Comments on “Cancer and Vegetarianism”
Many people commented on yesterday’s post, Cancer and Vegetarianism, saying they wished the researchers had separated vegans from vegetarians.
In the paper, the authors stated, “…because of the small number of cancers among vegans, in this article the vegans are included in the vegetarian category.”
All we really know from that statement is that vegans didn’t have an unusually large number of cancers – so much that they would have reached some sort of statistical significance. It could also be that vegans have less cancer, or even a lot less cancer, but there was not enough data to create any sort of statistical significance.
I think it’s reasonable to hold out some hope that vegans will eventually be shown to have less cancer than meat-eaters or lacto-ovo vegetarians.
It could also be that except for in cases of very high amounts of animal products and very low amounts of fruits and vegetables, diet might not affect cancer that much. In the more moderate amounts of these foods, your body may be getting enough antioxidants, or have enough other mechanisms, to deal with carcinogens introduced by food.
I didn’t include a citation to the study in the original post:
Key TJ, Appleby PN, Spencer EA, Travis RC, Roddam AW, Allen NE. Cancer incidence in vegetarians: results from the European Prospective Investigation into Cancer and Nutrition (EPIC-Oxford). Am J Clin Nutr 2009;89(suppl):1S-7S.
Comments
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March 18th, 2009 at 4:27 pm
Interesting study – thanks for commenting on it Jack.
I’d be interested to see, in the EPIC-Oxford study, if there is a link between protein and fat intake and say cancer or other diseases? It would not surprise me. Both vegetarians and moderate meat eaters in the west consume lots of saturated fats and protein.
Another point of interest is the % of raw food. When it comes to vitamin intake – fruits and vegetables are best when fresh and uncooked?
Vegans can consume too much protein, fat and cooked foods too – but at least in theory – a vegan diet can offer a low-fat (no saturated fats) and healthy-protein base on a global level. Or would we start killing and milking animals while throwing away all fatty parts which represent most calories in animals?
I am not certain if we need more % protein when we reach adulthood than we need during babyhood when we are growing faster than ever. Yet most of us consume more protein than that when we start aging. Same with fat. What do other apes consume on average when they are adults – protein vs carbs vs fat(saturated vs unsaturated)?
Let’s not even start on sugars and carbs. But at the end of the day – most westerners know that a diet rich in unprocessed (cooked?) foods and not too much saturated fat is healthier than the alternative. Not many follow it.
March 19th, 2009 at 10:03 am
Hugo,
> Another point of interest is the % of raw food. When it comes to vitamin intake – fruits and vegetables are best when fresh and uncooked?
Some vitamins and minerals are better absorbed when food is cooked. It also depends on who much it’s cooked and in what medium.
> I am not certain if we need more % protein when we reach adulthood than we need during babyhood when we are growing faster than ever.
Recommendations for infants are 1.6 to 2.2 g/kg and recommendations for adults are .8 g/kg. It is true that most meat-eating adults get more than this, but vegans get about that much. I have a separate paper on EPIC-Oxford which shows the % of protein eaten by the vegetarians and vegans was 13% of calories, which is in alignment with recommendations. The meat and fish-eaters were about 16.5% and 14.5% respectively (and they ate about 10% more calories than the vegans).
Percentage of fat was 30.5% for vegetarians and 28% for vegans. Saturated fat was 9% for vegetarians and 5% for vegans.
I plan to put an analysis of this paper, as far as macronutrients go, on VeganHealth.org and will make a blog post when I do.
March 19th, 2009 at 12:13 pm
Thanks for the prompt replies Jack. I will stop praising you soon I promise – right now I am too exited that somebody has started blogging about vegan health on such a high level!
> Some vitamins and minerals are better absorbed when food is cooked. It also depends on who much it’s cooked and in what medium.
Sure – I know. Just like we could not digest some animal products “healthily” without cooking. My vegan dogs get beans which have to be processed for them to be able to absorb their protein etc – but it is still not their natural diet only because it is better to cook and puree the food.
I was more thinking of staple ape diets – fruits and leaves which have been around for millions of years – not e.g. beans, legumes or grains. Most apples, bananas, mangos, kiwis, oranges, young leaves etc lose vitamins drastically if cooked? We also do not know much about the value of live enzymes (are they not part of the anti-oxidants rather than only the vitamins and minerals)?
> I have a separate paper on EPIC-Oxford which shows the % of protein eaten by the vegetarians and vegans was 13% of calories, which is in alignment with recommendations. The meat and fish-eaters were about 16.5% and 14.5% respectively (and they ate about 10% more calories than the vegans).
Percentage of fat was 30.5% for vegetarians and 28% for vegans. Saturated fat was 9% for vegetarians and 5% for vegans.
Hmm. These study groups are all so similar – what was the point of studying them in the first place? The only deviation, as expected, seems to be saturated fat – almost 100% difference between vegans and vegetarians.
I have just made a quick & dirty calculation on the protein percentage in human breast milk – it seems to be 6.09%. If that and what you are saying is true – all groups studied consumed at least 100% more protein than what fast-growing babies get.
Based on the theory of evolution and that you cannot study natural behavior in a zoo – I would like to understand why human adults should consume more than 100% protein than human babies or than adult apes. I can understand why somebody trying to grow muscles in the gym might require more protein than a fast growing child – but more than 100%? I don’t know…
PS: How were our current protein “recommendations” derived, when and by whom? Also – what was the total calorie intake of these groups – I have a feeling that is was, also, roughly the same? Stop – just reread your reply and you already got the answer – only 10% less calories for vegans – that is disappointing. How the heck do vegans out there eat? 😉 They apparently do it for the health of the animals, the planet and hence for the health of other humans. That is fine with me – they seem to be as healthy if not healthier than the average eater and do so much good for everybody anyway.
March 21st, 2009 at 4:14 pm
Hugo,
> I have just made a quick & dirty calculation on the protein percentage in human breast milk – it seems to be 6.09%. If that and what you are saying is true – all groups studied consumed at least 100% more protein than what fast-growing babies get.
I’m not sure looking at infants’ protein intake as a percentage of calories is the most accurate way. It could be that, in comparison to adults, growing babies need energy much more than they need protein, and that would explain the lower percentage of calories.
> How were our current protein “recommendations” derived, when and by whom?
The Food and Nutrition Board of the Institute of Medicine Institute, which is part of the National Academy of Sciences determines them. You can read exactly how they did it here.
My understanding is that they base the recommendations mostly on nitrogen balance studies, in which they feed people protein (the only energy producing molecule that contains nitrogen) and figure out at what point are they losing the same amount of nitrogen than they are taking in. That is the point at which they are in balance.
March 23rd, 2009 at 3:40 pm
Jack,
Thanks a lot for your thorough reply.
In retrospect – I was too fast to jump on the protein bandwagon here. The protein percentages you had stated were not that high to start with. And yes we might need more protein after babyhood. But thanks you for the links and in indulging in a maybe personal interest of mine.
Fat is maybe more interesting to analyze as it represents the only substantial difference in the study between vegans and vegetarians. I am not a cancer patient but if I were to feel at risk – I would try to reduce my fat intake below the average 30% in the study and definitely try to increase my raw intake to 50%.
Any diet that you would recommend to a cancer patient based on the research you have seen so far?
March 23rd, 2009 at 4:14 pm
I haven’t seen much research on diets for cancer patients. The only thing that comes to mind is Dean Ornish’s work with prostate cancer patients. Here is an abstract.