4 Habits That Are Scientifically Proven to Spike Your Cancer Risk
Doctors say these daily activities can have dire consequences for your health.

It's easy to neglect your health when you're busy with day-to-day life. Things like exercise, healthy eating, and managing stress fall by the wayside as you tell yourself you'll worry about them later, when you have time (but when will that be?). But sticking with old habits can have potentially life-threatening consequences. According to the World Health Organization (WHO), lifestyle risk factors such as smoking, drinking alcohol, not eating enough fruits and vegetables, being overweight, and a lack of physical activity are responsible for 30 to 40 percent of cancer diagnoses. Read on to discover which daily habits you should stop now to slash your cancer risk and increase your odds of living a long, healthy life.
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1
Not wearing sunscreen

Though soaking up the sun's rays in moderation can be a great way to get more vitamin D, too much direct sun exposure can lead to several types of skin cancer. Skin cancer is the most common cancer in the U.S., and an estimated 20 percent of Americans will develop it in their lifetime.
Laura Purdy, MD, MBA, a board-certified family physician in Fort Benning, Georgia, tells Best Life, "It's essential to use some sun protection on any exposed skin area. Whether this is wearing a hat, donning long sleeves, or using sunscreen that has a sun protection factor of at least 30, not protecting your skin from the damaging UV rays of the sun can increase your risk of cancer later in life."
"Exposure to UV radiation causes premature aging and, unfortunately, damage to the skin that can lead to disease," explains Bridget Koontz, MD, a radiation oncologist with GenesisCare. "Even as we enter the colder months, it's critical for people of all ages and skin tones to practice sun safety to reduce their cancer risk."
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2
Taking too many supplements

Most of us probably assume that eating a healthy diet and taking a multivitamin are no-brainers for staying healthy. But when it comes to certain nutrients, getting more than your daily fill can be too much of a good thing. "High calcium intake may increase the risk of prostate cancer, and there's a potential association between vitamin D deficiency and colorectal cancer," Purdy explains.
According to a 24-year follow-up study published in The American Journal of Clinical Nutrition, daily calcium intakes exceeding 2000 milligrams were associated with a greater risk of prostate cancer and other deadly forms of the disease. Another study, a meta-analysis published in the British Medical Journal (BMJ) in 2019, found that vitamin D deficiency was associated with an increased risk of colorectal cancer, the second deadliest cancer in the U.S.
However, Purdy notes that many of these studies are ongoing and more research is required to determine the accuracy of these findings. The bottom line? Be aware of how many supplements you're taking to ensure you're not getting too much (or too little) of certain nutrients—and always speak with your healthcare provider before starting any new supplement.
3
Using tobacco

You can't write an article on habits that increase your cancer risk without mentioning tobacco. You likely know that smoking increases your lung cancer risk, but this habit is also linked to several other cancers. "Smoking tobacco also increases the risk of cancer to the voicebox, inside the mouth, esophagus, throat, urinary system, kidneys, and most of your gastrointestinal tract, including the liver, stomach, and pancreas. It can even increase your risk of leukemia," Purdy warns. The bottom line is that using tobacco in any form, whether smoking or chewing, drastically increases your risk of various cancers.
Smoking can also impair your body's ability to fight cancer. "What's unique about this particular habit is that the exposure to tobacco smoke can both cause cancer and block your body from fighting it," says Koontz. "This is because the poisonous ingredients found in cigarettes weaken the body's immune system, making it difficult to kill cancer cells."
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4
Drinking (too much) alcohol

If you enjoy having a cocktail with friends on occasion, or unwinding with a glass of wine after a long week, then by all means, go for it. However, making alcohol consumption a daily habit, or drinking more than the recommended amount per week, can drastically increase your chances of developing certain cancers. How much alcohol is considered too much? According to the National Institute on Alcohol Abuse and Alcoholism (NIAAA), low-risk alcohol consumption for women means no more than three beverages per day and no more than seven drinks per week. For men, avoid having more than four drinks daily, and don't exceed 14 beverages weekly.
"Alcohol can increase the risk of several cancers in the mouth, throat, and digestive system," cautions Purdy. "Also, there's an association between alcohol and increased risk of liver and certain breast cancers. This risk compounds even further if you're someone who both drinks alcohol and uses tobacco products."