Prioritize Organic Vegetables & Fiber, Avoid Ultra-Processed Food

We know that diet heavily influences health, and this may never be so true as when it comes to colon health, because everything you eat quite literally passes through your colon. Indeed, diet is recognized as a modifiable risk factor for colorectal cancer. First, what to avoid. Alcohol has been strongly associated with an increased risk of colon cancer. One meta-analysis of 57 studies from Asia, Europe, Australia, and North America found that moderate drinking (considered 1-4 drinks a day) was associated with a 21 percent increase in risk, while heavy drinking (more than four drinks per day) was associated with a 52 percent increased risk.⁴

Sugar-sweetened drinks like soft drinks have been linked with early-onset colorectal cancer. A study published in 2021 used the Nurses’ Health Study II (1991-2015) to investigate the association between sugar-sweetened beverage (SSB) intake in adolescence and adulthood and the risk of early-onset colorectal cancer. Compared with those who had less than one serving a week of SSB, the women who consumed more than two servings a day as adults had more than double the risk of early-onset colorectal cancer, with the risk increasing by 16 percent with each serving per day. Each serving per day between the ages of 13 and 18 was associated with a 32 percent higher risk of early-onset colorectal cancer.⁵

Sugar-sweetened beverages like soft drinks are a form of ultra-processed foods, and a 2022 study found that a diet high in ultra-processed foods—low in fiber and high in sugar and unhealthy fats—was associated with an increased risk of colon cancer, especially in men. Examples of ultra-processed foods included soft drinks, processed meats, packaged sweet snacks, instant soups/noodles, breads and breakfast foods like granola bars and cereal, and artificial sweeteners. The researchers found that the men who ate the most processed food had a 29 percent higher risk of developing colorectal cancer overall compared to those who ate the least amount; there was a 72 percent higher risk of distal colon cancer specifically (cancer in the lower colon). There was no significant association among women.⁶

So what do you eat for colon health?

Enjoy as many different vegetables and fruits, preferably organic, as possible, aiming to include vegetables in every meal. Veggies and fruit contain a plethora of phytonutrients, like polyphenols and flavonoids, that reduce inflammation, provide antioxidant protection, and promote a healthy bacterial balance in the colon.^{7 8} Like fresh produce, nuts contain an abundance of vitamins, minerals, and phytonutrients that promote colon health, and research has found a significant association between high nut consumption (more than three servings a week) and a reduced risk of colon cancer in both women and men. Different compounds in nuts have been shown to inhibit cancer cell proliferation, in colon cancer specifically, and stop tumor growth, as well as induce positive changes in the gut microbiota.⁹

Nuts, vegetables, and fruit are also excellent sources of fiber, which is highly protective of colon health, and most of us simply don’t get enough. There is plenty of research showing that increased fiber intake (both soluble and insoluble) reduces the risk of colon cancer. A recent study published in the medical journal The Lancet found that eating a lot of fiber from vegetables, fruits, and whole grains can decrease your risk of dying from several causes, including colon cancer. Risk reductions were greatest among those who consumed between 25 and 29 grams of fiber per day, “with additional benefits likely to accrue with higher intakes.”¹⁰

The Mediterranean Diet is one that is full of fruit, vegetables, whole grains, nuts and seeds, antioxidant-rich herbs and spices, healthy protein (including lots of fish), and nutritious fats. Its positive health effects have been studied for decades, and there is research showing that eating a Mediterranean-style diet can reduce the risk of colon cancer, in part through its influence on inflammation, the microbiome, and mitigating epigenetic changes that may play a role in the development of colon cancer.¹¹ And finally, buy and eat organic food whenever possible. Research has found a link between chronic pesticide exposure and colon cancer, and for most of us, diet is our largest exposure to pesticides.^{12 13}

Reinforce with Supplements

Probiotics

A healthy colon is teeming with a diversity of bacteria, but our modern-day lives can shift the balance to one of dysbiosis, or an imbalance of harmful bacteria that may lead to disease. In fact, researchers have found that patients with colon cancer have an abundance of certain pathogenic bacteria and lower amounts of health-promoting species, such as Lactobacillus and Bifidobacterium, suggesting that dysbiosis plays a role in the development of colon cancer.¹⁴ Animal studies have shown that alterations in the colon’s microbial community can directly contribute to tumor susceptibility, but that probiotics, including several species of Lactobacillus (L. acidophilus, L. salivarius, L. plantarum, L. rhamnosus) have protective effects and can inhibit precancerous growths. Research has shown that regular consumption of probiotics can improve the quantity and quality of bacteria in the colon, preventing dysbiosis, reducing inflammation and oxidative stress in the colon, and supporting overall colon health and function.^{15 16} It is best to consume a variety of species, including both Lactobacillus and Bifidobacterium.

