The Manual: Diet and prostate cancer

Newspapers and the internet are overflowing with stories about how different foods can protect against or cure cancer. Our Specialist Nurses give you the facts and answer common questions about links between food and prostate cancer.

Food is a massive part of most people's lives and enjoying what we eat can make a big difference to how we feel. A healthy, balanced diet is good for everyone. We don't know as much as we'd like about the effect of food on prostate cancer, but there are some foods which might make a difference. Extreme diets don't have clear evidence to back them up, so there's no need to exclude things completely or rely too much on one food. Balance is best. You can find out more in our fact sheet Diet, physical activity and prostate cancer.

Why are there so many mixed messages about diet and prostate cancer?

Partly it's because we don't know enough about the effects of what we eat. It is a hard area to do good quality research on, as we explain below. But there are also messages - online, in the media, down the pub - which give conflicting advice about what men should and shouldn't eat.

As frustrating as it is, the most reliable information about diet and prostate cancer is often not the seemingly simple message you might read in a headline.

So why don't we know more about food and prostate cancer?

Although we know food might have some effect, it's not easy to find out exactly what. We all eat lots of different foods, so it's difficult to separate the effects of one from another. Our diet also tends to vary over time.

On top of this, it's hard to separate the influence of food from other things which might affect cancer. For example, lifestyle treatments you're taking and your genetics.

Creating research trials which can take account of all these things is a challenge. But there is research happening and we are learning more all the time.   

Can my diet stop me getting prostate cancer?

A healthy diet - along with an active lifestyle - could play a part in reducing the risk. Men who are a healthy weight might be less likely to get aggressive or advanced prostate cancer. A healthy diet could also help protect against other cancers, heart disease and diabetes. 

And there's research that suggests certain foods might all help to prevent prostate cancer:

• soy foods and other pulses
• green tea
• tomatoes
• natural sources of the mineral selenium (like Brazil nuts and seafood rather than supplements)
• cruciferous veg (like broccoli, cauliflower and cabbage)
• pomegranate juice
• oily fish (like sardines or salmon). 

Cutting down on processed meat, burnt meat and red meat might be helpful too. But the research doesn't suggest that everyone needs to follow a strict diet that removes whole food groups (such as dairy, protein or starchy carbohydrates).

The strength of evidence for all of these different foods varies. Find out more on our Healthy living pages.

Is diet a cure for prostate cancer?

What you eat can't cure it, but it might make a difference. Research shows that for some men it could slow down the growth of prostate cancer. In particular, the foods mentioned above (Can my diet stop me getting prostate cancer?) might also have an impact on cancer that's already there.  

A healthy, balanced diet can also help you feel as fit and well as possible, keep your weight down, and reduce the risk of other health problems.

Lots of men say they feel more in control when they think about what they eat. You might notice benefits by making some changes. But food is a big part of life, so make sure that whatever changes you make, you still enjoy your food.

Can diet help me manage any treatment side effects?

Diet could play a part in managing some of the treatment side effects. For example, if you have problems with your bowels or with urinating, getting the right amount of fibre and water might make a difference. And erection difficulties can sometimes be improved by keeping to a healthy weight as well.

Find out more from your healthcare team and our Healthy living pages.

Are supplements or herbal medicines the solution?

There isn't much evidence that supplements (such as vitamins or minerals) can reduce the risk of getting cancer, or slow down its growth.

Some men like to take herbal medicines to help manage their prostate cancer or the side effects of treatment. But there is also very little evidence that they are effective.  Not all herbal medicines in the UK are licensed, and the quality can vary. It's hard to know what you're getting - especially if they are bought over the internet.

In fact, some herbal medicines and high doses of certain supplements could be bad for your health and interfere with treatments. Let your doctor know if you're thinking of taking a supplement or herbal medicine.

Sometimes, your doctor, nurse or dietitian might recommend a particular supplement. For example, calcium and vitamin D supplements for bone health, if you're on hormone therapy. But you'll usually be able to get the nutrients you need from a healthy, balanced diet.

Should I eat a special diet?

Unless your doctor, nurse or dietitian suggests you make specific changes, a healthy, balanced diet which involves some of the foods listed above is probably the best thing to follow.

Some diets recommend cutting out a whole food group, such as dairy foods. It's true that some research suggests cutting down on dairy if you eat very large amounts, but the evidence doesn't support cutting them out completely. It can be harder to get the right nutrients if you stop eating a certain type of food altogether.

Find out more before you make any major changes. Talk to your healthcare team and read about the evidence for different foods in our fact sheet. And you can find more infromation on diet and leading a healthy lifestyle in our Healthy living pages.