Most health scientists have been aware for a long time of the links between poor diet, obesity, smoking, alcohol and inactivity has with cancer. However, much of the research fails to reach the public. Here we share several studies from the last few years that provides substantial evidence for the link between diet and cancer.
The Wolfson Institute of Preventive Medicine Study
This major study was carried out by Professor Max Parkin of the Wolfson Institute of Preventive Medicine for Cancer Research UK and published in the British Journal of Cancer. Although the research looked at cancer in the UK, the results are relevant for all countries. The key findings are that 1 in 3 cancer cases can be prevented if people adopt a healthier lifestyle. The full report can be read here: The Fraction of Cancer Attributable to Lifestyle and Environmental Factors in the UK in 2010.
Major Lifestyle and Environment Risk Factors
The study examined the following 14 lifestyle and environmental risk factors (of which diet accounted for 4 of the factors):
- Tobacco – still the biggest problem, accounting for 23% of all cancer cases in men.
- Poor Diet – a diet lacking in fruits and vegetables, too much red and processed meat, too little fiber and too much salt are all risk factors. 9.2% of cancers are attributed to these factors.
- Bodyweight / Obesity – obesity is fast becoming a major problem. 5.5% of all cancers can be avoided if people just lost weight. Women suffer greater risk from obesity than men and it is the second biggest risk factor in women. Obesity is linked with cancers of the uterus, kidney and esophagus. Visceral obesity is especially problematic.
- Alcohol – around 4% of all cancer cases are caused by drinking too much alcohol. Alcohol is linked with cancers of the oral cavity and pharynx, larynx and esophagus.
- Occupation – Poor working conditions causes around 3.7% of cancers. Lung cancer and mesothelioma are the biggest problems.
- Sunlight and sunbeds – 3.5% of all cancers are caused by people laying on sunbeds. 85% of all malignant melanoma cases are attributed to sunbeds.
- Infection – infections cause around 3.1% of all cancers. Human papillomavirus (HPV), Helicobacter pylori, Epstein Barr virus, hepatitis B and C viruses, HIV and human herpes virus are all linked with cancer.
- Radiation – exposure to ionizing radiation is linked to 1.8% of all cancers.
- Deficient physical activity – not exercising is linked with increased risk of breast, colon and uterine cancers – even in people who are of a healthy weight.
- Reproductive factors – 2% of all cancers in women are linked with breastfeeding for less than 6 months (often not at all).
- Exogenous hormones – 1% of all cancers in women are linked to HRT.
Lifestyle, diet and exercise are key to avoiding cancer
Although some risk factors are harder to control, such as occupational, exposure to radiation during medical treatment, the remaining risk factors can all be avoided.
There is a good reason why regular exercise and eating a healthy and balanced diet is known as following a healthy lifestyle. Cancer has been the curse of western society for many years while lesser developed (developed in economic terms, not health terms) countries have seen far fewer cases. The reason really is down to diet and lifestyle.
For example, China and Singapore have both experienced a rapid rise in obesity related illnesses in the last few decades as they start to see more western style restaurants and culture infiltrate their society. Rising levels of obesity, increased consumption of red meat, and a reduction in consumption of fiber, has caused an increase in diabetes, cancer and digestive health problems.
The biggest cancer killers in the UK are still lung cancer and bowel cancer, which are caused primarily by smoking, drinking too much alcohol and eating a poor diet.
Other forms of cancer such as breast cancer and prostate cancer show that healthier diet can reduce incidence, with tomatoes warding off prostate cancer and yams being beneficial for women. However, overall diet that is varied, balanced and avoids junk food is all that you need to have to avoid many of the dietary risks.
Healthy Lifestyle Cuts Bowel Cancer By 23%
In October 2010 a study looked at rates of colorectal cancer (bowel/gut cancer) in Denmark and concluded that people who follow a healthy lifestyle, i.e. eat a healthy diet and exercise, have 23% less chance of developing bowel cancer. This is a significant reduction in risk.
The study was carried out by researchers from Institute of Cancer Epidemiology at the Danish Cancer Society in Copenhagen, Denmark and published in the British Medical Journal. The subjects of the study were 55,487 men and women aged 50-64 years at baseline (1993-7), not previously diagnosed with cancer.
The study looked at 5 factors that determine health:
- Physical activity and exercise
- Waist circumference
- Alcohol intake
- Diet and nutrition
Data was taken from lifestyle questionnaires in a cohort study. One very positive piece of data from the study was that 82% of subjects managed to do 30 minutes of exercise a day and 76% of subjects had a healthy waist size (at least, not obese) and 64% did not smoke.
However, it was not all good news. Only 2% of subjects actually followed a healthy diet all the time. In this study the definition of a healthy diet was:
- 600g of fresh fruit and vegetables a day
- 500g or less of red and processed meat per week
- 3g of dietary fiber per megajoule of dietary energy (like calories, only modern scientific units)
- 30% or less of total energy from fat
The study showed that people who followed the most lifestyle recommendations were less likely to develop bowel cancer. So those that did regular exercise, kept their waistline under control, did not smoke and drank moderately, and ate mostly a healthy diet, were the least likely to develop cancer.
