As a health professional, I feel compelled to address misinformation on social media on diet and cancer.
Here are some of the common myths explained for those who may otherwise be burdened with a constant barrage of confusing health messages. For a deeper dive into finding evidence based information, take a look at the blog post from AICR titled How to Find Reliable Cancer and Nutrition Information.
Myth #1—Eating Soy Increases Breast Cancer Risk
There is little denying that soy-based foods such as tofu, tempeh, edamame and soy milk are among the most misunderstood and unfairly demonized group of foods.
In addition to being an exceptional plant-based source of fiber, protein, iron and a variety of healthy fats, soy contains a wide array of healthy phytochemical compounds.
A sub group of these compounds very mildly mimic the female sex hormone estrogen, which in part has contributed to the idea that soy consumption is not suitable for women because it disrupts hormone levels and increases risk of conditions such as breast cancer.
There’s only one problem with this claim though that it is not evidence based information.
All of the best and most comprehensive scientific evidence demonstrates that women who consume more soy tend to, if anything, have a lower risk of breast cancer.
In fact, evidence from as far back as 2006 has suggested that soy-based foods may reduce breast cancer risk, although that claim is not fully conclusive it is certainly the case that soy has an at worst neutral influence on breast cancer risk.
Because soy intake is much more common in Asia than it is here in North America, most studies have taken place in that part of the world.
It’s possible as well that the protective effects of soy are brought out by a lifetime of consumption and genetic differences in the way soy is metabolized.
Myth #2—Artificial Sweeteners Cause Cancer
Also referred to as sugar substitutes, artificial sweeteners are compounds that offer a similar sweetness to naturally occurring sugars but contain little to no caloric value.
As a result, they are commonly used in products like diet soft drinks, sugar free gums/candy and other products like ice cream and yogurt where a reduction in sugar may be appealing to potential consumers.
There are a number of artificial sweeteners on the market, among the most prominent being sucralose, saccharin and aspartame.
Perhaps in part associated with their “synthetic” or laboratory produced origins, artificial sweeteners are often demonized in some circles of popular nutrition conversation—especially online.
In fact, it is not uncommon to encounter the sentiment that the consumption of these products is directly associated with an increased risk of various types of cancer.
And while we can fairly accept that these compounds are not super foods, we have to be honest when discussing the state of the evidence around their health effects.
Multiple large observational studies looking at cancer risk and the consumption of these products have not demonstrated any conclusive evidence of a connection.
Myth #3—Sugar Bad, Keto Good
The most pervasive aspect of modern nutrition discourse probably comes in the form of the anti-sugar, anti-carbohydrate movement.
The lines get blurred, however, when all sugar and even foods containing carbohydrates get thrown into the mix.
Foods such as fruits, starchy vegetables like sweet potatoes, legumes such as lentils and chickpeas as well as whole grains like quinoa, oatmeal, brown rice and the like are all very valuable.
There is in fact, as per AICR, strong and convincing evidence that high fiber foods like whole grains reduce colorectal cancer risk.
We also have to acknowledge that many foods that contain naturally-occurring sugars such as berries, cherries and squash contain unique dietary components (fiber, antioxidants) that have a strong potential to reduce the risk of certain types of cancer.
For those who already have been diagnosed with cancer, multiple large studies have failed to demonstrate that a very low carbohydrate ketogenic diet offers any sort of protection or outcome improvement.
In fact, if anything, studies show that higher fruit and vegetable consumption in cancer survivors has a protective effect.
- Wu J, Zeng R, Huang J, et al. Dietary Protein Sources and Incidence of Breast Cancer: A Dose-Response Meta-Analysis of Prospective Studies. Nutrients. 2016;8(11):730.
- Chen M, Rao Y, Zheng Y, et al. Association between soy isoflavone intake and breast cancer risk for pre- and post-menopausal women: a meta-analysis of epidemiological studies. PLoS One. 2014;9(2):e89288.
- Trock BJ, Hilakivi-Clarke L, Clarke R. Meta-analysis of soy intake and breast cancer risk. J Natl Cancer Inst. 2006 Apr 5;98(7):459-71. doi: 10.1093/jnci/djj102. PMID: 16595782.
- Maskarinec G, Ju D, Morimoto Y, Franke AA, Stanczyk FZ. Soy Food Intake and Biomarkers of Breast Cancer Risk: Possible Difference in Asian Women? Nutr Cancer. 2017;69(1):146-153.
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- Toews I, Lohner S, Kallenberg de Gaudry D, Sommer H, Meerpohl JJ. Association between intake of non-sugar sweeteners and health outcomes: systematic review and meta-analyses of randomised and non-randomised controlled trials and observational studies BMJ 2019; 364 :k4718 doi:10.1136/bmj.k4718
- 7. Römer, M, Dörfler, J, Huebner, J. The use of ketogenic diets in cancer patients: a systematic review. Clin Exp Med (2021).
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- 9. Sara Hurtado-Barroso, Marta Trius-Soler, Rosa M Lamuela-Raventós, Raul Zamora-Ros, Vegetable and Fruit Consumption and Prognosis Among Cancer Survivors: A Systematic Review and Meta-Analysis of Cohort Studies, Advances in Nutrition, Volume 11, Issue 6, November 2020, Pages 1569–1582.