Protein restriction in Chronic Kidney Disease

Wines get better with time-they say-but the same can’t be said with old hypotheses unsupported by good evidence. Hypothesis in question is that of dietary protein restriction in management of CKD. With the expanding armamentarium of CKD, when nephrologists were almost saying goodbye, the protein restriction debate was sparked by the latest KDOQI (2020) guidelines, by recommending Very Low Protein Diet (VLPD) (0.3-0.5gm/kg/day) with ketoanalogues in patients with pre dialysis CKD (1A recommendation). Debate was colored further by the NEJM review article as many doctors believe that the letters printed on those glossy color pages of the journal are as sacrosanct as religious texts of Bhagavad Gita or New Testament. For academic atheists like me, however, it’s a difficult pill to digest. 

Absence of enough evidence, possibility of harm, old, non contemporary nature of the evidence and better things that one can try in patients with CKD are the principal reasons why the idea of protein restriction is useless in current practice. We recently reflected upon this issue in a review which just underlines the famous quote by F Parsons-all a low protein diet does is to shrink the patient down to the size of his kidneys. VLPD may postpone the decision to start dialysis for a few months while increasing the risk of malnutrition and death in the bargain. 

Obesity and metabolic syndrome are precursors of the two most important CKD risk factors-diabetes and hypertension. They elevate CV risk manifolds and mitigation of this risk doesn’t need complex dietary plans but simply the restriction of salt, sugar and fat. This trio arguably underlies the major death toll, far greater than that of all the wars and natural calamities put together. Most of our patients don’t want to be bothered much about these: we know that, just talk about a diet for creatinine! Why we prefer to remain blind to the obvious and keep searching for illusory solutions in the diet is beyond comprehension. Probably, we feel so badly about salt, sugar and fat, that we simply love them!

CKD Diet: with a pinch of humor 

Visit to the nephrologist is incomplete without the discussion of diet-that’s what most patients in India believe. Many patient families hold a strong opinion (opinions are not the monopoly of guideline experts) that diet is far more important than medications, optimum blood pressure control, physical activity and moderation of caloric intake. As the menu of questions concerning CKD diet is far more diverse than that of an average Gujarati Thali, these diet talks exceed the typical time needed for the actual consultation. 

These sessions are greatly enjoyed by patients and families alike but are often irritating to the doctors and for the next patient waiting outside the chamber. As if this was not enough, even other specialist colleagues tell patients to ‘get the diet clarified by the kidney doctor’ as if the food eaten is metabolized by the kidney and nephrologists are in possession of additional qualification in nutrition science! I usually teach such colleagues a lesson by making sure that patient doesn’t see them back ever again(just kidding!). 

So let’s see what CKD diet is. Only thing that is clearly known about this diet is that it’s never the same for 2 different patients. Take for instance, the happy couple of Hansaben and Mukeshbbai, whom I saw in OPD at the beginning of my practice. Mukeshbbai, a gentleman in his 80s, with well controlled diabetes and hypertension, was rushed to my office after discovering that his eGFR has dropped to 60. Hansaben was a lady of discipline, and had taken over management of the kitchen after Mukeshbbai got to know about his kidney problem. After assessing his case, I assured the couple that the kidney problem isn’t that serious and you can be less restrictive about his diet. 

This information came as a disappointment and relief for Hansaben and Mukeshbbai respectively. Mukeshbbai was specifically fond of the ‘tomato-uttapam’ which (in addition to other tomato containing foods) was banned completely  in his diet for over a year. When I said that tomatoes won’t harm the kidney, Mukeshbbai was in tears, reflecting how deeply he loved that tomato uttapam. I was very happy to have helped him but this joy was short-lived as Mukeshbbai stopped seeing me thereafter. Surely Hansaben wasn’t happy with my ignorance about the intricacies of the CKD diet. However, Mukeshbbai, although now under the care of a different nephrologist, sees me once in a while (of course secretly) just to say thank you, while returning back from that famous South Indian food joint! 

Mukeshbbai got his tomato uttapam back, but I lost a patient. What is the use of the knowledge or the facts about the diet if that is going to take away your patients? Instances like these were so annoying in my initial practice that I was on the verge of being burnt out. But a senior nephrology colleague saved my life. I happened to attend his interesting lecture which literally enlightened me about CKD diet. 

First of all, he said, you have to actually come to share the belief that the “CKD diet” is the most important aspect of clinical practice although all of us are well aware that it’s sham. This is in the interest of maintaining your sanity in the practice and keeping your clientele.  Second, it is best to remain passive and patient in these discussions, saying less and listening more. This, however, doesn’t mean that you appear unsure/uncertain. A rule of thumb in practice is that the certainty of your advice should generally be inversely proportional to the strength of evidence on which it is based. Whether bajra roti is better than jowar roti or if seeds should be taken out of the capsicum or boiling dal at 100 degree centigrade for 20 min would be better than 80 degrees for 40 min, baby brinjal versus giant brinjal,-whatever the question may be, it’s far more important to be sure than correct. Don’t ever say that ‘either of these is ok’; as this will leave the patients restless and invite 10 more questions that were previously not on his/her question list (yes, like home BP chart, patients carry this always). Careful listening to each case will eventually help you understand the “CKD diet” of your patient-each one may have a little similarities-but is always unique, thanks to the rich vegetation and flora of our country. 

He emphasized the need to understand this area of our practice as a blessing in disguise. For example, a patient with diabetic nephropathy, experiencing steady decline in kidney function in spite of the best of your efforts. This is not a very comfortable scenario, when a patient, with his anxious daughter and son in law, are staring at you (when you are cluelessly going through all his previous records) with expressions showing variable proportions of hope, fear and anger. A nephrologist often feels cornered in this situation, with no clue as to how to break the ice, when daughter offers a respite by recalling that father ate 3 samosas at an anniversary party last week. You are relieved (that’s why I love this snack!), for at least another month until the next follow up. 

Finally, he narrated a story of a very senior physician who held very rigid and peculiar views about food and health, which in nutshell, summarized the CKD diet. The man in question had a roaring practice and saw hundreds of patients in a day. One of his recommendations was complete avoidance of bottle gourds/Dudhi. Being a very authoritarian figure, no one dared to question his peculiar dietary recommendations, and patients and doctors remained clueless about the rationale, which was to be inadvertently revealed by alcohol. In a party where he was celebrating his 80th birthday, after a couple of drinks, one of his students dared to ask him this question,”What is wrong with Dudhi in diet?” 

“Nothing, I just hate Dudhi!” 

Now, you can replace Dudhi with Chicken, Capsicum, Tomato or any damn thing and come with a customized CKD diet of your own. Moral of the story is that dietary recommendations are driven more by such personal biases than credible scientific evidence. 

May you be in private or academic practice, there is no getting away from the devil-CKD diet. So as don Carlene has famously said,”Keep your friends close, but enemies closer”. 

Happy Holi to all!