Cancer is a leading cause of death worldwide. According to the data provided by the World Health Organisation (WHO), cancer accounted for nearly 10 million deaths in 2020, or nearly one in six deaths. In 2025, an estimated 618,120 people will die of cancer in the United States, states a report by the National Cancer Institute.

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Therefore, it is essential to be aware of the factors that cause cancer and how to adopt lifestyle habits that reduce your risk. In a December 17 Instagram post, Dr Thomas Hemingway, MD, a board-certified physician, best-selling author and health educator with over 20 years of experience, highlighted the real cause of cancer.

In the post, Dr Hemingway highlighted the key factors that people think cause cancer and what actually causes cancer. Here’s what you need to know:

What people think drives cancer

1. Genes

2. Bad luck

3. Red meat

4. The sun

5. Age

6. Family history

What also drives cancer

According to Dr Hemingway, these are the crucial factors that increase the cancer risk:

1. Xenoestrogen exposure

The physician explained, “Plastics, fragrances, pesticides, and household chemicals mimic estrogen and overload your hormonal system.”

2. High intake of polyunsaturated fats (PUFAs)

PUFAs such as canola oil, etc., oxidise easily, driving inflammation and cellular stress that contribute to cancer risk, Dr Hemingway noted

3. Low progesterone

Progesterone balances estrogen, and when it’s low, estrogen becomes more inflammatory and proliferative.

4. Low thyroid function

“A sluggish thyroid slows metabolism and detox pathways, reducing the body’s ability to repair damaged cells,” the physician explained.

5. Exposure to heavy metals

According to him, metals such as mercury, cadmium, arsenic, and lead interfere with mitochondrial function and cellular regulation.

6. Nutrient deficiencies

Deficiency, especially of B vitamins, can increase the risk of cancer. “Missing key nutrients disrupts DNA repair, immune function, and healthy cell turnover,” the physician noted.

7. Chronically high cortisol

Next, he noted that chronic stress hormones suppress the immune system and create a pro-inflammatory internal environment.

8. Chronic exposure to artificial light

“Blue light at night disrupts circadian rhythm and melatonin—one of the body’s strongest anti-cancer hormones,” he highlighted.

9. Lack of sunlight

Low vitamin D also weakens immune surveillance and reduces your body’s natural cancer-fighting capacity.

10. Emotional stress and trauma

The physician highlighted how long-term emotional loads can suppress immunity, disrupt hormones, and raise inflammation—a triple whammy for cancer risk.

11. Poor sleep

Lastly, he emphasised that sleep loss disrupts hormone levels, weakens the immune system, and impairs the body’s nightly repair processes.

Note to readers: This article is for informational purposes only and not a substitute for professional medical advice. Always seek the advice of your doctor with any questions about a medical condition.

This report is based on user-generated content from social media. HT.com has not independently verified the claims and does not endorse them.