What do we know

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What do we know

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Lifestyle & Cancer
What do we know?
A GUIDE FOR HEALTH PROFESSIONALS

Introduction
In Australia, one in three men and one in four women will increased cancer risk was particularly strong.3 Together
be directly affected by cancer before the age of 75. The they are estimated to account for approximately 20-30%
number of new cancer cases diagnosed each year is rising, of cases of some common cancers such as breast (post-
with 106,000 cases being diagnosed in 2006 compared to menopausal), colorectal, endometrium, kidney and
around 89,000 in 2001.1 Recently, cancer has overtaken oesophagus (adenocarcinoma).4
heart disease as the greatest burden (in terms of death and
disability) of disease and injury in Australia.2 About 39,000 In 2003, the World Health Organisation (WHO) Report on
people die from cancer in Australia each year, with the most Diet, Nutrition and the Prevention of Chronic Diseases
commonly diagnosed cancers being prostate, colorectal, confirmed that diet is second only to tobacco as a
breast, melanoma and lung cancer.1 theoretically preventable cause of cancer.5 Dietary factors
are estimated to account for approximately 30% of cancers
Evidence is strengthening that body weight, physical activity in industrialised countries.
and dietary factors influence the risk of some cancers.
Alcohol is a risk factor for cancer of the mouth, pharynx,
,
In 2007 the World Cancer Research Fund (WCRF) found larynx, oesophagus, breast, colon and liver.3,6
that the evidence that body weight and physical inactivity

Key Messages
• Cancer is a major cause of illness and death in Australia.
• Diet is second only to tobacco as a theoretically preventable cause of cancer.
• There is convincing evidence that being overweight or obese increases the risk of developing some of the most
common cancers.
• There is convincing evidence that undertaking regular physical activity reduces the risk of developing some of the
most common cancers.
• There is convincing evidence that alcohol consumption increases the risk of developing some cancers, including
breast cancer.
• It is likely that eating more vegetables and fruit will reduce the risk of developing some cancers.
• The recommendations for reducing cancer risk are consistent with guidelines for heart disease and diabetes
prevention, as well as for general good health.

Regular physical activity, maintaining a healthy weight
and good nutrition can help prevent cancer.
Obesity Physical Activity
Obesity is regarded as a major risk factor for cancer, as Evidence suggests that 30-60 minutes per day of moderate
well as many other chronic diseases such as cardiovascular to vigorous physical activity may be beneficial to reduce the
disease and type 2 diabetes. risk of cancer.4

Obesity is linked to an increased risk of cancer of the There is convincing evidence that a lack of physical activity
endometrium, kidney, breast (only in post-menopausal is a risk factor for colon cancer. Cancer of the breast,
women), colon, oesophagus and pancreas.3-5 Other cancers endometrium, lung, pancreas and prostate have also been
also thought to be associated with body weight include linked with physical inactivity.3,4
cancer of the gallbladder and liver.3
Colon cancer is reduced by 40% among the most active
In Australia, obesity accounts for about 4% of the total individuals, compared with the least active.4 Studies for
cancer burden and causes nearly 8% of the total burden breast cancer have shown a 20-40% reduction in risk, in
of disease and injury.2 In 2005, over 20,000 Australians both pre- and post-menopausal women.4
had cancer as a result of being obese.7 Table 1 describes
the proportion of cancer attributable to overweight and The International Agency for Research on Cancer (IARC)
obesity factors. estimated that 14% of all cases of colon cancer and 11%
of post-menopausal breast cancers are attributable to
physical inactivity.4 Recent Australian data suggests that
physical inactivity accounts for 5.6% of the total cancer
burden and 6.6% of the total burden of disease.2

Table 1: Proportion of cancers attributable to overweight and obesity
Cancer Type Proportion of incidence Aspects of the association between overweight or obesity and cancer
attributable to
overweight or obesity
Endometrial cancer 39% Women with a BMI of >25 have a two- to three-fold increase in risk
Limited evidence suggests risk is similar in pre- and post-menopausal women
Risk is greater with upper body obesity
Oesophageal 37% Strong association between being overweight and adenocarcinomas of the lower
adenocarcinoma oesophagus and the gastric cardia, with a two-fold increase in risk in individuals with
a BMI of >25
Association seems greater in men than women
Renal (kidney) cancer 25% Individuals with a BMI of >30 have a two- to three-fold increase in risk compared to
those below 25
The effect is similar in men and women
Gallbladder cancer 24% Limited evidence available but there is a suggestion of almost a two-fold risk,
especially in women
Colon cancer 11% Association seems greater in men than women
Risk not dependent on whether person has been overweight in early adulthood or
later in life
Post-menopausal 9% Increase in risk of 30% in women with a BMI >28 compared to those with a
breast cancer BMI of <21

