Green vegetables, red meat and colon cancer: chlorophyll prevents the cytotoxic and hyperproliferative effects of haem in rat colon.

I've just had a long and fascinating telephone conversation with Jay Bryant. This has inspired me to write three new blog posts. This is the first. There's a recurring theme.

Om, nom, nom!

Lions are obligate carnivores, which means that they must eat meat. Wild lions also eat processed carbohydrates. Wait, WHAT?!?! The word "processed" has bad connotations. However, it merely means "having undergone a process", without specifying what the process is.

Lions tear open the stomachs of their prey. The contents spill out and some are consumed by the lions. What do herbivores eat? Green vegetable matter. Being chewed by the molars of a herbivore is technically-speaking food processing. So, on to the study in the title.

See Green vegetables, red meat and colon cancer: chlorophyll prevents the cytotoxic and hyperproliferative effects of haem in rat colon.

"In both studies haem increased cytotoxicity of the colonic contents approximately 8-fold and proliferation of the colonocytes almost 2-fold. Spinach or an equimolar amount of chlorophyll supplement in the haem diet inhibited these haem effects completely. Haem clearly inhibited exfoliation of colonocytes, an effect counteracted by spinach and chlorophyll. Finally, size exclusion chromatography showed that chlorophyll prevented formation of the cytotoxic haem metabolite. We conclude that green vegetables may decrease colon cancer risk because chlorophyll prevents the detrimental, cytotoxic and hyperproliferative colonic effects of dietary haem."

It's a rat study (experiments on humans are unethical), but there's Heme and Chlorophyll Intake and Risk of Colorectal Cancer in the Netherlands Cohort Study. Finally, there's Associations between Red Meat and Risks for Colon and Rectal Cancer Depend on the Type of Red Meat Consumed.

So, always eat greens with your red meat. A tablespoonful of cooked spinach is all you need.

EDIT: I just found Red meat and colon cancer: should we become vegetarians, or can we make meat safer?

"For instance, promotion of colon carcinogenesis in rats by cooked, nitrite-treated and oxidized high-heme cured meat was suppressed by dietary calcium and by α-tocopherol, and a study in volunteers supported these protective effects in humans."

As dietary calcium binds to haem iron, this suggests that other binding agents would work e.g. phytates (in whole grains) and tannins (in tea).

α-tocopherol is a fat-based antioxidant. Vitamin E supplements contain D α-tocopherol.

The Bear Essentials.

I'm writing about bears. Why? I was having a discussion, oh alright then, argument with a vegan lady. There was a thread on a message board about the slaughter of pigs and she argued that humans are not designed/evolved/w.h.y. to eat meat based on the following list:

Meat-eaters: have claws
Herbivores: no claws
Humans: no claws

Meat-eaters: have no skin pores and perspire through the tongue
Herbivores: perspire through skin pores
Humans: perspire through skin pores

Meat-eaters: have sharp front teeth for tearing, with no flat molar teeth for grinding
Herbivores: no sharp front teeth, but flat rear molars for grinding
Humans: no sharp front teeth, but flat rear molars for grinding

Meat-eaters: have intestinal tract that is only 3 times their body length so that rapidly decaying meat can pass through quickly
Herbivores: have intestinal tract 10-12 times their body length.
Humans: have intestinal tract 10-12 times their body length.

Meat-eaters: have strong hydrochloric acid in stomach to digest meat
Herbivores: have stomach acid that is 20 times weaker than that of a meat-eater
Humans: have stomach acid that is 20 times weaker than that of a meat-eater

Meat-eaters: salivary glands in mouth not needed to pre-digest grains and fruits.
Herbivores: well-developed salivary glands which are necessary to pre-digest grains and fruits
Humans: well-developed salivary glands, which are necessary to pre-digest, grains and fruits

Meat-eaters: have acid saliva with no enzyme ptyalin to pre-digest grains
Herbivores: have alkaline saliva with ptyalin to pre-digest grains
Humans: have alkaline saliva with ptyalin to pre-digest grains

Based on a chart by A.D. Andrews, Fit Food for Men, (Chicago: American Hygiene Society, 1970)

The fact that humans can't digest cellulose (the stuff that plant cell walls are made of) seemed to have been conveniently left off the above list, so I pointed out that if she wanted to play the list game, perhaps she should read http://www.second-opinions.co.uk/carn_herb_comparison.html. Someone then posted a link to Humans are Omnivores. Humans are omnivores. End of.

Then I had a thought. Bears have a digestive system similar to ours. Here's a list of some bears and their characteristics:

Polar Bears: Body composition: Variable (they have a layer of blubber for thermal insulation and they gain body fat when food is plentiful to sustain them through times when food is unavailable). Activity: Very active (pregnant females hibernate). Fertility: On average 2 cubs every year. Diet: 99% meat (there may be some vegetable matter in the guts of the animals that they eat).

American Black Bears: Body composition: Leaner than Polar Bears as ambient temperatures are higher. Activity: Very active (even active when hibernating). Fertility: 2-3 cubs every 2 years. Diet: 10-15% meat, insects & plants.

Brown Bears: Body composition: Leaner than Polar Bears as ambient temperatures are higher. Activity: Very active (even active when hibernating). Fertility: On average 2 cubs every year. Diet: 90% plants, insects, fish and small mammals.

Giant Pandas: Body composition: Fat. Activity: Sedentary. Fertility: 1 cub every 2 years (if the mother has two cubs, she lets one of them die, as she can only raise one cub at a time). Diet: 99% bamboo shoots, but will eat meat, fish and eggs when made available by humans.

Do you see a pattern, here?