Posted by: themossreports | November 20, 2010

Does Dairy Cause or Promote Breast Cancer?


Does cheese promote breast cancer?

A 1995 prospective study from Norway once showed that a high consumption of whole milk increased the risk of breast cancer: “Consumers of 0.75 litres or more of full-fat milk daily had a relative risk of 2.91 compared with those who consumed 0.15 litres or less” (Gaard 1995).

However, a new study from the Norwegian Women and Cancer contradicts this. The authors looked at the consumption of  specific dairy products, as well as total dairy, in almost 65,000 women between the years 1996 and 2006. During this time, 218 of the premenopausal and 1,189 of the postmenopausal women developed breast cancer. Their conclusion was that “total dairy, adult, and childhood milk consumption was not associated with either pre- or postmenopausal breast cancer risk.”

Previous studies also have failed to establish a dairy-breast cancer link. These have included two epidemiological studies (Moorman, 2004 and Parodi 2005), a metaanalysis (Boyd 1993) and a pooled analysis of cohort studies (Missmer 2002). They all concluded that there is no evidence for a strong association between dairy consumption and breast cancer risk.

This is similar to the conclusions of Shin et al. at Harvard that there was  “no association between intake of dairy products and breast cancer in postmenopausal women” (Shin 2002). However, this recent Norwegian study failed to confirm Shin’s finding that “among premenopausal women, high intake of low-fat dairy foods, especially skim/low-fat milk, was associated with reduced risk of breast cancer” (ibid.).

Defenders of the low-fat vegan (LFV) diet, such as Prof. T. Colin Campbell, point out that there was no group in this Norwegian study that avoided dairy on principle (Campbell 2010).

In the study’s convoluted English, the low dairy consumption group was defined as those participants who had “‘no milk consumption as a child or 1st quartile of dairy consumption as adult and not more than next-lowest consumption (1–3 glasses/day)….” Thus, by my reading, if you did not drink milk as a child but now consumed a limitless amount of dairy, you were still ranked as a low consumer! On the other hand, you are also a low consumer if you drink the equivalent of an 8 oz. glass of milk per day. The low consumer group could therefore contain alot of people who, by vegan standards, would be high consumers. Any difference between such “low consumers” and strict vegans would not show up in this analysis.

While the present study certainly does not support the LFV hypothesis in regard to breast cancer, advocates of that diet do have a point when they object that any beneficial effect of strict dairy avoidance would be unlikely to show up in such a study.

References

Boyd NF, Martin LJ, Noffel M, Lockwood GA, Trichler DL. A meta-analysis of studies of dietary fat and breast cancer risk. Br J Cancer. 1993;68:627–636.

Campbell TC. Personal communication, Nov. 17, 2010.

Gaard M, Tretli S, Løken EB. Dietary fat and the risk of breast cancer: a prospective study of 25,892 Norwegian women. Int J Cancer. 1995;63(1):13-17.

Hjartåker A, Thoresen M, Engeset D, Lund E. Dairy consumption and calcium intake and risk of breast cancer in a prospective cohort: the Norwegian Women and Cancer study. Cancer Causes Control. 2010;21(11):1875-1885.Moorman PG, Terry PD. Consumption of dairy products and the risk of breast cancer: a review of the literature. Am J Clin Nutr. 2004;80:5–14.

Missmer SA, Smith-Warner SA, Spiegelman D et al. Meat
and dairy food consumption and breast cancer: a pooled analysis
of cohort studies. Int J Epidemiol. 2002;31:78–85.

Parodi PW. Dairy product consumption and the risk of breast cancer. J Am Coll Nutr. 2005;24:556S–568S.

Shin M, Holmes MD, Hankinson SE, et al. Intake of dairy products, calcium, and vitamin d and risk of breast cancer. J. Natl. Cancer Inst. 2002;94(17):1301-1311.

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Responses

  1. While I do not support veganism, I do support a very low dairy intake. A recent powerful study has been published showing a very significant increase in prostate cancer by men who eat diary. In the light of this, if the link between dairy and breast cancer is inconclusive, a better study needs to be designed. Hillel Fridman

  2. G’day Dr.Ralph.
    Robert Cohen,PHD has extensively covered the cancer-dairy connection at his website:
    http://www.notmilk.com
    -just click ‘ NEWSLETTER
    Read NOTMILK Newsletters’
    in the upper right corner
    cheers

  3. There is virtually no evidence of a connection between milk/dairy products and cancer, other than prostate cancer. I can quote any number of papers if necessary. In the latter the connection is only between milk and prostate cancer, not dairy products (eg cheese) in general. The chances are the connection is coincidental. That is, high milk consumption in the presence of a vitamin D and vitamin K2 deficiency may cause calcium to be deposited where it should not be, in the arteries and prostate. As well, a deficiency of monounsaturated and omega 3 fats coincidental with high milk fat consumption may be unhelpful. But should we blame milk and dairy products for our dietary shortcoming? The illogical answer of the dairy bashers, is yes. As an aside, there is a considerable body of research which indicates a powerful protective effect of milk against Metabolic Syndrome (diabetes and cardiovascular disease). The ideal is a diverse diet such as the Medierranean diet, which has a little bit of everything – including dairy products.

