red and prosessed meat linked to cancer

[demi]

im sure everyone's heard on the news, multiple times no doubt, about the link between prosessed and red meats and cancer, most commenly cancer on the digestive system ( colon, bowel ect ). i think the last thing i heard about it was something llike "2 rashers of bacon a week could give you cancer!" . obviosly this is sumwhat dramatised for making a good news story, but its based in truth.

ok, please correct me if im wrong but im pretty sure about this one. iv been having a debate elsewhere with somone who is adament that this is just more media hype. but i have looked and found an abundant amount of scientific papers published in peer reviewed journals which back this up, yet the person still isnt convinced. am i wrong or are they just 1 can short of a six pack?



look here for example: http://www.plosmedicine.org/article/inf ... ed.0040325

[Susie]

I don't know, but I think I'm on your side. I've just read the China Study, which does the link between meat (or actually animal protein in general) and cancer, and I thought it was fairly convincing but I'm never sure enough of my grasp of scientific method to judge properly (please don't make me read Ben Goldacre right this minute, Demi, I'm having a difficult week ).

[The Riff-Raff Element]

The abudance of papers do not propose a causal link: that was made by the media. There are suggestive statistics, but with these types of studies, isolating a firm, proven, link with an identified cause is very, very, difficult. There are just too many lifestyle variables to take into account. So you're both right, in a way.

[the.fee.fairy]

I think you're both right. As said above, there are so many lifestyle issues to take into account.
If you believe everything in the media about cancer, you'll never eat or drink anything again (fruit - pesticides, water - chemicals etc.).

Personally, I believe that the medical profession still does not know exactly what causes cancer. They are making educated guesses at a lot of things but no-one knows exactly what causes it. It all depends on genetics, lifestyle, habits, even location! Some cancers are unknown in certain parts of the world, whereas some are prevalent.

For example, Breast cancer is virtually unknown here in China, but throat cancer is the most common. They don't have huge incidences of colon cancer, but it's one of the most common in the UK. This could be because of the toilets - they have squat toilets generally here, or it could be to do with lifestyle - lots of rice and oil used in cooking here as opposed to the UK. The strange thing is the breast cancer thing. Doctors in the West (according to the media) speculate that foods such as tofu (high in phyto-oestrogens) are promoting breast cancer in the west, yet it's a commonly eaten food here and they have very low incidences of breast cancer. The women here do not generally breast-feed their children, so one of the best preventatives recommended in the West is completely ignored here, yet they still have a lower breast cancer chance.

Cancer is a mutation of cells - they suddenly 'turn' and start multiplying. It can be predicted, but I don't personally think it can be prevented. It's like anything else genetic - you have blue eyes because your parents both have the recessive gene. You're pre-disposed to breast cancer because of something in the genes.

I read recently that there is a higher percentage of Scandinavian people who are naturally immune to the HIV virus. Genetically, the Scandinavian pool has evolved to be immune to HIV. There are no HIV preventatives (no vaccination - only lifestyle preventatives), yet this particular gene pool has somehow produced an immunity.

I believe that genetics has a higher part to play in whether you get some kind of cancer than lifestyle or what you eat/drink. If you are pre-disposed to cancer in your genes, then you're likely to get it. Eating/drinking/smoking/using whatever is just going to bring the cancer forward.

[demi]

yes, i agree with what your saying but......

when i was at uni we even touched on this in class, about meat being carcinogenus and fruit and veg being cancer inhibitors. so why would they teach that in human biology in the text books if it was just a 'possible' link? ( im going to try to find where it says that from my books )


i agree that in many cases there are probably many facters which contribute to cancer. but this link has been researched again and again, in many many studies, over many decades and they always draw the same conclusion. to quote from the paper i linked to in OP as an example:


"Conclusions
Both red and processed meat intakes were positively associated with cancers of the colorectum and lung; furthermore, red meat intake was associated with an elevated risk for cancers of the esophagus and liver."

how can the come to the same conclusion again and again and still only be a 'possible' link?

