Breast cancer is the most common cancer for U.S. women. The American Institute for Cancer Research estimates that 1 in 3 breast cancer cases in the U.S. could have been prevented by being physically active, maintaining a healthy diet and weight, and not drinking alcohol. In this bulletin we will review the latest evidence about breast cancer risk, survivorship and lifestyle behaviors. Lifestyle behaviors can include eating and drinking habits and physical activity.
Meats (Smoked, Grilled and Processed)
In previous bulletins, we have discussed how high-temperature cooking methods such as grilling and smoking meat can create hazardous compounds (heterocyclic amines and polycyclic aromatic hydrocarbons, or PAHs) in meats. These can cause changes in DNA and increase risk of developing certain cancers like breast cancer. We have also reviewed ways you can reduce the production of those toxic compounds, such as marinating meat 30 minutes prior to cooking with vinegar, lemon or wine and herbs. Click here to read those tips and more.
Until now, no studies have examined whether intake of this PAH source influences survival after breast cancer. A recent study published by the Journal of the National Cancer Institute found that high intake of grilled, barbecued and smoked meat after breast cancer diagnosis increases risk of death in breast cancer survivors. The study includes 1,508 women diagnosed with breast cancer. The researchers assessed their intake of grilled, barbecued and smoked meat for a median follow-up of 17.6 years. The assessment included pre- and post-diagnosis intake and the amount of exposure.
High consumption of grilled or barbecued meat (beef, lamb and pork) was considered to be that eaten 11 or more times a year pre-diagnosis and 9 or more times post-diagnosis; high consumption of grilled or barbecued poultry or fish was defined as 10 or more times a year pre-diagnosis and 7 or more times a year post-diagnosis. Smoked meat (whether smoked with barbecue sauce or not) were defined as high intake if eaten more than 5 times a year pre- or post-diagnosis, while smoked poultry and fish was considered high if consumed at least once each year pre- or post-diagnosis.
High intake of grilled, barbecued or smoked meat prior to cancer diagnosis was linked to a 23 percent increase in mortality, compared to low consumption of these foods. High intake of smoked beef, lamb or pork was linked to a 17 percent increase in mortality and a 23 percent increase in breast cancer-specific mortality.
However, eating large amounts of grilled, barbecued or smoked meat of any sort before cancer, and very little after diagnosis, was not seen to raise a person’s overall mortality risk. Continued high intake of meats prepared this way after diagnosis, however, increased the overall mortality risk by 31 percent.
Although no association seems to be reported for the consumption of dietary carbohydrates, glycemic index or glycemic load and breast cancer risk, eating carbs with a high glycemic index and high glycemic load may elevate blood insulin and reduce Insulin Growth Factor (IGF-I) binding proteins. This in turn results in increased bioavailability of IGF-I. This protein may reduce programing cell death, which is one of the main cancer-preventive mechanisms the body uses to prevent breast cancer development and progression. Moreover, some studies have shown that IGF-I and estrogen act synergistically and potentially lead to breast cancer.
There is evidence that people who consume a diet high in fats and saturated fats before developing breast cancer may have an increased risk of dying following diagnosis. However, more studies are needed.
Some studies suggest that women with ER-positive breast cancer may have increased risk of recurrence if they have more than one or two drinks per week. This is far below the standard health recommendation, which says that women should consume no more than one drink per day. Alcohol increases estrogen levels in the body, and some health experts believe that through this pathway, alcohol increases the risk of estrogen-sensitive cancers. This includes estrogen receptor positive (ER-positive) breast cancer, the most common type of breast cancer. Beyond the estrogen connection, alcohol itself is believed to be carcinogenic, or cancer-causing.
Fruits and Vegetables (Protective Effect)
Recent studies have shown that high intake of fruits, non-starchy vegetables, fiber, beta carotenes, and calcium may be related to reduced risk of breast cancer, due to their cancer-preventing vitamins and phytonutrients including antioxidant vitamins C and E, folate, dietary fiber, dithiolthiones, glucosinolates, indoles, isothiocyanates, protease inhibitors and phytochemicals such as lycopene, phenolic compounds, and flavonoids.
Although more studies are needed to estimate the amount and type of plant-based foods required to reduce cancer risk, studies suggest that people who eat more foods containing fiber (both before and after diagnosis) have a lower risk of dying from breast cancer.
Soy food and isoflavone intake seem to have a protective role against breast cancer, mainly in Asian populations. This may be due to the increased consumption of phytoestrogen-food by those populations, as they generally have a diet rich in vegetables and fruits but low in animal protein.
In conclusion, plant-based diets such as the Mediterranean diet, vegetarian diet, vegan diet, prudent diet or the New American Plate from the AICR may be beneficial in reducing breast cancer risk. These diets are rich in fruit, vegetables, legumes (beans, chickpeas, lentils), whole grain cereals, and low in carbohydrates (especially those with simple sugars) and red meat (less than 18 ounces per week). They will help you avoid barbeque, smoked and grilled meats, sweet beverages, processed meat like ham and bacon, and alcohol. In addition to considering a plant-based diet, increasing physical activity may be advised for cancer prevention and to reduce risk of breast cancer recurrence.
Recipe of the Week: Grouper Provencal
3 tablespoons olive oil
1 pound grouper fillets
1/2 onion, finely chopped
1 1/2 cups chopped canned tomatoes
1/2 cup pitted cured black olives
3 tablespoons parsley
Dash of red pepper flakes
Salt and pepper
In a large skillet heat 2 tablespoons olive oil over medium high heat. Pat fillets dry and season with black pepper. Carefully place fillets in pan and quickly brown on both sides. Transfer to baking dish and place in 200 degree oven and bake for 10 to12 minutes.
Add 1 tablespoon olive oil to same pan and cook onion for 1 minute. Stir in garlic and cook for 30 seconds. Add tomatoes and stir to combine. Bring to a simmer and cook for 3 to 4 minutes. Stir in olives, parsley and red pepper flakes.
Remove fish from oven and place on serving plates.
Top with sauce and serve with whole wheat pasta, brown rice, quinoa or on a potato puree bed.
*Recipe via The Food Network