Obesity and Cancer Risk: A Comprehensive Guide

Obesity not only affects appearance and cardiovascular health but is also a cause of increased risk for many types of cancer. When the body accumulates too much excess fat, it causes hormonal imbalances, chronic inflammation, metabolic disorders, and insulin resistance. These factors create a favorable environment for cancer cell development. Obesity has been proven to contribute to at least 13 types of cancer, including breast, endometrial, colorectal, and kidney cancers, making it a major public health threat.

1. The Link Between Obesity and Cancer Risk

The connection between obesity and cancer risk has been clearly established through numerous scientific studies. Obesity is a condition where the body has excess fat, which can alter many biological processes in the body, increasing cancer risk.

Studies also emphasize that the relationship between obesity and cancer risk varies by gender and age:

• Post-menopausal women: Higher risk of breast cancer if obese due to increased estrogen from fat tissue
• Men: Obesity is linked to colorectal and prostate cancer risk
• Young people: Obesity from a young age, especially during puberty and early adulthood, can increase cancer risk later in life due to prolonged exposure to risk factors

2. Why Does Obesity Cause Cancer Risk? 

How is the mechanism of obesity causing cancer explained? The development of cancer related to obesity is explained through several complex biological mechanisms.

• Hormonal Disorders: Obesity, especially visceral fat, increases the production of hormones such as estrogen, insulin, and insulin-like growth factors (IGF). High levels of estrogen are thought to increase the risk of breast cancer (post-menopausal), endometrial cancer, and ovarian cancer. Insulin and IGF promote cell growth, which can lead to uncontrolled cell division and increased cancer risk.
• Increased Chronic Inflammation: Excess fat, especially visceral fat, tends to create a chronic inflammatory environment in the body, thereby creating conditions for obesity-induced cancer. Fat cells secrete inflammatory mediators such as cytokines and adipokines, increasing the development of pre-cancerous cells and reducing the immune system’s ability to fight cancer cells. This inflammatory condition is closely related to the development of colorectal cancer and pancreatic cancer.
• Changes in Cellular Environment: Obesity leads to oxidative stress and DNA damage, increasing the risk of cell mutations, which leads to cancer development. Fat cells also affect the body’s ability to destroy cancer cells, creating conditions for them to grow and spread.
• Immune System Disorders: Excess fat tissue can reduce immune system function, weakening the body’s ability to recognize risk factors while interfering with the process of destroying cancer cells. This is especially important in the early stages of cancer, when the immune system can destroy abnormal cells before malignant tumors form

3. Types of Cancer with High Risk Due to Obesity

What cancers does obesity cause? Obesity has been proven to be a risk factor for many types of cancer. Studies show that obesity increases the risk of at least 13 different types of cancer.

3.1. Breast Cancer (Post-menopausal) 

Post-menopausal women with obesity have a higher risk of developing breast cancer. This is primarily related to increased estrogen levels from fat tissue. High estrogen levels promote abnormal growth of breast tissue cells. The risk of breast cancer in obese women can increase by 30-50% compared to those with normal weight.

3.2. Endometrial Cancer 

Obesity is one of the biggest risk factors for endometrial cancer (uterine cancer). Excess fat increases estrogen levels without the balance of progesterone, leading to endometrial cell proliferation. Obese women have a 2-4 times higher risk of endometrial cancer compared to women of normal weight.

3.3. Colorectal Cancer 

Obesity increases the risk of colorectal cancer, especially in men. This may be related to metabolic disorders, chronic inflammation, and insulin resistance. Obese people have a 30-50% higher risk of developing colorectal cancer.

3.4. Kidney Cancer 

Obesity increases the risk of kidney cancer, especially renal cell cancer. Excess fat causes chronic inflammation and oxidative stress, damaging kidney cells. The risk of kidney cancer in obese people is 70% higher than in people of normal weight.

3.5. Esophageal Cancer (Adenocarcinoma) 

Obesity increases the risk of esophageal cancer, especially adenocarcinoma. Obesity causes gastroesophageal reflux, damaging the esophageal mucosa, leading to cancer cell development. The risk of esophageal cancer is higher in obese people compared to normal-weight individuals.

3.6. Liver Cancer

 Obesity is a significant risk factor for liver cancer. Excess fat causes non-alcoholic fatty liver disease, leading to chronic hepatitis and potentially liver cancer. Obese people have a higher risk of liver cancer due to inflammation and metabolic disorders in the liver.

3.7. Pancreatic Cancer 

Obesity is related to increased pancreatic cancer risk. Insulin resistance and elevated insulin levels can promote cancer cell development in the pancreas. Obese people have a higher risk of pancreatic cancer compared to those of normal weight.

3.8. Gallbladder Cancer 

Obesity can cause gallstones and gallbladder inflammation, increasing gallbladder cancer risk. The risk is higher in obese people, especially women.

3.9. Ovarian Cancer 

Obesity is related to increased ovarian cancer risk, especially due to excess fat increasing estrogen levels in the body. Obese women have a higher risk of ovarian cancer compared to women of normal weight.

3.10. Stomach Cancer (Upper Stomach) 

Obesity, especially abdominal fat, increases the risk of stomach cancer, particularly in the upper stomach near the esophagus. This may be related to inflammation and gastric reflux. The risk of stomach cancer is higher in obese people, especially men.

