A greater intake of certain B vitamins is associated with a lower risk of developing breast cancer, according to the data from a new European study led by the CIBERESP group at the Escuela Andaluza de Salud Pública and published in "The American Journal of Clinical Nutrition".
The results of the study, in which researchers from ibs.GRANADA and the Universidad de Granada also participated, have been made known in the framework of Breast Cancer Awareness Month.
The work analyzes the role of nutrients involved in the methylation cycle or one-carbon metabolism, a set of processes essential for cellular functioning and the regulation of gene activity. Among these nutrients are folate and vitamins B2, B6 and B12.
The research has been developed from data from the European cohort "EPIC" ("European Prospective Investigation into Cancer and Nutrition"), including and includes 6,134 women from seven European countries: 3,067 women with a diagnosis of invasive breast cancer and 3,067 women without the disease, selected as a comparison group.
The results showed that a greater dietary intake of vitamin B2 (riboflavin) and vitamin B12 (cobalamin) was associated, for each vitamin separately, with an approximately 6-7 percent lower risk of breast cancer for each increase of one standard deviation in its intake.
In addition, women with a higher combined intake score of B vitamins -calculated from the intake of folate and vitamins B2, B6 and B12- showed a 17 percent lower risk than those with the lowest score.
"These results show a statistical association, but do not allow us to state that consuming more B vitamins on its own reduces the risk of developing breast cancer", clarified Dafina Petrova, co-responsible researcher of the CIBERESP group.
The research team also studied whether alcohol consumption influenced the relationship between B vitamins and the risk of breast cancer. The results suggest that the inverse association observed between the intake of these vitamins and the risk of developing the disease weakens as alcohol consumption increases.
Alcohol can interfere with folate metabolism and with other processes related to DNA methylation, a mechanism that is involved in the regulation of gene activity. "In any case, the results should not be interpreted as meaning that an adequate intake of vitamins offsets the risks associated with alcohol consumption," says the first author of the study and researcher at CIBERESP, José María Gálvez.
The role of genetics in breast cancer risk
The research team also analyzed whether genetic predisposition influenced the risk of breast cancer through scores that combine information from multiple genetic variants related to one-carbon metabolism.
When analyzing all the participants, no consistent association was observed between the studied polygenic risk scores and the overall risk of developing breast cancer. However, among premenopausal women, a genetic score associated with lower expression of certain genes in adipose tissue was linked to a 12 percent higher risk of developing the disease.
"This finding suggests that certain genetic mechanisms could be related to breast cancer risk differently depending on menopausal status. Nevertheless, this is a specific result that requires confirmation in other populations," explains the research team.
On the other hand, the study found no significant interactions between the genetic variants analyzed and the nutrients studied in relation to the risk of breast cancer.
The research has been carried out in collaboration with two other groups from CIBERESP, linked to the Fundación para la Formación e Investigación Sanitarias de la Región de Murcia and the Instituto de Salud Pública de Navarra, as well as with researchers from the International Agency for Research on Cancer (IARC) and Imperial College London.