Breast cancer is currently the most common cancer in women in many countries worldwide, including the UK. Incidence has more than doubled over the last 50 years. It now affects one in eight women in Britain at some time in their life.
Causes
Eight out of nine breast cancers occur in women without a family history of breast cancer. With so many changes in our diet, environment and lifestyle since the beginning of the 20th century, it is difficult to pinpoint the factors that contribute towards breast cancer. Having children later in life is associated with a higher risk, as is not having children – possibly because of the lack of extra progesterone that is present during pregnancy (breast cancer tends to occur where there is oestrogen dominance). Other factors include smoking, rapid growth and a greater adult height, a high body mass, weight gain in adulthood, alcohol, fat intake, consumption of dairy and/or meat, and exposure to environmental chemicals.
The oestrogen link
Three in every four breast cancers are oestrogen positive, meaning their growth is stimulated by oestrogen. Many factors can lead to un-opposed oestrogen. Stress, for example, raises cortisol and competes with progesterone for receptor sites (progesterone helps balance oestrogen). Xenoestrogens from the environment can also increase risk of cancer. There are also nutritional and genetic factors to consider. Synthetic hormones, such as contraceptive pills and HRT are strongly linked to the development of breast cancer. There is a 50% greater risk in women who took the Pill before the age of 20. The New England Journal of Medicine reported that “studies over a six-year period have shown that the longer HRT is taken there is a fourfold increased risk of developing breast cancer”.
Prevention
For prevention to be effective, it has to respect the fact that the cancer process is multi-factorial. If a person has cancer, or early-stage cancer risk, these prevention factors have to be applied aggressively.
Control factors that stimulate growth
Insulin resistance: Eating too much sugar and refined carbs promotes high insulin levels, which stimulate the growth of breast cells. High-GL diets also lead to weight gain – another risk factor for breast cancer. Both healthy and cancerous breast cells have receptors for insulin, although research has shown that breast cancer cells have more of these receptors. Once insulin has attached to the receptor, it encourages the cell to divide and multiply, encouraging the tumour to grow.
There is a complex web between oestrogen, insulin and fat. Hormones are fat-like and a high-fat diet or high-GL diet is more likely to lead to high hormone levels. Some oestrogen is made in fat cells, so obese people make more. Eating sugary foods not only leads to obesity, but also ‘insulin resistance’. In reality, a low-GL diet is the best way to both lose fat and reduce your risk of breast cancer. The fewer fat cells you have, the less oestrogen you tend to make.
Why milk is a four letter word: Another major promoter of insulin that is strongly linked to breast cancer is milk. Milk contains insulin-like growth factor (IGF-1). This hormone simply does what it’s meant to do – stimulate growth. It also stops overgrowing cells from committing suicide, a process called apoptosis. IGF-1 has been found to directly stimulate the growth of cancer cells. Having a high IGF-1 level as a pre-menopausal woman just about doubles your risk of cancer overall.
If you have breast cancer I recommend the complete avoidance of dairy products. If you don’t have cancer, keep your intake of dairy products low; that is, below half a pint a day and ideally less than two pints a week. Read my Special Report: The Milk/Cancer Link for more details.
Reduce your oestrogenic load
Environmental oestrogens: Xenoestrogens are increasingly being recognised as a likely link in the growing incidence of breast cancer. Many of these compounds mimic oestrogen, sometimes latching onto the oestrogen receptor sites on cells, triggering abnormal growth messages. To minimise your exposure avoid the most harmful sources and switch to alternative foods, toiletries, household products and packaging. You can find a detailed list in my Special Report: Oestrogen dominance – how to avoid it and reduce your risk of cancer. Eating organic foods as much as possible, avoiding fatty foods wrapped in cling-film and reducing your intake of animal fats (which are more likely to accumulate hormone-disrupting chemicals) further reduces your load.
Phytoestrogens: These plant oestrogens are very, very weak. They still lock into the oestrogen receptors but can lessen growth messages by blocking the receptors from receiving more powerful messages. Much attention has focused on soya due to its high levels of phytoestrogens, however other pulses (for example chickpeas) have high levels too. Generally make sure you eat at least some beans, lentils, rye, raw nuts or seeds every day. When you do have soya, try fermented soya products such as natto or tempeh, as the protective components are more active. In terms of seeds, flax and pumpkin are the best anti-cancer varieties.
Liver detoxification: Hormones are broken down by the liver. If your ability to detoxify is under par, oestrogens can keep circulating. This is probably why drinking alcohol increases risk for breast cancer. The better your diet and intake of antioxidant nutrients and fibre, the more efficient your liver at clearing excess oestrogen. I recommend drinking no more than four glasses of wine a week and eating at least five servings of fresh fruit and veg a day – especially important are the liver friendly foods such as onions, garlic, artichokes, watercress and rocket. Broccoli (and other cruciferous vegetables) both support the liver and are especially rich in di-indolylmethane (DIM), which mops up excess oestrogens.
Supplements
Antioxidants: free radicals are a critical factor in the development of most cancers. I recommend you eat the foods with highest antioxidant ratings – generally foods with a strong green, yellow, orange and red colour. It’s also advisable to take the full range of antioxidant nutrients, including vitamins A, C, and E, and the minerals zinc, selenium, and manganese.
Vitamin D: Several studies have found that adequate levels lower the chances of developing breast cancer. A team of cancer prevention specialists at the University of California, San Diego, found that women with the highest level of vitamin D in their blood (up to 130 nmol/L) had a 50% lower risk of breast cancer than those with the lowest level of 32 nmol/L. In fact, they estimated that 600,000 cases a year of breast and colorectal cancer could be prevented by an adequate intake of vitamin D.
B vitamins: these are involved in breaking down oestrogen and clearing it from the liver. Vitamins B12, folate and B6 are also vital for keeping your homocysteine level down – DNA repair is largely done by methylation, and raised homocysteine levels are an excellent predictor for cancer. I recommend testing your homocysteine with a home-test kit. Having a low level is consistent with having a long and healthy lifespan.
Salvestrols: Single cancer cells are continually forming in our bodies to some extent, but most are destroyed before they develop into malignant tumours. Salvestrols in the diet may be a mechanism by which this ongoing prevention of cancer occurs. You can read more in my Special Report: Salvestrols – a major breakthrough in cancer prevention. Since the Salvestrol concentration of foods varies enormously, getting higher amounts means taking supplements. I take an antioxidant formula every day that contains Salvestrols in the form of resveratrol, and also a vitamin C supplement containing black elderberry and bilberry extracts, both rich sources.
Resources:
In the last decade there has been so much positive research showing how to make yourself cancer-proof that I’ve completely rewritten my book Say No to Cancer, which is now more than double the size, and contains all the latest research on preventing and helping fight cancer.
https://www.bio-hormone-health.com/2011/05/18/natural-progesterone-as-a-preventive-for-breast-cancer-by-dr-david-zava/
https://www.bio-hormone-health.com/2010/03/15/what-is-oestrogen-dominance/