Highly processed foods
katueng/ShutterstockWe've long known that processed foods with an excess of sugar, sodium, saturated fats, and chemical ingredients can contribute to health conditions such as heart disease, diabetes, and obesity… but cancer? According to a study by French and Brazilian researchers, a 10 percent increase in consumption of ultra-processed foods was associated with a 12 percent increase in the risk of overall cancer and an 11 percent increase in breast cancer. So, what qualifies as an ultra-processed food? Things like mass-produced bread and baked goods, soda, instant noodles and soups, salty and sweet snacks, and chicken nuggets. Less-processed foods, such as pasta, canned vegetables, and freshly baked bread, weren't found to raise cancer risks. These are the cancer-fighting superfoods you should be eating every day.
Rasyidien/ShutterstockThose perfectly darkened-to-a-crisp potatoes may not be so perfect after all—they may actually be carcinogenic. According to a study from the UK's Food Standards Agency (FSA), the culprit is acrylamide, a chemical that's created when starchy foods are cooked at high temperatures. Even though a desired browned crispness may seem "natural" when cooking starches, it can potentially increase risk of cancer and possibly affect nervous and reproductive systems. Burnt or blackened starches have the highest amounts of the toxin, and darkly toasted bread is also a problem. To limit acrylamide creation and consumption, the FSA recommends cooking starches to a light-golden color instead of a dark brown.
taveesak srisomthavil/ShutterstockHere are some sobering statistics: Having just one alcoholic beverage per day could increase your risk of breast cancer by 5 percent, your risk of oropharyngeal cancer by 17 percent, and your risk of esophageal cancer by 30 percent. According to the American Society of Clinical Oncology (ASCO), those numbers go up significantly the more you drink, with those who have more than four drinks per day incurring five times the risk of various throat cancers. ASCO also notes that an estimated 5 percent of new cancers and 6 percent of cancer deaths worldwide can be directly linked to alcohol consumption. So you may want to skip that next round… and cut back on the cocktails in general. Check out these 15 things cancer doctors do to avoid cancer.
Brent Hofacker/ShutterstockYes, it's delicious, but eating too much bacon can be risky. That goes for other processed meats like hot dogs, sausage, ham, and deli meats. After a review of more than 800 scientific studies, the World Health Organization classified meat that has been salted, cured, fermented, or smoked as a carcinogen. Eating 50 grams, or the equivalent of four strips of bacon or one hot dog, every day raises a person's risk of developing colorectal cancer by 18 percent. Another study from the American Institute for Cancer Research and the World Cancer Research Fund found a similarly increased risk for cancer of the lower stomach. The takeaway? If you want to enjoy the occasional processed meat product, go for it—but make sure it's only an occasional indulgence.
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vengerof/ShutterstockBBQ may be a beloved summer tradition, but grilled meat can actually damage your DNA. According to the National Cancer Institute, cooking meat at high temperatures over an open flame or pan-frying it creates two chemicals that can increase your risk of cancer—heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs). And it's not just red meat that's affected; you're equally at risk eating chicken that's cooked this way. How big is the risk? One study found that frequently eating charred meat elevates your risk of developing pancreatic cancer by 60 percent, while another found it nearly doubles the risk of breast cancer in postmenopausal women. Don't miss these 10 other surprising things that can raise your cancer risk.
Lukas Gojda/ShutterstockNo matter how you cook it, consuming red meat may increase your risk of cancer. Eating red meat has been linked to pancreatic, colorectal, and stomach cancers, and the World Health Organization labeled it as "probably carcinogenic" in the 2015 report that also gave processed meats the thumbs-down. Furthermore, researchers from the University of Leeds, who studied more than 32,000 women over 17 years, found that those who regularly ate red meat had higher rates of distal colon cancer (area where feces are stored) compared to those who followed a red-meat-free diet. While that study did not explore the reason, other researchers observing the stool of men and women who consumed a high-meat diet saw high levels of N-nitroso compounds (NOCs), which are potentially cancer-causing chemicals.
