Breast Cancer Prevention

By Dr Sandra Cabot

Breast cancer is a frightening illness. Globally, a case of breast cancer is diagnosed every 29 seconds and one woman in the world dies of breast cancer every 75 seconds. With statistics like this, it is no wonder that more women fear breast cancer than any other illness. They fear it because nearly every woman personally knows someone who has died of the disease, and most women think there is nothing they can do to prevent it.

Many women feel powerless over their ability to prevent breast cancer; they know they can reduce their risk of heart disease by keeping their cholesterol down and exercising; they can reduce their risk of osteoporosis by ensuring a high intake of calcium and vitamin D; but when it comes to breast cancer prevention, a common statement is “but what can you do about that?”

The media would have you believe there isn’t much you can do to prevent breast cancer; it basically boils down to your genes. Consequently many women believe that breast cancer is caused by a combination of bad genes and bad luck. Therefore they assume the only thing you can do to protect yourself against breast cancer is make sure you have regular mammograms; that way at least the cancer will be detected early and your chance of survival is greater.

Fortunately, this is not the whole story.

When it comes to genetics, only five to ten percent of breast cancer cases can be explained by genes, and just having a bad gene does not guarantee that you will develop breast cancer. Even women with the BRCA1 and BRCA2 breast cancer genes only have a 40 to 80 percent chance of developing breast cancer.

What most women don’t realise is that both smoking and being overweight independently double the risk of breast cancer in women with these genes. Very few women are aware that being overweight of being a diabetic increases the risk of breast cancer; of the consuming more than two alcoholic drinks per day increases the risk by 40 percent.

Conversely, most women don’t realise the powerful cancer preventive properties of specific nutrients and foods.

Women who are vitamin D deficient at the time of diagnosis of breast cancer are 94 percent more likely to have their cancer metastasise (spread) and are 73 percent more likely to die in the next ten years than women who are not deficient.

Turmeric can protect breast cells from the cancer causing effects of pesticides, and flaxseeds can actually shrink breast tumours.

A great deal of exciting research has been conducted on the prevention of breast cancer, but sadly this research never reaches the public, so women remain ignorant of this vital information.

With that in mind, Naturopath Margaret Jasinska and I wrote The Breast Cancer Prevention Guide so that women can be well informed and become proactive about breast cancer prevention.


Breast health recommendations:

  • Have regular breast checks from your doctor and perform breast self examinations every 2 months – this is best done just after your menstrual bleeding has finished.
  • Avoid excess alcohol intake.
  • Include plenty of antioxidant rich foods in your diet, such as raw vegetables and their juices, raw fruits and white or green tea.
  • Include phyto-estrogen rich foods in your diet such as nuts, seeds and legumes (beans, peas & lentils).  Phyto-estrogens help to protect oestrogen receptors in breast tissue from more powerful, harmful oestrogens.
  • Keep your weight in the healthy range and exercise regularly.
  • Minimise your exposure to and protect yourself from toxic chemicals (such as pesticides, insecticides, solvents, glues, dyes etc) and avoid heating food in plastic containers or plastic wraps. Don’t drink hot beverages from Styrofoam cups. Install a water filter in your home.
  • Ensure you receive enough of the nutrients vital for supporting healthy breast tissue – these are vitamin D, iodine and selenium.
  • If you have lumpy breasts, it may be wise to avoid prolonged use of oral contraceptives which contain synthetic oestrogens.


Essential Nutrients for Healthy Breasts

Vitamin D

Vitamin D is a hormone-like substance that is produced in the skin during exposure to sunlight.  It has many important functions in the body, including strengthening bones, promoting a healthy immune system and protecting against a wide range of diseases.

Vitamin D helps to regulate cellular replication in a very important way. Specifically vitamin D helps cells to differentiate (become specialised), and inhibits cells from proliferating, or growing in an out of control way.  It is thought that these are the reasons why vitamin D deficiency increases the risk of various types of cancer, including breast cancer, as well as cancer of the colon and prostate.

