Mediterranean Diet Associated With Reduced Cancer Incidence
The current issue of the British Journal of Cancer includes a report associating the traditional Mediterranean diet “…with markedly and significantly reduced overall cancer….”
Researchers from the University of Athens, the International Agency for Research on Cancer, and the Harvard School of Public Health looked at 25,623 participants of the Greek portion of the European Prospective Investigation into Cancer and nutrition (the EPIC study). Adherence to the Mediterranean diet was assessed with a food-frequency questionnaire.
Cancer developed in 851 participants over an average follow up of 7.9 years. Non-melanoma skin cancers were not included since they are usually not serious or life-threatening. The common cancers in men involved the lung, prostate, colon, and stomach. For women, common cancers were breast, colon, ovary, and uterus.
Participants’ conformity to the Mediterranean diet was graded on a 10-point scale based on consumption of vegetables, legumes, fruits and nuts, cereals, fish, meat and meat products, dairy products, ethanol (alcohol), and the monounsaturated to saturated lipid ratio. A score of zero indicated minimal adherence; maximal adherence scored a nine.
Every two-point increase in adherence was associated with a 12% reduction in the incidence of overall cancer. So those participants with greatest conformity to the traditional Mediterranean diet had a dramatically reduced incidence of cancer compared to those with minimal adherence.
The researchers cite three independent studies that found a similar association between the Mediterranean diet and cancer. The study at hand was not sufficiently powered to determine reliably which specific cancers were reduced with the Mediterranean diet. Other studies indicate that the reduced cancers are prostate, breast, colon, and uterus.
The researchers surmise that the cancer-reducing benefit of the Mediterranean diet relates to the whole diet rather than to individual components.
Steve Parker, M.D., author of the award-winning Advanced Mediterranean Diet: Lose Weight, Feel Better, Live Longer
July 11th, 2008 at 4:47 pm
Very interesting. Are there any hypotheses at the level of cellular biochemistry which attempt to explain why cancer risk is reduced on the Mediterranean diet?
July 11th, 2008 at 8:36 pm
Good question, Dave.
Benetou et al don’t address that at all, somewhat surprisingly. C. La Vecchia and C. Bosetti touch on it in “Diet and cancer risk in Mediterranean countries - open issues,” in Public Health Nutrition, 2006, vol. 9, pp.1077-1082. Here’s a link:
http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=960020
They mention folate and vitamin B-related metabolic genes, flavonoids with antioxidant/antimitogenic/antiproliferative potential, and resveretrol, among others. Also suppression of neoplastic tranformation by omega-3 fatty acids.
-Steve
July 11th, 2008 at 11:00 pm
Hey, Dave, I just spent about 45 enjoyable minutes at your health and nutrition blog, The Spark of Reason. Thank you. I’m linking to it.
http://sparkofreason.blogspot.com/
The best one-word description of your blog I can think of is “iconoclastic.” And I mean that as a complement. I’m sure we have much we disagree on, but would agree that the scientific method is the best way to approach those differences.
-Steve
July 12th, 2008 at 6:10 pm
Hi Steve. I absolutely take the description “iconoclastic” as a complement. Thanks for the link to my blog and the article.
I think you might be surprised at how many things we might agree upon. The belief in scientific hypotheses is never absolute, only shades of gray between the absolutes of “true” and “false”. The degree of belief in a hypothesis is a function of the available information, and thus if two rational people have the same information, they should have the same belief. So it’s important to share information, and for everyone to consider ALL of the relevant information, otherwise science degenerates into arguments over dogma (which sadly occupies far too much of the time and energy).
The article you linked to was interesting, and certainly contained some good detailed biochemical hypotheses as to why certain aspects of the Mediterranean diet could be suppressive toward cancer development. But I thought the section on the supposed detrimental effects of red meat was pretty thin, giving only statistical associations and simply asserting that read meat is bad while providing no hypothesis as to causality. While I have no doubt the statistics play out as described, those don’t really provide an answer to the question “does red meat cause cancer?”
I think it’s an interesting question in the context of the Mediterranean diet, as it is broadly defined as “more of this, less of that” for lots of different types of food. Suppose I flush the grains and pulses and replace those calories with grass-fed beef. Is there any biochemical reason to believe my risk of cancer is increased? I haven’t been able to find any, but maybe you have some more information on this topic, which I would love to see.
July 12th, 2008 at 10:44 pm
You’re right again, Dave. The section on detrimental effects of meat was inadequate. And I don’t recall them mentioning grilled meats or processed meats high in nitrates (nitrites?), which might have a stronger biochemical link with cancer causation.
Off the top of my head, I’m not aware of any studies proving that grass-fed beef directly causes cancer.
-Steve
July 13th, 2008 at 2:19 pm
It’s interesting to dig in to the various “diets” and start pulling out the bits that make sense from a biochemical perspective. When you do this, certain commonalities start to pop up, like some level of reduction in carbohydrates, fruits and veggies for micronutrients, etc. I’m a big fan of meat, and for grass-fed meat there’s plenty of biochemical reasons to like it (omega-3, complete protein, etc.) But muscle meat is probably one of the least nutritious parts of an animal outside of the hooves and hair. Organ meats are considerably more nutrient dense (see my “Cow Guts” meal here: http://www.nutritiondata.com/facts/recipe/515206/2?nc=1), but it’s hard to get this stuff anymore.
July 14th, 2008 at 11:22 am
Yeah, my local Safeway stopped carrying caribou bone marrow.
-Steve
July 14th, 2008 at 4:03 pm
7-11 carries it. North of the Arctic Circle . . .
July 15th, 2008 at 9:56 am
If we start drilling ANWR, Safeway may stock it again.