Those who ate one or more servings a day of high-fat dairy had a 49% increased risk of dying from breast cancer and a 64% higher risk of dying from any cause.
The scientists at the Kaiser Permanente Division of Research in the U.S. found low-fat dairy products did not have the same effect.
Low-fat dairy foods do not contain the same levels of oestrogen, a hormone which can increase the risk of breast cancer.
Dr. Susan Kutner said the new research showed the importance of a low-fat diet, as well as exercise and weight management, in preventing a recurrence of breast cancer.
Kutner said, “Women have been clamoring for this type of information.
“They’re asking us, ‘Tell me what I should eat’. With this information, we can be more specific about recommending low-fat dairy products.”
Dr. Bette Caan, a senior author of the study, published in the Journal of the National Cancer Institute, said, “Switching to low-fat dairy is an easy thing to modify.”
The 12-year study of 2,000 women with the disease looked at consumption of cream, whole milk, condensed milk, pudding, ice cream, custard, flan, plus cheeses and yogurts that were not low-fat or non-fat.