- By Julie Stefanski
- In 2018
- November 27, 2018
Dairy & Cancer Risk: What Did the Experts Really Conclude?
By Julie Stefanski MEd, RDN, CSSD, LDN, CDE
If you had to pick one area of medical nutrition therapy that has the greatest amount of misinformation perpetuated by social media, would you pick cancer? Certainly, information geared towards weight loss dominates twitter and Instagram, but cancer misinformation can harm someone at a very vulnerable spot in their life when decisions about care are crucial to good outcomes.
Karen Collins, MS, RDN, CDN, FAND a Nutrition Advisor for the American Institute for Cancer Research is on a mission to correct social media misinformation when it comes to cancer. Recently Karen has found a significant amount of grossly misinterpreted facts surrounding the landmark report on diet, physical activity and cancer that was jointly released by the American Institute for Cancer Research and the World Cancer Research Fund this past spring. This report which can be accessed here is considered the most authoritative analysis of the body of worldwide cancer research.
Unfortunately several social media posts stating that dairy causes cancer have been attributed to the AICR/WCRF report and this misinformation has been shared extensively across the Internet.
Do We Need to Give Up Dairy To Reduce Cancer Risk?
“The AICR/WCRF report actually has no recommendation pro or con on dairy due to limited evidence. However, it notes a probable reduction in colorectal cancer risk with dairy, so information in any blog post that says dairy is discouraged is blatantly incorrect regarding the report’s findings,” Karen explained.
Whether or not to consume cow’s milk products is a question that is often asked of registered dietitian nutritionists. In terms of cancer, Karen points out how difficult it is tease out this information from the research. “While dairy products, and increased calcium consumption, are associated with lower risk of colorectal cancer, the AICR/WCRF report found data on many other types of cancer including ovarian and breast to be too limited to draw any conclusion. She added, “While limited evidence does suggest potential for increased risk of prostate cancer with diets high in dairy products or calcium, the relationship is unclear when analysis is stratified by prostate cancer type. Evidence rated “limited” is not strong enough to support any recommendation.”
Consumption of red and processed meat is a separate area that the report concluded there was enough evidence to make a recommendation. Karen elaborated, “The AICR/WCRF report identifies red meat that is not processed as a reasonable choice as part of a diet to reduce cancer risk, if amounts are limited to no more than 12-18 ounces/week. Processed red meat is identified as a food to ‘eat little, if any’.”
Why is it so difficult to tease out what foods effect cancer risk?
As an expert in nutrition and cancer Karen shared that it’s often difficult to break down recommendations into simple guidelines. “First, cancer is complex. Scientists try to piece together research results about mechanisms in short-term controlled trials, and results regarding associations (which are not cause-and-effect) from observational studies,” explained Karen. “Research shows potential for diet to play a role at multiple stages in the process of cancer development, which generally spans may years. Even in cohort studies with long follow-up, diet assessment may miss some times that are important. For example, emerging evidence suggests that at least for some cancers, diet, physical activity and body composition at time periods from early life and in adolescence could play a role. Almost all long-term studies are missing this information.”
Some studies may also focus on isolated cells or the mechanism of action in animals. While this can provide valuable information, animals may not digest or metabolize nutrients or other compounds in exactly the same way as humans. Other factors such as our microbiome and individual differences in our genetic polymorphisms may impact our unique risk.
Our Diets Are Complex
Evidence suggests that overall dietary pattern and the way nutrients work together is much more important to cancer risk than single nutrients. Rather than focusing on small, individual studies that focus on single foods for dietary advice, Karen recommends focusing on the big reports which put the individual studies in context. “The AICR/WCRF report notes a potential for a 40% reduction in cancer risk by keeping the whole package of AICR/WCRF recommendations for a plant-focused (not necessarily plant-exclusive) diet, adequate physical activity, avoiding/limiting alcohol, maintaining a healthy weight, avoiding tobacco, and avoiding excess sun.”
While we can’t correct all nutrition misinformation on the Internet, together we can make sure we’re not sharing posts which are not factual or evidence-based.
For reputable cancer organizations to follow on social media Karen recommends:
American Institute for Cancer Research (on Twitter: @aicrtweets )
*AICR also has a blog where RDNs may find helpful commentary on headlines; subscribing is an option — blog.aicr.org
National Cancer Institute (on Twitter: @NCIprevention )
Oncology Nutrition Dietetic Practice Group (on Twitter: @onc_dpg)
World Cancer Research Fund International (on Twitter: @wcrfint)
American Cancer Society (on Twitter: @AmericanCancer )
Centers for Disease Control – Cancer (Twitter: @CDC_Cancer )
American Association of Cancer Research (Twitter: @AACR)
Check out Karen’s other social media picks for cancer focused info:
Danielle Penick, MS, RD, CSO, LDN — @DaniellePenick on Twitter; @Survivors’ Table on Facebook)
Julie Lanford, RD, CSO, LDN — @CancerDietitian on twitter
Anne McTiernan, MD, PhD — (researcher at Fred Hutchinson Cancer Research Center) – @AMcTiernan on Twitter
Julie Gralow, MD – medical oncologist specializing in breast cancer who offers helpful insights, too — @jrgralow on Twitter
Julie Stefanski MEd, RDN, LDN, CDE is a Food, Nutrition & Dietetics subject matter expert for OnCourse Learning, a Relias Company and a national spokesperson for the Academy of Nutrition & Dietetics. You can connect with her on social media @foodhelp123 on Twitter and Instagram.