Vegetarianism and cancer

By Cancer Rose

1 December 2020

The fact that eating habits have an influence on the risk of developing cancer, and that the incidence of cancer among vegetarians in particular is lower than among people having a meat diet, has already been the subject of scientific studies [1].

A more recent publication [2] than the above-mentioned one, analyzing 86 cross-sectional studies and 10 prospective cohort studies, reports a significant protective effect of a vegetarian diet on the incidence and mortality of ischemic heart disease (-25%), and on overall cancer incidence (-8%). The vegetarian diet was found to significantly reduce the overall risk (-15%) of developing cancer.

But a post by the physician essayist and novelist, Dr. Luc Perino, whose articles [3] we often relay, testifies to another aspect of the behavior of vegetarians and vegans that could have an effect on the reduced incidence of cancer among this group of people, namely the lower participation in screening.

Non-carcinogenic diet and participation in screening / opinion column by Luc Perino

We publish here, with the kind permission of Dr. Perino, the post that you can read, among many others, on the author's blog [4]:

There is no longer need to conduct studies in order to prove that lower meat consumption reduces the incidence of cardiovascular disease. The subject is no longer under debate since half a century. Decreased meat consumption and physical exercise have contributed to the new gains in life expectancy observed in recent decades. 

We also know that low-meat diets reduce the risk of colon cancer. In recent years, the large number of vegetarians has made it possible to carry out studies of greater statistical value on the effects of such diets on health. The question of cancers has obviously been addressed and it appears that in addition to colon cancer, the vegetarian diet also reduces cancers as unexpected like breast and prostate cancer. Generally speaking, all cancer risks are reduced to a greater or lesser extent.

Confounding factors such as tobacco have obviously been taken into account, and some studies went so far as to consider other confounding factors such as personality traits and other elements of a reasonable vegetarian lifestyle (excluding fanatical vegans). For example, vegetarian women take fewer hormone treatments during menopause and further reduce their risk of breast cancer.

The funny thing, if I dare to phrase it this way, is that vegetarians participate much less in organized cancer screening programs. Some will conclude that they are carriers of unknown cancers that will develop sooner or later. This hasty conclusion, somewhat tainted by pro-screening ideology, is contradicted by lower overall cancer mortality among vegetarians of all ages who are followed for a long time.

This is explained by the fact that many of the cancers detected are either false positives or cancers that would never have had a clinical manifestation before death from another cause.

Vegetarians therefore have fewer clinical cancers, fewer detected cancers and fewer virtual or sub-clinical cancers. The health benefit of this triple protection is even greater than that already observed in the reduction of mortality. Indeed, the anxiety associated with all screening and the biographical stigma associated with a cancer diagnosis aggravates morbidity and mortality. We know that all cancers, whether clinical, screened or virtual, have the same psychological and biographical repercussions.

We will not go so far as to encourage vegetarians in their diagnostic recklessness, as this could shock the academy. Nevertheless, we must congratulate them for their sanitary perspicacity and their serenity in the face of pathological destiny, without forgetting to praise their climatic altruism.

Study on participation in screening

In the bibliography of this post, cited by the author, we find a study published in the BMJ in 2017 on health behaviors according to population groups following specific diets [5].

31,260 participants were studied from four diet groups (18,155 meat eaters, 5,012 fish eaters, 7,179 vegetarians, 914 vegans) in the British EPIC-Oxford cohort [6]. 

Compared to meat eaters, vegetarian and vegan women reported lower participation in breast cancer screening, and vegetarian men were less likely to undergo PSA testing for prostate cancer. 

No difference was observed in women for cervical cancer screening. 

For women in all non-meat eating groups there was also a lower consumption of hormone replacement therapy for menopause compared to meat eaters. 

Less use was observed for any kind of medication in general among participants in all no-meat groups. 

Conclusion

Behavioral differences, rather in the sense of lower participation in breast cancer screening, prostate cancer screening, lower hormone replacement therapy and overall drug use were observed in the non-meat diet groups. Apparently these population groups are thus less exposed to the risk of developing cancers, less exposed to clinical cancers (revealed by symptoms), and to sub-clinical cancers (not symptomatic), whose over-detection unbridled by mass screening feeds over-diagnosis, and all this in a context of less anxiety, less morbidity and less premature mortality among vegetarians, observed even in the long term, probably in relation to a healthier general life behavior, and not only due to vegetarianism alone [7].

References

[1] https://academic.oup.com/ajcn/article/89/5/1620S/4596951?searchresult=1

[2] https://pubmed.ncbi.nlm.nih.gov/26853923/

[3] https://cancer-rose.fr/2017/07/04/les-billets-de-luc-perino/

[4] https://lucperino.com/715/vegetariens-et-cancers.html

[5] https://bmjopen.bmj.com/content/7/12/e018245

[6] The Oxford Component of the European Prospective Investigation into Cancer and Nutrition (EPIC) is a prospective cohort of 65,000 men and women living in the UK, many of whom are vegetarians.

[7] https://theconversation.com/les-vegetariens-vivent-ils-plus-longtemps-probablement-mais-pas-parce-quils-sont-vegetariens-72929

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Cancer Rose is a French non-profit organization of health care professionals. Cancer Rose performs its activity without advertising, conflict of interest, subsidies. Thank you to support our activity on HelloAsso.