mesothelioma

If you are over 40, have your risk factors assessed by your GP. Photograph: IMANE/Image Point FR/Corbis

What's the best way to protect ourselves from ill health as we get older? While there's nothing we can do about some factors - such as the genes we inherit from our parents - there are steps we can take to minimise the risk of a painful and disabled old age. We take a look at five age-related ailments and diseases and explain how to cut the chances of them developing. As you will see, many of the same preventative strategies - not smoking, eating and drinking healthily, exercising and watching your weight - offer protection against a range of serious health conditions.

Cancer

Research now shows that half of all cancers could be prevented by lifestyle changes.

Stop smoking: It not only causes lung cancer but also increases the risk of mouth, stomach and cervical cancer. Pipes, cigars, roll-ups and low-tar cigarettes are no healthier as alternatives. Second-hand smoke is a risk factor, too: avoid living in a smoky atmosphere.

Drink less alcohol: It's a risk factor for seven cancers and a recent study showed than even a daily glass of wine increases a woman's chance of breast cancer. The less you drink, the lower the risk: a maximum two units a day for women and three to four units for men is recommended by Cancer Research UK. A unit is half a standard (175ml) glass of wine, a half pint of standard beer or one measure of spirits.

Eat a healthy diet: It should include five daily portions of fruit and vegetables (thought to cut the risk of several types of cancer), plenty of wholegrain bread and cereals (cuts the risk of bowel cancer), and only a small amount of saturated fat (linked to breast cancer). Eat less red and processed meat (a risk factor for bowel and possibly stomach cancer) and cut down on preserved foods high in salt (they could increase stomach cancer risk). Steer clear of vitamin supplements: recent research has shown they don't protect against disease.

Maintain a healthy weight: It can reduce cancer risk. You can find out if your weight is healthy for your height using the body mass index (BMI): multiply your height by itself (in metres) and then divide by your weight (in kilograms). Anything between 18 and 25 is healthy.

Exercise regularly: It's thought to reduce the risk of bowel and breast cancer. Just 30 minutes of moderate activity a day, at least five days a week, is enough. Any exercise will do, as long as it makes you slightly warm and out of breath. Split it up into 10-minute sessions if it suits you.

Take care in the sun to reduce the risk of skin cancer. Stay in the shade between 11 and 3, or cover up; in the sun, use sunglasses with standard UV protection, a wide-brimmed hat and a broad spectrum sunscreen (which protects against both UVA and UVB rays) with an SPF of at least 15; apply liberally and often. Avoid sunbeds - they're no safer.

Take part in the national screening programmes for breast and bowel cancer (the last is still being rolled out). Screening may detect pre-cancerous changes as well as early-stage cancer. What age you'll be offered it depends on where you live in the UK, but when you're eligible you should receive an invitation.

Talk to your GP if you're worried about a family history of cancer. You may qualify for special screening and referral to a genetics centre.

If you're a woman, bear in mind that HRT increases the risk of breast cancer, as does the contraceptive pill (although the risk returns to normal ten years after you stop using the pill). Having children, especially early on in life, reduces the risk of breast cancer, as does breastfeeding; the longer you breastfeed the greater the protection.