Fishing for ways to help reduce breast cancer risk – Dr Nina Bailey

The small pink ribbon that adorns the clothes of thousands of women across the UK is undoubtedly recognised as a symbol of hope and unification for breast cancer sufferers and their families. Breast cancer is currently the most common cancer in the UK, with around 46,000 newly diagnosed cases arising each year and October this year brings with it a hope to increase awareness and raise money towards much needed research. Whilst breast cancer can affect men, it is generally women who will develop the disease, and it is thought that around 1 in 9 postmenopausal women will develop breast cancer.

We know that age is a key risk factor for developing breast cancer because the majority of invasive cancers are generally found in women over the age of 55 (and are hence generally postmenopausal). However, about 5% to 10% of breast cancer cases are thought to be hereditary, resulting directly from gene mutations that are inherited from a parent. Mutations in two key genes involved in regulation of cell growth, called BRCA1 and BRCA2, will increase the risk of developing breast cancer by as much as 80%. So, if someone in your family has suffered from breast cancer, then there is an increased chance that you may develop the disease at some point in your life.
However, there is increasing evidence that making simple diet and lifestyle changes can directly influence a woman’s chances of developing the disease later in life. Much of the information that is gathered on diet and cancer risk comes from large studies called cohort studies that recruit people (without disease) and follow them over a period of 10-20 years. After a period of time information can be gathered on what these people ate and what diseases they developed. One particular research project called EPIC (European Prospective Investigation into Cancer) started in 1992 is now producing clear and interesting information on the role of diet on breast cancer risk. For example, consuming a diet comprising mostly fruits, vegetables, fish, and olive/sunflower oil, along with avoidance of Western-type foods (such as meat products, pizza/pies, cakes, butter/cream and alcohol) may contribute to a substantial reduction in postmenopausal breast cancer risk (Collet et al, 2009).
A later study showed that in postmenopausal women, there was a strong inverse association with diets that included fish, but not for vegetarian diets when compared to red meat eaters (Cade et al, 2010). Simply put, this means that eating fish, but excluding meat from the diet is generally thought to offer the best protection against breast cancer risk. So why would this be? It may well be that the amount of fish consumed need to offer protection is simply more than the average person consumes, and therefore you would need to consume fish on a daily basis to ensure the best possible protective benefits. Eating fish daily would therefore replace or reduce the amount of red meat consumed.
Given that it is the omega-3 content of fish that offer protection, the alternative to looking forward to a fish supper seven days a week is to supplement the diet with highly purified fish oils. Omega-3s, such as eicosapentaenoic acid (EPA), have been previously shown to have a favourable effect on the BRCA1 and BRCA2 genes and are thought to have anti-cancer properties, certainly in vitro ( Bernard-Gallon et al, 2002). However, whilst performing experiments in test tubes can give extremely promising results, it is studies using humans that are needed to verify such findings.
This is where we can turn back to our cohort studies for information. Indeed, a recent study of 35,000 postmenopausal women has shown that women who regularly took fish oil supplements were 32% less likely to develop breast cancer over the next six years when compared to those individuals who did not supplement with fish oils. Most importantly was that this protection was shown to be against invasive duct breast cancer which is the most common form of the disease (Brasky et al, 2010).

So what we learn from such studies is that supplementing the diet can help reduce the chances of developing breast cancer, but that we probably need to be taking high doses for many years to ensure this protection. So when you go to your health shop to pick up your omega-3 remember that not all oils are the same, in both quality and strength. To ensure the maximum benefits for long term health seek out a high strength EPA product such as Vegepa.

Bernard-Gallon DJ, Vissac-Sabatier C, Antoine-Vincent D, Rio PG, Maurizis JC, Fustier P, Bignon YJ. Differential effects of n-3 and n-6 polyunsaturated fatty acids on BRCA1 and BRCA2 gene expression in breast cell lines. Br J Nutr. 2002 87:281-9.

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