EPA & DHA

The development of colon cancer is driven, in part, by chronic inflammation. Indeed, those with inflammatory bowel diseases, such as colitis or Crohn’s disease, have an increased risk of developing colon cancer.¹⁷ The omega-3 fats EPA and DHA are well-documented to have potent anti-inflammatory effects and play an important role in maintaining colon health. Epidemiological studies have found that indigenous populations in Greenland who eat a traditional diet rich in omega-3 fats have a significantly lower incidence of colon cancer, while a typical Western diet, high in processed omega-6 fats, is associated with a high risk for inflammatory bowel disease and colon cancer. The omega-3 fats EPA and DHA reduce inflammation, inhibit the proliferation and metastasis of cancer cells, and induce apoptosis of cancer cells. Research has also shown that taking fish oil in combination with curcumin or the flavonoid quercetin has additional beneficial effects in the colon.¹⁸ Most of us don’t eat enough cold-water fatty fish to get the 3,000 mg per day that is recommended for optimal benefits. A supplement can easily provide these amounts.

Cranberry

These little berries are packed with a plethora of health-promoting phytonutrients that have anti-inflammatory actions, antioxidant power, and anti-carcinogenic properties; they are also a good source of fermentable fiber (fiber that health-promoting gut bacteria use as food). One of the benefits of cranberry is that it maintains its bioavailability in the gastrointestinal tract, where the colon is easily able to absorb its beneficial compounds. In a mouse model of colon cancer, 12 weeks of cranberry supplementation (freeze-dried cranberry powder added to their regular food) reduced inflammatory cytokines and promoted the production of anti-inflammatory cytokines in the colon, improved gut barrier function (key to overall gut health), reduced cell proliferation and induced apoptosis in colorectal tissue, and overall inhibited intestinal tumor development.¹⁹

An earlier study found that administering cranberry juice for 15 weeks to rats with colon cancer led to a 77 percent reduction in the number of “aberrant crypt foci,” a precursor to polyps and one of the earliest changes seen in colon cells that may lead to cancer.²⁰ And finally, in another animal model of colon cancer, mice that ate a diet with a whole-fruit powdered extract added (equivalent to about one cup of cranberries for humans) had about half the number of colon tumors as the mice who had no cranberry extract; the tumors were also smaller.²¹

Vitamin D

According to the American Cancer Society, low vitamin D levels are a risk factor for colon cancer, and studies have shown that higher vitamin D levels are associated with lower colon cancer incidence, reduced polyp recurrence, and are related to better overall survival of those with colon cancer. A recent study showed that women who consumed higher amounts of vitamin D had a significantly lower risk of developing polyps, as well as early-onset colorectal cancer.²² Vitamin D regulates a number of genes which control the growth, differentiation, and survival of cancer cells; it also has anti-inflammatory properties.²³

In one study, researchers fed mice what they called a typical Western-style diet—high in fat (40% of total calories) and low in fiber (equivalent to about 9 grams in a human diet). They also gave the mice inadequate amounts of calcium and vitamin D—equivalent to about 220 mg/day for calcium and 50 IU/day for vitamin D. Another group received the high-fat, low-fiber diet, but adequate levels of calcium and vitamin D (equivalent to the maximum daily intake for adults). After two years, the mice fed the inadequate calcium and vitamin D diet had almost three times as many colon tumors as the control group. Further, the standard diet that included adequate amounts of calcium and vitamin D significantly inhibited tumor development, with no tumors found in the colons of the mice in that group.²⁴

Note: If you are currently undergoing cancer treatment, please check with your doctor before taking supplements.

References

1. ACS Medical Content and News Staff, American Cancer Society. “Colorectal Cancer Rates Higher in African Americans, Rising in Younger People.” September 3, 2020
2. American Cancer Society. “Key Statistic for Colorectal Cancer.” https://www.cancer.org/cancer/colon-rectal-cancer/about/key-statistics…
3. Eric M. Montminy, Meijiao Zhou, Lauren Maniscalco, et al. Shifts in the Proportion of Distant Stage Early-Onset Colorectal Adenocarcinoma in the United States. Cancer Epidemiol Biomarkers Prev 1 February 2022; 31 (2): 334–341. https://doi.org/10.1158/1055-9965.EPI-21-0611
4. Redirko V, Tramacere I, Bagnardi V., et al. “Alcohol drinking and colorectal cancer risk: an overall and dose-response meta-analysis of published studies.” Annals of Oncology, Sept 01, 2011; Vol 22(9) doi: https://doi.org/10.1093/annonc/mdq653
5. Hur J, Otegbeye E, Joh H, et al Sugar-sweetened beverage intake in adulthood and adolescence and risk of early-onset colorectal cancer among women Gut 2021;70:2330-2336. http://dx.doi.org/10.1136/gutjnl-2020-323450
6. Wang L, Du M, Wang K, Khandpur N, Rossato S L, Drouin-Chartier J et al. Association of ultra-processed food consumption with colorectal cancer risk among men and women: results from three prospective US cohort studies BMJ 2022; 378 :e068921 doi:10.1136/bmj-2021-068921
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