An Australian study conducted in 2001, detected mild or moderate vitamin D deficiency in more than one in three women during summer, and one in two women during winter.  This is quite shocking, as we live in the sunburnt country!  Those most at risk of vitamin D deficiency include people with dark skin, women who practise veiling, people taking certain medications (such as anti-epileptic drugs), and people who spend most of their time indoors.  Sunscreen inhibits the manufacture of vitamin D.

It’s healthy to get some regular exposure to the sun’s rays on uncovered skin; however prolonged sun exposure can be hazardous and inconvenient, and vitamin D is found in very few foods; therefore supplementing with vitamin D may be the best option. Your body’s level of vitamin D can be accurately tested with a blood test.


Iodine is a trace mineral that has a number of important health promoting functions in the body.  Seventy to eighty percent of the iodine in your body is stored in your thyroid gland, as it is needed for the production of thyroid hormones. Interestingly in women, a large amount of iodine is also stored in breast tissue. 

Research has shown that iodine deficiency increases the risk of fibrocystic breast disease.  This is where the breasts become lumpy and painful, particularly before menstruation when multiple cysts can be felt. Taking supplemental iodine helps to resolve these symptoms for the majority of women.

Studies have also shown that iodine acts as an antioxidant in the breasts, protecting breast tissue from free radical damage.  In this way it helps to protect breast tissue against cancerous changes.

Iodine deficiency is an increasingly common problem in Australia.  The majority of the world’s iodine is found in the oceans; however small amounts are also found in the soil.  Unfortunately many parts of Australia, especially inland areas, have soils very deficient in iodine.  Studies done in the last five years have identified iodine deficiency as a common problem among adults, children and pregnant women. Your iodine level can be checked with a urine test.

Seafood that comes from the ocean (rather than that which is farmed) is a good source of iodine.  Seaweeds (such as arame, wakame, nori and kombu) are an excellent source of iodine; unfortunately it is not commonly eaten by most Australians.  Kelp is a type of seaweed that is naturally rich in iodine and it is available in supplement form.


Selenium is a mineral that acts as a powerful antioxidant and free radical scavenger.  It is a great protector and detoxifier; this is because it is required for the production of glutathione peroxidase, an enzyme necessary for detoxification and protection of the body against free radical damage. Free radicals are produced in the body from toxic chemicals, excess sugar intake, smoking, pollution and stress. Free radicals are capable of causing damage to the DNA inside cells which speeds up the ageing process and increases the risk of cancer.

Selenium has been shown to stimulate apoptosis (cell death) in tumour cells, and a low selenium status predicts a poorer outcome in those with certain cancers.  Geographic studies have shown that people who live in areas with selenium deficient soils and have a low selenium intake have higher cancer mortality rates.

Women who have the BRCA1 gene, which is a mutated gene that places them at greatly increased risk of breast cancer are known to have more chromosome breaks (which can promote cancer) than women without this gene.  Research has shown that when women with the BRCA1 gene were given supplemental selenium for three months, their number of chromosome breaks was reduced to normal.

Obtaining adequate selenium from diet alone is very difficult because very few foods are a rich source of selenium.  Brazil nuts, crab and salmon provide some selenium, however using a selenium supplement will ensure you receive optimal levels of this vital mineral.


–Pasco JA, Henry MJ, Nicholson GC, et al. Vitamin D status of women in the Geelong Osteoporosis Study: association with diet and casual exposure to sunlight. Med J Aust 2001; 175: 401-405.
–Linus Pauling Institute Oregon State University
–Hansen CM, Binderup L, Hamberg KJ, Vitamin D and cancer: effects of
1,25(OH)2D3 and its analogs on growth control and tumorigenesis. Front Biosci. 2001 6:D820-48.
–University of Maryland Medical Center
— The Journal of Clinical Endocrinology & Metabolism Vol. 84, No. 2 821
–Kowalska E et al., Increased Rates of Chromosomes Breakage in BRCA1
Carriers are Normalized by Oral Selenium Supplementation, Cancer Epidemiology
Biomarkers and Prevention 2005