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Comment by manmal | Hacker News Reader

This is strange. Even if vegetable intake is not beneficial against cancer - should higher veg consumption not crowd out red meat (I think you eat less meat when eating more vegetables), leading to less cases of colon cancer? Also, what about vegetables with high fiber that gets converted to butyrates, and is thus anti-cancer? Is it all BS? Or is "overall cancer" a metric where high fiber might decrease colon cancer but leads to more cancers in other areas?

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Have always been wondering about the supposed actual mechanism of how any meat would lead to colon cancer more/easier/likelier than fibrous foodstuffs, given that it is fibers that tend to end up in the colon whereas meat tends to be entirely liquefied in the stomach (not just softened and mashed as most plant foods are) and the resulting liquid near-on fully absorbed in the small intestines. Especially as the colon's entire purpose is to hold refuse and foreign substances. So somehow a few drops of leftover meat-liquid micro/macronutrients create more damage than roughage and seeds and such? Curious to hear from the better-informed non-epidemiologists out there ;)

possibly acids making it from the stomach to the colon?

>There are several potential reasons to explain how red and processed meat may cause bowel cancer. Red meat contains a compound which gives it’s red colour, haem, which promotes the formation of potentially carcinogenic N-nitroso compounds. In addition when red meat is cooked at high temperatures, this results in the production of compounds (heterocyclic amines and polycyclic aromatic hydrocarbons) that can cause bowel cancer in people with a genetic predisposition. In addition processed red meat has nitrites, as well as nitrates added to it as preservatives and these are thought to cause cancer. Processing also changes the nature of the meat, which may play a role in its link to cancer.

http://www.wcrf.org/int/blog/articles/2015/10/red-meat-and-b...

Interesting theories! And appropriately cautiously formulated, too.. a lot more to actually investigate then:

> how red and processed meat may cause bowel cancer

> compounds that can cause bowel cancer in people with a genetic predisposition

> nitrites, as well as nitrates and these are thought to cause cancer

> which may play a role in its link to cancer.

Do you know if steamed or boiled meats generate HAs and PAH?

I've know about both for a while and switched to only eating meat I've steamed or boiled.

http://cancerpreventionresearch.aacrjournals.org/content/4/2...

>The mechanism is not known, but heme iron has a catalytic effect on (i) the endogenous formation of carcinogenic N-nitroso compounds and (ii) the formation of cytotoxic and genotoxic aldehydes by lipoperoxidation. A review of evidence supporting these hypotheses suggests that both pathways are involved in heme iron toxicity

The irony is, of course, heme iron is the highest bioavailability form of iron, and is one of the main reasons to consume meat in the first place:

http://europepmc.org/abstract/med/3290310

> Food iron is classified as heme or nonheme. Approximately half of the iron in meat, fish, and poultry is heme iron. Depending on an individual's iron stores, 15% to 35% of heme iron is absorbed. Food contains more nonheme iron and, thus, it makes the larger contribution to the body's iron pool despite its lower absorption rate of 2% to 20%.

AFAIK is red meat not causing cancer per se. While there has been a correlation between red meat intake and colon cancer shown, the studies that have shown this didn't differentiate between highly processed products made out of red meat (think of sausage) and rather natural meat (think of steak) itself. The processed stuff is packed with all kinds of sugar, preservatives, flavor enhancer and colouration which might be the cause for the higher rates of colon cancer. To my knowledge these highly processed meat products are not common in Japan.

i think the most important take away with nutrition is eat what your ancestors ate. you're probably not japanese so its less likely that the results apply to you.

I myself switched from drinking soda to OJ. my health declined slowly for a long time until I found out my body doesnt like oranges.

fruit can be healthy but i doubt we are supposed to eat all fruit diets. Astin Kutcher took on Steve Job's all fruit diet and ended up in the hospital with pancreatitis. And we all know what happened to Steve Jobs.

OJ is just sugar water though, the value of fruit is (I think) the whole fruit.

true, but i have an even stronger alergic reaction to the fruit :)

its also worth noting that fruit is sugar water. its 98-99% water + 2% sugar and fiber

Hm. I've heard lots of different angles on not eating fruit but never got these numbers. Thanks!

> its also worth noting that fruit is sugar water. its 98-99% water + 2% sugar and fiber

Oranges, apples, etc are only 85% water. Grapes 80%. The rest is fiber and is likely why your body tells you to stop eating them. Two and a half apples is a lot less appealing than a can of soda (actual sugar water).

The whole percent water thing is completely meaningless though, human brains are 85% water and babies are 80%.

The proportion of water is certainly not meaningless when considering the expected caloric intake of a food administered ad libitum. Satiety is partially controlled by stretch receptors in the gut lining and common sense will tell you it's much harder to consume the same amount of calories from a 2g/100mL sugar solution as from a 10g/100mL solution.

ah, i grossly over estimated the % water in those fruits. interestingly though, fruit juices fall in the 80-90% range I just read.

And the sugar is the wrong one - fructose which is metabolized mainly by the liver whereas glucose is used by all cells in the body.

What about the ones that include the pulp?

the ones with pulp are still providing you with a massive amount of sugar relative to pulp

you can easily drink the equivalent of 12 oranges, in one drink but very very few people can eat 12 oranges in one sitting

there is wisdom in that nature packages sugar with fibre, at times lots and lots of fibre (cane sugar for example)

Cane sugars good and/or not too bad? We used to munch on that as kids, although more often than not we just sucked on it, so probably not so good.

No difference chemically between cane sugar and sugar from beet. It's sucrose i.e., glucose and fructose joined together.

Sucked from cane is not too bad; in that form it has a lot of other nutrients that make it easier for the body to handle.

When it's refined into crystals, is when it does more damage, particularly when consumed to excess.

Depending on how many years you want to go back in your diet, it might be quite hard to find it, artificial selection has rendered most of the food our ancestors ate non-existent.

Which ancestors? When?

By some accounts my ancestors have been eating potatoes and roast meat with quite a lot of beer and / or apple cider, for quite some time.

Dude, OJ isn't healthy.

I tried OJ once, first breakfast in US, OJ instead of milk, puked exactly one hour later, never drank it again. So much for the health benefits of fruit juice.

Any thoughts on what happened? Health benefits aside, vomiting after drinking orange juice is hardly a typical reaction.

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