Diet, lifestyle and breast cancer recurrence

You may have heard that diet and lifestyle can affect the risk of breast cancer coming back, also known as recurrence.

The World Cancer Research Fund (WCRF) recommends that people who have had breast cancer follow advice to reduce their risk of cancer coming back. This includes:

• Eating a healthy diet that is high in fibre and low in saturated fats
• Being physically active
• Maintaining a healthy weight
• Limiting alcohol

High-fibre foods

There is some evidence that fibre may reduce the risk of breast cancer recurrence, but further research is needed to find out more.

High-fibre foods tend to be lower in calories and can help you feel full for longer. Experts think fibre has many health benefits including improving digestive health and helping prevent heart disease and some cancers.

High-fibre foods include:

• Wholegrain foods such as brown rice, oats, wholewheat couscous and quinoa
• Pulses such as lentils and beans
• Starchy foods such as potatoes and sweet potatoes, ideally with their skins on
• Vegetables and fruits

Saturated fats

There is some evidence that saturated fat may increase the risk of recurrence, but further research is needed to find out more.

It’s a good idea to limit the amount of fat you eat, particularly saturated fat because it increases the risk of conditions such as heart disease.

Foods high in saturated fat include:

• Butter
• Fatty cuts of meat
• Processed meats such as sausages
• Full-fat dairy products, including whole milk, cream and hard cheese
• Chocolate, biscuits and cakes

Try to replace these with healthier fats such as:

• Olive oil, rapeseed oil and their spreads
• Oily fish such as salmon and mackerel
• Avocado
• Nuts and seeds

Soya

Soya foods such as soya milk and tofu contain natural compounds called phytoestrogens. Foods like chickpeas and linseeds also contain phytoestrogens.

Phytoestrogens have a chemical structure that is similar to the hormone oestrogen, but their effects are much weaker. As oestrogen can encourage some breast cancers to grow, some people worry whether foods or supplements containing phytoestrogens might have the same effect and increase the risk of recurrence. But phytoestrogens are not the same thing as female hormones and don’t affect your body in the same way.

Current evidence suggests a diet containing naturally occurring phytoestrogens is safe if you’ve had breast cancer and may be beneficial.

Phytoestrogens are also found in herbal remedies including:

• Black cohosh
• Red clover
• Sage

These are sometimes taken to relieve hot flushes and other menopausal symptoms. However, they are not recommended because the evidence on their effectiveness and safety is limited and conflicting.

Soya supplements are also not recommended for people with breast cancer as we need more research to determine their safety.

Dairy

There is no evidence that dairy products increase the risk of breast cancer recurrence.

You can eat or drink dairy products like milk, cheese and yoghurt as part of a healthy diet. They’re an important source of protein, calcium and certain vitamins.

Some dairy products are high in fat. Because maintaining a healthy weight can reduce the risk of breast cancer coming back, try to eat higher-fat dairy foods like cheddar cheese and double cream in small amounts. You can also opt for lower-fat options like semi-skimmed or skimmed milk or low-fat cheese. Check the labels as some low-fat foods contain a lot of sugar, which can also cause weight gain.

If you prefer to follow a dairy-free diet, try to make sure you’re still eating calcium.

Foods high in calcium include:

• Fish with edible bones including anchovies, sardines, pilchards and whitebait, or canned fish that contains soft bones such as tinned salmon
• Dark green leafy vegetables like kale
• Foods with added calcium, such as dairy-free milks and yoghurts

Sugar

There’s no evidence that following a sugar-free diet will reduce your risk of breast cancer recurrence.

You can still eat sugar, but try to have sugary foods and drinks like biscuits, sweets and fizzy drinks in moderation as eating lots of sugar can lead to weight gain. Opt for healthier sweet foods like fruit if you can.

Organic foods

Some people eat organic foods as a way of reducing pesticides in their diet. However, no association has been found between eating an organic diet (before or after diagnosis) and the risk of breast cancer recurrence.

“Superfoods”

“Superfood” is a marketing term used to describe foods that are apparently beneficial for preventing or treating a range of health conditions. It is not based on scientific evidence.

Foods promoted as superfoods include:

• Blueberries
• Raspberries
• Green tea
• Broccoli

There is no evidence that any single food can reduce the risk of breast cancer developing or coming back.

Some people who have had breast cancer consider following a special diet. They include:

• The Bristol Whole Life Approach to healthy eating
• Dairy-free diets
• Macrobiotic diets

These diets often encourage eating or avoiding certain types of food.

There’s no conclusive evidence that special cancer diets like these reduce the risk of breast cancer recurrence.

Special diets are often very restricting, expensive and can sometimes lead to a lack of nutrients. This may result in other conditions such as anaemia (too few red blood cells in the body), or bone conditions such as osteopenia or osteoporosis.

If you’re thinking about changing your diet or want to find out more about different diets, you may find it helpful to talk to your treatment team or a dietitian.

Studies have shown drinking alcohol increases the risk of getting breast cancer. It’s less clear if drinking alcohol affects the outlook (prognosis) of breast cancer.

NICE (National Institute for Health and Care Excellence) recommends that people who’ve had breast cancer limit their alcohol intake to below 5 units a week.

You can find out how many units are in your drinks by using an online unit calculator. As a general guide:

• Half a pint of average-strength (4%) beer = 1 unit
• A 175ml glass of wine (12.5%) = 2 units
• A single 25ml measure of spirits (40%) = 1 unit

Learn more about calculating alcohol units on the NHS website.

There is emerging evidence that smoking may affect the risk of breast cancer recurrence but further research is needed to find out more.

Smoking causes a range of health conditions. If you want to stop smoking there are programmes to help. Speak to your pharmacist, GP or practice nurse for advice.

Physical activity may reduce the risk of recurrence but further research is needed to find out more.

Regular physical activity can help improve your long-term health, and has been shown to reduce the risk of health conditions such as heart attacks, strokes and some cancers.