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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

								
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