Age, lifestyle, diet and reducing your risk

The exact reason why a person has developed cancer is not usually known. But we do know some of the things that cause, or influence, our risk of developing cancer. We call these things risk factors.

You can reduce your risk of getting cancer by making positive lifestyle choices. Not smoking, eating a healthy diet and keeping physically active are some of the ways you can do this.

But there are some risk factors you can’t control. Age is a major risk factor for cancer. 63% of people who get cancer (more than 3 out of 5) are over the age of 65.

Making changes to your lifestyle doesn’t guarantee that you won’t develop cancer. Cancer develops because of many different factors, many of which we cannot control.

This makes checking your body and taking part in cancer screening programmes really important for everyone. Your GP can give you more information about national cancer screening programmes and advice about lowering your risk of cancer.

What is the risk of getting cancer?

Most of the time, we don’t know exactly what causes any particular cancer, but we do know some of the risk factors for cancer. Having a particular risk factor doesn’t mean that you will definitely get cancer.

Some risk factors are very likely to cause cancer, whereas others will only slightly increase the risk of getting it. Usually cancer is the result of a combination of several risk factors.

Having a particular risk factor for cancer doesn’t mean that you will definitely get cancer – just as not having it doesn’t mean that you won’t.

Smoking is a good example of this. If you smoke, it isn’t certain that you will get lung cancer – just as if you don’t smoke, it’s not certain that you won’t. But smoking will greatly increase your risk of getting lung cancer. About 9 out of 10 people who develop lung cancer are smokers.

For most people, increasing age is the biggest risk factor for developing cancer. In general, older people (those over 65) are far more likely to develop cancer than younger people (those under 50).

Cancer is very common. Most of us have relatives who have had cancer. Some people worry that a history of cancer in their family greatly increases their risk of developing it. But, in fact, fewer than 1 in 10 cases (5–10%) are associated with a strong family history of cancer.

How diet can help reduce your risk of cancer

Macmillan Specialist Dietician Helen Kennedy explains how a healthy diet can reduce your risk of cancer and help if you're having treatment.

About our cancer information videos

How diet can help reduce your risk of cancer

Macmillan Specialist Dietician Helen Kennedy explains how a healthy diet can reduce your risk of cancer and help if you're having treatment.

About our cancer information videos


One of the biggest risk factors is increasing age.

Cancer can occur at any age but the risk of developing a cancer increases as we get older. More than three out of five people who get cancer (63%) are over the age of 65, and more than a third (36%) are over 75.


We know that many cancers could be prevented by lifestyle changes. Up to 40% of cancers in the UK could be prevented by lifestyle changes.

For example, it’s estimated that 57% of bowel cancers in men and 52% in women could be prevented by changes in lifestyle.

Making these changes doesn’t guarantee that you won’t get cancer, but they will make it less likely and will improve your health generally.


If you smoke, giving up is the healthiest decision you can make.

Smoking is the single biggest avoidable cause of cancer. In the UK about 1 in 5 cancers (19%) and more than 1 in 4 cancer deaths (about 29%) are caused by smoking. It increases the risk of many cancers including cancers of the mouth, throat, lung, bladder, kidney, pancreas, bowel, stomach and cervix.

Breathing other people’s smoke (passive smoking) also increases your risk of developing cancer.

Help is available if you want to give up smoking. Ask your GP for advice, or contact your national stop smoking service.

Smokefree (England)

Tel 0800 022 4332

(Mon-Fri, 9am-8pm, Sat-Sun, 11am-4pm)

Smokeline (Scotland)

Tel 0800 84 84 84

(Mon-Sun, 8am-10pm)

Stop Smoking Wales (Wales)

Tel 0800 085 2219

(Mon-Fri, 9am-5pm)

Smokers’ Helpline (Northern Ireland)

Tel 0808 812 8008

(Mon-Fri, 4pm-8pm)

Keep to a healthy weight

The latest figures for the UK estimate that more than half of women (50%) and about 2/3 (66%) of men are overweight.

Being overweight increases the risk of several cancers including cancers of the pancreas, bowel, womb (uterus), and kidney as well as breast cancer after the menopause.

If you’re overweight getting back to a healthy weight will help reduce your risk of cancer.

Your GP can advise you on the ideal weight for your height. The best way to lose weight is through a combination of eating a balanced diet and being more physically active.

Eat a healthy diet

A healthy diet can reduce cancer risk, particularly the risk of developing bowel cancer.

To reduce your cancer risk, eat plenty of fibre and at least five portions of fruit and vegetables a day.

Limit your intake of red meat and avoid processed meat. Processed meats are meats that have had preservatives added or that have been preserved by salting, curing or smoking. They include sausages, ham and burgers.

Limit how much alcohol you drink

Drinking alcohol, especially drinking more than the recommended limits, increases cancer risk. About 4 in 100 cancers in the UK (4%) are linked to alcohol.

