Women on diets low in fat and rich in fruits, vegetables and cereals are at lower risk of dying from breast cancer than those who follow a high-fat diet, according to the results of a major new study released Wednesday. .
The findings, based on the latest analysis of the federally funded Health Initiative, constitute the first randomized clinical trial showing that diet can reduce the risk of breast cancer death in postmenopausal women, the report said. researchers. Past observational studies – which do not measure cause and effect – have resulted in inconsistent results.
The results "are exciting and empowering for the patient," said Elisa Port, head of breast surgery at Mount Sinai Health System, who did not participate in the study. "It's an awakening for women – they can do something instead of waiting for the shoe to fall."
The trial involved more than 48,000 women who did not have breast cancer when they participated in the study conducted in 40 centers across the United States. From 1993 to 1998, women were randomly assigned to either follow their usual diet, in which fats accounted for an average of 32% of daily calories, or try to reduce their fat intake to 20% of calories while consuming daily portions of vegetables, fruits and fruits. and cereals.
The food intervention group did not reach the goal; they managed to reduce their fat consumption to about 24.5%, and then "drifted up to about 29%," according to Rowan Chlebowski, lead author of the study, of the Los Angeles Biomedical Research Institute's Harbor-UCLA Medical Center. The group members lost 3% of their weight on average. Nevertheless, women in this group who developed breast cancer were less likely to die than those who followed their usual diet and developed the disease.
Chlebowski said the study showed that women could improve their health by making modest changes to what they eat and in what quantity. "It's dietary moderation, it's not like eating twigs and branches," he said. "That's what people ate, say, 20 years ago, before you could get 900 calories in a chocolate bar."
The food intervention lasted 8.5 years and featured several sessions with nutritionists. The last analysis represents a follow-up of almost 20 years.
Breast cancer experts generally praised the study, but expressed some reservations. On the one hand, the study was not designed to determine if a low-fat diet was making a difference in mortality, but if such a diet could initially reduce the risk of breast cancer. breast.
Previously published data showed that the diet did not result in a statistically significant consequence. In addition, breast cancer experts have noted that the benefit of mortality has taken almost 20 years to materialize. Some also said that it was not clear which food component was responsible for the benefit – reduced fat content or additional fruits, vegetables and cereals?
The study authors said the dietary modification group used a diet similar to that called DASH – for dietary approaches to stop hypertension – designed to prevent or treat hypertension.
The new study "adds more evidence on the impact of the diet but I will not support it to recommend a specific diet for a patient", since people react differently to different diets, depending on their biology, said Neil Iyengar, doctor. Oncologist at Memorial Sloan Kettering Cancer Center. "I tell patients that if they eat more plant-based foods, have less red meat, reduce alcohol and maintain a healthy weight, they may have a reduced risk of cancer recurrence." breast or death. "
The study did not examine the impact of diet on the risk of recurrence of breast cancer. A separate study seeks to determine whether weight loss, achieved by reducing calories and increasing physical activity, reduces the risk of recurrence. The study, called the Breast Cancer Weight Loss Study, or BWEL, is led by the Dana-Farber Cancer Institute.
The study comes as more and more evidence is accumulating about the link between overweight and obesity and a number of cancers. Being obese and overweight – long involved in heart disease and diabetes – has been associated in recent years with an increased risk of developing at least 13 types of cancer, including malignant tumors of the stomach, pancreas, colorectal and liver, as well as postmenopausal breast cancer.
The study will be presented in the coming weeks at the annual meeting of the American Society of Clinical Oncology in Chicago.