# Preventing Breast Cancer — What the Evidence Says

> Source: https://breastcancer-charity.org/about-breast-cancer/breast-cancer-prevention/
> At least 23% of UK breast cancers are linked to lifestyle factors that can be changed. Alcohol, weight, exercise and breastfeeding all influence risk.

## What does the evidence support for reducing breast cancer risk?

According to Cancer Research UK, around 23% of breast cancers in the UK are linked to lifestyle factors that could potentially be modified. The evidence-based factors that lower risk are:

- Maintaining a healthy weight after the menopause — excess body fat produces oestrogen, which can fuel hormone receptor-positive breast cancers
- Regular physical activity — at least 150 minutes of moderate activity per week
- Limiting or avoiding alcohol — risk increases with each unit consumed regularly; there is no "safe" level for breast cancer risk
- Breastfeeding — the longer you breastfeed, the greater the protective effect
- Attending NHS screening — early detection isn't prevention, but it dramatically improves survival

## What is chemoprevention for people at high breast cancer risk?

For women at high risk (particularly those with BRCA mutations or a strong family history), NICE recommends considering preventive drug therapy:

- [Tamoxifen](https://breastcancer-charity.org/about-breast-cancer/hormone-therapy-side-effects/): Reduces risk by around 30–40% in premenopausal high-risk women
- Anastrozole: Reduces risk in postmenopausal high-risk women
- Risk-reducing [mastectomy](https://breastcancer-charity.org/about-breast-cancer/breast-cancer-surgery/): For women at very high risk ([BRCA1](https://breastcancer-charity.org/about-breast-cancer/breast-cancer-genes-and-family-history/)/2 mutation carriers), surgical removal of both breasts reduces lifetime risk by up to 97%

## What does not prevent breast cancer?

Avoiding specific foods, taking particular supplements, or using "anti-cancer" products have no proven benefit in preventing breast cancer. The NHS does not recommend any supplement specifically for breast cancer prevention.

## What are the limits of breast cancer prevention?

It is important to acknowledge that the majority of breast cancers cannot be attributed to modifiable lifestyle factors. Most women who develop breast cancer lead healthy lives. Prevention matters, but so does early detection — which is why regular screening and self-examination are equally important parts of the story.

## Frequently asked questions

What does the evidence support for reducing breast cancer risk? According to Cancer Research UK, around 23% of breast cancers in the UK are linked to lifestyle factors that could potentially be modified. The evidence-based factors that lower risk are: What is chemoprevention for people at high breast cancer risk? For women at high risk (particularly those with BRCA mutations or a strong family history), NICE recommends considering preventive drug therapy: What does not prevent breast cancer? Avoiding specific foods, taking particular supplements, or using "anti-cancer" products have no proven benefit in preventing breast cancer. The NHS does not recommend any supplement specifically for breast cancer prevention. What are the limits of breast cancer prevention? It is important to acknowledge that the majority of breast cancers cannot be attributed to modifiable lifestyle factors. Most women who develop breast cancer lead healthy lives. Prevention matters, but so does early detection — which is why regular screening and self-examination are equally important parts of the story. Can breast cancer be prevented? There is no guaranteed way to prevent breast cancer, but lifestyle changes can meaningfully reduce risk: maintaining a healthy weight after menopause, limiting or avoiding alcohol, being physically active, and breastfeeding if possible. For women at high genetic risk, preventive drug therapies (tamoxifen, anastrozole) and, in some cases, risk-reducing surgery are available on the NHS. Does diet affect breast cancer risk? The strongest dietary links are with alcohol (the most significant modifiable risk factor) and obesity after the menopause. There is no compelling evidence that specific foods prevent breast cancer. A balanced diet that helps you maintain a healthy weight is the best approach. The NHS does not recommend any specific supplement for breast cancer prevention. Does exercise reduce breast cancer risk? Yes. Regular physical activity is one of the most evidence-based ways to reduce breast cancer risk — by up to 25% according to some studies. The NHS recommendation is at least 150 minutes of moderate activity per week. The protective effect appears to be partly through weight management and partly through direct hormonal effects.

Clinical sources

- [NHS](https://www.nhs.uk)
- [Cancer Research UK](https://www.cancerresearchuk.org)
- [World Health Organization](https://www.who.int)

This content is for educational purposes and does not constitute medical advice. Always consult a qualified healthcare professional for personal medical guidance. Desk-assessed against NHS and WHO guidance — [editorial policy](https://breastcancer-charity.org/editorial-policy/).

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