Cancer: diet and physical activity's impact

Cancer: diet and physical activity's impact

Facts

• Cancer accounts for 7.1 million deaths annually (12.5% of the global total).
• Dietary factors account for about 30% of all cancers in Western Countries and approximately up to 20% in developing countries;
• diet is second only to tobacco as a preventable cause.
• Approximately 20 million people suffer from cancer; a figure projected to rise to 30 million within 20 years.
• The number of new cases annually is estimated to rise from 10 million to 15 million by 2020.
• More than half of all cancer cases occur in developing countries.

Cancer is becoming an increasingly important factor in the global burden of disease. The estimated number of new cases annually is expected to rise from 10 million in 2000 to 15 million by 2020.

Some 60% of these cases will occur in the less developed parts of the world. More than 7 million people now die each year from cancer. Yet with the existing knowledge, at least one-third of cancer cases that occur annually throughout the world could be prevented.

While tobacco use is the single largest causative factor -accounting for about 30% of all cancer deaths in developed countries and an increasing number in the developing world – dietary modification and regular physical activity are significant elements in cancer prevention and control.

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Overweight and obesity are both serious risk factors for cancer.

Diets high in fruit and vegetables may reduce the risk for various types of cancer,

while high levels of preserved and/or red meat consumption are associated with increased cancer risk.

What is cancer?

Cancer is used generically for more than 100 different diseases, including malignant tumours of different sites, such as breast, cervix, prostate, stomach, colon/rectum, lung and, mouth.

Other examples of cancer are leukaemias, sarcomas, Hodgkin´s disease and non-Hodgkin´s lymphomas.

The disease arises principally as a consequence of individual exposure to carcinogenic agents in what individuals inhale, eat and drink, or are exposed to in their personal or work environment.

Personal habits, such as tobacco use, dietary and physical activity patterns - as well as occupational and environmental conditions - rather than genetic factors, play the major roles in the development of cancer.

Extent of the problem

Many of the chronic disease risks, and the diseases themselves, overlap.

In developed countries, cancer is the second-biggest cause of death after cardiovascular disease (CVD), and epidemiological evidence points to this trend emerging in the less developed world.

This particularly true in countries of "transition" or middle income countries, such as in South America and Asia. Already more than half of all cancer cases occur in developing countries.

There are approximately 20 million people living with cancer at the moment; by 2020 there will be an estimated 30 million. And the impact is far greater than the number of cases alone would suggest. Regardless of prognosis, the initial diagnosis is often perceived by patients as life-threatening, with over one-third of sufferers experiencing clinical anxiety and depression. Cancer can also be profoundly distressing as well as economically disruptive to patients’ families. The clinical care of cancer patients is a costly element in public health budgets.

Diet and physical activity’s impact

Dietary factors are estimated to account for approximately 30% of cancers in western countries, making diet second only to tobacco as a preventable cause of cancer. This proportion is thought to be about 20% in developing countries and is projected to grow.

As developing countries become urbanised, patterns of cancer, particularly those most strongly associated with diet and physical activity, tend to shift towards the patterns of economically developed countries.

 

Cancer rates also change as populations move between countries and adopt different dietary patterns.

 

The relative importance of cancers as a cause of death is increasing.

The incidence of lung cancer and cancers of the colon and rectum, breast and prostate, generally increases in parallel with economic development, as stomach cancer declines.

 

Cancer is also strongly associated with social and economic status.

Cancer risk factors are highest in groups with the least education. In addition, patients in the lower socioeconomic classes have consistently poorer survival rates than those in higher strata.

 

In recent years, substantial evidence has pointed to the link from overweight and obesity, to many types of cancer such as oesophagus, colorectum, breast, endometrium and kidney.

The composition of the diet is also important since fruit and vegetables may have a protective effect by decreasing the risk for some cancer types such as oral, oesophageal, gastric and colorectal cancer.

 

Regular physical activity has also been seen to have a protective effect in reducing the risk of breast and colorectal cancer.

 

High intake of preserved meat or red meat might be associated with increased risk of colorectal cancer.

 

Another aspect of diet clearly related to cancer risk is the high consumption of alcoholic beverages, which convincingly increases the risk of the oral cavity, pharynx, larynx, oesophagus, liver and breast cancers.

What can be done?

The wealth of knowledge that already exists about cancer risk factors provides obvious and ample scope for action to reduce the cancer burden of all countries.

After tobacco, overweight and obesity seems to be the most important avoidable cause of cancer.

Given that poor nutrition, physical inactivity, obesity, tobacco and alcohol, are risk factors common to other chronic diseases, such as CVD, type 2 diabetes, and respiratory diseases, conducting a cancer prevention programme within the context of an integrated chronic disease prevention programme would be an effective national strategy.

Dietary factors that convincingly increase risk are:

• Overweight and obesity,
• Excess alcohol consumption (more than 2 units a day)
• Some forms of salting and fermenting fish
• Very hot (thermally) salty drinks and food
• Aflatoxins (fungal contaminants sometimes found on foods such as grains, peanuts, tree nuts, and cottonseed meal)

EVIDENCE	DECREASED RISK  적으면 위험	INCREASED RISK  많으면 위험
Convincing	Physical activity (colon, breast)	Overweight and obesity (oesophagus, colorectum, breast, endometrium, kidney)
Probable	Fruit and vegetables (oral cavity, stomach, colorectum).	Preserved meat (colorectum) oesophagus. Salt-preserved foods and salt (stomach). Very hot (thermally) drinks & food (oral cavity, pharynx, oesophagus
Possible/ insufficient	Fibre, soya, fish, n-3 fatty acids, carotenoids, vitamins B2, B6, folate B2, B6, folate, B12, C,D, E, calcium, zinc, selenium,non-nutrient plant constituents, (eg allium, lignans, compounds, flavnoids, isoflavones)	Animal fats, heterocyclic amines, polycyclic aromatic hydrocarbons, nitrosamines

 http://www.who.int/en/

gsfs_cancer.pdf

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Healthy diets and regular, adequate physical activity are major factors in the promotion and maintenance of good health throughout the entire life course.

Unhealthy diets and physical inactivity are two of the main risk factors for raised blood pressure, raised blood glucose, abnormal blood lipids, overweight/obesity, and for the major chronic diseases such as cardiovascular diseases, cancer, and diabetes.

• Overall, 2.7 million deaths are attributable to low fruit and vegetable intake.
• Overall, 1.9 million deaths are attributable to physical inactivity.=

gsfs_cancer.pdf

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