Change your diet and influence your outcome

The predicted increase in the global cancer burden over the next 20 years is so huge that we are not going to be able to "treat our way out of the problem", despite the huge investment being pumped into improving treatments worldwide, a major cancer conference at Trinity College Dublin (TCD) will hear this week.

While the development of new and better treatments is valuable, there is a need for a better balance between investment in improving treatments, and in the prevention and early detection of disease to deal with the huge cancer burden coming down the line, according to Dr Christopher P Wild, director of the International Agency for Research on Cancer based in Lyon, France.

Wild is one of the keynote speakers at TCD's ninth International Cancer Conference, which starts tomorrow. The Irish Cancer Society and TCD have also teamed up to hold Ireland's first Cancer Week, which runs until Sunday.

The focus of the week is “living well with cancer”, and the aim is to highlight the increasing rates of cancer survivorship and the number of people who are living well with, and beyond, cancer. More than 60 per cent of people in Ireland survive for five years or longer after a cancer diagnosis and go on to live a normal and healthy life.

Wild says there were just over 14 million new cases of cancer worldwide in 2012 and this is predicted to jump to 22 million in 2030. In Ireland, the number of cancer cases is predicted to increase by about 50 per cent in that time.

“This is a huge increase in total numbers in less than 20 years with the largest increases in the less-developed regions of the world,” says Wild. “The increase is predominantly driven by ageing populations as well as population growth. People are living longer – life expectancy is improving but chronic diseases like cancer are increasing.”

Layered on top of the demographic drivers, changes in underlying risk factors such as smoking and obesity could see the incidence of new cases of cancer rise even higher, Wild adds.

“The best estimate at the moment is that if we implement the knowledge we have about causes of cancer such as smoking, excess sun exposure, excess alcohol consumption, weight control, chronic infection and environmental contamination, something like 50 per cent of cancers can be prevented.

However, we still do not understand the causes of quite a lot of cancers and we need to put more effort into understanding these causes and associated risk factors.”

Better understanding

Wild says the exciting advances being made in cancer genetics research in terms of gaining a better understanding of the changes occurring in cancer cells at a molecular level could not only benefit the development of better treatments, but help to prevent and identify disease earlier. This would be particularly helpful in cancers of the pancreas, brain and kidney, where little is known about their causes.

“It is now possible to look at all the molecular changes you see in a cancer, the alterations that are taking place in the genes, and this information is being used to try to develop treatments to target specific changes. We may be able to work backwards and use this vast increase in knowledge that has not yet been exploited to understand more about the cause of the disease,” says Wild.

“For example, the toxin aflatoxin, which occurs in the diet in many parts of the world, leaves a fingerprint on DNA reflecting the patient’s original exposure. In the past, we could only look at one exposure at a time; now we can look at all the alterations in a cancer across the whole genome so there is a chance to see novel patterns of change that we can try to link back to a specific cause in environment or lifestyle.”

Wild says such detailed information would also provide a greater understanding of which precancerous cells will develop into cancer and which will not, avoiding the need to take such a cautious approach with cancers of the breast and prostate, for instance, and to over-treat patients.

Prevention principles The same principles that apply to preventing cancer in the first place apply to preventing it

recurring and would prevent much chronic disease if they were followed more widely, says Richelle Flanagan, dietitian and interim chief executive of the Irish Nutrition and Dietetic Institute and a member of the Healthy Ireland Council.

She will address the Irish Cancer Society’s national conference for cancer survivorship at the Aviva Stadium this weekend on the topic of diet and cancer prevention.

She points to the huge body of international evidence on the effect of diet and lifestyle factors in reducing cancer occurrence. “One of my main messages is that one-third of most cancers can be prevented by factors that we can control through healthy diet, exercise and maintaining a healthy weight. We need to focus on the things we can control.”

She adds: “People who survive cancer can sometimes be overzealous in terms of controlling their diet because they are naturally very anxious to do anything they can to stop the cancer from coming back or, if they have active cancer, to stop it from spreading.”

However, Flanagan says people do not have to resort to rigid diets but can follow the simple guidelines outlined in the panel on this page and make some healthy dietary changes. See cancer.ie

Eat well to stay well: Healthy eating tips

Be as lean as possible without being underweight. Aim for a body mass index (BMI) of 18.5 -25. More than 61 per cent of the Irish population are overweight (BMI over 25) or obese (BMI over 30).

Avoid sugary drinks and limit your consumption of foods from the top shelf of the food pyramid.

Eat a greater variety of fruit and vegetables. Eat plenty of greens and try to have as much colour on your plate as possible.

Eat wholegrains and pulses. Wholegrains contain vital vitamins and minerals including calcium, iron and B vitamins and are full of fibre, keeping you fuller for longer. Pulses such as chickpeas, butter beans and lentils are a good non-meat source of protein and are also high in fibre, vitamins and minerals.

Eat less than 18 ounces of red meat a week but do not cut this valuable source of energy from your diet without replacing it with other sources of iron such as chicken, fish and pulses.

The advice is not to drink at all if you are serious about preventing cancer. If you do drink, you should keep strictly within the guidelines of fewer than 11 units of alcohol for women and 17 units for men a week. One unit equals 100ml of wine, although the typical glass of wine is probably about 250ml.

Limit your consumption of salty, processed and packaged foods. Swap that popular Irish staple, ham, for cooked chicken breast, egg or tinned fish. The less processed food in your shopping basket, the less salt, nitrates and preservatives you are putting into your body.

Do not use supplements without first having a discussion with your consultant. The World Cancer Research Fund says the evidence is not strong enough in favour of using supplements to prevent cancer and, in some cases, certain supplements may accelerate cancer growth.