(HealthDay)—A healthy diet may help people with kidney disease live longer, researchers report.

They analyzed seven studies that included more than 15,000 people with chronic kidney disease, to assess the effects of a diet high in fruits, vegetables, fish, legumes, cereals, whole grains and fiber.

In six of the studies, a healthy diet was consistently associated with a 20 percent to 30 percent lower rate of , and with 46 fewer deaths per 1,000 people over five years. But the study did not directly prove that a healthy diet would lengthen life.

The international team of researchers found no significant association between a and risk of .

The findings were published Dec. 8 in the Clinical Journal of the American Society of Nephrology.

"Chronic kidney disease now affects about 10 percent to 13 percent of the adult population and substantially increases risks of cardiovascular complications and early death," said study leader Dr. Giovanni Strippoli, from the University of Bari in Italy.

"In the absence of and large individual cohort studies, this study is the best available evidence to drive clinical decision-making by patients and doctors on whole dietary approaches in ," Strippoli said in a journal news release.

Chronic kidney disease patients are told to restrict their intake of certain nutrients such as phosphorus, potassium, protein and sodium. But evidence suggests these restrictions—which can be difficult to follow—may do little to reduce patients' risk of premature death, the researchers said.