How to prevent cancer

Vegetables and FruitsSix years ago the World Cancer Research Fund and the American Institute of Cancer Research published the mother of all literature reviews on food, nutrition, physical activity and the prevention of cancer (1).

A panel of 21 world-renowned scientists reviewed the research evidence and drew conclusions based on in-depth analysis of over 7,000 scientific studies published on cancer prevention over the last 50 years.

As a result of this review they made a number of recommendations:

  1. Be as lean as possible without becoming underweight
  2. Be physically active for at least 30 minutes per day
  3. Limit consumption of energy-dense foods and avoid sugary drinks
  4. Eat more of a variety of vegetables, fruit, whole grains and pulses
  5. Limit consumption of red meats and avoid processed meats
  6. If consumed at all, limit alcoholic drinks to 2 per day for men and 1 per day for women
  7. Limit consumption of salty foods and foods processed with salt
  8. Don’t use supplements to protect against cancer
  9. Do not smoke or chew tobacco
  10. Breastfeed exclusively for up to 6 months and then add other liquids and foods
  11. After treatment, cancer survivors should follow the recommendations for cancer prevention.

Since then further research has been conducted to see whether compliance with these recommendations has any effect on the risk of death from cancer and other diseases.

The findings were published in the American Journal of Clinical Nutrition on 3 April 2013 (2).

Researchers investigated nearly 380,000 people in nine European countries over 12 years and examined their diet and lifestyle to see how closely they complied with seven of World Cancer Research Fund/American Institute for Cancer Research’s (WCRF/AICR) Recommendations for Cancer Prevention.

They found that the risk of dying from several diseases, including cancer, circulatory diseases and respiratory diseases, can be reduced by 34 per cent if these recommendations are followed.

Those who most closely followed the WCRF/AICR Recommendations had a 50 per cent reduced chance of dying from respiratory disease, 44 per cent for circulatory disease and 20 per cent for cancer, when compared to the group with the lowest level of compliance.

The Recommendations with the greatest impact on reducing the risk of death from disease were being as lean as possible without becoming underweight (22 per cent reduced risk) and eating mostly plant foods (21 per cent).

In terms of cancer, limiting alcohol consumption and following the plant food recommendation reduced the risk of dying from the disease by the greatest margin, at 21 per cent and 17 per cent respectively.

The study is the first to examine breastfeeding as part of a combination of lifestyle changes to see what effect it has on risk of dying.  It showed that women who breastfed for at least six months had a reduced risk of death from cancer (ten per cent) and circulatory disease (17 per cent).

Although the WRCF/AICR recommendations were focused on the prevention of cancer, this study shows that adherence to these recommendations also reduces the risk of other diseases.

The bottom line is that maintaining a lean body by consuming a predominantly plant-based diet, being physically active and minimising intake of alcohol is most likely to protect you from cancer.  Looking after yourself in this way will also help to reduce your risk of circulatory and respiratory diseases.

If you would like to learn about how to introduce more plant-based dishes into your diet why not sign up for free email updates with information, recipes and news and visit my website at http://www.cookingforhealth.biz.

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References

1. World Cancer Research Fund/American Institute for Cancer Research. Food, Nutrition, Physical Activity, and the Prevention of Cancer: a Global Perspective. Washington DC : AICR, 2007.

2. Adherence to the World Cancer Research Fund/American Institute for Cancer Research guidelines and risk of death in Europe: results from the European Prospective Investigation into Nutrition and Cancer cohort study. Anne-Claire Vergnaud et al. 3 April 2013, American Journal of Clinical Nutrition.

Fish oils and psychosis

Recent evidence published in Archives of General Psychiatry suggests that fish oil supplementation may reduce the risk of transition to psychotic illness in people at very high risk of these disorders.

The use of antipsychotic medication for the prevention of psychotic disorders is controversial. Long-chain omega-3 polyunsaturated fatty acids may be beneficial in a range of psychiatric conditions, including schizophrenia. Given that omega-3 polyunsaturated fatty acids are generally beneficial to health and without clinically relevant adverse effects, their preventive use in psychosis is of considerable interest.

Previous studies have found low levels of omega-3 and omega-6 polyunsaturated fatty acids in people with schizophrenia, and some scientists have suggested that problems with fatty acid metabolism could play a role in the development of the disorder. However, studies looking at the effects of omega-3 polyunsaturated fatty acid supplementation in people with schizophrenia have so far been inconclusive. Types of omega-3 fatty acids are found in oily fish, certain vegetable oils and in fish oil capsules.

A randomized, double-blind, placebo-controlled trial was conducted between 2004 and 2007 in the psychosis detection unit of a large public hospital in Vienna, Austria.

The aim was to determine whether omega-3 polyunsaturated fatty acids reduce the rate of progression to first-episode psychotic disorder in adolescents and young adults aged 13 to 25 years with subthreshold psychosis.

Eighty-one individuals at ultra-high risk of psychotic disorder participated in the trial. These participants had at least one of the following risk factors for psychosis:

• low levels of psychotic symptoms (delusions, hallucinations, suspiciousness, or conceptual disorganisation measured on a standard scale),

• transient psychosis, i.e. lasted less than a week and resolved without antipsychotic medication, or

• having either a schizotypal personality disorder or a first-degree relative (such as a mother, father, sister or brother) who had psychosis, plus the participant experienced a significant reduction in ability to function in the last year.

A 12-week intervention period of 1.2 g per day omega-3 polyunsaturated fatty acids or placebo was followed by a 40-week monitoring period; the total study period was 12 months.

Researchers monitored how much of their supplements the participants took by monitoring the number of pills they had left and by taking blood samples. The placebo pill contained coconut oil (which does not contain omega-3 polyunsaturated fatty acids) and an equivalent amount of vitamin E to the fish oil capsules, plus 1% fish oil to make the taste of the capsules similar.

