Is cancer a lifestyle disease?

like 865 Posted By : ScienceIndia Administrator

Image: Tumour cells at work. (https://commons.wikimedia.org/wiki/File:Diagram_showing_a_malignant_tumour_CRUK_069.svg)

Lifestyle diseases are those diseases caused due to disharmonious relationship with the environment. Their frequency of occurrence increases with industrialization and modernisation or development index of a country. It is quite high in many western countries due to changes in the food habit like readymade fast foods and sedentary lifestyle. Lifestyle diseases include asthma, chronic liver disease or cirrhosis, chronic obstructive pulmonary disease, Type 2 diabetes, osteoporosis, depression, obesity, heart disease, stroke, and cancer. The World Health Organisation (WHO) has warned that more than 270 million people are susceptible of falling victim to diseases linked to unhealthy lifestyles. It is expected that cancer will overtake the heart disease as the world's number one killer by the end of 2020.

Cancer is a group of diseases that can occur in any type of cells and 70% - 90% of it is caused due to environmental factors. Tobacco consumption either as chewing or smoking contributes to about 50% of all cancers. Others include red meat, fats, sugars, alcoholic beverages, along with many fast foods containing preservatives and other food additives.  Lambe in 1815 has observed that excess consumption of food in general and especially rich in meat in particular with low intake of fruits and vegetables are particularly factors contributing to cancer. Industrialization has seen increase in pollutants in our air and water streams.  All these factors are posing a very serious threat to our health especially that of cancer which has got the dubious distinction as the number one ‘Disease of Civilization’.

Different cancers are linked with different life styles. The biological mechanism that explains how a life style intervention increases cancer risk may be different for different cancers. A major outcome of lifestyle changes experienced by India is the rapid increase in junk food consumption. Junk food and fast food which uses excessive salt, sugar, trans fatty acids and preservatives like MSG (mono sodium glutamate) sodium nitrites, potassium bromate etc are known to cause cancers in humans when consumed in excess. This high sodium content in our diet increases our risk of stomach cancers. Cancer cells need glucose to thrive and with our increased sugar intake in the form of sweets increase our risk of developing Cancer. The exact mechanisms are not known for any of the cancers. However, other possible mechanisms include alterations in sex hormones (e.g., estrogens, progesterone, and androgens), may account for their increased risk for cancers of the breast, endometrium, and colon cancers. Vegetables and fruits contain pesticides, most of which mimics structure of estrogen and when ingested, provoke a weak estrogenic effect on our systems. This could lead to estrogen positive (ER+ve) breast cancers. HPV (Human Pappiloma Virus) which causes cervical cancer through sexual contacts has been implicated in the pathogenesis of cervical cancer, the number one gynaecological cancer in the world.

Obesity has been estimated to account for about 40 percent of endometrial cancer cases in affluent societies. A number of mechanisms have been proposed for the adverse effect of obesity on colon cancer risk. One of the major hypotheses is that high levels of insulin or insulin-related growth factors in obese people may promote tumour development. Overweight and obese individuals are two times more likely than healthy weight people to develop a type of oesophageal cancer called oesophageal adenocarcinoma. An increased risk of this disease has also been associated with weight gain, smoking, etc.

Cancer is a preventable disease and the earlier it is diagnosed the better the chances of survival. Keeping fit, eating a healthy, balanced, diet and cutting down on alcohol and smoking can reduce the risk of developing cancer. There is now strong evidence that people can make lifestyle changes to reduce their risk. It is estimated that about a third of the most common cancers could be prevented through eating a plant-based diet like fruits and vegetables rich in fibre content, taking regular exercise and maintaining a healthy weight. Women can prevent the occurrence of the fatal breast cancer by adopting a healthy lifestyle, which includes eating healthy, curbing alcohol and exercising, according to a study. Maintaining sexual relationship with a single partner could prevent HPV infection and thereby cervical cancer.

In addition to lifestyle interventions, regular visits for cancer screening, physician counselling, and chemoprevention for individuals at high risk for cancer are important for prevention. Thus adopting a healthier lifestyle is easier for people who eat healthy food, work,exercise, play, or go to school in an environment that supports healthy life style. 

 

Article by:

Dr. Lekha Dinesh Kumar

Principal Scientist

Centre for Cellular & Molecular Biology

Hyderabad 500007, Telangana.

Email: lekha@ccmb.res.in