UKC

Previous thread:

https://www.ukclimbing.com/forums/off_belay/vegan_diet-695545?v=1#x8884696

In reply to Shani (https://www.ukclimbing.com/forums/off_belay/vegan_diet-695545?v=1#x8885121)

First off, major apologies for the insanely slow reply (so slow I've had to start a new thread...) and also for the slightly snotty tone of my last post. I find the whole 'veganism = unnatural and therefore bad' argument extremely frustrating.

Animals turn a good load of stuff i can't eat (like grass), in to stuff i can, like steak. So I'm not overly fussed by fortified animal feed.

Of course if you can provide any research on the matter I'm keen to learn and happy to follow evidence.

That's true, but primarily for ruminants; monogastric omnivores (e.g. pigs, poultry) are much closer to humans than cattle in their diet and alimentary physiology.

There are two angles here: (i) whether agricultural animals provide good proof of principle data for the efficacy of nutritional supplements in man, and (ii) whether the forms of micronutrients in nutritional supplements given to animals are the same or similar [as the micronutrients] that are subsequently consumed by people in products derived from those animals.

I would argue strongly for the former point and tentatively for the latter (in certain circumstances); I’ll focus on the first here.

In addition to the similarities between humans and other omnivores, comparisons to herbivores aren’t as cut and dried as one might think. Iron is an example of a micronutrient that a lot of veggies and vegans worry about:

Mrs Cow eats grass and uses foregut fermentation to degrade the cellulose and whatnot enough to produce a nutritionally accessible digesta. Once it passes into her small bowel a proportion of the ferrous iron present will be absorbed by the action of DMT-1 (a metal transport protein). If the soil growing Mrs Cow’s grass isn’t rich in iron, her farmer may give her supplemental iron as a top up.

Vegetarian and vegan people can digest iron rich plants (leafy greens, peas etc.) and absorb the ferrous iron in them in exactly the same way as Mrs Cow. If concerned about their iron status, they can take similar iron supplements to Mrs Cow, such as ferrous sulphate – for which there is oodles of efficacy data (The down-side of ferrous iron is GI side-effects). https://www.ncbi.nlm.nih.gov/pmc/?term=ferrous+sulfate+efficacy

Now, alternatively, if you or I eat a delicious ribeye steak cut from Mrs Cow's carcass, we will still absorb ferrous iron by DMT-1 but, it being red meat, a significant proportion of the iron will be present as haem (a coordination complex between iron and a porphyrin ring) which has a different (and much more efficient) uptake pathway (via HCP1).

Thus the advantage of eating red meat is that overall iron bioavailability is much higher than for plant sources.

However, there is a correlation between incidence of colorectal cancer and the consumption of haem iron (and only haem iron, not supplemental or plant iron). This raises the question: is it healthier to get iron from meat or from plants with occasional supplementation?  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2840051/

The jury is out on that. I suspect that a veggie heavy diet with sporadic red meat intake is marginally healthier than all out veganism but I am damn certain that a good vegan or vegetarian diet is far healthier than one which is high in red and/or processed meat. https://bmcmedicine.biomedcentral.com/articles/10.1186/1741-7015-11-63

When you consider the myriad of unhealthy/risky behaviours and habits people indulge in for pleasure, the claim that we eat red meat because it's good for us rather than because it's delicious falls a little flat. Ultimately there are plenty of viable alternatives and substitutes for animal products in the developed world. The argument that we should eat meat etc. because we evolved to do so is a specious one and a cop out. People need to take honest responsibility for the costs of their consumption: be it the battery hens that lay our eggs, the dairy cows with ulcerating feet that produce our milk, the child labourers who produce our clothes or the untold millions of rodents and other ‘pests’ who die excruciating deaths (from poison) so we can eat our grains/bread/pasta/etc.   

Disclaimer: I'm not a vegan; I'm a scumbag. And I'm not claiming any moral high-ground here.

You’ve got too much time on your hands bud 

Haha. UKC beats writing my thesis... 

In fact, I wonder what proportion of UKC browsing time is pure procrastination? 90%?

I thought the OP wrote some interesting stuff, so I'm glad he has.

Great post.  

To complicate the mix, you have Impissible Foods using a plant derive heme complex to give their vegan burger that real, blood soaked flavour.  All the benefits and drawbacks of animal refined and concentrated heme with a side order of a less well tested complex that hasn’t been consumed for long enough or in large enough quantities to understand if it’s better or worse than the animal ones for cancers.

+1 to impossible foods for causing a massive schism in the US vegan community that clearly separated the ideologically driven from those wishing to affect good changes.

I never pretend that I eat meat for physical health.  However it is worth considering that mental health is tied up in food both directly (sensation of pleasure) and indirectly (as yet poorly understood but I’ll-bet-my-last “-dollar-it’s-massive interaction of food, the microbiome and the mind). Which just makes it even harder to separate diet and health.  

