Leaching vegetables: Is it advantageous or deleterious for renal failure?


Chronic kidney disease affects more than 1.3 billion Indian.  The number has doubled in the past 15 years showing the burden of the disease on the population. Thus, following a “kidney-friendly” diet is crucial for positive long-term outcomes.

Kidneys play a pivotal role in the regulation of electrolytes but when the kidney loses its function, multiple derangements like accumulation of potassium, phosphorus occur in blood. Thus, patients are advised to monitor their dietary intake of protein, sodium, potassium, and phosphorus among other restrictions.

It is the responsibility of dietitians to help patients and their families in careful selection of foods and by preparing foods in such ways that minimize potassium, phosphorus consumption as well as teach them how to flush excess potassium.

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Why is potassium restriction important in renal failure?

High potassium levels can cause severe muscle weakness or an irregular heart rhythm that can be dangerous. When potassium is very high, the heart can stop beating unexpectedly and cause sudden death. High potassium levels can be life threatening without noticeable manifestations or symptoms (and therefore it is known as a silent killer).

vegetables in renal diet

The normal serum potassium (level of potassium in blood) is 3.5 mEq/L to 5.1 mEq/L. But in renal disease, when serum potassium is above 5.2mEq/L, dietary potassium needs to be limited. In general, most experts believe that people with impaired kidney function should eat less than 2000mg of potassium per day. But there is no food that does not contain potassium. Even the most nutritious fruits and vegetables contain a certain amount of potassium.

All green leafy vegetables like spinach , fenugreek leaves , parsley , and colocasia leaves  contain a huge amount of potassium. Recently, legumes have also been considered as a good source of protein for renal patients. However, despite their benefits, guidelines still recommend a limit to their consumption by these patients because of legumes’ high potassium and phosphorus content.

high potassium food

Other common potassium high foods to avoid are :

  • Potatoes
  • Banana
  • Jaggery
  • Nuts and raisins
  • Coconut water

How can we reduce potassium in food?

Potassium levels can be diminished in certain vegetables by cooking in a process called leaching. This method can be applied to certain vegetables ( potatoes, sweet potatoes, carrots, beets) and dals .

What is leaching ?

Leaching is a process of soaking raw or frozen vegetables in water for at least 2 hours or overnight before cooking to “pull” some of the potassium , phosphorus out of the food and into the water and then discarding the water . When cooking them, five times more water than vegetables to be used. Before the procedure , vegetables should be chopped in small pieces.

leaching process of vegetables:

Let’s try leaching on potatoes. Despite having high potassium, our favorite potato can be incorporated in the patient’s diet by following process:

leaching potatoes
  • Rinse the raw potatoes thoroughly with water
  • Peel and soak it in cold water .
  • Chop the potatoes into a few pieces.
  • Rinse in warm water for a few seconds.
  • Soak for about minimum of two hours or overnight in cold water.
  • Cook  with five times the amount of water to the amount of potato.
  • Drain excess water and cook the potatoes as desired. And, also try to season potatoes with herbs instead of salt.
  • Pulses can also be cooked in exactly the same way to reduce potassium content.

But can leaching really solve the problem ?

Several studies show that potato soaking is ineffective to reduce full potassium  from fresh raw potato despite following this laborious culinary technique. The whole process takes a lot of time that can be troublesome for the people to do everyday.

From the nutritional aspect, one of the concerns about soaking vegetables is nutrient loss. Water-soluble vitamins like vitamin C, vitamin B,  minerals and phytochemicals that have antioxidant properties leach out of vegetables into the cooking water. Renal failure is hypercatabolic disease, which means body’ metabolism becomes doubled leading to the increased need of nutrients but due to leaching out of nutrients , nutritional value of foods are compromised.

green vegetables

Also chopping vegetables into small pieces and then soaking them is even worse because more surface area is exposed to the water and the air, which also oxidizes some nutrients. After soaking for such a long time,  if the vegetables go really mushy, if they are bland looking, if the flavor is reduced, patients not only lose the nutrients, but it’s not going to make them  want to eat it as well since they already have a reduced appetite. Since leaching eliminates all other essential nutrients and vitamins with potassium, it is recommended to leach only vegetables, which are high in potassium , and other all low-to-medium-potassium vegetables to be cooked in a normal way.

foods to lower potassium

Dietitian could be the best person to guide the patient in choosing the food containing less amount of potassium which do not require leaching of green leafy vegetables after monitoring the patient’s serum potassium level.

