Vitamins and calcium supplements can dramatically reduce the risk of breast cancer - even when you take them at the standard daily dose. Vitamin supplements reduce the risk by around 30 per cent, and calcium supplements do even better, and lower the risk by 40 per cent. But it's all about developing good habits, and taking the supplements every day, and for a while. "It is not an immediate effect. You don't take a vitamin today and your breast cancer risk is reduced tomorrow," said Jaime Matta, one of the researchers from Ponce School of Medicine in Puerto Rico. The research team discovered the effectiveness of vitamins when they compared a group of 268 women with breast cancer with457 healthy women. They discovered that the supplements helped repair DNA, a complex biological process involving more than 200 proteins that, if disrupted, can lead to cancer. (Source: American Association for Cancer Research, 101st annual meeting, 2010).