Certainly my happiness in meat is tainted these days, as is my pleasure in driving, and my enjoyment of the central heating.  I can see how easily environmental in un-sustainability becomes a focus for depression, if not perhaps a trigger.  So I try and make changes, but the more I research and the more I change, the more I realise how little it matters, and how late it would be even if magnitudes more people changed.

You should do a study...

I’m shagging no one but my wife!

Apology accepted. Arguably i did enter the argument with sleeves rolled up, so aplogies also.

The argument you've paraphrased above emerges from thinking about diet from an evolutionary perspective. This is what made me give up veganism a decade ago. I think it is the correct lens through which to determine the likely content of good and bad diet.

Historically I've taken some beastings on UKC regarding low carb diets over the past decade (see my bio), and have lost interest in continually wading through either the research or biology.

But i will take issue with the characterising of meat as unhealthy - even among the unhealthy:

https://www.ncbi.nlm.nih.gov/pubmed/27560647

You might be "damn certain that a good vegan or vegetarian diet is far healthier than one which is high in red and/or processed meat", but i am damn certain that red meat is healthier than (heavily) processed food including all ghe fake meat veg*n food that can simply NOT have existed in our evolutionary past.

As to the dangers of processed meat, this gives some perspective (by Ben Goldacre's mentor no less): 

http://www.dcscience.net/2009/05/03/diet-and-health-what-can-you-believe-or...

Knowing that processed meats did not exist in our evolutionary past, I would question the need to wade through DC science arguments. The greater problem for any of us who wish to consume meat in this day and age is that *non-organic* farm produced meat bears little resemblance to that which our evolutionary ancestors consumed.

While not necessarily disagreeing with possible dangers of processed and "non-organic" meat I also don't know if all humans have been cooking (heat processing) food long enough (one million years?) for their digestive system etc to adapt to it. They would have had shorter lifespans; development of cancer and other diseases commoner in old age might have been immaterial. I imagine getting enough food of any sort would often be a major health factor. Many people today probably just eat too much of everything, multiplying any toxic effects.

Pure ignorant speculation on my part. 

You don't need to cook an animal to eat it. The thrust of you argument around digestive tract adaption, IIRC, is dealt with via the Expensive Tissue Hypothesis and Kleiber's Law.

Reference to the above:

https://www.scribd.com/doc/20045146/The-Expensive-Tissue-Hypothesis

"If an encephalized animal does not have a correspondingly elevated BMR [which according to Kleiber, it can’t], its energy budget must be balanced in some other way.  The expensive-tissue hypothesis suggested here is that this balance can be achieved by a reduction in size of one of the other metabolically expensive organs in the body (liver, kidney, heart of gut).  We argue that this can best be done by the adoption of a high-quality diet, which permits a relatively small gut and liberates a significant component of BMR for the encephalized brain.  No matter what was selecting for encephalization, a relatively large brain could not be achieved without a correspondingly [sic] increase in dietary quality unless the metabolic rate was correspondingly increased.

At a more general level, this exercise has demonstrated other important points.  First, diet can be inferred from aspects of anatomy other than teeth and jaws.  For example, an indication of the relative size of the gastro-intestinal tract and consequently the digestibility of the food stuffs being consumed is provided by the morphology of the rib cage and pelvis.  Second, any dietary inference for the hominids must be consistent with all lines of evidence.  Third, the evolution of any organ of the body cannot be profitably studied in isolation.  Other approaches to understand the costs of encephalization have generally failed because they have tended to look at the brain in isolation from other tissues.  The expensive-tissue hypothesis profitably emphasizes the essential interrelationship between the brain, BMR, and other metabolically expensive body organs."

Agree, eg oysters. Though cooking probably assists ingestion and digestion, kills some microorganisms and parasites, and enhances flavour. The point I was trying to make is that cooking has similarities to processing in that a vast number of new chemicals are probably produced by surface burning and heating, of which some may be toxic (occasional scare stories in the media about toast etc). Also some nutrients may be lost during cooking.

Still trying to get to grips with your reference! Presumably our teeth and digestive tract including, I think, shorter intestine than herbivores are indicative of our omnivore ancestry.

PS Just back from a good value Full English in new cafe. Yum. I certainly don't eat like this most days though.

More calories to digest raw meat than if the same amount of raw meat is minced & cooked. 

https://www.ncbi.nlm.nih.gov/pubmed/17827047

Think of fire and cooking as in part, outsourcing the digestion process.

Yes.

Then that counts as an advantage - we're not averagely short on calories are we?

Excellent well thought out post. I salute you sir

In light of the Expensive Tissue Hypothesis, you're wrong - certainly in an ancestral sense.

That's not been the case for most of human history, pre-history and evolution over millions of years.

pardon me - I thought the discussion was - what is correct now in our age ? in all events - a good reminder how awfullly our diet has changed - esp given decline in energetic demand of your average office/factory employee

To think purely in terms of calories will lead to erroneous conclusions around appropriate diet.