[demi]

ok, iv just found in one of my books about cancer. but it only mentions colorectal cancers in like 2 sentences:

from the book 'biology' 7th edition , by Raven, Johnson, Losos, Singer

page 141

"colorectal cancers appear to be fostered by the high-meat diets so favored in the united stated"

page 897

"the human colon has evolved to prosess food with a relativly high fiber content. diets that are low in fiber, which are common in the united states, result in a slower passage of food through the colon. low dietry fiber content is thought to be assosiated with the level of colon cancer in the united states, which is amung the highest in the world."


i had another book but its back in scotland so i dont have acsess to it just now, but it was saying about fruit and veg being cancer inhibitors.

anyway, its been a long time since i was reading about this and i put my hands up as this book is using words like 'appear to' and 'thought to be'. so yes you're right it seems, they still dont know 100%. i was sure about it too, but its been ages since i was reading about it.

[The Riff-Raff Element]

You get this stuff all time, Demi. A little while back there was a piece in one of the blats that suggested a link between smoking & HIV infection, ie, that smokers were more likely to be infected. A quick glance at the source material and it became clear that no link between the two was actually suggested, but simply that smokers were more likely to be risk takers and hence more likely to have unprotected sex. Lifestyle factor, in other words.

Scientists, for all their protestations of purity, are just as likely as anyone else to use weasel words to make a certain impression, particularly if their objectivity is copromised by the need for funds or a personal prejudice.

[Odsox]

"Conclusions
Both red and processed meat intakes were positively associated with cancers of the colorectum and lung;

How can "they" make such sweeping and ambiguous statements ?
Also, what is the definition of "processed" meat, surely ALL meat we eat is processed in some way or another .. cooking is processing.
If they mean bacon and sausages, which they normally do, what is the "processing" that makes it carcinogenic ?
I make my own sausages out of minced pork, (home made) bread crumbs, sage leaves, salt & pepper. What is the difference between that and a shepherds pie made out of minced pork, sage, salt & pepper with bread crumbs on top ?
If they mean additives like sodium nitrite and/or potassium nitrite why don't they specify that instead of such scaremongering terms.

The other "favourite" carcinogen of course is smoked meats, if you combine that with red meat then everyone who eats barbecued steak is doomed.

[gregorach]

And then, of course, there's the question of absolute and relative risk ratios... For example, this meta-analysis finds that:

A daily increase of 100 g of meat was associated with a 14% increased risk of colorectal cancer (odds ratio 1.14, 95% confidence interval 1.04 to 1.25).

A daily increase of 25 g of processed meat was associated with a 49% increased risk (odds ratio 1.49, 95% confidence interval 1.22 to 1.81). Processed meat was defined as processed, cured or nitrate meat, or sausages.

But without knowing the absolute risk, that's not really very informative - for example, if your absolute risk of developing colorectal cancer is 1%, then eating an extra 100g of meat per day (which seems like a fair bit to me) would increase that to 1.14%, which is hardly earth-shattering. According to this, the most significant factor affecting the risk of developing colorectal cancer is a family history of it (genetics), followed by age. So I would say that you probably don't need to worry too much unless you're already at elevated risk because of your family history...

(Also, I absolutely love that definition of processed meat, which basically boils down to "Processed meat is defined as processed meat." Brilliant!)

[Odsox]

And then, of course, there's the question of absolute and relative risk ratios... For example, this meta-analysis finds that:

Processed meat was defined as processed, cured or nitrate meat, or sausages.

Also, I absolutely love that definition of processed meat, which basically boils down to "Processed meat is defined as processed meat." Brilliant!

............. or sausages.
That's it then, no more home made sausages for me.

[Green Aura]

Yeah, right.

[oldjerry]

Since we last dicussed this,about 8 weeks ago,reassured by the reaction from all of you,I have eaten Bovril on toast for breakfast everyday and (this may not be truly scientific) I'm still feeling OK.

It is getting a bit boring though,I might switch to Nuttella.Is that safe?

[The Riff-Raff Element]

Since we last dicussed this,about 8 weeks ago,reassured by the reaction from all of you,I have eaten Bovril on toast for breakfast everyday and (this may not be truly scientific) I'm still feeling OK.

It is getting a bit boring though,I might switch to Nuttella.Is that safe?

Elevated risk of squirels I understand.

[oldjerry]

[Susie]

Can anybody link me to a proper refutation of the China Study? I'd just be interested to see the scientific arguments against it, because when I google I just get nonsense on blogs about it being vegan propaganda (which it certainly isn't: he advocates animal testing).