Healthy habits reduce the risk of breast cancer

Having a healthy diet and lifestyle reduces your risk of developing breast cancer.  I have always known that to be the case, but now research published in the journal Breast Cancer Research has come to the same conclusion.

Exercising regularly, maintaining a healthy weight and keeping alcohol intake low all reduce the risk of developing invasive breast cancer after menopause.  This is according to analysis on research carried out on nearly 86 thousand post menopausal women.  The benefits were experienced both by women with a first degree relative who has had breast cancer, and women with no family history of the disease.

It is important to remember that only 5 to 10 percent of breast cancer cases can be attributed to genetics.  The media may have you convinced that breast cancer is largely a genetic disease and there is very little you can do to reduce your risk of developing it.  This is far from the truth; what you eat, what you think and the lifestyle you lead have a far greater impact on your risk of developing breast cancer than genes.

If breast cancer does run in your family, it may be shared lifestyle habits that are placing you at increased risk more than actual genes.  One of the researchers involved in this study made some interesting comments:

“It's important to note that a family history of breast cancer can arise in part due to shared unhealthy behaviors that have been passed down for generations.  Untangling the degree to which genes, environments, and behaviours contribute to the disease is difficult. But our study shows that engaging in a healthy lifestyle can help women, even when familial predisposition is involved.”

The following factors increase your risk of developing breast cancer:

  • Being overweight.  Carrying excess body fat places you at high risk for a number of reasons.  Fat cells produce a type of oestrogen called oestrone.  Breast cancer cells are very sensitive to this hormone; it encourages them to grow and spread.  Being overweight, particularly around your waist means you have high blood insulin levels.  Insulin is a fertiliser for tumour cells.  Lastly, fat cells produce a host of inflammatory chemicals, which have a detrimental effect on your immune system.  The more fat cells you have (and the bigger they are), the more inflammation is in your body.
  • Lack of exercise.  Exercise helps to keep your body weight down and your insulin level low.  Exercising regularly helps to improve energy, self esteem and the resolve to eat well.  Physically active women are 25 percent less likely to develop breast cancer.
  • Alcohol.  Alcohol is a class one carcinogen: a known cancer causing agent.  Many people are unaware of that, or choose to ignore it.  Low alcohol consumption helps to reduce the risk of heart attacks and strokes, but any alcohol you consume does raise your risk of cancer.  Most people realise there is an association between alcohol consumption and throat cancer and pancreatic cancer, but a strong relationship does exist between alcohol and breast cancer.

Research has shown that moderate to heavy alcohol consumption increases the risk of recurrence of breast cancer after the initial diagnosis, and increases the risk of a woman dying from breast cancer.  This effect is stronger in overweight women and post-menopausal women.  Heavy alcohol consumption is classed as more than 14 drinks per week for women.  Alcohol consumption triggers your liver to produce a protein called insulin-like growth factor 1.  This protein promotes cell replication in your body.  Alcohol also reduces the ability of your liver to break down and excrete oestrogen.  This leaves higher amounts of oestrogen in your body, capable of stimulating the growth of cancerous breast cells.

The most important nutrients for healthy breast tissue

Having a healthy diet is paramount.  However, even people who eat well are commonly deficient in certain key nutrients required for healthy breasts.  The most important nutrients are:

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.

When it comes to your immune system, vitamin D helps cells to replicate correctly.  It 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 in winter.  Those most at risk of 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.

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.


Iodine is a trace mineral that has a number of important functions in the body.  70 to 80 percent of the iodine in your body is in your thyroid gland, as it is needed for the production of thyroid hormones that control metabolism.  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.  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 have soils very deficient in this mineral.  Studies done in the last five years have identified iodine deficiency as a common problem among adults, children and pregnant women.

Seafood that comes from the ocean (rather than that which is farmed) is a good source of iodine.  Seaweed is 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.  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 capable of causing damage to cell membranes, the DNA inside cells; they speed up the ageing process and increase 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.

As you can see, there are many ways you can help to promote the health of your breasts.

J Clin Oncol. Published online August 30, 2010.
Robert Gramling, Timothy L Lash, Kenneth J Rothman, Howard J Cabral, Rebecca Silliman, Mary Roberts, Marcia L Stefanick, Rosanne Harrigan, Monica L Bertoia and Charles B Eaton. Family history of later-onset breast cancer, breast healthy behavior and invasive breast cancer among postmenopausal women: a cohort study. Breast Cancer Research, 2010; 12: R82 DOI: 10.1186/bcr2727