Nutrition and Cancer: An Introductory Guide


Chemotherapy and surgery may currently preside as the most effective treatments for cancer, but they can’t do what nutrition therapy can—they can’t (reasonably) prevent the cancer from forming in the first place.

This is the perfect complement to the holistic health movement; the mindful practice of prevention long before any warning signs occur.

The proper dietary choices and eating patterns can sharply reduce the risk of dozens of cancers in even genetically predisposed people, while at the same time conferring a huge list of benefits like improved mood, physical fitness, reduced risk of heart disease, and more.

But thanks to the deafening echo chamber that is the homeopathic/health product market, it seems like everything both causes and prevents cancer. 

It’s time to cut through the noise with evidence-based findings—let’s start by isolating specific foods and nutrients that can affect cancer risk. 

Pro-Cancer Foods

To be clear, none of these claims are guarantees; there will always be exceptional cases of people who consume pro-cancer foods and never develop cancer (and vice versa).

However, findings like this review from the Hallelujah Acres Foundation in Ellensburg, WA, have clearly outlined connections between dietary choices and cancer risk, both in the pro-cancer and anti-cancer department. 

According to this review, which cited data from more than 200 other studies, here are some foods and general dietary patterns that can significantly increase the risk of developing certain cancers:


Sugars in their natural forms (e.g., fruit) have a useful role to play in fueling important cellular processes, but it’s probably not news to you that Americans are overdoing it. 

When glycemic load (i.e., the extent to which a food item raises blood sugar levels) is too high for too long, risk factors for gastric, ovarian, colon, and several other cancers increase significantly, per the Hallelujah Acres Foundation study.

Fiber acts as a crucial buffer when consumed with sugar, as it slows down glucose absorption and chops off the top of that harmful blood sugar spike.

The bad news is that most people are extremely deficient in fiber, but the good news is that consciously addressing this “fiber gap” (while cutting back on added sugars) gives you two ways to reduce glycemic load. 

Red Meat

Cooking certain meats at high temperatures (grilling, frying, etc.) encourages the formation of chemical compounds called heterocyclic amines, which have been reliably linked to cancer.

Unfortunately for our ongoing love affair with red meat, beef is at the absolute center of this connection.

According to the review, red meat consumption was strongly correlated with colon or colorectal cancer in 21 of 26 studies examining the relationship. 

Omega Fatty Acids

Omega fatty acids are essential for many functions, but when the ratio of omega-3 to omega-6 acids is skewed in a certain direction, cancer risk increases.

Particularly, a deficit of omega-3 fatty acids has been shown in many studies to promote breast cancer.

Omega-3 fatty acids promote the production of two breast tumor suppressor genes labeled BRCA1 and BRCA2. 

Omega-3 fatty acids are found abundantly in salmon, nuts and seeds, and other routinely under-consumed foods

Whatever Leads to Obesity

This factor is more open-ended, lumping in a lack of exercise and a large roster of high-fat, sugary foods. 

Point being, the state of obesity in itself has been strongly implicated by the Hallelujah Acres review and many others as a pro-cancer element, as “significant positive associations were found between obesity and higher death rates for the following cancers: esophagus, colon and rectum, liver, gallbladder, pancreas, kidney, stomach (in men), prostate, breast, uterus, cervix, and ovary.”

The mechanisms involved here are numerous, but for cancer prevention and many, many other reasons, the key takeaway is to target a healthy weight using exercise and smarter dietary choices. 

Thankfully, it’s not all bad news; here’s a short sample of some of the most potent anti-cancer foods and dietary patterns: 

Anti-Cancer Foods

Once again, these aren’t guarantees, but the following foods have consistently proven their ability to decrease cancer risk:

Flax Seed

Ticking several of the boxes unticked by the above problems, flax seed provides generous helpings of fiber and omega-3 fatty acids.

In a study by the University of Toronto involving the treatment of cancer-induced mice with flaxseed lignan, researchers found that flax seed prevented both tumor load and metastasis (spreading). 

Fruits and Vegetables

Mom was right—the evidence for the anti-cancer effects of fruits and vegetables is so plentiful, it could never be succinctly described in one article.

Suffice it to say, a diet rich in fruits and vegetables is highly beneficial in this regard; the Hallelujah Acres Foundation study noted that 128 out of 156 studies measuring these benefits noted a “protective effect of fruits and vegetables.” 


If ever there were a single nutrient that could rival the anti-carcinogenic potency of fruits and vegetables, it just might be selenium.

Selenium promotes upwards of a dozen anti-cancer mechanisms, such as the formation of natural killer cells, the inhibition of pro-inflammatory molecules, directly decreasing tumor growth, and many more.

Foods high in selenium include Brazil nuts, tuna, eggs, and chicken, among others. 

Nutrition Therapy Approaches for Cancer Support

Dieting for cancer prevention doesn’t stop after diagnosis; it merely shifts gears to complement your treatment options and treatment-related or cancer-related symptoms.

For example, cancer patients (with or without chemo) often experience cachexia (muscle wasting), fatigue, and nutritional deficiencies, all of which can be addressed with certain dietary choices.

This study by the Indiana University School of Medicine entitled “Nutritional Interventions for Cancer-Induced Cachexia” explains that omega-3 fatty acids, curcumin (in turmeric), certain micronutrients, and resveratrol can help cancer patients maintain a healthier weight.

Additionally, the still-emerging field of immunotherapy for cancer—treatments focused on training the patient’s immune system to combat the cancer—can rely on nutrition to meet therapeutic targets more effectively.

This study from the Università degli Studi di Milano in Milan, Italy, called out several dietary patterns that may improve the immune response to cancer, including the Mediterranean diet, vegetarianism, and the traditional Japanese diet.

Many foods and nutrients are associated with the anti-inflammatory and otherwise immune-boosting benefits of these diets, but the general consensus is that a high intake of fruits, vegetables, nuts, polyphenols, and other natural, plant-based foods will bolster immunotherapy treatments by improving various aspects of the immune response.

Finally, the intestinal microbiome, which refers to the billions of benevolent bacteria that live in the human digestive tract, has many important roles in supporting immunity, cancer or otherwise. 

We can feed and/or supplement these bacteria using prebiotic- and probiotic-rich foods like:

  • Garlic
  • Onions
  • Sauerkraut
  • Yogurt
  • Flaxseed
  • Asparagus
  • Kombucha
  • Tempeh
  • Fermented cheese


Whether you’re genetically predisposed to cancer or not, diagnosed or in preventive mode, nutrition is more than an afterthought.

As we like to recommend, the more natural and well-balanced your diet is, the less you have to dig into the details of which (processed) foods cause cancer or other health problems. 

In other words, load up on the fruits and vegetables, watch the sugar and red meat, and you’ll have far fewer health concerns to contend with.

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