets
There are some similarities and differences between plant-based diets and vegetarian diets in terms of what they consist of and reasons one chooses that type of eating pattern.
Different types of vegetarian diets
All vegetarian diets include plant foods but vary in terms of what kind of animal foods they include. Here are the basic types of vegetarian diets:
- Lacto-vegetarian: includes diary – eliminates meat, poultry, eggs, fish/seafood.
- Lacto-ovo vegetarian: includes dairy and eggs – eliminates meat, poultry, fish/seafood.
- Pescatarians – includes fish (may or may not include dairy and eggs) – eliminates meat and poultry.
- Vegan: includes plant foods – eliminates all animal products.
Similarities between plant-based diets and vegetarian diets
Plant-based and vegetarian eating patterns all limit amounts of animal products (in varying degrees).
Difference between plant-based diets and vegetarian diets
One main difference between these eating patterns is why people follow them in the first place. Surveys have shown that most people choose a vegetarian/vegan diet mostly due to ethical concerns, like animal rights. Plant-based eating is more driven by a person’s health concerns rather than ethics.
Another key difference is the inclusion of processed foods. There are many processed foods that happen to be vegan… things like Oreo’s, Bacon Bits, potato chips, and processed vegan meats for example. Not to say all vegan/vegetarians eat these foods all the time – but just because someone is vegan, doesn’t necessarily mean they are eating “plant-based”. You can be vegan/vegetarian without eating fruits and vegetables at every meal.
As mentioned above, a plant-based diet is not only about incorporating more whole plant-foods, it is encouraging less intake of packaged/processed foods. Packaged foods, even ones that are labeled as “plant-based” or “vegan” can be high in sodium, added sugar, fat and contain preservatives that are not ideal for kidney and overall health.
How can plant-based diets help chronic kidney disease?
The picture on the left shows some complications that occur when kidney function declines. Many of these symptoms may not occur in early chronic kidney disease. Making diet changes sooner may help you avoid these complications and – spoiler alert – diet may help you control these symptoms if you are experiencing them.
CKD problem: Waste products and toxins build up
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 should avoid high protein intake, especially from animal products, due to the waste product produced by protein metabolism. Plant-proteins are less protein dense than animal sources, allowing you to reduce your protein intake without necessarily reducing the volume of food.
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 from 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. Each sodium bicarbonate tablet contains about 178 mg sodium, so it can add some extra sodium to the diet, which may not be ideal.
Studies have shown, plant-based diets can improve metabolic acidosis just as well as sodium bicarbonate. 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 the 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
The bones in our body are constantly being broken down and built back up. Along with providing our body structure, bones are a reserve for 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 its 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. Studies have shown we absorb as little as 30% of the phosphorus found in plant foods.
Phosphorus is also found in animal products, and we may absorb up to 80% of this type of phosphorus. Phosphorus added to foods has the highest absorption rate at 90-100%. Since plant-based diets are higher in plant foods and lower in processed foods/animal products, they are not associated with high blood phosphorus levels.
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! Plant 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…
The benefits of plant-based diets come from whole-plant foods rather than fancy packaged foods plastered with claims of being “plant-based”. Following a diet rich in plant-foods can help manage many of the complications that arise with chronic kidney disease.
It’s never too early or too late to adopt plant-based eating habits. Small, sustainable changes 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!
