Question: I have been told that eating dairy foods causes cancer, is this true?

Answer: To begin with, what type of cancer are you referring to? Cancer is not a single disease but over 200 different diseases that fall under the classification of cancer.

There are cancer causing substances where it is easier to make a definitive statement, but trying to determine a connection between a food and ‘cancer’ is very difficult due to a multitude of variables (meaning lots of other factors involved). For example, if someone smoked cigarettes for 30 years and developed lung cancer are we going to say it was the glass of milk they drank every night? After sunbathing on a beach for 20 years and developing melanoma are we going to say it was the ice-cream consumed while ‘roasting’ that caused cancer?

When looking at human subjects we rely heavily on observational research which although cannot prove cause and effect can give us patterns of disease. If it were true that eating dairy foods caused cancer you would see multiple studies that consistently showed a marked increased risk of cancer that was dependent on dairy intake. This is not the case.

The American Institute of Cancer Research Continuous Update Project (CUP), is an ongoing program that analyzes cancer prevention and survival research related to diet, nutrition and physical activity. They collaborate with scientists from all over the world looking at thousands of studies and evaluate the data.

The latest CUP report conclusion regarding dairy and colorectal cancer stated ‘consumption of dairy products probably protects against colorectal cancer’. What is pertinent here is the use of the word probably, this is the type of terminology that you find in legitimate scientific reporting. Additionally, a large meta-analysis (lots of studies combined into one) found that women with the most dairy (low fat) in their diet had a 15% reduced risk of breast cancer. However, another large observational study found that dairy is neither protective against, nor increases the risk of breast cancer — neutral in other words.

There is a small group of women who due to a genetic defect can’t metabolize a carbohydrate in milk and this puts them ‘at risk’ for developing ovarian cancer. But you know what? Being tall is also a risk factor for ovarian cancer and yet there are millions of tall women in the world who do not develop ovarian cancer.

It is important to report science without bias, in other words you must report the truth even if it does not fit your hypothesis (idea you want to prove). Unfortunately, there are groups often with doctors involved who ‘cherry pick’ data in order to support their claims. You will find bias in extreme groups, people trying to sell a book or a specific program or product.

We can suggest that eating a plant based diet (which does not mean totally eliminating all animal products) being a healthy body weight, exercising, not smoking, limiting alcohol, not relying on dietary supplements for nutrients, and getting regular check-ups (especially if you have cancer in your family), is the best bet to reduce your risk of developing cancer.

From the American Medical Association report, ‘ethical physician conduct in the media’, and which I include as a reminder to anyone in health care who deals with the general public, ‘A message that is inaccurate, questionable or false may still be perceived as authoritative because it comes from a physician. Material that is of poor quality and does not meet expected standards of scientific rigor can mislead individuals who do not question the content of the message, while the promotion of such subpar work can erode the public’s trust in the larger medical community.’

Coming soon to the Community Cancer Center website, various tools to help the lay person evaluate health information on the internet and how to spot ‘pseudoscience’. In other words how to identify misinformation in the cancer world.

Bottom line: If you have questions about cancer, ask an oncologist (experts in the field of cancer).

People can choose not to eat dairy for a whole host of reasons, but don’t let biased reporting about cancer risk be one of them.

Ally Gottfried is a registered dietitian at the Community Cancer Center in Roseburg. She has over 20 years of experience in hospitals, pediatric health and community settings.

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