Get Proactive: How to Eat to Prevent Cancer

Cancer doesn't have to be inevitable – an astounding one-third​ of the most common cancers can be prevented through diet and lifestyle. Our comprehensive advice from leading experts can help you maximize your health and reduce your risk.
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Cancer doesn't have to be inevitable – an astounding one-third​ of the most common cancers can be prevented through diet and lifestyle. Our comprehensive advice from leading experts can help you maximize your health and reduce your risk.

Hungry for more advice? See The Best and Worst Foods for Cancer Prevention.

Nobody ever wants to hear those three terrifying words: “You have cancer.” And yet, the American Cancer Society reports that slightly less than one in two men and slightly more than one in three women will develop cancer in their lifetime. Additionally, the American Institute for Cancer Research (AICR) reports that cancer is one of the most feared diseases, and most people feel there is nothing they can do to help prevent it. But the reality is that one-third of the most common cancers can be prevented through diet and lifestyle choices such as exercise, according to AICR.

It is estimated that only 5 to 10% of all cancers are related to genetic defects. A genetic defect is an anomaly in a person's DNA (think of the BRCA mutation that increases risk of breast and ovarian cancers, brought into the public eye by Angelina Jolie's case); a family predisposition, on the other hand, implies an increased risk, but not to the same degree as a defective gene. That means that the majority of cancers are not linked to genetic abnormalities, and are linked to other factors such as smoking, our environment, poor diet, physical inactivity and obesity. The good news is that simple changes can significantly reduce cancer risk. For example, the National Cancer Institute reports that exercising 30 to 60 minutes a day can reduce the risk of developing colon cancer by 30 to 40%.

What’s more, research suggests that even genetic predisposition to cancer can be influenced through diet and lifestyle. Pioneering genomics researcher Craig Venter, PhD, emphasizes that you have more control over your health than you may believe. “Genes are absolutely not our fate,” he says. “They can give us useful information about the increased risk of a disease, but in most cases they will not determine the actual cause of the disease, or the actual incidence of somebody getting it.”

Diet is one of the most profound ways you can reduce your risk of developing cancer, according to Lise Alschuler, ND, FABNO, co-creator of the Five to Thrive cancer prevention plan. Alschuler, along with many other cancer experts, recommends the Mediterranean diet to her patients as the best way to reduce cancer risk.

Prevent Cancer By Eating the Mediterranean Way

Countless studies have confirmed the cancer-protective effects of the Mediterranean diet. A recent one, published in the May 2015 issue of the British Journal of Cancer found that women who ate a Mediterranean diet reduced their risk of developing uterine cancer by 57%.

Hallmarks of the Mediterranean diet are fruits, vegetables, whole grains, nuts, spices and olive oil. This diet also includes yogurt and red wine in moderation. As for protein, the emphasis is on fish, cheese, eggs and poultry, with red meat eaten only a few times per month.

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Why is the Mediterranean diet so effective at reducing cancer risk (and many other diseases)? “The Mediterranean diet consists of whole, minimally processed foods brimming with health-protective elements, such as antioxidants, anti-inflammatory compounds, fiber, healthy fats and beneficial bacteria,” says Conner Middelmann-Whitney, nutrition expert, chef and author.

Another key benefit of the Mediterranean diet comes from its wide array of colors. Hundreds of studies have shown that people who eat more colorful fruits and vegetables are less likely to get cancer. Researchers have identified more than 25,000 different phytonutrients in plant-based foods. Best of all, the Mediterranean diet is delicious, inexpensive and convenient.

“Mediterranean cuisine is about flavors, freshness and improvisation rather than formalized recipes and culinary techniques,” says Middelmann-Whitney. “Unlike so many modern fad diets, this diet is also time-tested as people living around the Mediterranean Sea have been eating this way for around 5,000 years.”

Meat or No Meat?

While the Mediterranean diet is not vegetarian, it does focus largely on fruits, vegetables and whole grains. This may be another key to its success – the AICR, the World Cancer Research Fund International and most other cancer organizations recommend a plant-based diet with limited red meat.

See alsoWhy You Should Eat More Plants.

“Consumption of greater than 18 ounces of red meat per week has been linked to increased colon cancer risk,” says Jessica Iannotta, MS, RD, CSO, CDN, chief operating officer of Meals to Heal. “The key is to consume two-thirds or more of your plate as plant foods so the animal protein then becomes a side portion.”

While many studies indicate that vegetarians have a lower risk of several cancers, it seems that including fish in your diet may provide an added protective benefit. A 2015 study in JAMA Internal Medicine demonstrated that pesco-vegetarians who consume fish on a regular basis have lower rates of developing colon cancer than vegetarians, vegans or meat eaters.

But experts don't necessarily recommend cutting out lean meats entirely. “I do not recommend that my patients become vegetarian or vegan,” said Donald Abrams, MD, a cancer and integrative medicine specialist at the University of California, San Francisco Osher Center for Integrative Medicine. “Processed meats should be avoided entirely, but I do recommend limited amounts of lean red meat.”

Alschuler agrees. “The type of meat is important, and not all red meat is bad,” she explains. In fact, studies demonstrate that lean, grass-fed beef is actually a source of healthful essential fatty acids. Furthermore, Alschuler explains that farm-raised fish, especially salmon, can be high in toxic chemicals such as antibiotics. “I always emphasize that my patients should choose organic meat and wild-caught fish whenever possible,” she says. She also says that chicken is another protein source to choose carefully. Non-organic chicken is notorious for containing antibiotics, hormones and even traces of arsenic.

How to Live the Anticancer Lifestyle

Exercising, managing stress and getting enough sleep can all reduce cancer risk. Perhaps most importantly, if you smoke, you should quit. Smoking is a leading and direct cause of a variety of cancers – not just lung.