Bagels, white bread, and white rice
Mehaniq/ShutterstockEven if you've never smoked, eating a diet rich in certain high glycemic index foods can increase your risk of lung cancer by 49 percent, according to researchers from the University of Texas MD Anderson Cancer Center. Eating high-glycemic foods quickly elevates your blood sugar and increases the presence of insulin-like growth factors that are linked to an increased lung cancer risk, according to the researchers. You don't have to ditch all carbs. Choose lower glycemic index options, such as 100% stone-ground whole wheat bread and rolled or steel-cut oats.
Very hot coffee
taa22/ShutterstockScientists at the World Health Organization's International Agency for Research on Cancer say coffee itself is not carcinogenic, but they do add this caveat: Coffee (or tea) consumed at very high temperatures can increase the risk of esophageal cancer. It's not that high temps activate some kind of carcinogenic compound—it's that constantly scalding your throat with hot liquid could lead to tumor development. According to another study published in the Annals of Internal Medicine that looked at tea drinkers, if you also smoke and drink alcohol in excess, you raise your risk five-fold. So let your beverage of choice cool off a bit before drinking it…and cool it on the other risky behaviors, too.
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Pashu Ta Studio/ShutterstockCutting dietary sugar can cut your risk of cancer. One study found that women who'd consumed the most sweets increased their risk of breast cancer by 27 percent. As glucose and insulin rise, they boost estrogen levels—and that can potentially lead to breast cancer. Another study, published in the journal Nature Communications, found that sugar stimulates tumor growth. Cancer cells need lots of quick energy to grow—more so than regular cells—and consuming high amounts of sugar helps feed them. Here are 6 good habits proven to prevent breast cancer.
Gtranquillity/ShutterstockMen, this one is specific to you: Consuming too much dairy may increase your risk of prostate cancer. And though milk has been studied the most, ice cream, cheese, and other assorted milk-based products may also be a problem. According to Healthline, some researchers believe the strong associations between milk intake and prostate cancer may be due to milk's fat, calcium, and hormone content, while others theorize that ingesting dairy could alter vitamin D and testosterone levels. A 2016 study deemed the dairy-cancer link inconclusive, but if you're at risk for prostate cancer or already have it, talk to your doctor about your diet. Here are 8 myths about prostate cancer all men should know.
Menli/ShutterstockIt's not the popcorn that's the problem here—it's the popcorn bag, the inside of which contains a chemical that keeps kernels from sticking to it. As the bag heats up, the coating decomposes, creating perfluorooctanoic acid, which has been linked to an increased risk of liver and prostate cancers. To avoid this chemical, make your own popcorn: Here's a recipe for homemade microwave popcorn. For similar health hacks, check out these 8 tips to prevent prostate cancer.
Africa Studio/ShutterstockWhile past studies have shown a link between dietary cholesterol and colon cancer, researchers did not understand the exact mechanism behind it, until now. Researchers at UCLA who studied cholesterol in rats found that high levels increased the replication of intestinal stem cells (ISCs), which in turn spurred the growth of gut tissue lining—and also sped the growth of tumor cells, causing them to grow 100 times faster. Yes, you read that right: 100 times faster. While past research had conjectured that a diet high in saturated fat might increase risk for a variety of cancers, including lung, breast, and prostate, more recent thinking is that it's your sources of dietary fat matter most.
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lovelyday12/ShutterstockAccording to Australian researchers just one soft drink per day raises your risk for a bevy of cancers, including liver, prostate, ovary, and gallbladder. In this study, obesity and other weight considerations weren't found to be a factor in cancer development, just drinking sugar-laden drinks. And don't think you're safe choosing diet sodas either: Previous studies have linked artificial sweeteners to obesity, stroke, and dementia, as well as cancer. Here are the 50 best healthy-eating tips nutritionists want you to know.