Dairy Products Protect Against Colon Cancer, Study Finds
Research shows dairy consumption provides stronger protection for colorectal health than previously known, with a daily calcium intake equivalent to one glass of milk cutting risk by 17%.
STORY AT-A-GLANCE
A study involving 542,778 women found that consuming 300 milligrams of calcium daily (equivalent to one cup of milk) reduced colorectal cancer risk by 17%, while 200 grams of dairy milk daily lowered risk by 14%
Calcium protects against colorectal cancer by binding to bile acids and free fats in the intestine. It also strengthens the gut barrier and reduces gene mutations linked to cancer development
Dairy milk contains additional protective compounds like conjugated linoleic acid, butyric acid and sphingomyelin, which have shown anti-cancer properties in animal studies
Processed meats were also found to increase colorectal cancer risk by 8% per 30-gram daily consumption, primarily due to preservatives and harmful compounds produced during high-temperature cooking
For optimal nutritional benefits, opt for raw, grass fed dairy instead of conventional pasteurized milk varieties, as it retains more beneficial fats, nutrients and natural enzymes
Colorectal cancer is the third most common cancer worldwide, with over 1.9 million new cases reported annually.1 This disease, characterized by abnormal growths in the colon or rectum that become cancerous over time,2 often develops silently, with symptoms like blood in the stool, abdominal pain or unexplained weight loss appearing only in advanced stages.3 4 Left untreated, colorectal cancer will spread to other organs, significantly reducing survival rates.
Your diet plays a role in either increasing or reducing your colorectal cancer risk. Findings from the largest study ever conducted on diet and colorectal risk,5 led by researchers from the University of Oxford, shed new light into how specific dietary factors influence this risk. Among the many variables analyzed, calcium emerged as a key nutrient for maintaining a resilient colon lining.
Recent Study Shows Calcium Protects Against Colorectal Cancer
Published in Nature Communications,6 the featured study explored the relationship between diet and colorectal cancer risk among 542,778 women in the U.K. The research analyzed 97 dietary factors, focusing on their impact on the development of colorectal cancer. The participants in the study, predominantly middle-aged and older women, were followed for an average of 16.6 years.
During this period, 12,251 cases of colorectal cancer were documented. Researchers found a strong inverse association between calcium intake and colorectal cancer risk. Those who consumed 300 milligrams (mg) of calcium per day — about the amount in one 8-ounce glass of milk — experienced a 17% reduction in colorectal cancer risk.7
“Calcium was found to have a similar protective effect in both dairy and non-dairy sources.” Keren Papier, Ph.D., a senior nutritional epidemiologist at the University of Oxford and lead author of the study, said in a report published in Health.8 However, she noted, “We don’t know whether calcium supplements would have the same effect as calcium from food appears to.”
To put this into perspective, the study’s findings demonstrated a stronger protective effect than previously reported in the 2018 World Cancer Research Fund (WCRF) meta-analysis,9 which observed only a 9% reduction for the same calcium increment.
The featured study also reported a 14% reduction in colorectal cancer risk per 200 grams of dairy milk consumed daily, compared to the 6% risk reduction reported by the WCRF for the same amount.10 The researchers explained the mechanisms of action behind calcium’s effects:
“The probable protective role of calcium may relate to its ability to bind to bile acids and free fatty acids in the colonic lumen, thereby lowering their potentially carcinogenic effects.
Furthermore, experimental work in rats has shown that having higher levels of dietary calcium in the colonic lumen reduces colonic permeability, particularly if dietary phosphate levels are also high, thereby helping protect the intestinal mucosa from being injured by potentially harmful luminal contents (e.g. bile acids).
Other experimental work suggests that calcium may also have direct effects on colonic tissue, for example, calcium may promote colorectal epithelial cell differentiation, enhance apoptosis and reduce DNA oxidative damage in the colorectal mucosa. Laboratory studies also suggest that dietary calcium may reduce the incidence of KRAS [gene] mutations in the colon.”11
Essentially, calcium protects the colon by helping neutralize harmful substances that damage the gut lining, as well as strengthening the gut barrier, promoting healthy cell function and apoptosis, repairing DNA and reducing gene mutations linked to colorectal cancer.