I would recommend all readers to use potassium calculator once. Every year many of my kidney patients suffer cardiac arrest just because of potassium imbalance. Only if they knew what caused the potassium level to shoot up. Grab your opportunity today and save yourself and your dear ones today. Kidney disease or diet restrictions does not always cut down to a bland food. Check your safe food options today without delay.

Here is a video to show you how to use world’s first food potassium calculator, please watch it till end and do not forget to like and subscribe our channel.

Published by Dr.Pratim Sengupta

Dr. Pratim Sengupta thinks of himself as conscious, living, soulful being with an inner urge to break the inertia of life. He feels that life is nothing but a material expression of the Supreme Almighty Consciousness. His conscious existence empowered him to see, to hear, to talk, to interact, to feel, to dream, to ask questions, and to seek solutions to every problem. In the flow of life, as he grew up, he understood that knowledge of life is the only way to understand the scientific basis of conscious existence. Hence Dr. Sengupta felt the urge to study the science of life – i.e. Medicine. After he completed his higher secondary education from the Ramakrishna Mission Vidyamandira in Belurmath, he joined the MBBS (Bachelor of Medicine, Bachelor of Surgery) course at RG Kar Medical College, Kolkata. The professional packaging of knowledge in terms of a time-bound, goal-oriented syllabus frustrated him a bit, but nevertheless ignited the urge within him to study further. He thus went on to his post-graduation (MD) in Medicine from IPGMER and SSKM Hospital, Kolkata. During his MD training, he got a glimpse of the vastness of knowledge, and the quest to learn precisely the facts of life narrowed down his area of interest to the functioning of the kidneys and the specialisation of Nephrology – a discipline that is complex, yet relatively new and still evolving in terms of complete understanding of renal physiology and pathology. So, Dr. Sengupta decided to study and train for the DM (Doctorate of Medicine) degree in Nephrology. Right from the start of his career, Dr. Sengupta was passionate about Research. During the MD programme he worked on Cirrhotic Cardiomyopathy, Autonomic Neuropathy of Lupus, and Insulin resistance in Diabetics. All these research studies were published in national journals. During his postdoctoral study in Nephrology, he worked on Hemodialysis efficiency, and suggested an angular placement of the Dialyser in order to increase efficiency. This innovative concept was accepted for presentation at the World Congress of Nephrology, Milan, in 2009, and also published in Hemodialysis International. Dr. Sengupta also worked on Plasmapheresis – a blood filtering technique by which toxic and pathogenic immunoglobulins can be removed from the body. He studied the role of Prethymectomy Plasmapheresis in Myasthenia Gravis patients, and his findings were published in the journal Interactive Cardiovascular and Thoracic Surgery. The patient-empowered nutritional model for nutritional care of kidney patients is another interesting and innovative area in which Dr. Sengupta has worked for quite a long time. Dr.Pratim Sengupta won the Bharat Jyoti award for his excellency in the field of medicine. He is also the president of our non-governmental organization, The Kidney Care Society. His tireless contribution to provide quality living for his patients is worth mentioning. He introduced Mukti, blending ancient Indian yoga with modern medicine for well being of every patient. He has also introduced an unique online course "Art of Living with diabetes" which is a complete solution to diabetes management. He has authored many books, blogs, for the patients. Searching and researching for solutions to problems in the field of Nephrology remains the passion and dream of Dr. Pratim Sengupta, and he intends to persist on this journey as long as he is conscious. Meanwhile, even as he pursues his dreams, Dr. Sengupta diligently puts into practice all he has learned about Nephrology over the years, at the Belle Vue Clinic in Kolkata and ILS hospital,Dumdum where he is available for his patient

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