Things are changing quickly in the ketogenic diet world, and the use of dietary therapy in adults is a primary example of that. When we published our 4th edition of this book, we devoted only two paragraphs to discussing this topic. Now there is a good bit more to say. This chapter was written primarily by James Rubenstein with the added advice of Dr. Mackenzie Cervenka, who heads our epilepsy diet center for adults.
In the 69 years that passed between the report of what happened to 100 adults treated at Mayo Clinic in 1930 and a paper from Jefferson University in Philadelphia reviewing results from treating 11 adults (later expanded to 26), there were no other studies published in English-language medical journals. This was probably due to an incorrect perception that the diet was ineffective for adults. The truth is, the results were similar—that is, in the earlier study, 56% of patients had greater than 50% decrease in seizures, and 12% became seizure free. In the later study from 1999, the numbers were 54% and 27%. Of more interest, those results match up closely with the results most ketogenic diet centers report in longer term studies in children, where we expect 10% of patients to be seizure free, 25% to have 90% decrease in seizures, and 50% to have greater than 50% decrease.
Which, of course, leads to the question, “Why aren’t adults using the ketogenic diet more?” The current thought we hear most often is that doing the diet in adults (starting with teenagers over 17 years old) is just “too hard.” Even in the rare instances where their physicians are aware of the potential benefits that the ketogenic diet offered, adults often are simply unwilling to try it because of “the severe lifestyle change” required—no fast food, limited alcohol, no high carb snacks, and so forth.
However, the introduction of the modified Atkins diet (MAD) by our group and of the Low Glycemic Index Treatment (LGIT) at Massachusetts General in Boston may have changed all that. We elaborate on how those diets are initiated and managed in Section IV, but suffice to say, the relative ease with which these two newer alternatives to creating ketosis can be implemented has changed things pretty dramatically for older patients.
We have learned a lot about the use of MAD in adults:
• Initiation is rapid, and adults will begin to respond quickly if they are going to respond at all (mean 5 days).
• Although the amounts of fluids, protein, and calories are unrestricted, it is very important for extra amounts of fat to be eaten daily.
• Adults can start at a slightly higher total carbohydrate allowance than children (20 grams versus 10 grams) and liberalize up to 25–30 grams after several months.
• Two months on MAD is likely a long enough trial on the diet to assess efficacy, as opposed to 3–6 months for children on the ketogenic diet.
• Lowering body mass index (BMI) and achieving weight loss both correlate with better response in adults, which is not true in children, when analyzed at 3 months. This may be due to compliance.
• Many adults who started the ketogenic diet as children can continue to do well when they are switched to the MAD.
• Cholesterol increases do occur; they need to be monitored and if changes in the types of fats don’t work, then a statin medication should be considered.
• Weight loss can occur—if it’s planned, that’s great.
• Kidney stones and constipation can occur, but risks can be lessened by staying hydrated.
• If adults are not seizure free, they often stop the diet (no matter how tough their seizures have been to control).
FIGURE 25.1
The Adult Epilepsy Diet Center team at Johns Hopkins Hospital.
We are not the only center interested in the use of diets for adults. As of the writing of this chapter, 41 adults have tried the MAD (as documented in the literature). Forty-seven percent had a greater than 50% decrease in seizures by 3 months; many of whom felt better and had improved concentration. A very high proportion of adults who tried MAD these have complex partial seizure disorders, many of whom had prior placement of a vagus nerve stimulator (VNS) and previous intracranial epilepsy surgery before MAD was tried.
In August of 2010 we opened an Adult Epilepsy Diet Center here at Johns Hopkins. Dr. Mackenzie Cervenka is the medical director of the center (second from left in the photo above).
Another center opened in London in January of 2011 through Matthew’s Friends. More and more epilepsy centers, neurologists, and dietitians are offering the diet to adults.
We anticipate treating increased numbers of patients as both they and their doctors learn about the potential benefits of a treatment previously thought to only be significantly beneficial to children. There are many unanswered questions about diets and adults, which may be solved by the next edition of this book:
• Do cholesterol increases lead to problems in adults who are on these diets for epilepsy?
• Is it safe during pregnancy? Is it perhaps even ideal for pregnancy (compared to anticonvulsants with known risks for birth defects)?
• Can it be done with limited dietitian support, knowing that many adult dietitians are not familiar or comfortable with treatment of epilepsy patients?
• Is the compliance issue really a problem, or can the diet be made easier?
• Should patients fast when starting the diet?
• How long should patients remain on the diet?
• Are there adults who are more likely than others to do better (e.g., certain kinds of seizures)?