Can diet affect breast cancer risk? 

Your diet may influence your risk of developing cancer, including breast cancer. Some foods or food components may be protective, while others may increase your risk. Because the effects of a healthy diet on your breast cancer risk take a long time to show, consistent, long-term healthy eating is crucial.

Eating Habits That May Influence Your Breast Cancer Risk 

1. Fruits and vegetables

A diet high in fruits and vegetables may help reduce the risk of breast cancer.

Eating more non-starchy vegetables and foods rich in carotenoids (natural pigments, typically yellow, orange, and red) (see table 1) may lower the risk of oestrogen receptor-negative (ER-) breast cancer.

Fruits and vegetables provide fibre, antioxidants, and other beneficial plant nutrients that may help protect our cells from damage and support overall health.

Table 2: Examples of vegetables and fruits high in carotenoids or that are non-starchy

How to eat more fruit and vegetables.

Eat a wide variety of fruit and vegetables (including those rich in carotenoids) every day to ensure a good mix of different nutrients – no single fruit or vegetable provides all the nutrients you need to be healthy.

Aim for at least three portions of non-starchy vegetables and two portions of fruit daily (around 400g in total).

Try gentle cooking methods, such as steaming or lightly frying in olive oil at low temperatures, to preserve nutrients and avoid excess fat.

2. Carbohydrates and fibre

Carbohydrates are the body’s main source of energy, and are found in foods such as bread, rice, pasta, fruit, legumes and vegetables. There are two main types: simple (e.g. sugar and glucose) or complex (e.g. starches found in foods like potatoes, wholegrains and pulses) carbohydrates.

The evidence linking total carbohydrates or sugar intake to an increased breast cancer risk is limited ​. Some studies suggest a possible link between added sugar or foods that cause rapid spikes in blood sugar and an increased risk, but results are mixed.

Diets high in added sugar can promote weight gain. Being overweight or obese is a risk factor for breast cancer in men and post-menopausal women.

There is growing evidence that diets high in fibre are associated with a lower risk of breast cancer.

See our fibre and breast cancer key fact sheet for more details.

How to eat the right amount of carbohydrates and fibre. 

Choose complex carbohydrates such as wholegrains, legumes, and vegetables. They provide long-lasting energy, promote fullness, and support a healthy weight. 

Eat around 30g of fibre per day from foods like wholemeal bread and pasta, oats, lentils, beans, and fruit and vegetables.  

Eat less foods with added sugars, commonly found in soft drinks, biscuits, cakes, and sweets. These are high in simple carbohydrates and are high in calories, but little nutrients.

3. Fats

Fats have many essential functions in the body, including supporting hormone production and helping absorb fat-soluble vitamins (A, D, E, and K). The main types of fats found in foods are unsaturated, saturated, and trans fats (see Table 2 below for examples and how they differ from each other). Unsaturated fats are generally beneficial, while saturated and trans fats are best limited.

Studies suggest that eating a high amount of unsaturated fat known as polyunsaturated (see table 2 for more details) may reduce your risk of breast cancer. Eating a high level of trans fats, saturated fats, and dietary cholesterol may increase your risk.

Although eating some fat is part of a healthy diet, it is high in calories. A diet high in fat can lead to weight gain. A well-established risk factor for breast cancer in men and post-menopausal women.

How to eat the right fats. 

Less than 30% of your total calorie intake should come from fats. 

Include foods rich in unsaturated fats (see table 2 below). These are needed to stay healthy and to help maintain normal cholesterol levels. 

Eat less food that is high in saturated fats and avoid trans fats where possible (see table 2 below).

Table 2: Types of fats and where they are found

* Unsaturated fats are usually liquid at room temperature. MUFA’s and PUFA’s differ in their chemical structure

** Saturated fats are typically solid at room temperature

*** Trans fats are made artificially using heat and pressure

4. Red and processed meat

Red meat (such as beef, pork, lamb or goat) is a good source of protein. However, if eaten in high amounts (more than 90g (cooked weight) a day) may increase your breast cancer risk. However, evidence remains mixed and inconclusive.

Processed meat (e.g. ham, sausages, bacon, tinned meats) has been linked to a slightly increased breast cancer risk.

How to eat less red and processed meat. 