Additional Dairy Nutrients That Support Colon and Gut Health
The featured study12 also noted that dairy milk's protective effects against colorectal cancer involves more than just its calcium content. According to the authors:
“If the protective role of dairy milk and the other dairy-related foods is not wholly attributed to its calcium content, other possible mechanisms may relate to conjugated linoleic acid, butyric acid and sphingomyelin which are present in dairy milk and have been shown to inhibit chemically induced colon carcinogenesis in some animal models.”13
Conjugated linoleic acid (CLA), naturally occurring in milk fat, has anti-inflammatory and anticancer properties.14 Chronic inflammation plays a significant role in gut-related issues, including leaky gut, irritable bowel syndrome (IBS) and colorectal cancer. Another study published in Nutrition Reviews15 in February 2025 supports these findings, stating:
“[C]onjugated linoleic acid metabolites produced by certain gut microbiota have demonstrated an anticarcinogenic effect in CRC (colorectal cancer), influencing pathways for inflammation, proliferation and apoptosis.”16
As for butyric acid, this short-chain fatty acid (SCFA) supports your gut health by nourishing colonocytes, reducing inflammation and enhancing the gut’s natural defense mechanisms.17 18 Meanwhile, sphingomyelin, a type of lipid found in milk fat, has been shown in animal studies to suppress early-stage colon cancer development by interfering with the early stages of tumor formation.19
To access these beneficial milk compounds, it’s essential to choose grass fed milk, ideally raw or minimally processed, as it contains higher levels of CLA, butyric acid and other health-promoting nutrients compared to milk from grain-fed cows (more about this below).20 21
Processed Meats Increase Colorectal Cancer Risk
While the study highlighted the protective role of dairy in reducing colorectal cancer risk, it also underscored a significant dietary factor associated with higher risk — processed meats. This aligns with the evaluation of The International Agency for Research on Cancer (IARC), which classified processed meats as Group 1 carcinogens, meaning there is sufficient evidence of their cancer-causing effect in humans.22 According to the researchers:
“We found an 8% higher risk of colorectal cancer per 30 g/day higher red and processed meat consumption; this is equivalent to a 29% higher risk per 100 g/day, which is substantially larger than the 12% higher risk per 100 g/day reported in the 2018 WCRF dose-response meta-analysis.”23
The risk is largely attributed to how these meats are preserved and cooked. Nitrates and nitrites, commonly used as preservatives in processed meats, convert into N-nitroso compounds in the body, which are known to damage DNA and promote cancer development.
High-temperature cooking methods, such as frying or grilling, also produce harmful compounds like heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs), which are both carcinogenic and contribute to mutations in colon cells that lead to cancer over time.24
These findings highlight the need for a more mindful approach to meat consumption. I recommend you opt for fresh, pasture-raised meats over processed varieties while paying attention to your protein intake. Most adults need 15% of their daily caloric intake from proteins, which is approximately 0.6 to 0.8 grams per kilogram of your ideal body weight each day. This refers to the optimal weight for your height, age and gender, rather than your current weight.
Your proteins shouldn’t come exclusively from muscle meats — one-third of it needs to be from collagen-rich sources, such as bone broth and slow-cooked gelatinous cuts like oxtail to ensure a proper ratio of amino acids, which reduces oxidative stress and supports connective tissue, gut health and detoxification.
When It Comes to Dairy, Raw Grass Fed Is Your Best Option
In terms of nutritional quality and the impact on your health, there’s a big difference between grass fed dairy and conventionally produced dairy from concentrated animal feeding operations (CAFOs). Cows raised in CAFOs are fed a diet high in grains like corn and soy while being exposed to antibiotics and hormones to maximize production. This industrialized feeding model alters the nutritional profile of the milk these cows produce.
In contrast, grass fed cows graze on pasture, consuming their natural diet of fresh grass and forage, which enhances the quality of their milk. The research is clear — CAFO milk tends to have lower levels of omega-3 fats,25 CLA and fat-soluble vitamins A, D and K2, while being higher in omega-6 fat linoleic acid, which promotes inflammation when consumed in excess.26 27
Moving beyond the feeding practices, the way milk is processed also makes a major difference in its health benefits. Pasteurized milk — the standard for most store-bought dairy — undergoes high-heat treatment to kill harmful bacteria. While this process addresses food safety concerns, it also destroys many of the beneficial enzymes, vitamins, fats and beneficial bacteria that make milk a valuable dietary choice.
One of the most significant losses in pasteurized milk is lactase, the enzyme responsible for breaking down lactose, the naturally occurring sugar in milk. Without lactase, many individuals experience digestive discomforts such as bloating, gas or cramps when consuming dairy. Raw milk, however, retains its natural lactase, making it easier to digest, particularly for those who are lactose-sensitive.28
Pasteurization also alters the structure of milk proteins, making them harder to digest and more likely to cause inflammation or allergic reactions in sensitive individuals.29 Raw milk, with its unaltered proteins and natural enzymes, is easier to digest and reduces these issues, particularly for those with sensitive digestive systems.