Alcohol especially increases the risk of cancers of the mouth, throat and gullet (oesophagus). It is also linked to cancers of the bowel, liver and breast. In general the more you drink the more your risk increases.

The European Code Against Cancer recommends that, to reduce cancer risk, men should drink no more than two units of alcohol a day and women no more than one unit a day.

A unit is half a pint of ordinary strength beer, lager or cider, one small glass (125ml) of wine or a single measure (25ml) of spirits.

Keep physically active

Many studies have found that regular physical activity can reduce the risk of cancer. Lack of physical activity increases the risk of bowel cancer, womb cancer and post-menopausal breast cancer. It may also increase the risk of other cancers, such as lung cancer and prostate cancer.

Being physically active doesn’t necessarily mean going to the gym - regular walking, cycling or swimming can be enough.

Try to do at least 2½ hours of moderate intensity physical activity a week. This could be made up of 30 minutes of activity each day for five days. You could even break it up further into 10 minutes of activity, three times a day.

During moderate-intensity activity, you’re still able to talk, but your breathing is quicker and deeper. Your body is warming up, your face may have a healthy glow and your heart is beating faster than normal but not racing.

If you’re not used to exercise, your GP can advise you on getting started.

Take care in the sun

Spending some time outdoors in the sun helps you stay healthy, but it’s also important to protect your skin from burning as this can increase your risk of skin cancers.

Our bodies use the UVB rays in sunlight to make vitamin D, which is important for bone health and reduces the risk of many illnesses, including cancer. 

Most people can get enough exposure to UVB rays by going outside regularly, without sunscreen on, for a few minutes during the middle of the day. The amount of sun exposure you need depends on your hair and skin type. But it’s important not to stay out long enough to let your skin redden or burn.

If you are going to be out in the sun for longer than a few minutes, use a sun cream that protects against both UVA and UVB rays, with a sun protection factor (SPF) of at least 15.

You should wear loose, cotton clothes that cover your body, as well as a hat. Take extra care with children. Avoid using a sun bed or sunlamp. If it’s important for you to look tanned, use fake tanning lotions or sprays.

Have safe sex

Viruses play a role in the development of some types of cancer. Generally, these viruses are sexually transmitted, but some of them can also be transmitted through blood (for example, if drug users share a needle).

Human papilloma virus (HPV) plays a role in many cases of cervical cancer, and it also increases the risk of developing head and neck cancer, anal cancer and cancers of the vulva or penis.

Hepatitis B and C can increase the risk of liver cancer, and the HIV (Aids) virus can increase the risk of developing lymphoma and sarcoma, although this is rare.

Practising safer sex by using condoms or other barrier methods of contraception and not sharing needles can help protect you from contracting these viruses.

Know your body

If you know your body and what is normal for you, it will help you to be aware of any changes.

Sometimes people, particularly as they get older, think a change in their body isn’t worth bothering their doctor about. But, if you notice a change in how you feel or how your body works and you’re not sure why it’s happened it’s better to be safe and get it checked out.

The European Code Against Cancer recommends that you should go to see your doctor if you have:

  • a lump anywhere on your body
  • a sore or ulcer that doesn’t heal within a few weeks
  • a mole that changes shape, size or colour or bleeds
  • a cough or hoarseness that lasts for more than three weeks
  • shortness of breath
  • loss of appetite, ongoing indigestion or difficulty swallowing
  • a change in bowel habit that lasts for more than two weeks
  • blood in urine, bowel motions, spit or vomit or abnormal bleeding from your vagina
  • unexplained weight loss or tiredness
  • unexplained ache or pain that last for more than four weeks

Most of the time these changes aren’t due to cancer but, if you do develop cancer, finding it early can make a big difference, so get them checked out.

It’s important to see your GP if you have an unexplained or ongoing change in your body.

Cancer screening

Screening tests aim to detect cancer early, when treatment is most effective.

In the UK, there are screening programmes for bowel cancer, breast cancer and cervical cancer. If you’re registered with a GP, you should automatically be invited to screening when you reach the age each screening programme starts.

Finding cancer early can make a big difference to the success of treatment.

There’s more information about the screening programmes on these websites: (England) (Scotland) (Wales) (Northern Ireland)

If you are still worried

A common reaction to serious illness in the family, or to bereavement, is to feel more vulnerable to the same disease. If you can’t stop worrying, you may find it helpful to speak to a counsellor. You can ask your GP for details of a local counselling service, or call our cancer support specialists on 0808 808 00 00.

The mental health charity MIND has published a leaflet called How to Stop Worrying. You can order a copy from or by calling 0845 766 0163.

Back to Potential causes of cancer

Low immunity

People with low immunity are more likely to develop some types of cancer.

Viruses and bacteria

You can’t catch cancer from someone else. But some viruses may increase your risk of developing cancer.

Human papilloma virus (HPV)

Human papilloma virus (or HPV) is a common infection. Some types of HPV can increase the risk of developing cancer.

HPV vaccines

There are two vaccines currently available across the UK to prevent human papilloma virus (HPV).