Coffee drinking linked with reduced risk of colon cancer in women

This week, I’ve been lucky enough to have been on trip (part work, part pleasure) in Kenya. In fact, one of the reasons this blog is being posted a little later than usual relates to the fact that I’m in the wilds, and finding internet access has not been straightforward.

Earlier this week, I was stationed at a hotel just outside Nairobi, which abutted a coffee plantation. In the past I have highlighted the relationship coffee consumption has with benefits for health including a reduced risk of diabetes [1], metabolic syndrome [2], cardiovascular disease in women [3], and a reduced risk of death in individuals with type 2 diabetes [4]. I’m keen to dispel the notion of coffee as a distinctly unhealthy beverage.

This week, further research emerged which supported the inclusion of coffee in the diet. It came in the form of a study published in the International Journal of Cancer which looked at the relationship between about 96,000 Japanese women and men aged 40-69 [5]. Even after taking into account other factors that might affect colon cancer risk (such as exercise habits and other dietary factors), women drinking three or more cups of coffee a day had half the risk of developing colon cancer compared with those who drank no coffee at all. No benefit in terms of colon cancer risk reduction, however, was found in men.

Epidemiological studies of this nature can show associations between things but cannot prove ‘causality’ ” in other words, this most recent research does not prove that coffee drinking leads to a risk reduction in colon cancer in women. However, as I have pointed out in the past, coffee is rich in ‘antioxidant’ substances known as ‘polyphenols’ that one would expect might have disease-protective properties (including a reduced risk of cancer). Also, coffee has a laxative effect on the gut. It’s believed that this may reduce the risk of any potentially cancer-causing substances in the faeces exerting their effect.

References:

1. Greenberg JA, et al. Coffee, diabetes and weight control. Am J Clin Nutr 2006;84:682-93

2. Hino A, et al. Habitual coffee but not green tea consumption is inversely associated with metabolic syndrome An epidemiological study in a general Japanese population. Diabetes Res Clin Pract. 2006 Oct 27; [Epub ahead of print]

3. Andersen LF, et al. Consumption of coffee is associated with reduced risk of death attributed to inflammatory and cardiovascular diseases in the Iowa Women’s Health Study. American Journal of Clinical Nutrition. 2006;83(5):1039-1046

4. Bidel S, et al. Coffee consumption and risk of total and cardiovascular mortality among patients with type 2 diabetes. Diabetologia 2006;49(11):2618-2626

5. Lee KJ, et al. Coffee consumption and risk of colorectal cancer in a population-based prospective cohort of Japanese men and women. Int J Cancer. 2007 Sep 15;121(6):1312-8.

4 Responses to Coffee drinking linked with reduced risk of colon cancer in women

  1. Jean 3 August 2007 at 2:48 pm #

    Interesting note about coffee and a reduction in the risk of colon cancer for women. Does this apply equally to coffee and decaffeinated coffee?

  2. Bill Cockerill 5 August 2007 at 8:56 am #

    Maybe. There is an American study from 2005 at the link attached. They looked at men and women drinking caffeinated and decaffeinated coffee and concluded that :
    “Consumption of caffeinated coffee, tea with caffeine, or caffeine was not associated with incidence of colon of rectal cancer, whereas regular consumption of decaffeinated coffee was associated with a reduced incidence of rectal cancer.”
    I can’t find the full text of the Japanese study John Briffa describes above without paying money for it but I’m sure this paper would comment on the findings of this American one.

    As John often describes, as in all epidemiological studies, you would have to wonder what lifestyle differences there might be between those who drink decaff to normal coffee that the study could not measure? These unmeasured lifestyle choices may well explain the difference in cancer rates found. So the type of coffee someone chooses to drink is associated with certain lifestyle choices which may really protect you against cancer.

    Unsurprisingly causality problems occur throughout science. Global warming is thought to be “caused” by carbon dioxide as it is increasing rapidly in line with global temperatures over the last 1,000 years. However, if carbon dioxide increases as a result of the sun warming (say from sun spots) then we are not to blame for climate change (by the way I think we are!).

  3. Bill Cockerill 5 August 2007 at 8:58 am #

    The link didn’t come through. Here’s the paper described above
    http://jnci.oxfordjournals.org/cgi/content/full/97/4/282

  4. Liz Clarke 6 August 2007 at 3:15 pm #

    Was there any difference between pre- and post-menopausal women?

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