The higher the intake of red meat the higher the risk of breast cancer finds new research.
Experts suggest that eating higher intakes of red meat in early adulthood might be associated with an increased risk of breast cancer.
It also found that women who eat more legumes (such as peas, beans and lentils), poultry, nuts and fish might be at lower risk in later life, suggests a paper published on bmj.com today.
So far, studies have suggested no significant association between red meat intake and breast cancer. However, most have been based on diet during midlife and later, and many lines of evidence suggest that some exposures, potentially including dietary factors, may have greater effects on the development of breast cancer during early adulthood.
A team of US researchers investigated the association between dietary protein sources in early adulthood and risk of breast cancer. They analysed data from 88,803 premenopausal women (aged 26 to 45) taking part in the Nurses’ Health Study II who completed a questionnaire on diet in 1991.
Red meat items included unprocessed red meat (beef, pork, or lamb and hamburger) and processed red meat (such as hot dogs, bacon and sausage); poultry included chicken and turkey; fish included tuna, salmon, mackerel, sardines; legumes included beans, lentils and peas; and nuts.
Nine categories of intake frequency were recorded from “never or less than once per month” to “six or more per day.” Factors such as age, height, weight, race, family history of breast cancer, history of benign breast disease, smoking, menopausal status, hormone and oral contraceptive use were taken into account. Adolescent food intake was also measured and included foods that were commonly eaten from 1960 to 1980, when these women would have been in high school. Medical records identified 2,830 cases of breast cancer during 20 years of follow-up.
Putting these real life data into a statistical model allowed the researchers to estimate breast cancer risks for women with different diets. They estimated that, for each step-by-step increase in the women's consumption of red meat, there was a step-by-step increase in the risk of getting breast cancer over the 20 year study period.
Sally Greenbrook, Senior Policy officer at Breakthrough Breast Cancer, said: “We don’t yet know enough about the link between breast cancer and diet so this is quite an interesting study. We would welcome more research into this in order to help us identify what kind of impact red meat could have on breast cancer risk.
“Some people may be concerned, especially with barbecue season approaching, so we advise that everybody follows a varied, balanced diet for general health and wellbeing – this includes fruits, vegetables, pulses and whole grains, and limited red meat, processed meat, animal fat, sugary or fatty processed food, salt and alcohol. It’s already been proven that women can reduce their breast cancer risk by maintaining a healthy weight, reducing alcohol consumption and increasing the amount of physical activity they do.”
The authors conclude that higher red meat intake in early adulthood “may be a risk factor for breast cancer, and replacing red meat with a combination of legumes, poultry, nuts and fish may reduce the risk of breast cancer.” Further study of the relation between diet in early adulthood and risk of breast cancer is needed, they add.