WASHINGTON (Reuters) - A low-fat diet may protect women from ovarian cancer, U.S. researchers said on Tuesday.
Researchers tracked about 49,000 post-menopausal women from around the United States for about eight years. About 40 percent of them were asked to cut nearly in half the amount of fat in their diet. The others were asked to eat their usual diet.
No difference was seen in ovarian cancer risk in the first four years of the study. But in the final four years, the women who ate a diet lower in fat were 40 percent less likely to develop this cancer than the other women, the study found.
"We're pleased to be able to say something positive to American women that following a low-fat diet is quite likely to reduce their risk of ovarian cancer," Ross Prentice of the Fred Hutchison Cancer Research Center in Seattle, who led the study, said in a telephone interview.
The findings were published in the Journal of the National Cancer Institute.
The research was the latest to investigate whether there is a link between diet and disease. Previous studies have implicated dietary factors in some other types of cancer.
Ovarian cancer is not often diagnosed in its early stages when it is most treatable, and its causes have remained unclear.
The American Cancer Society said ovarian cancer ranks as the fifth-leading cause of cancer death in U.S. women and is expected to kill about 15,000 American women this year. It said about two-thirds of women who develop ovarian cancer are 55 or older and it is a bit more common in whites than blacks.
A personal history of breast cancer or a family history of breast or ovarian cancer appear to raise risk for the disease. Previous research had found a higher rate of death from ovarian cancer in overweight women, with the risk 50 percent higher in the heaviest women.
But a possible link with a high-fat diet had remained controversial.
Symptoms of ovarian cancer are vague and often are attributed to other illnesses. The tumour commonly has spread beyond the ovaries once the disease is diagnosed.
The average age of the women at the start of the study was 62. The women in the study who were asked to change what they ate were directed to lower their fat intake to 20 percent of their overall diet and increase their consumption of fruits, vegetables and whole grains.
Prentice said a diet with fat making up about 35 percent of the intake is common in the United States. He said the women who made dietary changes on average cut their fat intake to about 24 percent of their diet, not quite making the goal but still making a significant reduction.
Women who had the largest fat intake before entering the study experienced the largest reduction in risk, the researchers said.
Many of the women who took part in the study are now being tracked for an additional five years, Prentice said.