Why a Nutritional Blog?

Date: 05/11/2012 - Posted by J.J. Carrero - 16 Comments Why a Nutritional Blog?





Why a renal nutrition blog?

“Nutrients are the substrates for energy, tissue synthesis and metabolism. A continuing supply of nutrients is necessary for an individual to live”

This sentence summarizes the principles of the Science of Nutrition, and it feels hard to refute.


The Science of Renal Nutrition in chronic kidney disease (CKD) has evolved dramatically during the last decades and clearly shows that CKD patients not only have difficulties in meeting energy and calorie needs, but also have altered metabolism that rapidly depletes their body fuels. This multifactorial condition has been termed Protein-energy wasting (PEW) and is one of the strongest factors associated with the poor survival of this patient group.


In this complex scenario, CKD patients are also in need of integrated nutrition assessments, identification of those  at greatest risk for PEW, multiple dietary instructions to maintain an adequate supply of protein and energy while at the same time reducing intake of phosphorus, sodium, potassium and fluids and finally, aggressive nutrition support interventions in those with moderate to severe PEW.  


Dietary restrictions are hard to comply and sometimes go against usual recommendations for a healthy diet. Patient’s compliance with these dietary instructions depends on appropriate advice by healthcare professionals. Patient’s management of their nutritional status depends, at the same time, on up-to-date knowledge by healthcare professionals on the causes, clinical signs and therapeutic options available.


Internet offers an invaluable opportunity to create virtual interest groups, surpassing distances and geographical boundaries. We thought it would be useful and relevant to create a place in NDT-e where to exchange professional experience and gain insight into clinical renal nutrition practice around the world. Blogs are rapidly evolving as a dynamic and interactive platform for these initiatives and it is with great pleasure that we initiate with this post the adventure of a “Renal Nutrition Blog”.


Our thoughts for this blog include:

  1. Discussion on innovative or controversial topics on nutritional management and clinical practice in patients with CKD.
  2. To create an interactive journal club experience where authors can discuss with bloggers the implications and applicability of their recent publications.
  3. Create a virtual community support for patient care.
  4. Offer information on renal nutrition education initiatives for both patients and healthcare staff.


Our first initiative was to run a small survey regarding knowledge in renal nutritional management. This survey ran during the summer in the NDT-e platform. We were impressed by the high participation obtained, with more than 1100 respondents!  Results are briefly discussed in this link (http://www.ndt-educational.org/nutrition.htm). However, we will take the opportunity to discuss some of these topics in more detail in upcoming posts.


The success of the blog depends on your interests and participation.

  • What topics/problems you would find interesting and relevant for your practice? We could invite worldwide experts to discuss with you these issues in the blog.
  • Have you published recently on aspects related to renal nutrition and would like to expose them to the renal community? Please contact us and allow us to learn from your work!
  • Are you aware of educational initiatives, courses, workshops or symposia on renal nutrition? Let us know and we can increase awareness through this platform!
  • Do you have other ideas and/or would like to participate actively in this initiative? Great, just contact us!


Juan Jesús Carrero

Karolinska Institutet, Sweden.


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Kalantar-Zadeh Kamyar, Tuesday, January 15 2013
Congratulations on this important blog. I would like to share this paper in JReN:
J Ren Nutr. 2013 Jan 9. pii: S1051-2276(12)00226-9. doi: 10.1053/j.jrn.2012.11.001. [Epub ahead of print]
Let Them Eat During Dialysis: An Overlooked Opportunity to Improve Outcomes in Maintenance Hemodialysis Patients.
Kalantar-Zadeh K, Ikizler TA.
address: kkz@uci.edu.

Excerpts from the Abstract (posted on Pubmed.gov):
... Monitored, in-center provision of high-protein meals and/or oral nutritional supplements during hemodialysis is a feasible, inexpensive, and patient-friendly strategy despite concerns such as postprandial hypotension, aspiration risk, infection control and hygiene, dialysis staff burden, diabetes and phosphorus control, and financial constraints. ... If more severe hypoalbuminemia (<3.0 g/dL) not amenable to oral interventions prevails, or if a patient is not capable of enteral interventions (e.g., because of swallowing problems), then parenteral interventions such as intradialytic parenteral nutrition can be considered. Given the fact that meals and supplements during hemodialysis would require only a small fraction of the funds currently used for dialysis patients this is also an economically feasible strategy.

