The Ketogenic Diet is being studied as a possible good option for patients with kidney damage.
Today we bring to you a very interesting study, not of the highest scientific quality, but equally interesting.
Medicine and a Ketogenic Diet
In the world of Nutrition and Medicine there is much suspicion about ketogenic diets because of their supposed poisonous effect on renal function.
This is usually justified by its higher relative content in protein.
Although, as I have commented many times, a ketogenic diet will not always have a high protein content and most of the time it is a high fat, moderate or adequate protein diet, and restricted in carbohydrates.
The study in question (Bruci et al., 2020) is a real-life study (this may be good or bad depending on what we look at), is observational and prospective, and performed on 92 patients with Obesity.
The patients were followed for three months.
This diet is characterised by the following points and that condition the entire study:
- Calorie intake between 500 and 800 kcal/day, i.e. a very aggressive calorie restriction.
- Carbohydrate count: <20 grams daily.
- 1-1.5 grams of protein/kg of weight, ideally daily.
- 15-30 grams of fat daily.
- Based on food substitutes that mimic a Mediterranean diet.
Results of the Study
Now we will tell you the more important findings of this work, which are not few:
- Liver enzymes AST and ALT decreased.
- The amount of triglycerides decreased considerably, which is reflected in lower intra-hepatic triglyceride content and smaller liver size.
- There were no changes in the ion balance.
- There was a slight loss of water (Total Body Water) due to the increased natriuresis produced by this type of diet.
- Uric acid was not elevated in contrast to previous observations.
How much weight did the patients lose?
An average weight loss of 20% of the initial weight is a clinically significant result.
A slight increase in calcium and phosphorus (not beyond normal range) that can be attributed simply to hemoconcentration.
Levels of PTH, a hormone that regulates phosphocalcic metabolism, remained unchanged.
This reassures us, as one of the adverse effects of this type of intervention so limited in calories is bone loss that generates an upward regulation of PTH and a subsequent increase in calcium and phosphorus.
Ferritin levels, an acute phase reactant, decreased, which could reflect less systemic inflammation in patients who followed VLCKD.
The most interesting finding of this study was that, within the group with slightly altered renal function (GFR 60-90 or stage 2 CRF) a large percentage (27%) RECOVERED renal function, raising its glomerular filtration rate above 90 ml/min/kg2.
What type of protein is recommended?
In chronic kidney disease, the source of protein is as important as the total amount of protein.
In this respect, we have to make several distinctions:
- Protein from red meat is discouraged by most clinical practice guidelines
- The protein from white meat, fish and egg appears to have a neutral effect and therefore does not seem to worsen kidney function
- Protein from plant sources may even have a renoprotective effect and is the field where most research is currently being done in the field of dietetics in nephrology.
However, it would have been interesting to include patients in at least grade 3 chronic kidney failure (GFR 30-60) or at least 3b (45-60), since stage II is often reversible with weight loss or correction of cardiovascular risk factors such as high blood pressure.
That said, other limitations of the study were that beta-hydrotutirate was not tested in capillary blood, a method much more precise than the urine strips and the acetoacetate measurement used.
Finally, because of the nature of the study (real-life study), it is uncontrolled work, which also limits the results.
If we can take anything from this work it is corroborating that:
- Very powerful weight loss (20% is a lot of lost weight) can be achieved in a relatively short time (three months); and
- Moreover, not only did it not worsen renal function, but in many cases improved it, something that had not been previously described in the literature, as far as we know.
I hope this has been useful!
We’ll see you in the next post. Big hugs and keep going!
- Bruci, A., Tuccinardi, D., Tozzi, R., Balena, A., Santucci, S., Frontani, R., Mariani, S., Basciani, S., Spera, G., Gnessi, L., Lubrano, C., & Watanabe, M. (2020). Very low-calorie ketogenic diet: A safe and effective tool for weight loss in patients with obesity and mild kidney failure. Nutrients.
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