Nutrition for Breast Cancer Survival

By Dr Malcolm Mackay

Heart disease is the leading cause of death in breast cancer survivors. A whole foods, plant-based diet, low in fat, is the only diet that has been proven to reverse heart disease.

There is a substantial body of evidence for the role of diet and lifestyle on breast cancer risk and breast cancer survival. Some of this data is observational – eg. women who eat soy have less chance of recurrence; some is from laboratory work – eg. blood from women on plant-based diets is more effective at killing breast cancer cells in a petri dish, and other evidence comes from research on other hormone driven cancers – eg. a randomised controlled trial found that the progression of prostate cancer could be stopped with a plant-based diet and lifestyle program. There are reasonable grounds to assume that most factors that affect the risk of getting breast cancer have a similar effect on the risk of recurrence or progression of established breast cancer. There are several studies underway investigating the effect of a whole foods, plant-based diet on women with breast cancer. You do not have to wait for the results before taking action as all of the strategies we suggest have side benefits rather than side effects and are compatible with conventional medical therapy.

Nutrition research often focusses on the effects of individual foods on breast cancer, and this guide will mention some of these, however, the whole is greater than the sum of the parts and our approach is more a whole diet and lifestyle approach than an ingredients list of special cancer fighting foods.

Some of the observed associations between nutrition and cancer are backed up by our understanding of the mechanisms that promote or inhibit cancer. Animal protein promotes cancer development at all stages, from the initial mutation though to cancer progression years or decades later. Some of the cancer promoting effects of meat and dairy are thought to be due to stimulation of growth regulating systems like the hormone IGF-1 produced by the liver and the cellular growth regulator, mTOR. Excess oestrogen caused by dietary and lifestyle factors promotes growth, particularly in the breast and reproductive organs. The more we study the phytonutrients in plants (substances that are not ‘essential nutrients’ but are essential for good health) the more mechanisms we discover that protect against and inhibit cancer growth.

Excess oestrogen contributes to many women’s health problems including breast cancer. Many breast cancers are oestrogen positive (have receptors for oestrogen and grow more when exposed to oestrogens). Breast cancer hormonal therapy aims to block this effect. However, there are also dietary and lifestyle factors that can reduce oestrogen.

Strategies to reduce oestrogen:

  • Don’t eat other animal’s oestrogens (dairy foods, chicken, eggs)
  • Reduce exposure to oestrogen-like chemicals (eat from the bottom rung of the food chain – plants, not fish, buy organic if you can)
  • Increase oestrogen excretion by eating more dietary fibre (esp. flaxseed)
  • Block some of the effects of oestrogen with plant phytoestrogens (eg. soy)
  • Limit dietary fat intake (oils, nuts and seeds)
  • Exercise
  • Maintain a lean body (fat cells make oestrogen)
  • Avoid alcohol (blocks oestrogen deactivation in the liver)
  • Limit caffeine (increases oestrogen levels)

Dietary Guidelines for Breast Cancer Survivors:

  • Eat a whole foods, plant-based diet:
    • Make whole grains, starchy vegetables, and legumes your main source of calories rather than nuts and seeds
    • Use only whole grains at home, preferably more intact forms rather than flour products
  • Use no oil in home cooking, not even olive oil or coconut oil
  • Include phytonutrient-rich foods with every meal
    • Berries, mushrooms, garlic and onion, spices
    • Green leafy vegetables are superfoods – eat them in abundance several times per day
    • Cruciferous vegetables* – broccoli, cauliflower, cabbage, bok choy, rocket (arugula) etc

* When cruciferous vegetables are chewed, crushed or chopped (while raw) an enzyme produces sulphoraphane. The enzyme is destroyed by cooking but not the sulphoraphane. Methods to increase sulphoraphane content include: eating it raw, adding some raw cruciferous (or mustard seed) to the cooked cruciferous, or leaving chopped cruciferous to stand before cooking. Broccoli sprouts are extremely high in sulphoraphane and are easy to grow in your kitchen.

  • Include a tablespoon of ground flaxseed (available at supermarkets) in your daily diet
  • Keep salt intake low for immune health and cardiovascular health
    • High salt foods include bread and many condiments
  • Get your nutrients from food, not supplements except for:
    • Vitamin B12, Vitamin D if you lack sun exposure
  • Avoid alcohol – even one drink per day increases breast cancer risk significantly
  • Limit caffeinated beverages

Raw vs cooked:

There are some nutrients that are more available in raw foods and some in cooked foods. Most nutrients and phytonutrients survive cooking. Totally raw food diets exclude some of the healthiest food groups (whole grains, legumes), reduce food diversity, reduce the volume of vegetables eaten (leafy greens, broccoli etc), and are often inadequate in total calories and relatively high in fat (nuts, seeds, oils provide most of the calories). Include cooked whole grains and legumes in your diet.

Gut microbiome:

The health of the body begins in the gut with the microbiome. If you feed your microbiome well with high fibre, starchy foods like legumes and minimally processed grains, it will repay you with post-biotics like short chain fatty acids. These microbial products regulate the immune system, reduce inflammation, improve metabolic health, keep you slim and even improve brain health.

Other lifestyle factors:

Exercise downregulates growth promoting hormones – oestrogen, IGF-1 and insulin – and is associated with lower breast cancer risk. Cancer remission testimonials often include a high level of physical activity in addition to a healthy plant-based diet. Sleep too, has been shown to boost immune function while lack of sleep has been associated with increased breast and bowel cancer. A healthy mind, stress optimisation and positive social interactions support physical health including an effective cancer fighting immune system. Lastly, purpose in life, and having a personal ‘why’ for a longer healthier life, seems to be an attribute of extraordinary cases of cancer survival.


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Page created 28 June 2020
Page last updated 28 June 2020