Contrary to widespread belief, raw milk is less likely to harbor hazardous bacteria linked to foodborne illness compared to its pasteurized counterparts. Despite assertions by the U.S. Food and Drug Administration30 and the U.S. Department of Agriculture (USDA)31 regarding the increased health risks associated with raw milk consumption, empirical evidence from foodborne illness data contradicts these claims.
For instance, an investigation conducted by Dr. Ted Beals, who was a pathologist, revealed that the risk of illness from raw milk is 35,000 times lower than from other common food sources.32 Additionally, research using CDC data demonstrated that while 1,100 illnesses were linked to raw milk from 1973 to 2009, pasteurized milk was responsible for over 422,000 illnesses in the same period, with at least 50 deaths attributed to pasteurized dairy.33
Raw Milk Also Contains Odd-Chain Saturated Fats
While much of the focus has been on dairy’s role in colon health, raw, grass fed dairy offers additional benefits beyond colorectal cancer protection. Specifically, it has a unique profile of odd-chain saturated fats (OCFAs), particularly pentadecanoic acid (C15:0) and heptadecanoic acid (C17:0). These fats are particularly beneficial for metabolic and cardiovascular health.
According to a study published in Metabolites,34 C15:0 is a newly discovered essential fat that plays a role in maintaining cellular health and reducing inflammation. It stabilizes cell membranes and reduces the risk of lipid peroxidation and ferroptosis, a type of cell death triggered by oxidative stress and abnormal iron levels.
The study highlighted how low circulating levels of C15:0 correlate with increased risks of chronic conditions like Type 2 diabetes, cardiovascular disease and nonalcoholic fatty liver disease (NAFLD). Researchers observed that sufficient levels of C15:0 help reduce mitochondrial dysfunction, protect cellular energy production and mitigate systemic inflammation.
Heptadecanoic acid (C17:0) complements these benefits. While your body synthesizes small amounts of C17:0, dietary intake from sources like grass fed raw milk is beneficial to maintain optimal levels. According to the Metabolites study, “combined serum C15:0 + C17:0 phospholipid concentrations were inversely correlated with triglycerides, cholesterol, insulin, leptin and PAI-1.”35 These are metabolic markers associated with chronic diseases.
When Can You Find Raw Grass Fed Dairy?
Finding high-quality, raw grass fed dairy takes a little effort, but the health benefits make it well worth the search. Start your search with local farms and co-ops that sell directly to consumers. These small-scale producers are more likely to offer organic, grass fed raw milk.
When visiting a farm, pay attention to how the cows are raised. Grass fed cows should have access to pasture and a diet based primarily on forage, not grains or soy. To give you a starting point, look American Grassfed Association (AGA)-approved farms.
These operations adhere to strict standards, including 100% grass-feeding, no confinement to feedlots and no use of antibiotics or hormones. Cattle are also humanely treated, and exclusively born and raised on American family farms.
Regulations on raw milk vary by state and region, so it’s important to understand the legal status where you live. In some areas, farmers sell raw milk directly to consumers. In other cases, consumers must join herd-share programs. These programs allow you to buy a “share” in a cow or herd, granting you access to its milk while staying compliant with local laws.36
Websites like Raw-Milk-Facts.com offer directories of raw dairy farms and provide details about legality in your state.37 For California residents, Raw Farm USA includes a store locator to find retailers that sell raw milk.38 Resources such as the Farm to Consumer Legal Defense Fund also provide additional guidance, including state-by-state reviews of raw milk laws and information on how to safely access raw dairy.
To ensure the safety and quality of raw milk, look for farms that regularly test for pathogens and share the results with their customers. Ask about their hygiene practices and milk-handling protocols. Certifications like those from the AGA or other trusted organizations indicate that the farm meets higher standards for care and production.
By tapping into these resources and seeking out raw, grass fed dairy, you’re making a choice that supports both your health and the livelihood of local farmers who are dedicated to sustainable, ethical and nutrient-rich food production.
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Sadly, with the help of an IFM naturopath, I have discovered that I am significantly allergic (CAT III - CAT IV antibodies) to all dairy. We're working on gut repair and maybe that might be resolved but as it stands now, any dairy adversely affects my health. And, before anyone comes in with raw or organic stories, that's all I have been consuming for years.
I didn't realize how much of food that I love is dependent on dairy in the mix. Butter, in particular, is one of the best things ever, followed closely by cheese. And here, no surprise, it will help most people to be more healthy! I am working diligently and praying to overcome this condition. It's a huge thing for me. 🙏