Source: International Agency for Research on Cancer (2002),4 Boyle et al. (2003),8 Bergstrom et al. (2001).9
Alcohol
Alcohol is one dietary factor where there is conflict between Two different methods of estimating the amount of cancer
risks and benefits for different chronic diseases. Whilst caused by alcohol have been reported in Australia as shown
alcohol is a risk factor for cancer, there is mixed evidence in Table 2:
in relation to cardiovascular disease. A high intake of
alcohol is associated with higher blood pressure and death • One method compared unsafe levels of alcohol
from stroke; however, a small amount of alcohol taken consumption with moderate or no consumption,
regularly may be protective against coronary heart disease.10 recognising the benefits of moderate alcohol
Therefore to minimise cancer risk, alcohol consumption is consumption for heart disease.12 This is consistent
undesirable; whereas to prevent heart disease, low alcohol with public health policy on alcohol consumption, which
consumption may be beneficial. is not to achieve zero alcohol intake in the population
but to use a harm minimisation approach.
There is no evidence from human studies that any alcohol
consumption provides protection against cancer. Alcohol is • In contrast, the other approach estimated the full
a significant risk factor for some cancers, particularly those attributable effect of alcohol consumption, including
of the mouth, pharynx, larynx, oesophagus, breast, liver, the apparent benefits of moderate consumption.13
colon and rectum.3,5,6 The rationale for this method was to take into account
the fact that alcohol even at low levels of consumption
Smoking and alcohol together have a synergistic effect on can raise the risk of some conditions, such as cancer.
upper gastrointestinal and aerodigestive cancer risk. The
combined effects of smoking and alcohol greatly exceed Australian data suggests that alcohol intake accounts for
the risk from either one of these factors alone.11 3.1% of the total cancer burden and a net effect (ie harmful
and beneficial effects) of 2.3% of the total burden of disease.2

Table 2: Cancer site and percentage attributable to alcohol
English et al. (1995)12 Ridolfo and Stevenson (2001)13
Males Females Males Females
Breast - 3% - 12%
Larynx 21% 13% 51% 46%
Liver 18% 12% 39% 35%
Oesophagus 14% 6% 46% 40%
Oropharynx 21% 8% 40% 31%

Vegetables and Fruit
Vegetables and fruit are a low energy density source of In 2003, IARC concluded that 5-12% of cancers could
nutrients (vitamins, minerals, phytochemicals and fibre) and be attributed to low vegetable and fruit consumption.14
can help people manage their weight. They also probably Australian data suggests that inadequate vegetable and fruit
protect against some types of cancer. consumption accounts for 2% of the total cancer burden
and 2.1% of the total burden of disease.2
The evidence supporting this particularly relates to cancers
of the digestive tract, such as cancer of the mouth, pharynx, Fruit and vegetables are best eaten whole, rather than
larynx, oesophagus, stomach, colon and rectum.3,5,14 There as a juice or individual nutrients in a supplement form, as
is also evidence that fruit may protect against lung cancer.3,14 some studies suggest that antioxidant supplements are not
Table 3 summarises the findings from several major reviews protective against cancer and may increase the risk of some
on vegetable and fruit consumption and the reduced risk of cancers and overall mortality.3,15
certain cancers.
Table 3: Conclusions regarding the cancer protective effect of vegetables and fruit

Organisation review Moderate evidence – Probable Lower evidence – Possible
WCRF/AICR 20073
Mouth (vegetables and fruit) Nasopharynx (vegetables and fruit)
Pharynx (vegetables and fruit) Colon and rectum (vegetables and fruit)
Larynx (vegetables and fruit) Pancreas (fruit)
Oesophagus (vegetables and fruit) Liver (fruit)
Stomach (vegetables and fruit) Lung (vegetables)
Lung (fruit) Ovary (vegetables)
Endometrium (vegetables)

IARC14 2003 Oesophagus (vegetables and fruit) Mouth (vegetables and fruit)
Stomach (fruit) Pharynx (vegetables and fruit)
Lung (fruit) Colon and rectum (fruit)
Colon and rectum (vegetables) Larynx (vegetables and fruit)
Kidney (vegetables and fruit)
Bladder (fruit)
Stomach (vegetables)
Lung (vegetables)
Ovary (vegetables)

WHO/FAO5 2003 Oral cavity (vegetables and fruit)
Oesophagus (vegetables and fruit)
Stomach (vegetables and fruit)
Colon and rectum (vegetables and fruit)

