Benefits of an All-Liquid Ketogenic Diet
To the Editor:
One of several barriers to the use of the ketogenic diet is its perceived unpalatability. We are still constantly surprised, however, by the lack of realization not only by pediatricians, but also by child neurologists and dietitians, that the diet can be easily provided as a liquid rather than heavy whipping cream, eggs, and tuna. Often physicians do not realize that the liquid form is perhaps the easiest method of providing the diet, most commonly for infants that are formula fed as well as for older children with gastrostomy tubes (1–3). Parents are often frustrated at their prior care after the diet is started conveniently and effectively as a liquid, after multiple medications had been tried and failed. Only a single abstract at the 2001 Child Neurology Society annual meeting described this so far, and this information apparently should be spread.
We reviewed the 226 patients started on the ketogenic diet at our institution from October 1998 to February 2004. Sixty-one (27%) children were totally formula fed, with almost exactly half (31 patients) formula-fed infants (mean age, 1.1 years), and the remainder were gastrostomy tube–fed children (mean age, 3.8 years). Approximately half of the infants had recalcitrant infantile spasms, and half of the older gastrostomy tube–fed children had either Lennox–Gastaut syndrome or intractable myoclonic epilepsy. All patients were provided a combination of Ross Carbohydrate-Free, Mead Johnson Microlipid, and Ross Polycose formula, as calculated by our dietitian to a 3:1 or 4:1 ratio of fat to protein and carbohydrate.
We found these 61 children had better seizure control than that described for the typical solid food–fed child, with 59% having >90% control at 12 months, compared with 27% in a larger cohort (4). Whereas 30% of children on the standard ketogenic diet discontinue because of restrictiveness, none of these 61 children did (4). Patients with excessive weight loss (or gain), low ketones, or hyperlipidemia had their diet quickly and easily titrated, as clinically necessary.
Many benefits are found in an all-liquid ketogenic diet. The formula is very palatable, with a taste similar to that of most other infant formulas. Beyond the infant age group, however, solid foods tend to be more palatable. In addition, it is easy to calculate for the dietitian, with three components combined, as compared with a plethora of individually planned meals and snacks. Less room for error occurs, and education is involved for parents. The presence of a gastrostomy tube also allows medications to be provided without carbohydrate sweeteners or flavoring. Patients who are ill on the ketogenic diet can occasionally have acidosis and dehydration, and having a gastrostomy tube helps avoid this. However, we do not advocate gastrostomy tubes for our patients with epilepsy unless deemed medically necessary. Last, insurance companies often cover formula, as it is being used as a medical therapy rather than for solely nutritional purposes.
In what other situations could a liquid ketogenic diet be beneficial? In any child in an intensive care setting for epilepsy, the diet can be easily started or continued via a temporary nasogastric tube. As the diet can be attempted for adults, perhaps a gastrostomy tube would be an ideal manner of providing such therapy (5). A liquid preparation also can be used as a supplement to solid foods.
