Cancer and your diet

We can lower our risk of developing certain diseases by eating a healthy balanced diet that is low in fat (especially saturated fat), salt and sugar, with plenty of fruit and vegetables and starchy foods, choosing wholegrain versions when we can. Here we focus on how you can lower your risk of developing cancer.

Understanding cancer

Cancer is a disease that affects the cells that make up our body. It happens when the genetic material (more commonly known as DNA) in our cells gets damaged causing them to grow out of control. It’s hard to say exactly why we get cancer, because there is no single cause – often it may be a combination of different things.

What happens?

To replace old or damaged cells in our body, new cells are made - this is called cell division. When this process goes wrong, cancer develops because the DNA within the cell becomes damaged in some way. Damaged or faulty cells can divide out of control, producing abnormal cancerous cells, often forming a lump or tumour. Sometimes the tumour keeps growing and damages parts of the body near to it. Sometimes cancerous cells can spread to other parts of the body and start growing there too.

Causes

All cancers begin in the same way. Cells become damaged, perhaps because they have been exposed to cancer causing agents (called carcinogens), such as chemicals from tobacco smoke, alcohol or prolonged exposure to strong sunlight.

Our bodies have natural defences that can often repair the damage, but if we’re repeatedly exposed to high levels of carcinogens, for example by smoking, our bodies may not be able to cope.

Damage to our cells can take place at any time in our lives, but what we eat and how active we are may affect our risk of developing cancer.

Some cancers are also linked to a person’s family history, but these are rare.

Who’s at risk and why?

Our risk of getting cancer is not simply down to our family history or bad luck. Very few cancers are completely inherited. Our diet and lifestyle can also affect our chance of getting the disease.

Our chances also increase as we get older. Two out of every three new cancers diagnosed in the UK are in people over 65 years old. But because cancer can be caused by a gradual build up of damaged cells over many years, it’s important to have a healthy diet and lifestyle when you‘re younger to help lower your risk of cancer in later life.

How does diet & lifestyle affect the risk of cancer?

We can help to lower our risk by eating a healthy, balanced diet and keeping to a healthy weight, as well as being physically active and not drinking alcohol or smoking.

How a healthy diet and lifestyle can help

Stories about different foods and diets linked to preventing cancer are often in the news. This is because there’s lots of research going on about diet and cancer. But it isn’t easy to study the link between diet and cancer because there are so many different factors involved and cancer can take years to develop. Most of the reliable research shows a link between a reduced risk of cancer and eating certain groups of foods such as fruit and vegetables, rather than specific foods, vitamins or other nutrients.

Eating a healthy, balanced diet

We can help ourselves to lower the risk of cancer by eating a healthy, balanced diet, with plenty of starchy foods, fruit and vegetables, and some foods that are good sources of protein such as meat, fish, eggs, beans, nuts, and dairy foods. Try to only eat small amounts of foods that are high in fat (especially saturated fat), salt and sugar.

Here are some tips to help you plan healthier meals:

• Use starchy foods – ideally wholegrain varieties like wholemeal bread, pasta, brown rice, beans, lentils, potatoes, chapatti - as the basis of your meals.



• Once you’ve decided on your starchy food you could then add lots of vegetables.
• Add a moderate amount of lean meat, eggs, low-fat dairy products, fish or alternatives such as beans or pulses.

Eat lots of fruit and vegetables

Eating plenty of fruit and vegetables may make you less at risk of developing some types of cancer. So try to eat at least five portions of a variety of fruit and vegetables every day.

Fruit and vegetables contain a complex mix of compounds and we don’t know exactly what is responsible for the anti-cancer effect. It’s probably the combined effect of all the compounds in them. That’s why it’s important to eat a variety of fruit and vegetables, rather than take vitamin supplements, or other chemicals extracted from fruit and vegetables.


Different fruit and vegetables contain different mixtures of compounds. If you eat lots of different types of fruit and vegetables, you will get the benefit of a wider range of these compounds.

What about beta carotene?

By eating lots of fruit and vegetables, you will be getting plenty of beta-carotene in your diet. The body converts this into vitamin A, which may help protect against cancer. But don't take beta-carotene supplements to try to help protect against cancer because high doses may in fact cause cancer. For most people, a healthy balanced diet gives us all the vitamins and minerals we need.

Go easy on the alcohol

Minimising how much alcohol we drink, or not drinking at all, is best to prevent cancer. The less we drink the better. It doesn’t matter whether we choose wine, beer or spirits – what’s important is how much alcohol we drink in total. So remember, drink alcohol in moderation, if at all.