Replace red and processed meat with organic poultry, sustainably sourced fish, or non-meat protein such as soybeans, nuts, eggs, tofu, or meat substitute (like mycoprotein – made from fermented fungus).

Limit red meat to no more than 3 portions per week, or roughly 350–500g (12–18oz) of cooked meat per week.

Avoid processed meat or only consume in very small amounts, if any.

5. Ultra Processed Foods (UPFs)

Processed foods are foods that have been altered in some way during preparation. Foods can be grouped based on how much they have been processed. The NOVA classification system places foods into four categories:

Table 3: Classification of foods based on how much they are processed (NOVA classification)

Diets high in UPFs have been linked to several health issues, including weight gain and obesity, These are known risk factors for breast cancer in men and post-menopausal women.

Studies suggest that eating more UPFs may be directly linked to a higher risk of breast cancer. However, further research is needed.

How to eat less processed food. 

Eat less packaged snacks, sugary drinks, and ready meals. 

Avoid food that has a long list of ingredients on the label. This is a sign that the food has been over-processed. 

Choose whole or minimally processed foods, such as fruit, vegetables, wholegrains, legumes, nuts and seeds. 

Try cooking your meals at home using fresh and seasonal ingredients. 

6. Dairy and Calcium

Eating moderate amounts of dairy products (e.g. milk, cottage cheese, yoghurt) may be linked to a reduced risk of breast cancer, possibly because of their calcium content.

Fermented dairy products like yoghurt or kefir contain probiotics (live microorganisms), which can influence the gut microbiota and may be beneficial in helping to reduce breast cancer risk, though more research is needed.

How to eat the right amount of dairy and calcium 

Choose unsweetened (no added sugar) dairy products like (organic) natural yoghurt, cottage cheese, and reduced-fat milk. These are good sources of calcium, protein, iodine, and B vitamins. 

Avoid sweetened yoghurts and flavoured milk drinks, which can be high in added sugar and calories. 

Try fermented dairy products such as yoghurt or kefir to benefit from their probiotic bacterial cultures that support gut health.

7. Soy and soy-based foods

There is growing evidence that eating soy foods in moderation may be associated with a reduced risk of breast cancer.

Soy contains isoflavones, which are naturally occurring plant compounds that have a similar structure to the hormone oestrogen. While there have been concerns that these might promote hormone-sensitive cancers, there is no convincing evidence that eating soy increases your breast cancer risk.

Soy and soy-based foods such as tofu, tempeh, and soy drinks are a good source of unsaturated fats, plant-based protein, B vitamins, iron, calcium, zinc, and other compounds beneficial to your health.

How to add soy to your diet 

Try adding 1-2 portions of minimally processed soy-based foods per day, such as tofu, unsweetened soy yoghurt, soy milk, edamame and tempeh (fermented soybeans). 

Speak to your healthcare professional before taking isoflavone supplements.

8. Micronutrients and supplements

Micronutrients are vitamins and minerals that are essential for your health but are only needed in small amounts.

Studies suggest certain micronutrients (e.g. vitamin D3, folate, and vitamin B6) may have protective effects against breast cancer.   

The evidence on nutritional supplements and breast cancer risk remains limited.

For information on vitamin D supplements, see our vitamin D and breast cancer risk Key Facts Sheet. 

The World Cancer Research Fund recommends meeting nutrient needs through a balanced, varied diet and does not recommend the use of supplements for cancer prevention.

Can specific diets prevent breast cancer? 

There is no single ideal diet for breast cancer prevention; rather, it is more important to consider the overall balance and proportions of different food groups.  

Many diets can support your health and help reduce your risk, including the Mediterranean diet and balanced plant-based diets. These diets typically focus on whole, minimally processed foods, with plenty of fruit, vegetables, and high-fibre foods, while limiting or avoiding red and processed meats.

The information has been written for members of the UK public. If you have been diagnosed with breast cancer, before changing any aspect of your diet, please consult a medical professional. Breast Cancer UK is a breast cancer prevention charity and is unable to offer specific advice about the diagnosis or treatment of breast cancer. If you are worried about any symptoms, please consult your doctor. 

Further reading

For more details and references, please see the Nutrition and Breast Cancer Risk review. 

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Drinking alcohol is a serious risk factor for breast cancer, for more information see our key facts sheet on alcohol and breast cancer risk. 

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