A diet rich in coffee, fruit and vegetables may protect against breast cancer, research suggests.
A new study presented at the European Congress on Obesity in Glasgow found a protective effect from a diet full of phenolic acids on the risk of post-menopausal breast cancer.
Phenolic acids are found in coffee, fruits, vegetables and whole grains.
Rich sources include raspberries, blueberries, apples, citrus fruits, plums, onions, coffee, red wine, cocoa and wholewheat, rice, corn and oats.
The study was led by a team from the University of Navarra and the University of Jaen in Spain.
They looked at the link between phenolic acids, including hydroxycinnamic and hydroxybenzoic acids, and breast cancer in 11,028 women.
During an average follow-up of almost 12 years, the researchers found 101 cases of breast cancer among the group of women.
All the women had completed a food questionnaire at the start of the study saying how often they ate 136 different food items.
Their intake of phenolic acids was calculated by matching food consumption data from the questionnaire with a database on the phenolic acid content of each food.
Researchers split women into three groups according to their intake of phenolic acids, with those with the highest consumption of hydroxycinnamic acids (a naturally occurring type of phenolic acid) having a 62% reduced risk of breast cancer compared with those with the lowest intake.
Chlorogenic acids, a type of hydroxycinnamic acid found in coffee, fruits, and vegetables were discovered to have the strongest effect.
Women consuming the most of this type of nutrient had a 65% reduced risk of breast cancer compared with those consuming the least.
The researchers concluded: “A higher intake of hydroxycinnamic acids, especially from chlorogenic acids – present in coffee, fruits and vegetables – was associated with decreased post-menopausal breast cancer risk.”
They said the diet could possibly reduce fat tissue inflammation, oxidative stress which can damage tissue, or resistance to insulin.
Dr Kotryna Temcinaite, research communications manager at Breast Cancer Care and Breast Cancer Now, said: “We’ve long known that eating fruit and vegetables as part of a balanced diet can help lower your risk of breast cancer by helping you maintain a healthy weight.
“While this study helps suggest a potential mechanism behind this benefit, further research is needed to understand the effect that phenolic acids found in foods such as fruit, veg and coffee may have on breast cancer risk.
“Supporting more women to make healthy lifestyle changes will be key to preventing more breast cancers – but the small number of breast cancer cases in this study makes it difficult to draw strong conclusions about the potential role of phenolic acids in cancer prevention.
“Further studies with follow-up to older ages that also monitor any changes to participants’ diets over time are now needed to better understand this link.
“In the meantime, while we don’t recommend drinking lots of coffee to try to reduce your breast cancer risk, we’d encourage all women to eat plenty of fruit and veg as part of a healthy, balanced diet.
“By taking steps to maintain a healthy weight, drink less alcohol and keep physically active, all women can help keep their risk of breast cancer as low as possible.”
Susannah Brown, acting head of research interpretation at the World Cancer Research Fund, said: “This is an interesting study that further confirms the importance of consuming a diet high in fruits and vegetables for cancer prevention.
“It also suggests some of the potential underlying biological reasons as to why fruit and vegetables are protective against cancer.”
Tam Fry, chairman of the National Obesity Forum, said: “This research pinning the reduction of breast cancer to the level of fruit and vegetable consumption should suggest to older women that they now make eating five-a-day a permanent choice.”