Our study reveals . . . that even modest differences in lifestyle might have a substantial impact on colorectal cancer risk, and emphasizes the importance of continuing vigorous efforts to convince people to follow the lifestyle recommendations.
Men we found to be better protected from bowel cancer by following a healthy lifestyle than women. It was also found that women tend to overestimate the consumption of healthy foods more than men. This situation is often seen by dieticians and weight loss advisers to women, as women will often think that they are eating a healthy diet while really they are consuming too many unhealthy snacks.
Conclusion of the Study
Adherence to the recommendations for physical activity, waist circumference, smoking, alcohol intake, and diet may reduce colorectal cancer risk considerably, and in this population 23% of the cases might be attributable to lack of adherence to the five lifestyle recommendations. The simple structure of the lifestyle index facilitates its use in public health practice.
So Called Healthy Fat May Cause Bowel Cancer
Research published in July 2009 showed that the fats found in margarine, consumed by many as they are not saturated (causing heart disease) may actually increase bowel cancer.
The problem lies with the presence of linoleic acid. In fact, these fats may be responsible for 1/3 of all bowel cancer cases.
Also, researchers found that a diet rich in omega 3 fatty acid, which is present in oily fish such as mackerel, salmon and herring, reduced the risk of developing ulcerative colitis by 77%. The researchers from EPIC (European Prospective Investigation into Cancer and Nutrition) admit further work is required in this field.
Green Tea Does Not Prevent Breast Cancer
The health benefits of green tea have been widely reported in recent years, however, much of the research on green tea is clouded by commercial interests and claims that often exaggerate its health benefits especially claims that green tea aids weight loss.
Many reports make wild claims that various “superfoods” can prevent or even cure cancer. One of the more abused claims is about green tea and its power to prevent cancer. However, research has found that this is not the case.
Recent research from Japan, published in Breast Cancer Research, has shown that the consumption of green tea does not result in any statistically significant reduction in the development of breast cancer.
Sencha and Bancha / Genmaicha Green Tea
The study looked at two types of green tea that are widely believed to have cancer fighting properties, Sencha and Bancha/Genmaicha. The results of the study led researchers to conclude that drinking green tea has no positive or negative effect on the development of breast cancer.
“In this population-based prospective cohort study, we found no overall association between green tea intake and the risk of breast cancer among Japanese women regardless of menopausal status. Our findings are in general agreement with those of three prospective studies, including two Japanese cohort studies, which found no association between green tea intake and breast cancer risk.”
The study did confirm that rates of breast cancer in Japan are still much lower than in other parts of the World. However, green tea is not the reason for lower risk.
This findings contradicted the results of previous studies. It is thought that previous studies relied too heavily on subjects recalling their diets and lifestyle choices years after.
Also the research paper discussed how different methods of preparing green tea can affect the amount of tea polyphenol and other nutrients present in the tea.
Is a Cure For Bowel Cancer Growing on a Bush Near You?
Every week scientists are discovering new foods that help prevent various cancers. In November 2010 a new “superfood” was announced – the humble black raspberry. Like blackberries, the black raspberry grows in abundance in hedgerows in temperate climates.
Scientists from the University of Illinois in Chicago found that consumption of black raspberries reduced incidence of bowel cancer tumors by 45% in mice. In the study freeze dried black raspberries were used which shows that the protective compounds do not rely on the fruit being fresh.
Anthocyanins in Black raspberries
Black raspberries contain high levels of anthocyanins which is an antioxidant found in many berries. However, it is not clear exactly why black raspberries are so effective at preventing bowel cancer. It is likely that there are other properties which make them unique in this respect.
Black raspberries are native only in America. There are two varieties, Rubus leucodermis, which grows in western North America and Rubus occidentalis in eastern North America. Rubus occidentalis is the commercial variety that is found in shops.
Black raspberries look very similar to blackberries but that is where the relationship ends. They taste very different and have a different combination of antioxidants to the red raspberry or the blackberry.
Once again this research highlights a simple problem in today’s society. We have moved into an age with increased cases of cancer and obesity while also reducing our consumption of healthy natural foods. Following a natural diet that is rich in fruits, berries and salad vegetables is the best way to prolong life and prevent cancer.
How To Protect Yourself Against Cancer
Cancer is a terrible disease that can strike perfectly healthy and fit people at any age. However, following a healthy lifestyle is the best way to reduce your risk of developing the disease. Cancer is a major cause of early death, and studies have shown that it really is our modern lives that lead to the development of cancer. 1 in 3 people are likely to develop cancer at some point in their lives. Although some forms of cancer are now treatable, such as skin cancer, many cases of cancer are still either too aggressive to control or just picked up too late to treat effectively.
