Women who lowered the fat in their diets while eating healthier foods had a lower risk of dying from breast cancer than those with higher-fat diets, new long-term research says.
In a federally funded clinical trial of nearly 49,000 women ages 50 to 79, researchers found women who reduced the fat in their diets to 25% or less and added more fruits, vegetables and grains had a 21% lower risk of death from breast cancer.
The women with low-fat diets had a 15% lower risk of death from any cause after being diagnosed with breast cancer, the study found.
“Ours is the first randomized, controlled trial to prove that a healthy diet can reduce the risk of death from breast cancer,” lead study author Dr. Rowan Chlebowski said in a statement.
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The clinical trial was carried out by the Women’s Health Initiative, and the research will be presented in June at the annual meeting of the American Society of Clinical Oncology in Chicago. The study has yet to be published in a peer-reviewed journal.
From 1993 to 1998, 48,835 postmenopausal women with no history of breast cancer were divided into two groups: one in which fat accounted for 32% or more of their daily calories and a second with a goal of lowering fat to 20% or less of their calorie intake and eating at least one serving of a vegetable, fruit and grain a day.
The women in the low-fat group were to keep their diets for 8½ years, though most reduced their fat intake to only 25% of their daily calories. The group had an average 3% weight loss.
Researchers followed the women for a median of 19.6 years. Almost 3,400 cases of breast cancer were diagnosed from 1993 to 2013.
“This is a wake-up call for women – there’s something they can do, rather than just waiting for the shoe to drop,” Elisa Port, a doctor at Mount Sinai Health System in New York who was not involved in the study, told The Washington Post.
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Chlebowski stressed the importance of the dietary change, calling it one of “moderation.”
“It’s not like eating twigs and branches,” he told The Washington Post. “It’s what people were eating, say, 20 years ago, before you could pick up 900 calories in one candy bar.”
The study looked at total fat reduction in diets, rather than comparing the types of fat.
Some experts said that although the research is significant, given the size of the trial group and the length of follow-up, it may not be clear if the benefit came only from lowering fat overall or also from increasing fruit, vegetable and grain consumption.
“It is very difficult to disentangle the individual components,” JoAnn Manson, a study co-author, told NPR. “The trial was designed to test reduction in total fat because the evidence at that time was … that reducing total fat could lower risk.
“Now, there’s much more evidence that, especially for (preventing) cardiovascular disease, the type of fat really matters,” she said.
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“It’s possible that if they designed this study today, they’d probably have a much bigger emphasis on saturated fat that comes from meats and dairy products,” Karen Basen-Engquist, who was not involved in the study and is a cancer prevention expert at the MD Anderson Cancer Center in Houston, told NBC News.
According to the National Breast Cancer Foundation, breast cancer is the most commonly diagnosed cancer among women. One in eight women in the USA will be diagnosed in their lifetime, the group said.
This article originally appeared on USA TODAY: Low-fat diet with more fruits and vegetables may decrease risk of dying from breast cancer