The research team used European data from the World Health Organization's burden of disease project, calculating the proportion of ill health and deaths attributable to food. The definition included food poisoning as well as dietary habits.

The information gathered was then backed up by an extensive review of published studies on the financial and health costs of disease and deaths related to food consumption.

The authors used a composite term to describe the impact of ill health and death, known as DALYs, or disability adjusted life years.

They calculated that 37% of DALYS were attributable to food related diseases, with just a fraction of this (0.2%) attributable to food poisoning. Cardiovascular disease, cancer, and diabetes account for most of this.

Clearly, diet is not responsible for all cardiovascular disease, diabetes, and cancer, which account for 28% of health service costs, amounting to an annual 18 billion in 2002.

But the authors calculate that food accounts for around a third, accounting for 10% of all DALYS and costing an annual 6 billion.

This is double the cost to the health service of road traffic accidents, over three times the cost of smoking, and significantly higher than the cost of obesity, estimated at 479 million.

The authors admit their calculations are crude, but suggest that they are probably reasonable. "The estimates suggest that the burden of food related ill health is large, compared with say, smoking, and suggests that [it] has been neglected by health and food policy makers," they say.

And they call for more specific government health targets on diet, equivalent to those already in place for smoking.

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But a similar primate study at the University of Southern California that Meshul is associated with is testing the hypothesis that glutamate does have an effect on behavior. "It turns out that, in time, these animals recover behaviorally from all of the motor deficits that are associated with (early-stage Parkinson's)," he said. "Our hypothesis is there may be changes in glutamate that account for these behavioral changes."

Dietary restriction's beneficial effect on neurological function has been studied in primates by scientists at the National Institutes of Health for 30 years, Meshul said. Researchers found that animals whose calorie intake was lowered by 20 percent aged better, suffered from fewer immunological disorders, displayed healthier hair and skin tone, and "looked significantly better than a counterpart that hasn't had a restricted diet."

"They live longer," Meshul said. "It's been known for many, many years that dietary restriction is good."

Scientists already have shown dietary restriction initiated before the onset of early Parkinson's can protect against neurochemical changes in the brain caused by the disease. In 1999, researchers found that mice on restricted diets for three months prior to an early Parkinson's diagnosis lost fewer dopamine-synthesizing neurons.

"There's not as much loss of dopamine if you restrict their diets ahead of time," Meshul noted.

Meshul's lab is finding that dietary restriction isn't the only way to boost neurological function in Parkinson's disease. Early results of another study the group is conducting have shown that rats with 90 percent loss of dopamine in the brain - or full-blown Parkinson's disease - under a four-week exercise regimen can run twice as long as parkinsonian rats that didn't exercise.

"We're trying to make the correlation that exercise definitely helps in terms of the parkinsonian animal and, in fact, in human studies it's been shown that any sort of exercise helps patients," Meshul said.

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