The simple step of sitting less can significantly reduce cancer risk. A 2014 study demonstrated that each two-hour-per-day increase in sitting time was linked to an increase in the risk of developing some cancers. That study led to headlines declaring that sitting is the new smoking, and several studies since then have drawn the same conclusion.

One of the reasons movement is so important is that it helps maintain normal body weight. According to the AICR, obesity is now directly linked to increased risk of nine different cancers including common cancers such as prostate, breast and colon. This is problematic considering that on average more than 35% of American adults are obese and another 30% are overweight.

Leading cancer organizations recommend at least 30 minutes of exercise five or more days a week. “Sprinkling 30 minutes of activity throughout the day is just as beneficial as doing it all at once,” says Matt Mumber, MD, radiation oncologist and co-author of Sustainable Wellness (New Page Books, 2012). “Every little bit of exercise, even those short bouts, really does add up.”

“The consistent piece of advice I give to all of my patients is to exercise,” says Tina Kaczor, ND, FABNO, a naturopathic oncologist in Eugene, Oregon, and the editor-in-chief of Natural Medicine Journal. “Exercise improves mood, enhances sleep, decreases fatigue and reduces not just cancer mortality, but overall mortality. I advise my patients to rekindle their love of activity and adopt something that is fun to do and then do it regularly.”

The next lifestyle factor to address is stress management. It is likely impossible to remove all stress from your life, but fortunately, you don’t need to do that to reduce cancer risk. “While we cannot often control the amount of stress we are under, we can control how we react to it, and we can support our bodies during stressful times,” says Alschuler.

Take time to relax every day.

Take time to relax every day.

How do you do this? “Focus on the things that bring joy to your life,” recommends Mumber. Taking nature walks, reading, journaling, meditating and many other practices can help you relax and get more joy out of life. The key is to find what resonates with you and then make time – even if it’s just a few minutes a day – to incorporate that activity into your routine.

Adequate rest is another key to reducing cancer risk. Numerous studies have illustrated the dangers of lack of sleep. Inadequate sleep is linked to reduced immunity, increased insulin resistance, poor digestion, hormonal imbalance, increased inflammation and weight gain. The reason this list is so long – and dangerous – is that your body systems are very active while you are sleeping. Researchers have discovered that while you sleep, brain cells shrink by 60% so that waste materials can be more easily removed from the brain. In addition, a full night’s sleep helps balance appetite hormones. When you don’t get enough sleep, your body produces more ghrelin, a hormone that stimulates appetite. That’s one connection between lack of sleep and obesity.

But while sleep is essential, sleeping pills are not the way to get it. A 2012 study demonstrated that even minimal use (just under 18 pills a year) of prescription sleeping medication was associated with a 3.6-fold increase in cancer risk compared to those who took none. Most natural health experts focus on dietary supplements such as L-theanine, magnolia, magnesium, melatonin and others before resorting to prescription sleep aids.

Get Supplemental Insurance

Dietary supplements are just that: supplements to a healthy diet. “In no way should dietary supplements ever take the place of eating a plant-based, whole-food diet,” says Kaczor. “That said, there are some foundational dietary supplements that have been scientifically shown to reduce cancer risk.”

One supplement that Kaczor and many other practitioners focus on is vitamin D because vitamin D deficiency is linked to many cancers, including breast and colon. “Optimal vitamin D levels and dosage are being hotly debated,” says Kaczor. “In my opinion, 40 to 60 ng/ml will help reduce risk of developing cancer.”

A simple blood test can determine vitamin D levels and ensure that those levels are maintained. “The dose of vitamin D supplement is dependent on the results of the blood test,” says Kaczor. Many studies have shown that omega-3 essential fatty acids can help reduce certain types of cancer risk. Omega-3 fatty acids are called “essential” because your cells need a certain amount to function properly and yet your body cannot manufacture them. Instead, you must consume them in your diet through fish, nuts and seeds.

Daily supplements like omega-3s can help you stay healthy for years to come.

Daily supplements like omega-3s can help you stay healthy for years to come.

But when it comes to omega-3 supplements in the form of fish oil, quality is key. “Omega-3 fatty acid supplements are only safe and effective if they are from a source guaranteeing that there are no contaminants and the oils are not rancid,” says Kaczor, who emphasizes that it may be worth spending a little more on this type of supplement. How do you know if a supplement is high quality? Smell it – it should never smell off or rancid. And to be sure about levels of environmental contaminants, you can contact the manufacturer to ask for documentation regarding environmental testing results. For those looking for a fish-free alternative, she says that flax oil and flaxseeds are also great sources of omega-3s.

In order to support immunity and reduce inflammation, Alschuler also focuses on probiotics; polyphenols, such as green tea, curcumin and resveratrol; and antioxidants like glutathione and coenzyme Q10.

“If you think of health as a three-legged stool, the three legs would be diet, movement and mental health,” says Alschuler, “and the seat on top of those legs would be dietary supplements.”

See also5 Supplements to Start Taking Now.

Building Your Cancer Prevention Plan

Research clearly shows that cancer is not inevitable. You can dramatically and positively influence health on a deep level through diet, lifestyle and supplements. And even if you are delivered the three words, “You have cancer,” you can still look for ways
to be a healthy person with cancer. If you or a loved one is diagnosed with cancer, we suggest seeking help from an integrative health care provider who can help you sort through your diet and supplement options.

“Most of cancer care focuses on what doctors do to you – surgery, radiation, chemotherapy,” says Mumber, who feels that just as much attention should be placed on reducing risk. “But what you do for yourself is equally important in preventing this disease.”


Karolyn Gazella has been writing and publishing integrative health information since 1992. She is the co-creator of the Five to Thrive cancer prevention plan and the publisher of Natural Medicine Journal.