Can diet lead to a lower risk of breast cancer? A new study published in the journal JAMA Internal Medicine suggests that women who eat a Mediterranean-style diet high in extra-virgin olive oil have a lower risk of breast cancer.
In the study, researchers found that women who followed a Mediterranean diet were 68 percent less likely to develop breast cancer than women who were advised to follow a diet low in fat.
The Spanish researchers followed more than 4,000 post-menopausal women over a five-year period. The participants, who had never had breast cancer, were asked to follow one of three diets: a Mediterranean diet high in extra-virgin olive oil, a Mediterranean diet high in nuts and a diet where they were instructed to reduce their fat intake.
After five years, 35 of the women surveyed developed breast cancer, and those women who followed the diet high in olive oil were least likely to develop the disease.
A Mediterranean diet is high in fruits, vegetables, legumes and nuts, and includes some fish and poultry. In the diet, olive oil replaces unhealthy fats such as butter. Previous research has shown that this style of diet cuts the risk of heart disease and stroke, and reduced the incidence of Parkinson’s disease and Alzheimer’s disease.
“This is the diet I recommend across the board to prevent disease,” said Michelle Ray, a registered dietitian at Novant Health Cancer Rehab & Wellness. Ray said she promotes this diet among her patients as the healthiest diet because it is plant-based.
Rather than calling it a “diet,” Ray said she believes it’s important to emphasize the idea of improving your lifestyle. “A diet has a beginning and an end,” Ray said. “This is about changing what you eat.”
A plant-based diet doesn’t mean becoming a vegetarian or experiencing deprivation, she said. “This way of eating emphasizes vegetables, fruit, whole grains, legumes, fish and lean proteins,” Ray added. “If you’re going to eat pizza, get one with a whole grain crust topped with vegetables.”
Though no food serves as a magic formula in the prevention of breast cancer, proper nutrition and healthy lifestyle can help keep your body healthy and reduce your risk of developing the disease, according to breastcancer.org.
The nonprofit offers the following suggestions on nutrition:
Eat a low-fat diet. Women had a reduced chance of recurrence when they only consumed 25 percent of their calories from fat, according to one study. Researchers for the Women’s Health Initiative trial found that a low-fat diet may reduce the risk of cancer in women who normally ate diets high in fat.
Also, a low-fat diet will help you lose weight.
“Diets high in fat lead to obesity, which increases the risk of breast cancer,” Ray said. She recommends that patients derive no more than 20 to 25 percent of their calories from healthy fats like olive oil, canola oil, avocados and nuts.
Eat a balanced diet. Aim for at least five cups of fruits and vegetables every day, and include food from other plant sources, such as whole-grain breads, nuts, seeds and beans.
“Five to nine servings of fruits and vegetables are optimal for cancer prevention,” Ray said. “By introducing more antioxidants into your body, you can better fight free radicals that cause cancer.”
Ray said she emphasizes eating vegetables over fruits since fruits are naturally higher in sugar and therefore higher in calories. When picking vegetables, pick darker color produce such as spinach, kale and greens; these are higher in nutrients, according to Ray.
She also warns patients to be cognizant about serving size. “A portion of fruit in a banana is the length from the base of your wrist to the top of your thumb,” she said. “When you go to the grocery to buy apples, the single serving apples on display are huge. The ones that are bagged are the right size. A portion of broccoli should fit in the palm of your hand.”
Reduce your exposure to pesticides. While there is no research showing that small amounts of residue in pesticides in produce increase the risk of breast cancer, many people worry about the safety of the chemicals in the body. Consider buying organic produce or using a special wash for your fruits and vegetables.
“Eating organic food is not a magic bullet to prevent cancer,” Ray said. “However, it’s a smart choice and a cleaner way of eating.”
Consumers should be smart when spending their dollars on organic foods. Ray recommends buying organic produce following the guide provided by the Environmental Working Group which has the “Dirty Dozen” items to buy organic. “These foods are more permeable to pesticides used on crops,” she said.
Other recommendations are organic cow’s milk, wild-caught fish, grass-fed beef and free-range chicken.
Lifestyle factors other than nutrition can also affect your risk of breast cancer. The American Cancer Society lists these other risk factors:
Drinking alcohol can increase your risk of breast cancer. Women who had one alcoholic drink a day had a small increase in breast cancer risk when compared to nondrinkers. Those who consumed two to five drinks a day had about one and a half times the risk of women who don’t drink.
“One drink a day is considered safe,” Ray said. However, serving size is important. “One drink is 5 ounces of wine or a 12-ounce beer or one and half ounces of liquor.”
Being overweight or obese can impact breast cancer risk in post-menopausal women. The American Cancer Society said that women who have more fat tissue after menopause have a higher risk of breast cancer due to higher estrogen levels. Overweight women also tend to have higher insulin levels, a condition which has been linked to breast cancer.
Exercise reduces breast cancer risk. A study from the Women’s Health Initiative found that just one and a quarter to two and half hours of brisk walking a week reduced a woman’s risk of breast cancer by 18 percent. Women who walked 10 hours a week had a greater benefit, according to the study.
“Cancer hates exercise,” Ray said. “People should aim for at least 150 minutes a week of exercise which is equal to a 30-minute walk, five days a week.”
Ray added, “When it comes to cancer, we can’t control our genetic predisposition or environmental factors, but we can control our diet and lifestyle.”