Kidney Stones Seen In Some Children On Keto Diet

What was studied

This study looked at kidney stones and kidney calcium buildup in children with drug-resistant epilepsy who were treated with a ketogenic diet (KD) or a modified Atkins diet (MAD) at one hospital clinic.

A total of 112 children started one of these diets, but the final analysis included 80 children who had enough follow-up information, lab results, and kidney ultrasound data. The researchers reviewed past medical records to compare children who did and did not develop kidney stones or nephrocalcinosis during treatment.

What they found

Among the 80 children studied, 11 developed kidney stones or nephrocalcinosis, which is about 14%. These problems were frequently asymptomatic. Children who developed stones were older when they started the ketogenic diet. Children on higher ketogenic ratios of 3:1 or more were more often represented among those who developed stones, but this result was not statistically significant. All stone cases happened in children on the ketogenic diet, and none were seen in the small modified Atkins group, but that group was too small to draw firm conclusions. Use of carbonic anhydrase inhibitor medicines, cause of epilepsy, mobility, feeding route, diet length, and number of seizure medicines were not significantly associated with stone development in this study. Most stone cases were managed conservatively, though 4 children had to stop the ketogenic diet. About 60% of the whole group had more than 50% seizure reduction.

Limits of the evidence

This was a retrospective study, meaning the researchers looked back at existing records rather than following children in a planned trial. That design cannot show whether the diet itself led to kidney stones. It was also done at a single center, with only 80 children in the final analysis, so the results may not apply to all children. The modified Atkins group was small, so the study cannot reliably compare MAD with KD. Some findings, such as the possible higher risk with stronger ketogenic ratios, were only trends and not statistically significant.

For families and caregivers

For families, this study suggests that kidney stones can happen in some children on a ketogenic diet, but they were often without symptoms and were usually managed without surgery. The diet was also associated with meaningful seizure reduction in many children. The main message is that careful monitoring, including lab checks and kidney imaging, may help detect problems early and allow many children to continue the diet.

What to watch next

Stronger evidence would come from larger, multi-center studies that compare ketogenic diet plans and follow children forward over time.

Terms in this summary

drug-resistant epilepsy

Epilepsy that does not improve enough after trying standard seizure medicines.

ketogenic diet (KD)

A high-fat, very low-carbohydrate medical diet used to help control seizures.

modified Atkins diet (MAD)

A less strict low-carbohydrate diet that may also be used to help control seizures.

nephrolithiasis

Kidney stones.

nephrocalcinosis

Calcium buildup in the kidneys.

carbonic anhydrase inhibitor (CAI)

A type of medicine, including some seizure drugs, that can affect body chemistry and may be relevant when studying kidney stone risk.

ketogenic ratio

The balance of fat compared with protein and carbohydrates in the diet; a higher ratio means a stricter diet.