14 DAY TRIAL // It is the fifth killer type of cancer for women, being diagnosed in 20,000 people annually in US alone, and 15,000 die of it in the same period. Women have 2 % chances of getting this cancer throughout their life. Moreover, the ovarian cancer is difficult detect in its early stages, when chances of being cured are higher.
A new research led by Dr. Ross Prentice of the Fred Hutchinson Cancer Research Center, in Seattle, has found out that post-menopausal women following at least 8 years a low-fat, high-fiber diet could cut by 40% the odds of developing this deadly condition. The greatest benefit was experimented by women whose first diet was fat-rich.
The women added on average one serving of fruits or vegetables to their daily diet and decreased their daily fat intake by about 8 %.
A research published in April discovered that higher intake of fruits and vegetables decreases the risk of head and neck cancers and low-fat diets that of breast and colorectal cancers.
Prentice's team selected about 50,000 postmenopausal women aged 50 to 79. About 20,000 of those women followed the low-fat diet in which fat represented under 20 % of daily calories. They also consumed at least 5 servings of fruits and vegetables a day and 6 servings of whole grains, and received diet-support group sessions in the first year.
The women's rates of ovarian and/or endometrial tumors were followed over the next 8 years. The percentages of ovarian cancer were about the same for women during the first 4 years of the trial, no matter if they followed or not the low-fat diet, but after 8 years of follow-up, the trend in the case of the dieting women was of a 40 % reduction in ovarian cancer levels. Not the same occurred with the endometrial cancer.
This was surprising, as some researchers speculated that more fat boosted estrogen levels in the body, increasing the risk of both ovarian and endometrial cancer. "The diet was developed especially for this research and doesn't follow any contemporary "popular" diets. In particular, the Women's Health Initiative intervention did not have a goal of restricting energy [calorie] consumption, though participating intervention group women did lose some weight. Nor was there an attempt to reduce carbohydrates. On the contrary, most of the reduced dietary fat was replaced by complex carbohydrates.", said Prentice.
"The potential link between dietary fat and cancer is not fully understood," he added.
The team observed decreased levels of blood estradiol, an estrogen hormone synthesized by the ovaries, in the case of women who were on a diet. "Estradiol is an important risk factor for cancer among women. This or other circulating hormones could have a stimulatory effect on epithelial [blood vessel] tissue in the ovary or breast, possibly including effects on cells in yet undiagnosed cancers", explained Prentice.
"The evidence for reductions in ovarian and breast cancer is strongest among women whose usual [prior] diet was relatively high in fat (e.g. more than 35 % of calories) who made a comparatively large fat reduction if assigned to the low-fat diet group", he added.