“Is there anything we can do in our daily lives to help reduce the risk of cancer?”
It is a question that many people may ask when thinking about their long-term health.
Cancer is not a disease that can be prevented simply by eating a particular food or taking a particular nutrient.
Many different factors are associated with the development of cancer. Some, such as age and genetic factors, cannot easily be changed, while others are related to lifestyle and environment, including tobacco use, alcohol consumption, diet, physical activity, body weight and certain infections.
Rather than relying on a single food, nutrient or health practice, it is important to understand what scientific research currently tells us and to look at our overall lifestyle.
In this article, “cancer prevention” does not mean that cancer can be completely prevented.
The National Cancer Center Japan explains that prevention in this context means reducing the risk of developing cancer rather than reducing that risk to zero.
What Is Cancer?
Our bodies are made up of an enormous number of cells.
Normal cells are carefully regulated. They divide when new cells are needed and stop multiplying when they are no longer required.
Genes within our cells play an important role in controlling these processes.
However, genetic changes can sometimes occur when cells divide. Genetic changes can also be associated with external factors such as tobacco smoke, certain viral or bacterial infections, chemicals and radiation.
The National Cancer Center Japan describes these genetic changes as mutations.
When multiple genetic mutations accumulate, some cells may eventually begin to grow without responding normally to the mechanisms that regulate cell growth. This can result in the formation of a mass of cells known as a tumour.
Tumours can be benign or malignant. Malignant tumours, commonly referred to as cancer, can invade surrounding tissues and may spread to other parts of the body.
Cancer Usually Develops Through Multiple Changes Over Time
A normal cell does not generally become a cancer cell because of a single change.
In many cases, cancer develops as multiple genetic mutations accumulate over time. The National Cancer Center Japan describes this process as multistep carcinogenesis.
This accumulation of genetic changes over many years is also one of the reasons why the risk of developing cancer generally increases with age.
However, having a genetic mutation does not necessarily mean that a person will develop cancer.
Cancer develops through a complex interaction of many factors, including ageing, genetic characteristics, lifestyle, infections and environmental influences.
There Is No Single Cause of Cancer
It is not appropriate to assume that someone developed cancer simply because they ate a particular food or followed a particular lifestyle.
According to the National Cancer Center Japan, lifestyle factors and infections are among the factors associated with cancer development in the Japanese population.
Current estimates suggest that approximately 43.4% of cancers among Japanese men and 25.3% among Japanese women are attributable to modifiable lifestyle factors such as tobacco and alcohol use, as well as infections.
This suggests that improving certain lifestyle habits and taking appropriate measures against preventable or treatable infections may help reduce the risk of developing cancer.
The “5+1” Evidence-Based Cancer Prevention Approach
Based on research involving the Japanese population, the National Cancer Center Japan has developed an evidence-based cancer prevention approach known as the “5+1” recommendations for cancer prevention in Japanese people.
The six areas are:
- Tobacco
- Alcohol
- Diet
- Physical activity
- Body weight
- Infection
The first five relate primarily to lifestyle, while infection is added as the “+1” factor.
Research involving Japanese adults has also found that people who followed more of the five recommended lifestyle practices tended to have a lower risk of developing cancer.
According to the National Cancer Center Japan, people who followed all five recommended lifestyle practices were estimated to have a 43% lower risk of developing cancer among men and a 37% lower risk among women compared with people who followed none or only one of these practices.
These figures do not mean that following healthy lifestyle habits guarantees that a person will not develop cancer.
Rather, the goal is to identify factors that we can influence in our everyday lives and make gradual changes that may help reduce our long-term risk.
Avoiding Tobacco Is Particularly Important
Tobacco use is one of the most important modifiable risk factors when considering cancer prevention.
Although the relationship between smoking and lung cancer is widely known, smoking is associated with an increased risk of many different types of cancer.
It is also important to consider second-hand smoke. Even people who do not smoke themselves can be exposed to tobacco smoke from others.
For people who currently smoke, quitting is one of the most important steps they can consider for their long-term health.
It Is Best to Avoid Alcohol
Alcohol consumption is another lifestyle factor associated with an increased risk of cancer.
According to the National Cancer Center Japan, alcohol consumption is associated with an increased risk of several cancers, including liver, oesophageal, colorectal and head and neck cancers.
From the perspective of reducing cancer risk, the National Cancer Center Japan states that not drinking alcohol is the best option.
For people who regularly drink alcohol, becoming aware of how much they consume and reducing their intake can be an important step towards healthier lifestyle habits.
Focus on Your Overall Diet Rather Than a Single “Superfood”
When searching for information about diet and cancer, it is common to encounter claims that a particular food, nutrient or ingredient can prevent cancer.
However, the evidence-based recommendations from the National Cancer Center Japan do not rely on any single food or nutrient.
The overall pattern of the diet is more important.
This includes limiting excessive salt intake, including vegetables and fruit as part of a balanced diet, and allowing very hot foods and drinks to cool before consuming them.
Dietary supplements and health foods should also not be regarded as substitutes for a balanced diet and healthy lifestyle.
In the next section, we will look at the remaining elements of the National Cancer Center Japan’s “5+1” approach, including physical activity, maintaining an appropriate body weight and measures relating to infection.
Physical Activity Is Another Important Lifestyle Factor
Regular physical activity is another factor to consider when looking at long-term health and cancer risk.
According to the National Cancer Center Japan, research involving Japanese people has found that those who are more physically active tend to have a lower overall risk of developing cancer.
Physical activity does not necessarily mean doing intense exercise every day.
