Pro-inflammatory Diet Tied to Increased Risk of Breast Cancer

By Megan Brooks

June 11, 2021

NEW YORK (Reuters Health) - Women consuming a more pro-inflammatory diet are at increased risk for breast cancer, especially premenopausal women, according to new research.

Foods that increase inflammation include red and processed meat; high-fat foods such as butter, margarines and frying fats; and sweets including sugar, honey, and foods high in sugar. Fruits, vegetables, legumes, tea and coffee all have potentially anti-inflammatory properties.

"Inflammation is one of the hallmarks of carcinogenesis. Low-grade chronic inflammation is associated with several cancers," Carlota Castro-Espin, a PhD student at the Catalan Institute of Oncology, in Catalonia, Spain, explained in her presentation.

"Diet contributes to the state of low-grade chronic inflammation but no single dietary components, except alcohol, have been found to be strongly associated with breast cancer," she noted.

To investigate, the researchers studied more than 318,000 women from the European Prospective Investigation into Cancer and Nutrition (EPIC) who were followed for 14 years, including 13,246 who developed breast cancer.

Dietary inflammatory potential was characterized by an inflammatory score of the diet (ISD) based on participant reporting of intake of 27 foods.

"Most studies examining diet and breast cancer risk have focused on single nutrients or foods rather than the whole diet. People consume food not nutrients, thus examining overall dietary patterns, rather than single components of diets can lead to more accurate conclusions when analyzing associations with a health outcome such as breast cancer," Castro-Espin said in a news release.

The results showed a positive association between ISD and breast-cancer risk.

Women in the highest quintile of ISD, indicating the most pro-inflammatory diet, had a significant 12% increase in risk of breast cancer compared with those in the lowest quintile of ISD (HR, 1.12; 95% confidence interval, 1.04 to 1.21).

After adjusting for relevant confounders, each increase of one standard deviation (1-SD) of the ISD increased the risk of breast cancer by 4% (hazard ratio, 1.04; 95% CI, 1.01 to 1.07), rising to 8% increased risk among premenopausal women (HR, 1.08; 95% CI, 1.01 to 1.14).

The association between pro-inflammatory diets and breast-cancer risk was independent of breast cancer hormone receptor subtype. There were no significant interactions between ISD and body mass index, physical activity or alcohol consumption.

"Our results add more evidence of the role that dietary patterns play in the prevention of breast cancer. With further confirmation, these findings could help inform dietary recommendations aimed at lowering cancer risk," Castro-Espin said in the news release.

This research had no commercial funding and the authors have no relevant disclosures.

SOURCE: American Society for Nutrition, held online June 7-10, 2021.