Seventy-six of 81 participants (93.8%) completed the intervention. By the end of the study (12 months), 2 of 41 individuals (4.9%) in the omega-3 group and 11 of 40 (27.5%) in the placebo group had transitioned to psychotic disorder (P = .007). The difference between the groups in the cumulative risk of progression to full-threshold psychosis was 22.6% (95% confidence interval, 4.8-40.4).

Omega-3 polyunsaturated fatty acids also significantly reduced positive symptoms (P = .01), negative symptoms (P = .02), and general symptoms (P = .01) and improved functioning (P = .002) compared with placebo.

The incidence of adverse effects did not differ between the treatment groups.

The researchers concluded that:

a 12-week intervention with omega-3 significantly reduced the transition rate to psychosis and led to significant symptomatic and functional improvements during the entire follow-up period (12 months)

This small study does seem to suggest that, at least in the short term, fish oil supplementation could prevent young people at high risk from progressing to psychotic illness. However, while the study was robust in its design it was too short to say whether the illnesses were prevented completely or just delayed.

Psychotic illnesses are serious conditions and if fish oils can be confirmed to prevent or delay their development in susceptible individuals this would be a very important finding. However, it will require larger, long-term studies to know if this is the case.

To learn more about the effects of what we eat on our mental health, why not come along to a Cooking for Health course on “Food and Emotions“, taught by nutrition consultant Dr Jane Philpott.

Preventing cancer through diet and physical activity

A new global policy report estimates that approximately 45 percent of colon cancer cases and 38 percent of breast cancer cases in the US are preventable through diet, physical activity and weight maintenance. The report also sets out recommendations for policies to reduce the global number of cancer cases.

 

policy_report_thumb1The overall message of the report, Policy and Action for Cancer Prevention, published yesterday by the World Cancer Research Fund (WCRF) and the American Institute for Cancer Research (AICR), is that all sections of society need to make public health, and cancer prevention in particular, a higher priority.

 

It includes estimates on the proportion of many different types of cancer that could be prevented through diet, physical activity and weight management. In the UK, akmost 40 per cent of the most common cancers could be prevented. That figure does not include smoking, which alone accounts for about a third of cancers.

 

Percentage of cancers that could be prevented via healthy diet, healthy weight and physical activity

 

US

UK

Brazil

China

Endometrium
(lining of the uterus)

70

56

52

34

Esophagus

69

75

60

44

Mouth, pharynx & larynx

63

67

63

44

Stomach

47

45

41

33

Colon

45

43

37

17

Pancreas

39

41

34

14

Breast

38

42

28

20

Lung

36

33

36

38

Kidney

24

19

13

8

Gallbladder

21

16

10

6

Liver

15

17

6

6

Prostate

11

20

n/a

n/a

These 12 cancers combined

34

39

30

27

 

Different Policy Recommendations For Different Groups

As part of the evidence-based report, thought to be the most comprehensive ever published on the subject, two independent teams of scientists systematically examined the evidence for how policy changes can influence the behaviours that affect cancer risk.  Following this, a panel of 23 world-renowned experts made a total of 48 recommendations, divided between nine different but often overlapping sectors of society – called “actor groups” in the report. These actor groups are: multinational bodies; civil society organizations; government; industry; media; schools; workplaces and institutions; health and other professionals; and people.

 

Among the recommendations:

  • Governments should require widespread walking and cycling routes to encourage physical activity.
  • Industry should give a higher priority for goods and services that encourage people to be active, particularly young people.
  • The food and drinks industry should make public health an explicit priority at all stages of production.
  • Schools should actively encourage physical activity and provide healthy food for children.
  • Schools, workplaces and institutions should not have unhealthy foods available in vending machines.
  • Health professionals should take a lead in giving the public information about public health, including cancer prevention.
  • People should use independent nutrition guides and food labels to make sure the food they buy for their family is healthy.

Professor Sir Michael Marmot, Chair of the WCRF/AICR Panel, said,

When people think of policy reports, they often think they only speak to governments. But the evidence shows that when it comes to cancer prevention, all groups in society have a vital role to play.

Panel member Tim Byers, MD, MPH of the University of Colorado Denver said,

Estimating cancer preventability is a very complex prospect that involves making a number of assumptions. Having said that, the figures in this report are as good an estimate it is possible to achieve about the proportion of cancer cases that could be prevented through healthy diet, regular physical activity and maintaining a healthy weight. On a global level every year, there are millions of cancer cases that could have been prevented. This is why we need to act now before the situation gets even worse.

The report also includes preventability estimates for the UK (which, like the US, is considered a high-income country), as well as for China and Brazil, which respectively represent low and middle-income countries.

 

Policy Report Represents the Next Step

The new WCRF/AICR Policy Report is a companion document to the expert report Food, Nutrition, Physical Activity and the Prevention of Cancer: A Global Perspective, which was published by AICR and WCRF in November of 2007. That expert report evaluated the scientific evidence from over 7000 studies and came away with 10 recommendations for lowering cancer risk.

The 2007 expert report identified the specific choices that people can make to protect themselves against cancer, but actually making those healthy choices remains difficult for many people,” said policy report panel member Shiriki Kumanyika, PhD, MPH, of the University of Pennsylvania School of Medicine. The policy report takes the next step – it identifies opportunities for us as a society to make those choices easier.

More information, including video interviews with panel members, Q and A documents, and other background materials, is available at: http://www.aicr.org/policy

Learn how to cook delicious food to boost your immune system and protect yourself and your family from cancer and other chronic diseases at Cooking for Health courses held throughout the year in Somerset, UK.