Carrero Juan Jesus, Friday, February 22 2013
Thanks Prof. Kalantar for letting us know about your recent work.
The majority of readers of NDT-e come from Europe, where provision of food in the dialysis session is often carried out.
I wonder if any would like to comment on this: have you frequently observed any of the concerns attributed to in-center provision of meals to dialysis patients (postprandial hypotension, aspiration risk, infection control and hygiene) that preclude this practice in the US?

Steiber Alison, Tuesday, January 15 2013
Dear Renal Nutrition Friends,

I want to bring the new malnutrition characteristics published by both the Academy of Nutrition and Dietetics and the American Society of Enteral and Parenteral Nutrition (White et al, Journal of Academy of Nutrition and Dietetics, Vol 112, issue 5, May 2012) into the discussion. While not specific to renal, I think it relates to Anthony's point on functional status and Maria's point that malnutrition or PEW can occur at any BMI. The paper outlines 6 characteristics (E intake, Wt loss, body fat loss, muscle loss, fluid accumulation, reduced grip strength) that may be used to diagnose malnutrition (yes they use that term...). Two of the 6 characteristics are needed to be present for the diagnosis. Some points that I really appreciate about this paper are: the diagnosis is an etiology based one - meaning they are really taking into account the impact of inflammation on nutritional status, hand grip is one of the parameters looked at, and poor nutrition can occur at any BMI. Unfortunately, these characteristics, in the way they are being presented, have yet to be validated....stay tuned. I look forward to the rich discussions that will take place on this excellent blog. Cheers - Alison

Carrero Juan Jesus, Friday, February 22 2013
Thanks Alison, this document was interesting to read and try to extrapolate to our population. As for the recently proposed ISRNM criteria, we must await diagnostic validation.

Sometimes I feel that in nephrology we confuse the diagnostic utility of biomarkers (to diagnose undernutrition/wasting) from their prognostic validity as predictors of outcomes.

Virtually any biomarker of nutrition strongly predicts outcome. However, it is harder to suggest which combination of biomarkers reflects the complexity of situations inferring in the undernutrition/wasting of CKD, and how to be sure that other tricky aspects of uremia are not influencing these outcomes.

To the readers: what clinical and biochemical signs do you more frequently used in your assessment in the nondialyzed and dialyzed CKD patient?

Meade Anthony, Tuesday, January 15 2013
Hi Juan and thanks for stimulating discussion from a truly multinational perspective. This motivated me to go back and re-read the Zoccali article which indeed is a good discussion. If we were to go purely on BMI then less than 3% of people starting RRT in Australia & NZ would be considered malnourished and more than 55% are overweight or obese. Measuring body fat is less important than being able to measure muscle mass and as rightly pointed out you can be obese and sarcopenic and this is a particularly bad combination on so many levels. Most of the methods described are about measuring body fat and not about measuring muscle mass, but measuring muscle mass and particularly changes in muscle mass over time is where we really need to focus. Unfortunately at the moment we don't have reliable ways of consistently measuring muscle mass. And to further complicate the issue, it is not muscle mass per se that is important but rather [i]functional[/i] muscle mass. Physical performance measures are better at giving us information about muscle status however even basic measures such as handgrip strength are rarely done in most people with CKD or on RRT despite very good evidence around their validity and usefulness.
Skinfold measures are an interesting discussion point as well. Skinfold measurements are far more reliable in healthier weight individuals and can be quite sensitive to subcutaneous body fat changes, particularly in athletes but i think their usefulness in obese people is limited. In athletic populations we monitor trends in weight and skinfolds and then assume we are also seeing changes in muscle mass as these parameters change, however these are also interpreted with functional strength and performance tests in practice (very different to what we do in CKD).

Last comment is to remind us all to think at both population and patient level. The big cohort studies looking at BMI data are not necessarily guiding us on individual patient assessment and there is no replacement for actually seeing the patient and assessing them physically! Performing skinfolds at least gets clinicians touching the patient (a good start) but other methods like SGA and PGSGA are particularly useful in making clinicians be a little more objective about physical changes and function as well as other nutrition indicators.

I look forward to others thoughts.

Carrero Juan Jesus, Friday, February 22 2013
Your words, coming far away from Australia, are refreshingly true. I would add that we seldom take into account the aging process. Given that the majority of your patients would be over the age of 60-65, there are natural body compositional changes that occur with aging that may be misunderstood as malnutrition signs. Elderly often have reduced muscle mass, low albumin, low food intake, and not because of that are malnourished. Does one size fit all?