Being fit and healthy helps prevent cancer, but you need to build up more barriers if you want to maximize your chances of avoiding it.
Cancer Influenced By Diet, Lifestyle and Environment
In a study on mummified bodies Prof. Rosalie David from the The University of Manchester concluded that cancer is not a natural disease. Although there have been cases of cancer in wild animals that are under great stress, it is generally only seen to any extent in humans.
It is also often thought that cancer is less common in ancient populations because it is mainly a condition of old age, however, in the mummified remains studied over the last 30 years there are many instances of age related diseases, such as osteoarthritis, but the cancer cases are just not there.
The evidence is that cancer is caused by our lifestyles today. Overeating, poor diet, lack of exercise, stress and consumption of other harmful chemicals (alcohol and nicotine) all contribute to cancer. Also, there is a rising concern that many household items such as cleaning agents and sprays may have carcinogenic properties.
Obesity and Cancer
The fastest growing health problem we are seeing at the moment is that of obesity. Humans are getting fatter, and this is a direct result of increasingly poor diets. Diets of the past would have been far healthier than today. Sugar was almost never eaten, saturated fat very hard to come by. People ate fresh fish, fresh vegetables and fruits and lean meats. Red meat was a rare treat and bread and cakes even rarer for many.
Today people obtain most of their daily energy requirements from refined sugars which are very energy dense and have little of nutritional value. Rather than a diet that keeps us lean and is full of nutrients, antioxidants and vitamins, it is fattening and unhealthy.
Some types of cancer are directly related to weight problems. Breast cancer is more common in overweight women, and bowel cancer more common in all overweight people. Also obesity leads to stomach, liver, kidney and gallbladder cancers.
It is not clear if in these cases it is simply too much fat that leads to cancer, or generally a poor diet and lifestyle, of which being overweight is just another effect. But the relationship between obesity and cancer is clear.
Eat and Live Like the Ancients
It seems that if you want to increase your chances of preventing cancer then eating a Paleo Diet / Caveman diet could well be the way to go. By following such a diet you stop eating breads, sugar, grains, alcohol and fatty red meats and instead eat fresh fruits and vegetables, lean meats and eggs.
There is a growing movement at the moment of people combining a caveman diet with intensive exercise programs. This combination seems to work best for reducing fat and losing weight. Intensive exercise also works the cardiovascular system and increase blood flow throughout the body which is thought to improve immune systems and help fight disease. Healthy diet and exercise is the key to long life. The Egyptians seemed to know this, and we certainly now know it. So what are you waiting for?
References and web resources:
- “The Fraction of Cancer Attributable to Lifestyle and Environmental Factors in the UK in 2010” (PDF) by Dr D Max Parkin; with Lucy Boyd, Professor Sarah C Darby, David Mesher, Professor Peter Sasieni and Dr Lesley C Walker; with a Foreword by Professor Sir Richard Peto. British Journal of Cancer Volume 105, Issue S2 (Si-S81)
- The causes of cancer you can control – cancerresearchuk.org – accessed 8th Dec 2011.
- Press Release: Cigarettes, diet, alcohol and obesity behind more than 100,000 cancers – cancerresearchuk.org – accessed 8th Dec 2011.
- Max Parkin, MD, Senior Epidemiologist. Profile on ctsu.ox.ac.uk
- “Association of adherence to lifestyle recommendations and risk of colorectal cancer: a prospective Danish cohort study” by Helene Kirkegaard, Nina Føns Johnsen, Jane Christensen, Kirsten Frederiksen, Kim Overvad, Anne Tjønneland. BMJ 2010; 341:c5504 doi: 10.1136/bmj.c5504 (Published 26 October 2010)
- “Linoleic acid, a dietary n-6 polyunsaturated fatty acid, and the aetiology of ulcerative colitis: a nested case–control study within a European prospective cohort study” The IBD in EPIC Study Investigators. Gut 2009;58:1606-1611 doi:10.1136/gut.2008.169078 – 23 July 2009
- “Green tea drinking and subsequent risk of breast cancer in a population-based cohort of Japanese women” (pdf) Breast Cancer Research 2010, 12:R88 doi:10.1186/bcr2756 Motoki Iwasaki et al
- “Black Raspberries Inhibit Intestinal Tumorigenesis in Apc1638+/− and Muc2−/− Mouse Models of Colorectal Cancer“. By Xiuli Bi, Wenfeng Fang, Li-Shu Wang, Gary D. Stoner and Wancai Yang. Cancer Prev Res; Published OnlineFirst November 2, 2010; doi:10.1158/1940-6207.CAPR-10-0124
- “Cancer: an old disease, a new disease or something in between?” by A. Rosalie David & Michael R. Zimmerman. Nature Reviews Cancer 10, 728-733 (October 2010) | doi:10.1038/nrc2914
- “Scientists suggest that cancer is man-made” Manchester.ac.uk. 14 Oct 2010.