Can Your Diet Influence Your Breast Cancer Risk? A Miriam Hospital Expert Says Yes
Posted Monday, October 01, 2012
October is Breast Cancer Awareness Month
Could what you eat potentially impact your risk of breast cancer or
breast cancer recurrence? According to Mary M. Flynn, PhD, RD, LDN,
research dietitian at The
Miriam Hospital, your nutritional habits can influence some risk
factors for breast cancer.
“I don’t think we will ever get to the day when we will say ‘Eat this
diet and you will never get breast cancer,’ but I think there are enough
published studies to make more specific diet recommendations than have
been made to date,” Flynn says.
Most women who are diagnosed with breast cancer are told to follow a
low-fat diet. However, Flynn says this is interesting because there are
no published studies that demonstrate women who eat a low-fat diet, or
simply decrease the fat in their diet, will lower their risk of breast
cancer or recurrence.
“To the contrary, I think you can make a better case that eating a
low-fat diet could increase your risk of breast cancer,” Flynn says.
This is because a lower fat diet typically increases blood levels of
glucose and the hormone insulin, which is needed to store blood glucose
and other blood nutrients. Excess levels of both blood glucose and
insulin – common in overweight or obese individuals – have been linked
to higher rates of cancers, including breast cancer.
Flynn adds that being overweight at time of diagnosis, as well as
gaining weight through cancer treatment, can also increase recurrence
risk. She believes achieving and maintaining a healthy body weight
is the most important thing an individual can do to lower their risk of
breast cancer and breast cancer recurrence.
She advises eating a healthy, plant-based diet full of fruits and
vegetables. Plant-based diets are not only linked to better overall
health, but all plant foods contain compounds known as phytonutrients
that have been shown to decrease risk factors for breast cancer and
other chronic diseases.
Flynn also recommends the following dietary changes:
Use extra virgin olive oil (the juice of the olive, a plant
product). Women raised on diets that include olive oil have a
very low breast cancer rates. In fact, some studies show
that the more olive oil a women has used in her life, the lower
her risk of breast cancer. Extra virgin olive oil is loaded with
risk-reducing phytonutrients and it can also improve insulin
function, leading to lower blood levels of both insulin and
glucose. However, Flynn cautions that not all extra virgin
olive oil sold in the United States is actually extra
virgin. She suggests consumers visit websites such as www.extravirginity.com
to make sure they are purchasing true extra virgin olive oil.
Eat more vegetables, especially those dark in color and from the
cruciferous or cabbage family. While it is great to eat a
variety of vegetables, studies have shown some vegetables are
better at preventing breast cancer than others. For example, the
deeper or darker a vegetable’s color, the healthier it is. The
color is due to cancer-fighting carotenoids, or the red, orange,
and yellow pigments in fruits and vegetables. Flynn
encourages the use of more frozen vegetables: because they are
kept on the plant longer than most “fresh” vegetables, they tend
to be darker in color, which boosts their health benefits. She
also says carotenoids need fat to be absorbed so it’s important
to cook vegetables in olive oil – which also helps them taste
Two carotenoids that appear to have importance cancer-prevention
roles are alpha-carotene and lycopene. Vegetables that contain
alpha-carotene include broccoli, carrots, kale, spinach and
other dark greens, sweet potatoes and winter squash. Lycopene is
found mainly in tomatoes, yet Flynn says we absorb lycopene best
when eating processed tomatoes, such as canned tomatoes or
commercial sauce, rather than fresh tomatoes. She recommends
including canned or processed tomato products weekly.
The cabbage or cruciferous family of vegetables (including
broccoli, brussel sprouts, cabbage, cauliflower and kale)
contain a phytonutrient that studies have shown can shift
estrogen metabolism to a form that does not drive breast cancer.
It can also prevent some cancers from starting.
Cruciferous vegetables contain sulfur components, which give
them their characteristic taste and smell. Many people do
not find this vegetable group very appealing due to the sulfur,
but Flynn says cooking – or especially roasting – these
vegetables in olive oil greatly improve their taste. She
suggests using one tablespoon of extra virgin olive oil per cup
of vegetables. Toss the vegetables in the olive oil,
arrange in a single layer in a baking pan or a sheet with a
small side (not a cookie sheet, or the oil might spill into the
oven) and roast for about 30 minutes at 400 F, turning the
vegetables over half way through.
Flynn also suggests avoiding or consuming less of the following foods:
Vegetable oils, such as soybean, safflower, corn oils,
and products made with them, including margarine, salad
dressing and mayonnaise. Vegetable oils are primarily
polyunsaturated fats, which oxidize or break down in the
body. Excessive oxidation can start and drive
Red meat, which has been related to a higher risk of breast
cancer, especially if grilled. Grilling produces chemical
compounds known as heterocyclic amines (HCA) that act like
nicotine and can drive cancers. Red meat also contains
amino acids that stimulate insulin production and increase
oxidation in the body, both of which can increase cancer risk.
Filed under: Comprehensive Cancer Center, Miriam,