According to the World Health Organization (WHO), cancer remains a leading cause of death globally, responsible for an estimated 10 million deaths in 2020, or about one in six deaths. It is often perceived as an unavoidable fate and one of the world’s deadliest diseases, but what if the key to preventing cancer is hidden in the choices we make every day? In fact, the WHO reports that 30–50% of all cancer cases can be prevented by modifying lifestyle habits such as diet, physical activity, smoking, alcohol consumption, and stress management. While genetics contribute greatly to cancer risk, it is our daily routines that either increase or reduce that risk. Let’s explore the science behind these lifestyle factors and how they can become our strongest defense against cancer.

Smoking

The tobacco epidemic remains one of the most significant public health problems worldwide, responsible for over 8 million deaths each year. More than 7 million of these fatalities are associated with direct tobacco smoking, while approximately 1.3 million result from second-hand smoke exposure among non-smokers. Tobacco in any form is detrimental to health, and even minimal exposure carries serious risks. Cigarette smoking is the most prevalent form of tobacco use globally. Tobacco smoke contains over 7,000 chemicals, with at least 250 identified as harmful and 69 known to be carcinogenic. Moreover, tobacco consumption remains the leading preventable cause of cancer mortality worldwide.

The American Cancer Society reports that smoking is responsible for approximately 80% of lung cancer cases and 80% of all lung cancer deaths. According to the WHO, lung cancer was the leading cause of cancer-related mortality worldwide in 2020, accounting for 1.8 million deaths. Besides, tobacco use is also linked to cancers of the bladder, esophagus, pancreas, kidney, stomach, and cervix. Therefore, quitting smoking is one of the most effective strategies for reducing the risk of cancer and significantly improving overall health and life expectancy. Quitting smoking at any age reduces cancer risk. The Centers for Disease Control and Prevention (CDC) states that 10-15 years after quitting, a former smoker’s risk of lung cancer is cut in half.

Diet

A diet high in processed foods, red meat, and refined sugars has been linked to an increased risk of cancer; however, consuming plant-based foods, fiber, and antioxidants provides protective health benefits. According to the World Cancer Research Fund (WCRF), consuming processed meat is a confirmed risk factor for colorectal cancer, while red meat consumption is likely to contribute to its development. Therefore, the WCRF recommends avoiding processed meat consumption and limiting red meat to a maximum of three servings per week, equivalent to approximately 350–500g of cooked meat or 700–750g of raw meat. It is also recommended to increase the intake of fruits, vegetables, whole grains, and legumes as they are valuable sources of nutrients and contribute to overall health.

Alcohol

The International Agency for Research on Cancer (IARC) classifies IARCas a Group 1 carcinogen, confirming its established link to cancer development. Research estimates that alcohol consumption contributes to approximately 5.5% of new cancer cases and 5.8% of cancer-related deaths worldwide. Moreover, alcohol use can negatively impact cancer treatment by delaying recovery, increasing the need for surgical interventions, and raising overall healthcare costs. It is a known cause of cancers of the oral cavity, pharynx, larynx, esophagus, liver, stomach, colorectum, and female breast. 

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The American Institute for Cancer Research (AICR) provided strong evidence that consuming approximately 10 grams of alcohol per day, the equivalent of a small glass of wine or beer, increases the risk of pre-menopausal breast cancer by 5% and post-menopausal breast cancer by 9%. For reference, a standard alcoholic drink contains 14 grams of alcohol.

The CDC recommends limiting consumption to two drinks or less in a day for men and one drink or less in a day for women. Moreover, choosing alcohol-free alternatives, such as herbal teas, juice, flavoured water, or mocktails can be a healthier option.

Physical activity

According to the World Cancer Research Fund (WCRF), regular physical activity is evident to reduce the risk of breast, colon, and endometrial cancer. Exercise supports cancer prevention by balancing hormone levels, lowering inflammation, and enhancing immune function. Moreover, the CDC reported that overweight and obesity are linked to an increased risk of developing 13 different types of cancer. Regular physical activity reduces estrogen and insulin levels, which are linked to hormone-dependent cancers such as breast and prostate cancer. The CDC recommends that adults aim for 150 minutes of moderate-intensity exercise or 75 minutes of vigorous-intensity activity per week, or a combination of both. Additionally, it is important to engage in muscle-strengthening exercises at least twice a week to improve strength.

Stress and sleep

Chronic stress and poor sleep quality and duration contribute to hormonal imbalances, immune suppression, and increased inflammation, which can potentially elevate cancer risk. According to recent research, chronic stress can trigger tumor formation and accelerate the progression of cancer. Moreover, the American Cancer Society has shed light on recent research showing associations between short sleep (4–5 hours) and long sleep (more than 9 hours) and increased cancer risk. Researchers conducting these studies suggest that insufficient sleep prevents the body from properly restoring and resting, potentially raising the likelihood of abnormal cell growth that could lead to cancer. Their findings indicate that short sleep may be associated with a higher risk of breast, colorectal, lung, and prostate cancers. Additionally, long sleep may be linked to an increased risk of colorectal and lung cancers.

Avoiding smoking, maintaining a healthy diet, engaging in regular physical activity, limiting alcohol intake, and managing stress and sleep effectively can significantly decrease the likelihood of developing cancer.

Shahd Abouelenen, Final-Year Medical Student at Gulf Medical University, UAE

Therefore, it is recommended to maintain a regular sleep schedule and aim for 7–9 hours of quality sleep per night. It is also advised to engage in stress-reducing activities, such as meditation, yoga, or deep breathing, to help alleviate stress and reduce the associated health risks.

Ultimately, cancer prevention is not only influenced by genetics; our lifestyle choices play a crucial role in lowering the risk of cancer. Avoiding smoking, maintaining a healthy diet, engaging in regular physical activity, limiting alcohol intake, and managing stress and sleep effectively can significantly decrease the likelihood of developing cancer. By making informed lifestyle changes, individuals can take proactive steps toward a healthier, cancer-free life.