Occurrence and characteristics of kidney stones in patients following a ketogenic diet

Relation

Acharya P, Acharya C, Thongprayoon C, et al. Frequency and characteristics of kidney stones in patients on a ketogenic diet: a systematic review and meta-analysis.diseases. 2021;9:39-42.

Study objective

The aim of this meta-analysis was to calculate an estimated pooled incidence of kidney stones in patients following a ketogenic diet and also to determine the most common type of kidney stones.

Draft

A systematic review and meta-analysis of 36 published clinical trials and observational studies (cohort, case-control, or cross-sectional) that reported the occurrence of kidney stones in individuals on a ketogenic diet.

Participant

The literature search, review and selection process ultimately resulted in the inclusion of 36 studies with a total of 2,795 pooled participants.

The investigators queried the following databases: MEDLINE, EMBASE, and Cochrane Database of Systematic Reviews.

When retrieving publications, the main search strategy used was: ('ketogenic diet' OR 'keto diet' OR 'Atkins diet' OR 'low-carbohydrate diet' OR 'low-carbohydrate diet') AND (nephrolithiasis OR 'kidney stones' OR 'kidney stones') . The initial search yielded 221 relevant studies. Two independent investigators reviewed these articles and a third investigator addressed any discrepancies.

Study parameters assessed

The parameters evaluated included the number of patients, mean age, gender, time to diagnosis of kidney stone after ketogenic diet, type of kidney stone, occurrence of kidney stones, and duration of follow-up.

Primary outcome measures

The primary endpoints included the incidence and type of kidney stones.

Key insights

Incident:The main finding of this study was that the estimated pooled incidence of kidney stones in patients on the ketogenic diet was 5.9% at a mean follow-up of 3.7 ± 2.9 years.

Because age was not a limitation, researchers were able to conduct a subgroup analysis that showed the estimated pooled incidence of kidney stones in children was 5.8% compared to 7.9% in adults.

Type:In reported studies, 48.7% of kidney stones were uric acid stones, 36.5% were calcium-based stones, and 27.8% were mixed uric acid and calcium-based stones.

Practice implications

Considering that the incidence of nephrolithiasis in the general population is reported to be 0.3% per year in men and 0.25% per year in women,¹Based on the results of this analysis, it is clear that following a ketogenic diet may increase the incidence of kidney stone formation. Therefore, doctors who prescribe ketogenic diets must consider whether the benefits of the ketogenic diet outweigh the risks. Patients and clients also need to be informed about the increased risk of kidney stone formation and strategies to reduce their formation.

Practitioners who prescribe ketogenic diets must consider whether the benefits of the ketogenic diet outweigh the risks.

While the exact mechanism of nephrolithiasis is still uncertain, it may likely be related to the chronic acidic physiological state that often results from a high-fat, moderately high-protein, and alkaline diet. If fluid intake is also restricted, the risk of kidney stone formation increases further.²In addition, chronic acidosis leads to bone demineralization, increased calcium excretion,^3.4and even uric acid crystals.²

Dietary modification and other medical/nutritional strategies may need to be implemented, particularly in patients with a history of kidney stone formation.

When it comes to diet, some modification options include:

1. Der Wechsel von purinreichem tierischem Protein, das nachweislich ein saures Milieu erzeugt, zu pflanzlichem Protein, was zu einer geringeren Harnsäureausscheidung führt.
2. Erhöhen Sie die Flüssigkeitsaufnahme, um das Risiko einer Nierensteinbildung zu verringern.^5,6

Regarding dietary supplements:

1. Eine Supplementierung mit oralem Kaliumcitrat, das den pH-Wert des Urins alkalisieren kann, kann gerechtfertigt sein. Es wurde gezeigt, dass Kaliumcitrat zu einer Verringerung der Nierensteinbildung führt. In einer Studie wurde die Bildung von Nierensteinen von 6,75 % auf 0,9 % ohne Nebenwirkungen bei Teilnehmern mit ketogener Ernährung reduziert.⁷
2. Ausreichende Calcium-, Magnesium- und Vitamin-D-Spiegel sind ebenfalls ein wesentlicher Aspekt zur Unterstützung der Knochengesundheit.^8,9

In patients with recurrent stone formation, screening for genetic variants that increase the risk of kidney stone formation (ie, renal sodium citrate cotransporter), regardless of diet, should be considered as part of a holistic and personalized approach.^10,11

The length of time on the ketogenic diet can also be a factor in the formation of kidney stones. For people following a ketogenic diet for weight loss, the risk of developing kidney stones can be reduced if the diet is followed in the short term.

Ultimately, the authors state, “These results may have implications for the prevention and treatment of kidney stones in patients treated with ketogenic diets.” Awareness of this risk by the physician and patient is essential information before proceeding with a ketogenic diet.