There’s a lot of information available about the role diet plays in breast cancer risk as well as breast cancer survival. In today’s blog we’ll take a look at what the science is telling us.
We should start by saying that contrary to some claims, there aren’t specific foods that can increase survival. Rather, there is considerable evidence that dietary patterns can make a significant difference for women fighting breast cancer. Let’s take a look at some of these.
Dietary fat intake
Much has been written about the potential health benefits of eating a high fat/very low carbohydrate diet. But what does the science tell us? In one study, the Women’s Intervention Nutrition Study (WINS), R.T. Chlebowski and colleagues demonstrated that when women reduced their fat intake to 20% or less, they reduced their risk of breast cancer recurrence by an average of 24%! A different study, though not specific to breast cancer, showed that reducing saturated fat intake to under 10% reduced cancer mortality by 45%! And yet, according to the CDC, women eating the Standard American Diet consume an average of 36.1% of their daily calories from fat! We have to assume this number is even higher for women following the currently popular high fat/low carb diet. This is very concerning for anyone battling breast cancer, and certainly not advisable, based on what the science is telling us.
Vegetables and fruits
Vegetables and fruits are fundamental to any healthy diet, and are part of nutritious dietary recommendations for the prevention of cancer as well as other diseases. As it relates to breast cancer, Cheryl Rock and colleagues assessed carotenoid levels of patients in a breast cancer diet trial and found that those in the top 2/3 of carotenoid levels over the course of the study were 33% less likely to have a breast cancer recurrence or new breast cancer. Carotenoids are found in both vegetables and fruits; yellow and orange fruits and vegetables and dark green leafy vegetables are particularly good sources. Dark green vegetables also contain lutein, including kale, collards, spinach and Swiss chard. Other high carotenoid vegetables and fruits include carrots, sweet potatoes, pumpkins, winter squash, apricots, mangoes, cantaloupe, and tomatoes. As far as fruit juices, while it’s OK to occasionally enjoy some of these fruits as juices, we generally recommend eating them as whole fruits. However, if you choose to drink juices, you might consider diluting them with water by 25% – 50% in order to reduce the sugar load. Eating whole fruit provides extra fiber and helps control calories as well as excess fructose consumption. As it relates to breast cancer, it’s important to note that high fiber intake is associated with lower overall mortality in breast cancer patients, including both breast cancer deaths and deaths from other causes. Foods high in fiber include raspberries, pears, barley, whole wheat spaghetti, brown rice (as opposed to white rice), beans (all types, e.g. split peas, lentils, kidney beans, black beans), green peas, broccoli, cauliflower, and turnip greens.
Carbohydrates
As previously mentioned, one very popular diet recommends restricting carbohydrates, which, unfortunately, doesn’t distinguish between refined carbohydrates, including pastries, white bread and white rice (which we should all limit or avoid), from complex carbohydrates, including unrefined whole grains, legumes, and oats, which are nutritious and actually help stabilize glucose. As those of you familiar with Life Over Cancer already know, simple and refined carbs can lead to glycemia and insulinemia, both of which can drive cancer growth. On the other hand, complex carbs do not raise blood glucose and insulin. In fact, the research demonstrates that controlling glycemia and insulin levels through the use of complex carbohydrates not only reduces the risk of cancer recurrence, but also reduces mortality!
In our next blog, we’ll take a look at the role of dairy, fish and fish oil and clear up the confusion about soy, which continues to be a subject of misinformation and controversy!