Other Dietary Factors
Wholegrain cereals and fibre in the prevention of colorectal cancer.3 There is some
evidence suggesting that a high consumption of milk and
A diet high in fibre may reduce the risk of colorectal cancer.
dairy foods, as well as a diet high in calcium, might increase
The WCRF recently found that foods containing dietary fibre
the risk of prostate cancer.3
probably reduce the risk of colorectal cancer and might
reduce oesophageal cancer risk.3 In addition, foods high in However, overall the proven health benefits of dairy foods
dietary fibre also play a role as a low energy density source outweigh the potential cancer risk. Calcium is an important
of nutrients and may help with weight maintenance. nutrient for bone and dental health, with dairy foods being
the major source of dietary calcium in Australia. Dairy foods
Meat are also a good source of protein, vitamin A, vitamin B12,
Research suggests that high red meat consumption and in magnesium, phosphorus, potassium, riboflavin and zinc.
particular processed meat consumption is associated with
a modest increase in colorectal cancer risk.3,16 Although Fat
inconclusive, some research suggests that the consumption Although there is no convincing evidence of a direct link
of burnt or charred meat may increase cancer risk.3 between fat intake and increased cancer risk, there is
suggestive evidence that a high fat diet may increase the
However, red meat is an important contributor to dietary
risk of breast cancer (in post-menopausal women) and lung
iron, zinc, vitamin B12 and protein in the Australian diet.
cancer, and diets high in animal fat may increase the risk of
Therefore the consumption of moderate amounts of
colorectal cancer.3 As high fat consumption can contribute
unprocessed lean red meat, together with plenty of fruit,
to obesity, and obesity is a strong risk factor for several
vegetables and wholegrain cereals is advised.
cancers,3-5 it is advisable to limit high-fat foods.
Fish and omega-3 fatty acids Salt
Experimental studies have shown that omega-3 fatty
Diets high in salt and salted foods have been linked to a
acids may play a role in cancer prevention.17 Some
probable increased risk of stomach cancer.3 Countries
epidemiological studies show higher intakes of fish and/
where salting of foods is a common preserving method
or omega-3 fatty acids may reduce the risk of developing
due to a lack of refrigeration for storage have an increased
colorectal, breast and prostate cancer but this research can
incidence of stomach cancer.18 However, the diets of those
only be described as suggestive not conclusive.
in industrialised countries include many processed foods
that contribute substantial amounts of salt to the diet.3
Dairy foods and calcium Therefore it is advisable to limit salt-preserved, salted or
In terms of cancer risk, dairy foods have shown both salty foods, including processed foods with added salt.
protective and harmful effects. Milk has a protective role
Summary
Table 4: Summary of strength of evidence on lifestyle factors and the risk of developing cancer
Evidence Decreased risk Increased risk
Convincing • Physical activity (colorectal) • Overweight and obesity (oesophagus, pancreas,
Evidence considered strong and colorectal, post-menopausal breast, endometrium, kidney)
consistent across study types. Studies • Alcohol (mouth, pharynx, larynx, oesophagus,
are of good quality, show a dose- colorectal - men, pre- and post-menopausal breast)
response association and robust evidence
• Red meat (colorectal)
from laboratory studies supporting the
association in humans is present. • Processed meat (colorectal)
Probable • Physical activity • Overweight and obesity (gallbladder)
Evidence did not meet the more rigorous (post-menopausal breast, • Alcohol (liver, colorectal - women)
.
criteria for a grade of “convincing” endometrium)
• Salt (stomach)
Studies are of good quality and robust • Fruit (mouth, pharynx, larynx,
evidence from laboratory studies oesophagus, lung, stomach)
supporting the association in humans
• Vegetables (mouth, pharynx,
is present.
larynx, oesophagus, stomach)
• Allium vegetables* (stomach)
• Dietary fibre (colorectal)
• Milk (colorectal)
Limited – suggestive • Physical activity (lung, pancreas, • Overweight and obesity (liver)
Evidence limited in consistency or pre-menopausal breast) • Red meat (oesophagus, lung, pancreas, endometrium)
quality, however data suggests the • Fruit (nasopharynx, pancreas, • Processed meat (oesophagus, lung, stomach, prostate)
presence of a relationship and it is liver, colorectal)
assumed that further study will clarify • Smoked foods (stomach)
• Vegetables (nasopharynx, lung,
the relationship. A dose-response effect • Grilled or BBQ animal foods (stomach)
colorectal, ovary, endometrium)
is not necessary, however evidence • Milk and dairy products (prostate)
from laboratory studies supporting the • Legumes (stomach, prostate)
• Cheese (colorectal)
association is required. • Dietary fibre (oesophagus)
• Total fat (lung, post-menopausal breast)
• Fish (colorectal)
• Animal fat (colorectal)
• Milk (bladder)
Substantial effect on risk unlikely • Alcohol (kidney)
Evidence from more than one kind of
study required and studies are of good
quality. However no demonstrable
dose-response and no strong and
plausible link to human cancer from
laboratory or human studies is present.