3.11. Cervical Cancer 

Some studies indicate that obesity may be linked to cervical cancer risk due to hormonal factors and prolonged inflammation.

3.12. Thyroid Cancer 

Obesity is also recognized as a risk factor for thyroid cancer, possibly due to the effects of hormonal disorders and chronic inflammation.

3.13. Multiple Myeloma 

Obesity is associated with increased risk of developing multiple myeloma, a type of blood cancer. Chronic inflammation factors and immune changes may play important roles in the development of this cancer.

Obesity-caused cancer has strong connections primarily related to biological mechanisms such as hormonal disorders, chronic inflammation, insulin resistance, and DNA damage. Maintaining a healthy weight and adopting a positive lifestyle can help reduce cancer risk and improve overall health.

4. How to prevent obesity and reduce cancer risk? 

Specific measures to help prevent obesity and minimize cancer risk:

4.1. Healthy Diet

• Increase consumption of vegetables and fruits: These foods are rich in fiber, vitamins, and minerals, helping maintain weight and reduce cancer risk.
• Choose whole grains instead of refined grains: Whole grains like brown rice, oats, and barley have higher fiber content, helping control blood sugar and support weight loss.
• Limit foods high in fat and sugar: Reduce consumption of processed foods, fast food, sodas, and foods high in saturated fats. These are factors leading to weight gain and obesity, thereby increasing cancer risk.
• Choose healthy fats: Consume sources of unsaturated fats like olive oil, nuts, avocados, and fatty fish. Healthy fats help reduce inflammation and cancer risk.
• Limit red meat and processed meats: Red meat and processed meats (like sausages, bacon) have been proven to be linked to colorectal and stomach cancer. Replace with protein sources from fish, poultry, beans, and low-fat dairy products.
• Reduce alcohol consumption: Alcohol can increase the risk of many types of cancer, especially breast, liver, and oral cavity cancer. Limit alcohol intake (no more than 1 drink per day for women and 2 drinks for men).

4.2. Regular Physical Activity

• Exercise regularly: Sports help burn calories, boost metabolism, and reduce weight. Physical activity also helps reduce inflammation, improve immune system, and lower cancer risk.
• Set a goal of at least 150 minutes of exercise per week: This is the minimum recommended level for moderate physical activity (like brisk walking, cycling) or 75 minutes of vigorous exercise (jogging, swimming).
• Combine different types of exercise: Consider combining both aerobic and muscle-strengthening exercises. This not only helps with weight loss but also improves overall health.

4.3. Maintain Healthy Weight

• Monitor weight regularly: Track Body Mass Index (BMI) and waist circumference to control obesity risk. Large waist circumference (over 94cm in men and over 80cm in women) is associated with higher risk of chronic diseases and cancer.
• Develop moderate eating habits: Eat smaller and more frequent meals to avoid excessive hunger leading to overeating. Create controlled eating habits, don’t skip breakfast, and reduce late-night eating.

4.4. Stress Management

• Practice stress management techniques: Prolonged stress can contribute to uncontrolled eating and weight gain. Yoga, meditation, and deep breathing techniques are useful methods to reduce stress.
• Get enough sleep: Lack of sleep is associated with weight gain and increased cancer risk. Try to get 7-9 hours of sleep each night to maintain overall health and support weight loss.

4.5. Minimize Exposure to Environmental Risk Factors

• Limit exposure to carcinogens: Reduce exposure to harmful substances like tobacco, UV radiation from the sun, and toxic chemicals.
• Use sunscreen: Use sunscreen to protect skin from UV damage, helping prevent skin cancer.

4.6. Reduce Tobacco and Alcohol Consumption

• Don’t smoke: Tobacco is one of the leading causes of many types of cancer, including lung, mouth, esophageal, and bladder cancer. Quitting smoking not only helps reduce cancer risk but also improves overall health.
• Limit alcohol: Alcohol is a risk factor for many types of cancer, including breast, colorectal, and liver cancer. Limiting alcohol consumption can help reduce cancer risk.

4.7. Regular Health Check-ups

• Regular health examinations: Conduct regular health checks to detect early risk factors related to obesity and cancer.
• Cancer screening: People with high risk factors (such as family history of cancer) should undergo regular cancer screening, especially for breast, colorectal, and prostate cancer.

4.8. Control Related Health Conditions

• Treat chronic conditions: Obesity often comes with chronic conditions like diabetes, hypertension, and cardiovascular disease. Good control of these conditions can help reduce cancer risk.
• Use medication under doctor’s guidance: If you’re dealing with weight issues or obesity-related conditions, consult a doctor for advice on medications or medical interventions.

Preventing obesity and reducing cancer risk requires a combination of healthy diet, regular exercise, weight control, stress reduction, and avoiding environmental risk factors. Maintaining a healthy lifestyle is not only important for preventing obesity but also crucial for reducing the risk of common cancers. If you have health issues, seek appropriate solutions for early treatment. Additionally, take proactive care of your health early to achieve effective weight loss, anti-aging, healthy living, and longevity.

Source: cancerresearchuk.org – mdanderson.org – mayoclinic.org