  4. Many thanks Ralph for digging beneath the headline of this study in your dependably concise way. This really is a very serious issue worthy of investigation beyond the warring factions, as dietary variations are probably the most significant factors generating the starkly differentiated statistics from different cultural groups. We desperately need to know exactly which factors are driving the relentless increase in incidence.

  5. These studies – milk, dairy, supplements – or the reporting of their conclusions, always seem to leave out key information. Was the milk hormone and anti-biotic free, for example, and if not perhaps it’s the extra/artificial hormones that affect hormone-sensitive cancers rather than the dairy product itself. The same questions for the meat-cancer connection studies. And what about goat milk? As for supplements, I seldom see what dosage is used (which is usually too low when it is reported) and information regarding the quality of the supplements. What value is debating the conclusions if the studies themselves are inadequate? How can we encourage more useful studies?

  6. Dr. Oz on his recent t.v. show reported his concern at the premature breast development in large numbers of girls, aged 7 to 10 years of age, and connected it to hormones in milk products. He decided to stop his own daughters from drinking milk from cows who had been given hormones. Young boys are also developing breasts at an early age. Doesn’t this give one pause?

    • Part of the situation with men getting breasts is simple overweight and metabolic syndrome due to the typical American diet. Since fat cells tend to produce estrogen by aromatizing testosterone, overweight and other things such as excessive beer consumption lead to an excess of estrogen.

  7. I am unclear why there is never mention in any of these studies about the fact that we do not have the capacity to striate for dairy products with hormones added versus dairy products that are produced without hormones, antibiotics, etc. This is particularly problematic for women with ovarian cancer who are told that they should not eat dairy. If you have OV CA and have had a bowel obstruction, it is seriously challenging to eat enough protein without using some dairy products. I do not believe that any of these retrospective studies have any validity (I am more likely to appreciate epidemiological studies, but in those there is so little control about remainder of lifestyle influences). Therefore, I do not think there should be presentation of this information without really determining how to evaluate all influencing factors. When someone has cancer, or is concerned about being diagnosed with cancer, they often take these smaller studies as completely valid. This only leads to more self blame, as opposed to looking at the bigger picture of true causes of cancers (incidence is up even if treatment is better!).

    Dr. Moss, when you present the much needed information in your newsletter, please include all of the limitations of this information. IF someone wants to do everything possible to benefit their health, they should be considering the positive benefit of limiting some of these food products in relationship to heart disease, etc. Finally, this also does not striate for the considerations pointed out by Yancy and his dietary suggestions in regard to whole milk versus skim milk, etc.
    Beverly

    • Dr Moss — a few people, myself included, have called for help regarding whether these studies took into consideration the hormone aspect of the milk. Have I missed a reply? Incompletely communication of studies like this do a great disservice to people already traumatized by a life-threatening illness. Soy, milk, wine, resveratrol, wheat germ extract, mushrooms, vitamins D, E, C, etc. – do they help to prevent cancer and recurrence of cancer or do they provoke it? The inconsistency in information and outcome might be in the structure of the studies themselves, but reporters of the “results” seldom delve further than the headlines. Do you have further thoughts on this, particularly the hormone connection?

  8. Hello… When this article first came out, I submitted a comment. It questioned the parameters of the study and if information was available related to whether or not the dairy used was hormone free or otherwise and how important this information would be to a valid study connected to hormone-sensitive cancers. The comments were not inappropriate. Could you tell me why they were not posted or if I somehow submitted incorrectly. Thank you.

  9. i know many people never thought that it was the substitution of water for milk that cause prolonged cellular dehydration , in turn cause the DNA compromised state of code transference and cancer cells to develop. By nature inants should drink only mother’s breast milk, Once the milk teeth in place, fresh fruits and fresh veggies should be the natural diet.

  10. I would add to the above caveats about whether the study differentiated hormone free milk, full fat vs. non-fat etc., that there also is no mention of different genetic make-ups; as I recall, not everybody digests milk easily; though I believe generally people from Northern and Eastern Europe do have the proper enzymes to digest milk through adulthood, but most other human populations need their milk products to be fermented or cultured in order to digest them. It certainly seems possible that this genetic factor should be added to the discussion


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