Recent statistics suggest that approximately 1 in 8 U.S women will develop invasive breast cancer during her lifetime, and 1 in 1000 men will also develop the disease1. Earlier diagnosis, advances in treatment and increased awareness have all contributed to an increased survival rate for patients with breast cancer.
Scientists studying breast cancer and diet have made significant advances over the last few years. Much of the research into breast cancer and diet are at a relatively early stage. However, there are findings that people can take heed of now, to help reduce the risk of developing this cancer, and to prevent recurrence of the disease.
Dairy and breast cancer risk
Eating dairy products such as milk, butter, and yoghurt, has been shown to be a possible risk factor for developing breast cancer2,3. This is thought to be either due to dairy sourced hormones4, high levels of fat, pesticide residue in the milk, or high levels of calcium.
The presence of hormones and growth factors in milk is one of the more commonly cited hypotheses amongst nutritionists. Insulin-like growth factor I (IGF-1) is a growth factor that has been shown to promote breast cancer growth 5,6. Milk naturally contains IGF-1, however, dairy farmers often give dairy cows bovine growth hormone (BGH), which further increases the concentration of IFG-1 in the cow’s milk7.
The saturated fat content of dairy products is also of concern to nutritionists, as high saturated fat intake has been associated with increased breast cancer risk. It has been suggested that high levels of saturated fat in the diet, increases circulating estrogen concentrations and raises the breast cancer risk8.
Breast cancer and the Mediterranean diet
Studies have shown that following a Mediterranean diet could reduce the risk of breast cancer. The Mediterranean diet refers to a diet traditional to countries such as Italy, France, and Greece. The diet includes large amounts of fresh fruit, vegetables, nuts, grains, olive oil and fish. Numerous studies have found an association between this diet and a reduced risk of breast cancer and breast cancer recurrence9,10,11.
It is thought that the health benefits of this way of living are related to the low amounts of animal-derived saturated fat, the phytonutrients gleaned from the fruits and vegetables, and the anticancer potential provided by compounds in olive oil. The extra virgin olive oil contains a compound called oleocanthal (OC). OC has been shown to induce necrotic and apoptotic cell death of cancer cells, without harming normal tissue cells12.
Breast cancer and carotenoids
Carotenoids are phytonutrients present in foods such as carrots, sweet potatoes, tomatoes and dark leafy greens. Carotenoid compounds include beta-carotene, lycopene, and lutein. A large breast cancer study, completed in 2013, showed a significant correlation between high carotenoid intake and reduced breast cancer risk13. Carotenoids are potent antioxidants that boost immune function. They are also thought to exert a strong anticancer effect on breast cancer cells by inducing cell suicide14.
Breast cancer and diet summary
Breast cancer sufferers can help to reduce their risk of disease recurrence by eating a Mediterranean-inspired diet, rich in fresh fruit, vegetables, whole grains and fish. Patients should include plenty of carotenoids containing foods in their diet. To reduce the risk of developing breast cancer, dairy products, and saturated fats should be avoided.
About the author:
Sonia Nicholas is a Clinical Editor, Biomedical Scientist and Founder of The Green Apple Club. Sonia reports on cutting-edge advances in clinical science and has a specialist interest in the relationship between food and cancer. Sonia writes extensively on how an anticancer diet can be used to help people fight cancer. You can learn more the cancer progression pathway, foods that promote cancer, and foods that prevent tumor cell growth in the book ‘Food to Fight Cancer: What Your Doctors Aren’t Ready to Tell You’ or visit www.thegreenappleclub.com.