Vitamin and calcium supplements may cut breast cancer risk

WASHINGTON, D.C. - April 18, 2010 (Cancer Digest) -Women who took vitamin and calcium supplements appeared to have a 30 percent to 40 percent reduced the risk of breast cancer, a new study shows.

Dr. Jaime Matta, professor in the Ponce School of Medicine, Puerto Rico, presented the findings today at the American Association for Cancer Research 101st Annual Meeting 2010.
"It is not an immediate effect. You don't take a vitamin today and your breast cancer risk is reduced tomorrow," Matta said in a prepared statement. "However, we did see a long-term effect in terms of breast cancer reduction."

The study included 268 Puerto Rican women with breast cancer and 457 healthy women with no breast cancer. In addition to controlling for known breast cancer risk factors including age, body mass index, family history, child bearing, breast feeding history and hormonal factors, the researchers also used a an immune system test to measure DNA repair capacity (DRC). This is the ability of the cells to repair errors in the duplication of chromosomes that can occur during cell division.

"This process involves at least five separate pathways and is critical for maintaining genomic stability," said Matta. "When the DNA is not repaired, it leads to mutation that leads to cancer."

The results showed that older women, those with a family history of breast cancer, no history of breastfeeding and had a low DNA repair capacity were more likely to have breast cancer than women who did not have those characteristics. When they then looked at vitamin supplements and calcium intake, they found vitamin supplements appeared to reduce the risk of breast cancer by about 30 percent. Calcium supplements reduced the risk of breast cancer by 40 percent. When they examined the level of DNA repair capacity, however, the lower the level of DRC, the less protective calcium supplements were. The link between vitamin supplements and breast cancer risk reduction remained. In other words, if the woman's DNA repair capacity is low, the calcium supplement had little effect.

"This suggests that DNA repair capacity explains this association," the researchers wrote. "In contrast, vitamins intake did not show an important change in the association with breast cancer when adjusting for DNA repair capacity. Calcium and vitamins' intake were strongly associated with higher levels of DRC."

"We're not talking about mega doses of these vitamins and calcium supplements, so this is definitely one way to reduce risk," Matta concluded.

SOURCE: adapted from press materials provided by the American Association of Cancer Research, and the presentation abstract: Yeidyly Vergne, Jaime L. Matta, Luisa Morales, et al; Consumption of vitamins and calcium reduces breast cancer risk by their regulation of the DNA repair capacity. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC.