Users Online: 800

Home Print this page Email this page Small font sizeDefault font sizeIncrease font size

Home | About us | Editorial board | Search | Ahead of print | Current issue | Archives | Submit article | Instructions | Subscribe | Contacts | Login 
     

   Table of Contents      
EDITORIAL
Year : 2014  |  Volume : 4  |  Issue : 1  |  Page : 1-3

Life-style modification and cancer prevention: Another weapon in war against cancer


Department of Medicine, Sultan Qaboos University Hospital, P.O. Box 35, Muscat 123, Oman

Date of Web Publication8-Jan-2014

Correspondence Address:
Ikram A Burney
Department of Medicine, Sultan Qaboos University Hospital, P.O. Box 35, Muscat 123
Oman
Login to access the Email id

Source of Support: None, Conflict of Interest: None


DOI: 10.4103/2231-0738.124608

Rights and Permissions

How to cite this article:
Burney IA, Al-Moundhri MS. Life-style modification and cancer prevention: Another weapon in war against cancer. Int J Nutr Pharmacol Neurol Dis 2014;4:1-3

How to cite this URL:
Burney IA, Al-Moundhri MS. Life-style modification and cancer prevention: Another weapon in war against cancer. Int J Nutr Pharmacol Neurol Dis [serial online] 2014 [cited 2019 Jun 17];4:1-3. Available from: http://www.ijnpnd.com/text.asp?2014/4/1/1/124608

According to the Globocan, 12.7 million people were diagnosed to have cancer in the year 2008 and 7.6 million died of cancer with a huge geographical variation. [1] Out of the total cases, 5.56 million (44%) were diagnosed in the developed countries, whereas, 7.1 million (56%) were diagnosed in the less developed regions (developing countries). However, out of the total number of cancer-related deaths, 2.7 million (35.5%) occurred in the developed countries, whereas, 4.82 million (63.2%) occurred in the developing countries. Clearly, the burden of cancer is higher in the resource-poor, developing countries. It has been estimated that by 2030, the figures would increase to 22.2 million cases and 17 million deaths, with significantly more deaths occurring in resource-strapped developing countries. The increase in the number of cases is likely to occur as a result of rapid social and economic transition and secondary to hormonal and dietary factors.

In their seminal paper, Doll and Peto examined the causes of cancer and a significant proportion were found to be attributable to life-style factors. [2] Today, almost 30% of all cancers are attributable to cigarette smoking, 20% to infections and about 20% to dietary factors and hence are potentially preventable. Furthermore, according to the estimates of World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR), about 20% of cancer deaths occur secondary to viral infections, such as the hepatitis B virus, hepatitis C virus and Human papilloma virus. [3] In addition, 30% of the cancer deaths could be attributed to lack of exercise and obesity, eating unhealthy food and tobacco and alcohol use. [3]

The burden of cancer can be tackled at several stages. Most emphasis is laid on early detection through screening and treatment with ever expanding armamentarium. However, a pragmatic, cost-effective, yet under-exploited weapon on the war against cancer is prevention. Preventive strategies include vaccination, chemoprevention, the use of natural and herbal products and prophylactic surgeries. Prevention of cancer through life-style modifications remains under-explored. Life-style modification includes eating prudently, regular physical exercise and avoiding risk factors, like cigarette smoking. It has been suggested that as many as one-third of cancers in "high-income" countries and one-fourth of all cancers in the "low-income" countries could be prevented through eating in a health conscientious manner, being physically active and maintaining a healthy weight. [3]

The major initiatives in this regard have been the European Prospective Investigation into Cancer and Nutrition (EPIC) study, the vitamins and life-style (VITAL) study and recommendations of WCRF/AICR. The EPIC is an ongoing prospective cohort study, initiated in 1992 in 10 European countries. [4] Dietary assessment is mainly carried out through a self-administered semi-quantitative food frequency questionnaire and information on a wide range of life-style factors and anthropometric measurements are collected together with blood samples. More than half-a-million men and women have been prospectively enrolled; mostly aged between 39 and 69 years and the investigator publish the updated results from time to time. In addition, the VITAL study recruited more than 77,000 volunteers, aged 50-76 years in the western Washington state between 2000 and 2002. [5] The participants completed a detailed questionnaire on supplement use, diet and risk factors for cancers and more than two-third provided deoxyribonucleic acid. The cohort has been prospectively followed-up for incident cancers. On the other hand, the WCRF/AICR released a set of recommendations in 2007, on diet, physical activity and weight management for cancer prevention on the basis of available evidence. [3] These include: Being as lean as is possible, regular physical activity, avoiding foods that promote weight gain, avoiding red and processed meat, judicious use of plant foods, restricting the intake of alcohol and for women, breast-feeding.

Obesity, physical inactivity and consumption of high calorie diet have all been associated with cancers of the colon, post-menopausal breast cancer, endometrium, esophagus and the pancreas. Obesity alone is implicated in the causation of 3% of all cancers in men and 9% in women. [6] Obesity and physical inactivity, together with the consumption of foods rich in saturated fatty acids produce a state of chronic inflammation, producing pro-inflammatory cytokines. A diet high in fat and refined sugars, together with physical inactivity and obesity leads to insulin resistance and hyperinsulinemia, leading to low levels of sex-hormone binding globulins and insulin-like growth factor binding proteins, leading to an increase in free insulin-like growth factor and sex hormones, such as estradiol and free testosterone. The increase in insulin-like growth factor and sex hormones lead to cell proliferation and inhibition of apoptosis. [7] Furthermore, preparation of red meat results in the production of either heterocyclic amines or polycyclic aromatic hydrocarbons, leading to increase in the nitrate and nitrite content in the diet, which are also carcinogenic, especially for the mucosa of the gastro-intestinal tract. Obesity, physical inactivity and consumption of high calorie-diets and foods rich in saturated fatty acids are all modifiable risk factors. The WCRF recommends, intense physical activity for 30 min every day, to maintain the body mass index within the normal range or at least to be as lean as is possible, to avoid energy-dense foods and to limit the consumption of red meat to 500 g/week (5 intakes of red meat per week). [3]

On the other hand, plant foods are known to protect against the cancers of the upper gastro-intestinal tract, mouth, larynx, pharynx, esophagus and the stomach. Plant foods are rich in dietary fiber and specific vitamins, such as, carotenoids, folates, which are known to have a high anti-oxidant activity. Specifically, tomatoes, pink grapefruit and watermelon are rich in lycopene; berries, grapes and prunes are rich in anthocyanins; carrots and mangoes are rich in α and β carotene; cantaloupe, peach and orange are a rich source of flavonoids and β-cryptoxanthin; spinach, avocado and turnip are rich in lutein; cabbage, broccoli, brussel sprouts and cauliflower are a rich source of sulforaphanes and indoles; and onion garlic and chives are rich in allyl sulfides. The WCRF recommends consumption of 400 g (five portions) of a variety of non-starchy vegetables and fruits per day. [3]

Dietary supplements do not have a protective role. Studies on fortification of diets or the use of supplements, such as, the β-carotene, vitamin A supplements etc., have been either negative or have actually shown a deleterious effect of supplementation. Similarly, the data on the use of dairy products are conflicting, at best. Therefore, the use of milk and calcium supplements may have a protective role for colorectal cancer, risk of prostate cancer has been shown to increase as a result of generation of free fatty acids, inhibition of proliferation of epithelial cells and possibly an increase in the insulin-like growth factor levels. The large women's health initiative randomized study failed to show an advantage of vitamin D and calcium supplementation on either the incidence or the mortality of invasive cancers. [8] The WCRF recommends against the use of dietary supplements. [3]

Life-style modification is an attractive and in many cases, an achievable target. It has been shown that a higher intake of red meat, fat and refined sugars are associated with a higher risk of recurrence of colon cancer, after treatment with surgery and chemotherapy. The risk was considerably lower in patients who consumed more of fruits, vegetables, poultry and fish. [9] However, the most important question to ask is whether life-style modifications actually lead to a reduction in the incidence of cancer and mortality and to what extent. More recently, the answers are beginning to emerge. The EPIC investigators reported that a greater concordance with the WCRF/AICR recommendations (out of a total of 6 for men and 7 including breast-feeding for women) was significantly associated with a decreased risk of cancer. [10] A 1-point increment was associated with a 5% risk reduction for all cancers, 12% for colorectal cancers and 16% for the stomach cancer. Furthermore, the data from the VITAL study cohort have been reported. [11] Using the Surveillance, Epidemiology and End Results database, 30,797 women aged 50-76 years were identified and the breast cancer risk was found to be reduced by 60% in women who met at least five recommendations, compared with those who met only one. Similarly, in a cohort of 65,322 volunteers, aged 50-76, the incidence of hematologic malignancies, especially the myeloid neoplasms reduced by 34% in cohort of people who carried out regular physical activity and the effect was dose dependent, with a greater reduction in the incidence of neoplasms in the people in highest tertile. [12] The real proof comes from the demonstration of a reduction in mortality from cancer by modifying the life-style. The EPIC investigators assessed 378, 864 participants from the European countries and at a median follow-up of 12.8 years, participants with maximum adherence of the WCRF recommendations had a 34% reduced risk of death compared with those who had least adherence to the recommendations. [13]

In conclusion, an effective, pragmatic, inexpensive, non-invasive and non-toxic weapon has emerged in the war against cancer. Preliminary analyses are very encouraging and the magnitude of benefit equals and in some cases outweighs the benefits achieved by the more intrusive, toxic and expensive weapons in the armamentarium.

 
   References Top

1.Available from: http://globocan.iarc.fr/factsheets/cancers/all.asp. [Last accessed on 2013 Jul 17].  Back to cited text no. 1
    
2.Doll R, Peto R. The causes of cancer: Quantitative estimates of avoidable risks of cancer in the United States today. J Natl Cancer Inst 1981;66:1191-308.  Back to cited text no. 2
[PUBMED]    
3.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.  Back to cited text no. 3
    
4.Gonzalez CA. The European prospective investigation into cancer and nutrition (EPIC). Public Health Nutr 2006;9:124-6.  Back to cited text no. 4
[PUBMED]    
5.White E, Patterson RE, Kristal AR, Thornquist M, King I, Shattuck AL, et al. Vitamins and lifestyle cohort study: Study design and characteristics of supplement users. Am J Epidemiol 2004;159:83-93.  Back to cited text no. 5
[PUBMED]    
6.Renehan AG, Soerjomataram I, Leitzmann MF. Interpreting the epidemiological evidence linking obesity and cancer: A framework for population-attributable risk estimations in Europe. Eur J Cancer 2010;46:2581-92.  Back to cited text no. 6
[PUBMED]    
7.Kantor ED, Lampe JW, Kratz M, White E. Lifestyle factors and inflammation: Associations by body mass index. PLoS One 2013;8:e67833.  Back to cited text no. 7
[PUBMED]    
8.Brunner RL, Wactawski-Wende J, Caan BJ, Cochrane BB, Chlebowski RT, Gass ML, et al. The effect of calcium plus vitamin D on risk for invasive cancer: Results of the Women's Health Initiative (WHI) calcium plus vitamin D randomized clinical trial. Nutr Cancer 2011;63:827-41.  Back to cited text no. 8
[PUBMED]    
9.Meyerhardt JA, Niedzwiecki D, Hollis D, Saltz LB, Hu FB, Mayer RJ, et al. Association of dietary patterns with cancer recurrence and survival in patients with stage III colon cancer. JAMA 2007;298:754-64.  Back to cited text no. 9
[PUBMED]    
10.Romaguera D, Vergnaud AC, Peeters PH, van Gils CH, Chan DS, Ferrari P, et al. Is concordance with World Cancer Research Fund/American Institute for Cancer Research guidelines for cancer prevention related to subsequent risk of cancer? Results from the EPIC study. Am J Clin Nutr 2012;96:150-63.  Back to cited text no. 10
[PUBMED]    
11.Hastert TA, Beresford SA, Patterson RE, Kristal AR, White E. Adherence to WCRF/AICR cancer prevention recommendations and risk of postmenopausal breast cancer. Cancer Epidemiol Biomarkers Prev 2013;22:1498-508.  Back to cited text no. 11
[PUBMED]    
12.Walter RB, Buckley SA, White E. Regular recreational physical activity and risk of hematologic malignancies: Results from the prospective vitamins and lifestyle (VITAL) study. Ann Oncol 2013;24:1370-7.  Back to cited text no. 12
[PUBMED]    
13.Vergnaud AC, Romaguera D, Peeters PH, van Gils CH, Chan DS, Romieu I, et al. 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 study1,4. Am J Clin Nutr 2013;97:1107-20.  Back to cited text no. 13
[PUBMED]    




 

Top
 
 
  Search
 
    Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
    Access Statistics
    Email Alert *
    Add to My List *
* Registration required (free)  

 
  In this article
    References

 Article Access Statistics
    Viewed1621    
    Printed61    
    Emailed0    
    PDF Downloaded127    
    Comments [Add]    

Recommend this journal