What the Diet Does
Normally, our bodies run on energy from glucose, which we get from food. We can't store large amounts of glucose, however. We only have about a 24-hour supply. When a child has no food for 24 hours -- which is the way the diet begins, usually in a hospital -- he or she uses up all the stored glucose. With no more glucose to provide energy, the child's body begins to burn stored fat.
The ketogenic diet keeps this process going. It forces the child's body to burn fat round the clock by keeping calories low and making fat products the primary food that the child is getting. In fact, the diet gets most (80 percent) of its calories from fat. The rest comes from carbohydrates and protein. Each meal has about four times as much fat as protein or carbohydrate. The amounts of food and liquid at each meal have to be carefully worked out and weighed for each person.
Doctors don't know precisely why a diet that mimics starvation by burning fat for energy should prevent seizures, although this is being studied. Nor do they know why the same diet works for some children and not for others.
Trying to put a child on the diet without medical guidance puts a child at risk of serious consequences. Every step of the ketogenic diet process must be managed by an experienced treatment team, usually based at a specialized medical center.
Chances of Success
Often, a period of fine-tuning is needed before it's clear whether or not a child is going to respond to the ketogenic diet. Doctors often ask parents to try the diet for at least one month, and even as long as two or three, if it's not working at first.
A child on the diet usually continues taking anti-seizure medicine, but may be able to take less of it later on. If a child does very well, the doctor may slowly taper the medication with the goal of discontinuing it altogether.
About a third of children who try the ketogenic diet become seizure free, or almost seizure free. Another third improve but still have some seizures. The rest either do not respond at all or find it too hard to continue with the diet, either because of side effects or because they can't tolerate the food.
A side benefit of the diet is that many parents say their children are more alert and make more progress when on the diet, even if seizures continue. If the diet seems to be helping, doctors will usually prescribe it for about two years. Then, they may suggest that parents slowly begin including regular food in the child's diet to see if the seizures can still be controlled, even with a normal diet.
Sometimes a small amount of seizure medication is started again after the diet is stopped. However, some children may be able to stay seizure free without any further treatment. If the seizures return, the doctors may recommend putting the child back on the diet.
Like all the other treatments for epilepsy, the ketogenic diet has some side effects, which may or may not affect a particular child. Some side effects may go away if caught and managed early on. Knowing what to look for can make a big difference. Reported side effects include dehydration, constipation, and, sometimes, complications from kidney stones or gall stones.
Adult women on the diet may have menstrual irregularities. Pancreatitis (inflammation of the pancreas), decreased bone density and certain eye problems have also been reported. Again, this is why the medical team closely follows children or adults who are on the diet.
The diet lacks several important vitamins which have to be added through supplements. Sometimes high levels of fat build up in the blood, especially if a child has an inborn defect in his ability to process fat. This possibility can lead to serious effects, which is another reason for careful monitoring.
Making the Decision
Most experts say the diet is worth trying when two or more medications have failed to control seizures, or when medications cause side effects that are having a harmful effect on a child's life. It also helps to have a child who is willing to try foods that he might otherwise not be enthusiastic about, and is tolerant and not fussy about eating.
The diet seems to work for more than one kind of seizure, and for children who have a lot of seizures or few seizures. But most doctors say it shouldn't be used instead of medications if the drugs are working and the child is not having bad side effects. Parents generally decide to try the diet because they hope it will give their child a better chance for a normal life.
However, the diet can be a barrier to some normal life experiences for children, especially those that revolve around food and holidays. And, like other treatments for epilepsy, it also can have side effects that affect some children more than others. So, as with any kind of treatment, there's a lot to think about before deciding to try the diet.
Going over all the possibilities with your doctor is the best way to make the decision. It may also be helpful to talk with other parents whose children have been on the diet.
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