Diets are gathering steam in mainstream medicine, writes Janet Cromley.
LYDIA BECKET was only one year old when the seizures started - racking convulsions that came in waves, often several a day.
For the next two years, her parents tried one medication after another: the same drugs that bring relief to many children with epilepsy just made her sicker.
Then Lydia's medical team put her on a ketogenic - or high-fat, low-carbohydrate - diet. Within a week, she was seizure-free.
"I don't know where we would be if it wasn't for that diet," says her mother, Camilla Becket.
The diet, which is more than 85 years old and has been extensively studied, made headlines earlier this month when British researchers presented the strongest evidence to date of its efficacy.
In a randomised, controlled study of 145 children aged two to 16 who had more than seven seizures a week and were unresponsive to medication, senior author Dr J Helen Cross of the Institute of Child Health and Great Ormond Street Hospital reported a 38 per cent reduction in mean seizure frequency among the 54 children assigned to receive the ketogenic diet.
The control group experienced an increase in seizures, according to the report, which appeared in the online edition of Lancet Neurology.
The results come as researchers and physicians are seeking ways to leverage the ketogenic diet to treat various other neurological disorders, including ALS, brain tumours, autism, Parkinson's disease, Alzheimer's disease, narcolepsy and migraines.
Many of these conditions respond to anticonvulsant medications, says Dr Eric Kossoff, medical director of the Ketogenic Diet Center at Johns Hopkins Hospital, and the ketogenic diet seems to act as an anti-convulsant.
Using diet to control disease is nothing new. "For many conditions, we have come to accept special diets as routine parts of medicine," says Dr George Christison, professor of psychiatry at Loma Linda University in Southern California.
Examples include diets low in simple carbohydrates (starches, sugars) for people with diabetes; low-fat diets high in fruits, vegetables and nuts for people with cardiovascular disease; phenylalanine-free diets for the genetic disorder phenylketonuria; low-sodium diets for hypertension; and low-fat diets for gallstones.
Some parents of children with autism spectrum disorders are putting their children on diets that eliminate foods with gluten and/or casein in the hopes that the diet may help, although the jury is still out on whether this diet is effective.
Most of these diets have an obvious cause-and-effect relationship to the disease, such as the lactose-free diet for the treatment of lactose intolerance and the gluten-free diet for coeliac disease. But diets without this clear connection to the causes of a disease are gathering steam in mainstream medicine as well.
According to Dr David Heber, director of the University of California, Los Angeles, Center for Human Nutrition: "Inflammation appears to be a common thread of many chronic diseases of ageing, like Alzheimer's, heart disease, diabetes and common forms of cancer."
An anti-inflammatory diet involves reducing total fat, which by its nature reduces the amount of omega-6 fats, which are believed to promote inflammation.
One consumes either fish three times a week or about 3g of fish oil supplement a day. This boosts levels of omega-3s, which have anti-inflammatory properties. Adherents also eat lots of richly coloured fruits and vegetables, which are also anti-inflammatory.
The role of inflammation in disease is the subject of a growing body of research, including a study of 28,263 women which appeared in the March 2000 New England Journal of Medicine, in which Harvard researchers found a strong link between a blood chemical linked to inflammation and cardiovascular health.
Alteration of diet may also be powerful in prevention and treatment of eye disorders, says Allen Taylor, director of the nutrition and vision research lab at the USDA Human Nutrition Research Center on Aging at Tufts University.
Taylor's group is studying the efficacy of a low-glycemic diet - a diet low in simple carbohydrates - in the prevention and treatment of macular degeneration and cataracts.
The group has found that controlling spikes in blood sugar can result in diminished risk for age-related macular degeneration and cataracts. This benefit is achieved with dietary measures as simple as replacing white bread and pasta with wholegrain breads and pastas, and by limiting sweet foods or drinks.
Diet has been shown to lower the risk of diabetes in people with pre-diabetes, which can develop into type 2 diabetes, sometimes even returning their blood sugar levels to normal.
In a three-year trial known as the diabetes-prevention programme, a low-fat, weight-loss diet (and exercise) reduced by 58 per cent the chances that a person with impaired glucose tolerance would go on to develop diabetes.
It did so more dramatically than the diabetes drug metformin. The results, published in the New England Journal of Medicine in 2002, were so pronounced that the trial was halted a year early.
In addition, a low-carb, ketogenic diet was found in a 16-week study of 28 overweight individuals with type 2 diabetes to reduce the need for diabetes medications. The study was published in 2005 in the journal Nutrition and Metabolism.
"For people who have a lot of trouble controlling their diabetes, a low-carb diet can be helpful," says Dr Christine Gerbstadt, a Florida-based physician and registered dietitian in private practice. "But the ketogenic component, the more severe carb restriction, may or may not have extra benefits."
Such a diet might be worth a try under medical supervision, she says - with the understanding that a diet rich in animal fats could present a health trade-off.
Mood disorders, such as attention deficit disorder, depression, anxiety and aggression, can be helped by diet, either when medications fail or as an adjunct to medications, says Dr Bill Sears, an associate clinical professor of paediatrics at the University of California, Irvine, School of Medicine.
"There's a lot of good science on food and the brain, particularly in the area of omega-3 fatty acids," Sears says.
"In fact, the first so-called medicine I prescribe for a child with any type of learning, behaviour or mood disorder is high doses of omega-3."
A 1998 study by Dr Joseph Hibbeln of the National Institutes of Health reported that countries with the highest rates of depression ate the least fish, whereas those with the lowest ate the most.
Not all studies, however, have reported a beneficial effect of omega-3s on mood disorders.
(Los Angeles Times, Washington Post Service)