Source: The World Cancer Research Fund (2007).3 *Allium vegetables include chives, garlic, leek, onion and shallots.

The Cancer Council NSW Recommendations
The Cancer Council NSW recommends that we all:
• Maintain a healthy body weight within a BMI range of 18.5 to 25
• Be physically active for at least 30 minutes, preferably more, on most days of the week, including some
vigorous activity
• Enjoy a balanced diet that includes at least two serves of fruit and five serves of vegetables each day
• Eat a variety of wholegrain, wholemeal and high-fibre foods such as cereals, breads, rice and pasta
• Have moderate amounts of fresh, lean red meat and limit or avoid processed meat
• Limit or avoid drinking alcohol
• Choose foods low in salt, sugar and fat, particularly saturated fat.
Reference List
1. Australian Institute of Health and Welfare. Cancer in Australia: 12. English D, Holman CDJ, Milne E, Winter MG, Hulse GK,
an overview, 2006. Canberra, AIHW. 2007 . Codde JP et al. The quantification of drug caused morbidity
and mortality in Australia. Commonwealth Department of
2. Begg S, Vos T, Barker B, Stevenson C, Stanley L, Lopez A. Human Services and Health. AGPS. 1995.
The Burden of Disease and Injury in Australia 2003. Canberra,
AIHW. 2007 . 13. Ridolfo B, Stevenson C. The quantification of drug-caused
mortality and morbidity in Australia, 1998. Canberra, AIHW.
3. The World Cancer Research Fund and American Institute for 2001.
Cancer Research. Food, nutrition, physical activity and the
prevention of cancer: a global perspective. Washington DC: 14. International Agency for Research on Cancer. Fruit and
AICR. 2007 . Vegetables. Volume 8. Lyon: IARC. 2003.

4. International Agency for Research on Cancer. Weight control 15. Bjelakovic G, Nikolova D, Gluud LL, Simonetti RG, Gluud C.
and physical activity. Volume 6. Lyon: IARC. 2002. Mortality in randomized trials of antioxidant supplements for
primary and secondary prevention: systematic review and
5. World Health Organisation. Diet, nutrition and the prevention meta-analysis. JAMA. 2007; 297(8): 842-857 .
of chronic diseases. Geneva, WHO. 2003.
16. Larsson SC, Wolk A. Meat consumption and risk of colorectal
6. International Agency for Research on Cancer. Carcinogenicity cancer: a meta-analysis of prospective studies. Int J Cancer.
of alcoholic beverages. Volume 96. Lyon: IARC. 2007. 2006; 119(11): 2657-2664.
7. Access Economics. The Economic Costs of Obesity. Canberra, 17. ,
Rose DP Connolly JM. Omega-3 fatty acids as cancer
Diabetes Australia. 2006. chemopreventive agents. Pharmacol Ther. 1999; 83(3):
217-244.
8. , , ,
Boyle P Autier P Bartelink H, Baselga J, Boffetta P Burn J et
al. European code against cancer and scientific justification: 18. Roder DM. The epidemiology of gastric cancer. Gastric
third version (2003). Ann Oncol. 2003; 14(7): 973-1005. Cancer. 2002; 5 Suppl 1: 5-11.
9. ,
Bergstrom A, Pisani P Tenet V, Wolk A, Adami HO. Overweight
as an avoidable cause of cancer in Europe. Int J Cancer. 2001;
91(3): 421-430.

10. National Health and Medical Research Council. Australian
Alcohol Guidelines: health risks and benefits. Canberra: AGPS.
2001.

11. Doll R, Forman D, La Vecchia C, Woutersen R. Alcoholic
beverages and cancers of the digestive tract and larynx. In:
Health Issue Related to Alcohol Consumption. Macdonald L
(editor). Oxford: Blackwell Science Ltd. 1999. pp. 351-393.

Further Information
The Cancer Council NSW
ABN 51 116 463 846
www.cancercouncil.com.au
CAN480 Date:11/07

The Cancer Council Helpline 13 11 20

The Cancer Council Australia (2007). National Cancer Prevention Policy 2007-09.
NSW: The Cancer Council Australia. Available on www.cancer.org.au