If your doctor recommended a drug that had a 30-50% chance of preventing a life-threatening disease and no side effects, would you take it? I would.
The good news is that 30–50% of cancers could be prevented by eating a nutritious diet, engaging in regular physical activity, and maintaining healthy metabolic function*, research suggests.
However, like many complex diseases, cancer is multifactorial, and I would be lying if I told you it can be fully prevented by avoiding sugar, eating a vegan diet, or intense daily exercise. That’s why I no longer talk about cancer prevention, but rather, about cancer protection or risk reduction.
If you’re dealing with cancer, dietary and lifestyle interventions can further help by giving you back a measure of control over your life. Cancer treatments can feel disempowering due to their physical, emotional, and social impacts. People feel stripped of autonomy and control. Mindful eating, enjoyable physical activity, and tools like savoring can support you and your caregivers through treatment and beyond.
Why Cancer Cannot Be Fully Prevented
Reasons why 100% cancer protection is impossible include:
- Aging is one of the strongest cancer risk factors. As we age, the likelihood of genetic mutations increases and cellular repair mechanisms become less effective. Older people more susceptible to cancers such as colorectal, breast, and prostate cancer.
- Genetic predisposition: An estimated 12% of cancers are linked to inherited genetic factors. While lifestyle changes can reduce overall risk, they cannot eliminate the underlying genetic susceptibility.
- Environmental factors: Exposure to environmental carcinogens, workplace exposure to toxic substances, UV radiation, and certain viruses can increase cancer risk. Mitigation strategies and vaccines can reduce but not eliminate exposure.
- Random mutations: Many cancers result from random DNA mutations during cell division.
What You Can Do to Lower Your Risk
- Get screened. Regular screenings catch certain cancers before they become life-threatening. Please get any screening tests your doctor recommends, no matter how unpalatable they may seem.
- Pap smears for cervical cancer.
- Colonoscopies for colorectal cancer.
- Mammograms for breast cancer.
- PSA screenings for prostate cancer.
- Avoid tobacco. Smoking is responsible for about 25% of all cancer diagnoses and 30% of cancer deaths in the U.S. It is linked to lung, throat, bladder, kidney, and pancreatic cancers. Avoiding tobacco products or quitting smoking is one of the most impactful steps you can take.
- Support metabolic function. Metabolic disturbances rooted in dysregulation of lipid metabolism, hormonal signaling, and inflammatory processes are associated with inflammation, insulin resistance, and several types of cancer, including breast, prostate, liver, kidney, and colorectal cancers (more here). I have written about metabolism and how to support it in a series of posts: here, here, here, and here.
- Eat a nutritious diet that includes fruits, vegetables, legumes, whole grains, herbs & spices, nuts & seeds. These foods are rich in antioxidants and fiber, which can protect against DNA damage and promote gut health. For more on this, read my blog post on Mediterranean cancer protection.
- Be physically active. A large study involving 1.4 million participants found that leisure-time physical activity significantly reduced the risk of 13 types of cancer. Risk reductions ranged from 10% to over 20%. In even better news, exercise doesn’t have to be intense to offer protection: a 2023 study found that brief daily bursts of vigorous activity, like climbing stairs or house cleaning, reduced cancer risks by up to 32% among non-exercising adults.
- Protect your skin. Skin cancer is one of the most preventable cancers. Use sunscreen with SPF 30+, wear protective clothing, and avoid tanning beds to minimize UV exposure.
- Limit alcohol intake. Alcohol increases the risk of several cancers, including liver, breast, and esophageal cancers. The less alcohol you consume, the lower your risk.
Small steps make a big difference
You don’t have to follow every recommendation perfectly to benefit from lifestyle changes. Even small adjustments, like eating a fruit or a vegetable at each meal or going for a 30-minute walk most days, can reduce your overall cancer risk. Cancer protection isn’t about perfection, it’s about making choices that support long-term health.
One easy way to learn about cancer-protective nutrition, movement, and stress-management is to join my hybrid community, Savor. We offer virtual cook-along classes, in-person and online physical activities, Zoom-based Community Conversations with medical experts, mindfulness & stress-management resources, and more.
You might also want to check out the bi-weekly nutrition webinars I teach for the Boulder Community Health Cancer Center; they are free and you don’t have to be a BCH patient to attend. Click here to register.
*Organizations like the WHO, CDC or the AICR recommend having a “healthy weight,” but as researchers are increasingly noting, it may be metabolic disturbances such as chronically elevated insulin that increase cancer risk, rather than elevated body weight or BMI. More on this in a future blog post.)