Try to be a healthy weight and get active

Apart from giving up smoking, keeping to a healthy weight is probably the most valuable thing we can do to lessen our risk. People who are overweight are more likely to develop some types of cancer. If we have too much weight particularly around our middle – if we are ‘apple shaped’ – this in itself can increase our chances of developing some cancers.

It’s also important to be active. This isn’t just because it can help us to control our weight. Some research shows that being active lowers our overall risk of cancer so the more physically active we are the better.

The most common cancers

The most common types of cancer in the UK are cancer of the breast, lung, bowel (colon and rectum) and prostate. These four types of cancer account for more than half of all new cases and almost half of all cancer deaths. What you eat may affect the risk of developing these types of cancer.

Breast cancer in women

Breast cancer is the most common cancer in women in the UK. It is a hormonal cancer and is influenced by our lifetime exposure to oestrogen, a female hormone. Oestrogen can stimulate cells to divide, so it could encourage cancers to grow.

Women who have had fewer menstrual periods, for example, because they started their menstrual periods late or started their menopause early, are at lesser risk. Pregnancy and breastfeeding also make women less at risk. Generally the more children a woman has, the earlier she has them, and the longer she breastfeeds, the lower the risk.

Weight and activity

Women who are overweight have a higher level of oestrogen in their body. Women who are obese after the menopause are more likely to develop cancer than women who are a healthy weight. Even being moderately overweight increases the risk.

Putting on weight during adult life and carrying fat around the middle (being ‘apple shaped’), may also increase the risk of developing breast cancer.

Women who are physically active are less likely to develop breast cancer. The more active we are throughout our lives, the better.

Drinking less alcohol also lowers the risk of breast cancer. The more alcohol a woman drinks, the greater her risk of breast cancer.

What you can do

• Try to stay a healthy weight for your height.



• Try to get some activity into every day.



• If you drink alcohol, drink it in moderation.



• If you have a baby, strongly consider breastfeeding. The longer you breastfeed, the greater the benefit for you and your baby.

Breast cancer can also develop in men, although this is extremely rare.

Lung cancer

One in five cancer deaths in the UK are from lung cancer and 80% of lung cancer deaths are due to smoking. Smoking also causes other cancers including cancer of the mouth, gullet [oesophagus], pancreas, kidney, stomach, cervix and nose.

Because smoking has such a strong influence on our risk of developing lung cancer, giving up is by far the best way to reduce your risk. It’s been suggested that eating lots of fruit and vegetables or taking certain supplements could lower the risk of lung cancer, but this has not been proven.

Dietary supplements have not shown to protect against lung cancer. If you do decide to take supplements, consult your GP as taking too much can be harmful.

People who are at increased risk of lung cancer, such as smokers, are advised not to take any beta-carotene supplements.

Bowel cancer

Bowel cancer (cancer of the colon or rectum) is the third most common cancer in the UK and is strongly affected by diet and lifestyle.

Being overweight and carrying fat around our middle (being ‘apple shaped’) makes us much more likely to develop bowel cancer.

Being physically active throughout our life lessens our risk of developing bowel cancer. This is because being active helps our gut and bowel to work better, which can help lower the risk of bowel cancer.

Red meat

Some evidence suggests that eating lots of red meat such as beef or pork and processed meat, such as ham, bacon and salami, could increase the risk of developing bowel cancer. Eating chicken or fish doesn’t seem to increase the risk so you could choose fish, chicken or beans instead of processed red meat.

However, it’s important to remember that red meat is a good source of iron, so if you generally only eat a small amount, it may not be a good idea to cut down. You could always swap some of the red meat you’re eating for alternative iron-rich foods such as pulses, green vegetables or fortified breakfast cereals.

More about iron

As part of a review on iron and health, the Scientific Advisory Committee on Nutrition (SACN) is looking at evidence that links eating red and processed meat with bowel cancer. SACN is an independent committee of scientific experts that advises the government on food-related issues. In the next few months this SACN report will be made public so anyone can comment on it. The Agency will review its own guidance on eating red and processed meat once it has looked at the SACN’s advice.

Constipation can also increase the risk of developing bowel cancer, so eating lots of fruit and vegetables and other fibre-rich foods such as wholegrain starchy foods may lower the risk, because the dietary fibre in these may prevent constipation.

What you can do

• Keep to a healthy weight.
• Keep physically active throughout your life.


• Eat at least five portions of a variety of fruit and vegetables each day.
• Eat lots of wholegrain starchy foods.
• Eat less red meat and processed meat.

Prostate cancer

Prostate cancer is now the most common cancer in men in the UK. Cases have been rising, but this may be due to better diagnosis.

There is no clear evidence of a link between diet and prostate cancer. However, eating a healthy diet can help to prevent other types of cancer and conditions such as heart disease.