Everyday activities such as walking, commuting on foot, doing housework and other forms of movement can all contribute to a more active lifestyle.
The important point is to avoid spending too much time inactive and to incorporate an appropriate amount of movement into daily life according to your age, physical condition and individual circumstances.
If you have an existing medical condition, are receiving treatment, or have concerns about exercising safely, it is advisable to consult a healthcare professional before significantly changing your activity level.
Maintaining an Appropriate Body Weight
Body weight is also included among the five lifestyle factors in the National Cancer Center Japan’s cancer prevention recommendations.
However, this does not mean that being as thin as possible is better.
Both excessive weight gain and being underweight may be associated with health concerns.
The National Cancer Center Japan therefore recommends maintaining an appropriate body weight rather than pursuing excessive weight loss.
Body mass index (BMI) is one commonly used measure for assessing body weight in relation to height.
BMI is calculated using the following formula:
BMI = body weight (kg) ÷ height (m) ÷ height (m)
BMI is only one general indicator and does not provide a complete picture of an individual’s health. Age, muscle mass, medical conditions and other factors also need to be considered.
Rather than focusing only on the number shown on a scale, it is useful to consider body weight as one part of an overall healthy lifestyle that includes a balanced diet and regular physical activity.
The “+1”: Infection
The final element of the National Cancer Center Japan’s “5+1” approach is infection.
This is particularly important because some cancers are associated with certain viral or bacterial infections.
Examples include:
- Helicobacter pylori (H. pylori) and stomach cancer
- Hepatitis B virus (HBV) and hepatitis C virus (HCV) and liver cancer
- Human papillomavirus (HPV) and cervical cancer
Having one of these infections does not necessarily mean that cancer will develop.
However, identifying an infection and receiving appropriate medical advice, testing, treatment or preventive care where applicable may help reduce cancer risk.
Because the appropriate approach differs depending on the infection, age, medical history and individual circumstances, it is important to consult a healthcare professional rather than attempting to diagnose or treat an infection yourself.
Cancer Prevention and Cancer Screening Are Both Important
Healthy lifestyle habits may help reduce the risk of developing cancer, but they cannot reduce that risk to zero.
This is why cancer screening also plays an important role.
The purpose of cancer screening is different from that of lifestyle-based cancer prevention.
Lifestyle measures aim to reduce the risk of developing cancer, while screening aims to detect certain cancers at an earlier stage in people who do not have symptoms.
In Japan, population-based screening programmes are recommended for several cancers, including stomach, colorectal, lung, breast and cervical cancer, depending on age, sex and other criteria.
The appropriate screening programme and frequency may differ according to where you live, your age, sex, medical history and individual risk factors.
If you have symptoms or specific health concerns, you should not wait for routine screening. Consult an appropriate healthcare professional.
Be Careful With Claims About “Cancer-Fighting” Foods and Supplements
When researching cancer prevention online, you may encounter information suggesting that a particular food, supplement, herb, antioxidant or other ingredient can “prevent cancer” or “fight cancer.”
Such claims should be approached carefully.
Evidence that a nutrient has a particular biological function does not automatically mean that consuming large amounts of that nutrient will prevent cancer in humans.
Likewise, results from laboratory or animal studies cannot automatically be applied to people.
The National Cancer Center Japan’s evidence-based recommendations focus on overall lifestyle factors rather than recommending a specific health food or dietary supplement as a method of preventing cancer.
Dietary supplements may have a place in helping some people meet particular nutritional needs, but they should not be considered a substitute for a balanced diet, appropriate medical care or recommended cancer screening.
Start With the Lifestyle Factors You Can Change
There is no lifestyle that can guarantee that a person will never develop cancer.
However, scientific evidence suggests that there are factors in our everyday lives that we can modify to help reduce our risk.
The National Cancer Center Japan’s “5+1” approach provides a practical framework:
- Do not smoke and avoid second-hand smoke.
- It is best not to drink alcohol; if you drink, limit your intake.
- Maintain a balanced diet and avoid excessive salt intake.
- Stay physically active.
- Maintain an appropriate body weight.
- Take appropriate measures regarding cancer-related infections.
There is no need to try to change everything at once.
Small, sustainable improvements in everyday habits can be more realistic than relying on extreme diets, excessive exercise or a single food or supplement.
Summary
Cancer develops through a complex interaction of many factors, and there is no single method that can completely prevent it.
Some factors, such as ageing and certain genetic characteristics, cannot be changed. Others, however, are related to lifestyle and infections and may be modifiable.
Rather than searching for a single “cancer-preventing” food or supplement, an evidence-based approach focuses on the overall picture: tobacco, alcohol, diet, physical activity, body weight and infection.
Regular cancer screening, where recommended, is also important because even people who follow healthy lifestyle habits can still develop cancer.
Understanding reliable health information and making realistic choices in everyday life can help us think about cancer prevention without being misled by exaggerated health claims.
Important Information
This article is intended to provide general health information based primarily on information published by the National Cancer Center Japan.
It is not intended to diagnose, treat, cure or prevent any disease, nor is it a substitute for medical advice, diagnosis or treatment from a qualified healthcare professional.
Cancer risk and appropriate preventive measures vary depending on age, sex, medical history, family history, lifestyle and other individual factors.
If you have symptoms, are concerned about your cancer risk, or have questions about screening, vaccination, infection testing or treatment, please consult an appropriate healthcare professional.
References and Further Information
The main medical and health information in this article is based on public information provided by the National Cancer Center Japan.
Please note that external websites may update or revise their content after this article is published.
