The ketogenic diet: Seizure control correlates better with serum beta-hydroxybutyrate than with urine ketones

The objective of this study was to determine the relationship between beta -hydroxybutyrate levels and seizure control in children on the ketogenic di et. Seventy-four children on the ketogenic diet presenting for routine foll ow-up visits had blood levels of beta -hydroxybutyrate correlated with thei r seizure control. Forty-two children admitted for initiation of the ketoge nic diet had urine ketones measured by dipstick and correlated with simulta neous blood levels of beta -hydroxybutyrate. Blood beta -hydroxybutyrate le vels statistically correlated with seizure control (P =.003). Children with blood beta -hydroxybutyrate levels greater than 4 mmol/L were significantl y more likely to have a decrease in seizure frequency than those with level s less than 4 mmol/L. Urine ketones of 4+ (160 mmol/L) were found on dipsti ck when blood beta -hydroxybutyrate levels exceeded 2 mmol/L. Seizure contr ol correlates with blood beta -hydroxybutyrate levels and is more likely wh en blood beta -hydroxybutyrate levels are greater than 4 mmol/L. The tradit ional measurement of urine ketones by dipsticks in children on the ketogeni c diet provides a less than optimal assessment of the degree of blood ketos is. Three to four plus (80-160 mmol/L) urine ketones are necessary, but not necessarily sufficient, to achieve optimal seizure control in children on the ketogenic diet. At present, however, urine ketones are the only readily available inexpensive approach to ketone assessment.