The diet that is recommended following a diagnosis of or treatment for breast cancer is the same as what is recommended for cancer prevention.
Obesity is a known risk factor for many cancers, including breast cancer. Emphasis is placed on consuming a healthy and balanced diet, more so than adhering to any particular dietary regimes. There are no specific foods that should be consumed or avoided.
A balanced diet refers to a diet that includes all nutrients necessary for your body’s normal function, and in adequate quantities to sustain a healthy weight or achieve weight loss. Adhering to a balanced diet means eating meals regularly throughout the day that consist of carbohydrates, protein and fats.
Carbohydrates are complex sugars that your body breaks down into glucose, essential for skeletal muscle, brain and heart function. Diets lacking in carbohydrates are associated with muscle breakdown, in order to meet the neural and cardiac energy needs, and are often nutritionally deficient.
Carbohydrate requirements vary between people; most women typically require four serves per day. It is recommended to eat carbohydrates that take a long time to digest (referred to as foods with a low glycaemic index), such as wholemeal and multigrain breads, wholegrain cereals and pasta, or brown rice. Importantly, these foods typically are high in fibre and low in saturated fat, and form a significant part of a healthy, balanced diet.
One to two serves of protein, such as lean meat, chicken, fish, dairy products and beans or legumes, are recommended for most people per day. Protein requirements may change depending on your body weight.
Diets high in saturated and trans fats are associated with a wide range of health concerns. Trans fats in particular are found in processed foods, and these should be minimised wherever possible.
Polyunsaturated and monounsaturated fats constitute a vital part of a balanced diet, and are found in foods such as fish, nuts, seeds, avocados and healthy oils such as olive and canola.
Two to three serves of calcium-containing foods are recommended for most women per day in order to maintain bone health. Sample foods include low-fat dairy products (milk, cheese and yoghurt), canned salmon with edible bones, soy products (such as tofu and soy milk), almonds, brazil nuts and sesame seeds.
Fruits and Vegetables
Fruits and vegetables in general are high in fibre, vitamins, minerals, antioxidants and phytochemicals (such as carotenoids and flavonoids). These nutrients have been shown to have protective effects against some cancers, coronary artery disease and Type 2 Diabetes Mellitus, among other chronic diseases. As foods that are typically low in energy-density, they play an important role in weight management.
No specific fruits or vegetables have been identified to be protective against breast cancer; however, they are an important part of a balanced diet. It is recommended that all adults consume at least two serves of fruit and five serves of vegetables per day.
Studies have consistently shown that increased alcohol consumption is associated with a increase in the risk of breast cancer. For every standard drink (10g of alcohol) consumed daily, the risk of breast cancer has shown to increase by 7-12%. If women choose to consume alcohol, it is recommended that this is limited to one standard drink per day – a small glass of wine – and that they have multiple alcohol-free days per week.
Vitamin Supplements and ‘Anti-Cancer’ Diets
There is no scientific evidence that supports the use of vitamin supplements or any ‘anti-cancer’ diets (including herbal products) to prevent the recurrence of breast cancer. Whilst benefits are seen in balanced diets with high fruit and vegetable consumption, this same benefit is not observed when similar vitamins are taken as supplements. Ultimately, your vitamin intake should be sourced from your dietary intake; a dietician or general practitioner may assist you when vitamin supplements are necessary.
Vitamin D is essential for health and wellbeing. There is some evidence suggesting that it may also have a role in preventing the development of breast cancer. Normal levels of vitamin D may improve survival of patients with a past history of breast cancer.
A very large study has shown in over 25,000 vitamin D results, there was high prevalence of vitamin D deficiency in Australian women and that the risk of breast cancer was 2-1/2 times more likely in women with low vitamin D concentrations (below 75 nmol/L). This suggests that vitamin D may play an important role in reducing risk of breast cancer.
Physical Activity and Exercise
Daily exercise is essential for maintaining a healthy weight, and has also been shown to directly reduce the risk of cancer recurrence through decreasing insulin and oestrogen levels in the body. High levels of these hormones have been implicated in breast cancer development.
It is recommended that all adults have at least two and a half hours of active physical exercise per week. This equates to 30 minutes five days per week, or around 50 minutes three days per week.
Exercise should be of moderate intensity, for example brisk walking or jogging, cycling or swimming. It should be of sufficient intensity to make you breathe faster without making you feel completely out of breath. Depending on the intensity of exercise, your muscles use different energy sources. Exercise of a moderate intensity will ensure that your body burns fat predominantly.