[Changes in serum levels of selenium, zinc and copper in patients on a ketogenic diet using Ketonformula]

Ketogenic diets tend to cause trace mineral deficiencies. Ketonformula is a foumula for a ketogenic diet developed by Meiji Co Ltd in Japan. No reports are available on the trace mineral deficiencies associated with a use of Ketonformula.

We monitored the serum levels of selenium, zinc and copper as well as the amount of the daily intake of these minerals before and at 6 months after the initiation of the ketogenic diet with Ketonformula in six patients with intractable epilepsy associated with severe motor and intellectual disabilities.

The median serum selenium concentration decreased from 7.0 (range, 6.5-12.3) microg/dl to 6.2 (5.4-10.9) microg/dl as a result of the 6-month-treatment with Ketonformula (p < 0.05, Wilcoxon signed-rank test). The median daily selenium intake decreased from 17.8 (15.0-27.0) microg/day at the baseline to 5.5 (5.0-22.0) microg/day after 6 months on the diet (p < 0.05). The median serum zinc concentration increased slightly (from 66.0 (46.0-84.0) microg/dl to 68.0 (46.0-71.0) microg/dl), but the difference was not significant. The median daily zinc intake, however, significantly decreased from 4.2 (3.7-6.0) mg/day to 2.2 (2.0-3.0) mg/day (p < 0.05). The median serum copper concentration also showed no significant decrease (from 134.5 (119.0-168.0) microg/dl to 126.0 (86.0-183.0) microg/dl). The median daily copper intakes, however, decreased significantly from 0.80 (0.35-1.30) mg/day to 0.30 (0.26-0.40) mg/day (p < 0.05).

The decline of the serum selenium concentrations and daily enteral intakes of selenium, zinc, and copper after 6 months on Ketonformula suggested that patients on this ketogenic formula needs close monitoring as well as supplementation of these trace minerals.