Avesani Carla, Thursday, January 03 2013
Dear Juan and Peter!

Congrats for starting this blog. I think this a great initiative. Now we can meet here for a virtual coffee and chat about nutrition and CKD.
I read the review from Dr Zoccalli. A great one, as usual. However, I have my concerns about using BIA to evaluate FM. My concern is that each equipment uses a different formula. I tested in our lab to calculate the FM using the same data of resistance and reactance in two very known BIA tetrapolar equipments. The difference was of about 2 to 3 kg and this could change diagnosis. The difference seems to be higher for obese individuals. Unfortunately this is not published (on the “to do list”). But to us, it alerted us to this issue of the formulas from the equipments. What do you think?

Carrero Juan Jesus, Friday, January 11 2013
Dear Carla,
thanks for the post and for sharing this information.
You touch a very important point in nutritional assessment: no method is exempt from limitations. BIA is an important assessment tool, but you are right to point out that each commercial device available nowadays is based on different algorithms and reference populations. This may make results not comparable among devices and, furthermore, differ importantly from one another.

"It is the part of a wise man not to venture all his eggs in one basket", and I think it is important to emphasize that nutritional screening and assessment should be done in the context of various complementary techniques. There are very simple tools to implement that may help us reinforce our diagnosis and would not necessary imply bigger costs or personnel resources.

At the same time, trends over time may be more relevant than single tests. This is clearly more evident in nutritional biomarkers and assessments that may be influences by acute phase protein synthesis or fluid overload. Such approach may reduce the impact of over/underestimation of the technique.

I wonder what our blog readers use in their units. Perhaps we should make a separate post about it? What do you think?

Stenvinkel Peter, Friday, December 07 2012
As obesity is a major driver of increased incidence of CKD nephrologists need to learn how to best measure it. In the a recent Ms by Zoccali et al (Curr Opin Nephrol Hypertens. 2012 Nov;21(6):641-6) different methods to estimate fat mass is reviewed. Their conclusion that skinfold thickness, waist-hip ratio and multifrequency BIA should be used instead of BMI is valid. Another easy measure of body fat content is conicity index (Ci), which estimates fat accumulation in the abdomen as the deviation of body shape from a cylindrical towards a double-cone shape. The present obesity survey in NDT-E on will let us know which methods nephrologists use in their clinical practice to estimate body fat content.

Mafra Denise, Thursday, November 29 2012
Hello Juan!
Congratulations for this blog!
I've sent to my students the site!

Carrero Juan Jesus, Friday, January 11 2013
Welcome Denise from far away Brazil. I look forward to your valuable input. Please, encourage your team to post comments and questions. It is nice to have this virtual proximity between Stockholm and Rio de Janeiro!

Chan Maria, Wednesday, November 21 2012
Hi Juan, Congratulations! It is great to see the “nutrition blog” in the NDT- EDUCATIONAL. As an ex-chair of the dietitians group in the ISRNM, I highly recommend the active participation of all renal clinicians including dietitians to the nutrition blog.
I just took part in the “obesity survey”. It was a “fun” way to refresh your knowledge on “Obesity in CKD”.
Our group has a recent publication on the baseline nutrition factors of incident dialysis patients and survival, J Ren Nutr 22(6): 547-557, 2012. We found overweight/ obesity (BMI 26 kg/m2) did not show any advantage on survival. In addition, the combination of malnutrition and overweight/or obesity was associated with a 3 fold increase in mortality risk compared to being well nourished with a BMI <26 kg/m2 (referent). A result echoed the work on obese sarcopenic subjects in your centre in Stockholm - Honda, et.al. Am J Clin Nutr. 2007 Sep;86(3):633-8.
There will be a lot of challenges ahead for the clinicians and researchers to manage the growing epidemic of obesity in CKD.

Carrero Juan Jesus, Friday, January 11 2013
Dear Maria,
we are honored that this blog reaches far away places such as Sidney. Thanks for reaidng us!
I find interesting that you stress the fact that obesity/overweight is not exempt from malnutrition. Sometimes we assume a state of health and wealth in those patients, and we may miss the opportunity to early detect and manage the onset of malnutrition/catabolism. How would do you tackle these situations in your unit?