Friday, February 26, 2010

Cancer - 10 years on we still don't know

We have attended two funerals this year to people of approximately our parents age (or younger!). One a great uncle who had a wonderful wife who I always enjoyed chatting to at family do’s. The other Tiffany attended last week a lovely women, Vanessa,  who along with her husband played an extremely meaningful part in our maturing into young adults. Very tragic in both cases, young grandchild and children who got on well with each other and family.

So it is with some interest I uncovered a paper on diet and cancer prevention that I photocopied from the journal when I was getting into the “wellness” space way back in 2001. Here are some quotes from this paper:
The war on cancer, after 30 years of effort, is only partially won. The age-adjusted cancer mortality rate has declined 1% per year.
 I find this staggering over a 30 years of concentrated effort we have not moved forward significantly. A TED talk by David Angus is great for those who want to know why. However we do know what we need to reduce our risk of cancer. 
It is now estimated that nutrition and lifestyle factors may be determinates of up to 80% of large bowel, breast and prostrate cancer cases and of one third of all cancer cases. 
Ok so 30% of our cancers could be eliminated by dietary and lifestyle changes. What upsets me is that this paper is all but 10 years old. Given the time since this paper I would have expected the public health people to be broad casting this far and wide. 
The ...... expert panel came to a scientific consensus that cancers are largely preventable and that the most effective means of reducing risks are avoiding tobacco use, consuming an appropriate diet and limiting exposure to occupational and other environmental carcinogens. The panel estimated that 30–40% of cancer cases throughout the world are preventable by feasible dietary means. The evidence is convincing—or probable—that diets high in vegetables and fruits protect against cancers of the mouth and pharynx, esophagus, stomach, colon and rectum, pancreas, lung, larynx, breast and bladder. Consumption of 400–600 g/d or more of fruits and vegetables and a variety of fruits and vegetables could, by itself, decrease the overall incidence of cancer by at least 20%, if implemented over time. 
So here we have more studies showing that diet is very important. Go measure out 500 grams of vegetables (vege's are better for you than fruits). This is equivalent to two 250ml cups. However it will be more like three cups because when serving out vegetables you have spaces between them so they are bigger volume than just water.This is quite a lot of vegetables!

Have a look at the following diagram, taken from the paper, of cancer development. Don't worry about the fancy names, see normal on the left and cancer on the far right. What the paper is saying is that the in-between steps can be prevented with nutrition and lifestyle changes.  

Cancer-causing agents and risk factors act or interfere with dietary constituents, such as tobaccos use, sedentary lifestyle, obesity, hormones and growth factors, radiation, environmental chemicals and infections agents.
Any thing on this list that concerns you? I get concerned that in the poor suburb we live in people burn rubbish all the time including plastics! 

The level of exposure of the cell DNA to those and other carcinogens depends largely on the general quality of diet; the presence of bioactivated dietary constituents, including antioxidant vitamins found in abundance in fruits and vegetables, counteracts the effect of these food carcinogens.

So what should be done about this information, the paper stated:

The national goal of cancer prevention programs is now focused on the need for dietary supplements, functional foods and drugs to prevent the onset of intraepithelial neoplasia or suppress or prevent its progression to invasive cancer.
Taking dietary supplements to increase our nutrition - what a clever idea (excuse the sarcasm!) 

A new paradigm for die and cancer prevention, research and strategy must be develop to include the nutrition modulation of the carcinogenesis pathway by nutrients, micronutrients and phytochemicals. This includes biomarkers of the consumption of key dietary compounds.
Markers of dietary compounds would be great. That would tell us how much nutrition we are truly eating as our food can be significantly modified in nutrient levels before we eat them. Furthermore people have different levels of absorption and utilization. Homocysteine and CRP are good starts, but we need many more.

By combining chemoprevention approaches using single nutrients with multiple dietary constituents and functional foods, the scope of the future cancer prevention strategies will be broadened. Research on eating behavior and change dietary patterns as well as psychobiological approaches must be included in any cancer prevention strategy. 
I like the psychological side of things, eating and emotion are closely linked. Furthermore we change slowly and don't like massive change. If you didn't grow up in a culture which ate insects it is rather difficult to imagine doing this - even if they are nutritional wonders. 

Reference: Vay Liang W. Go, Debra A. Wong and Ritva Butrum Supplement: AICR's 11th Annual Research Conference on Diet, Nutrition and Cancer. Diet, Nutrition and Cancer Prevention: Where Are We Going from Here? J. Nutr. 131:3121S-3126S, November 2001.

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