The Dangers of Eating Raw Meat: Reasons Beyond Microbes

[pa5tabear]

I know that cooking meat kills most microbes that will make you sick if consumed. This is the main reason why eating raw meat is dangerous. Are there other reasons as well? I assume it's "okay" to eat raw meat, but that the body will not digest it as easily, due to more protein structure/bonding that must be broken down before the amino acids can be utilized for energy or synthesis of proteins for regeneration.

 

[jim mcnamara]

'Humans have evolved to consume cooked foods' (E. O. Wilson 'The Social Conquest of Earth'). Meaning we derive nutrition more readlily from cooked than raw foods, as you noted.

The natural antigens in meat are denatured by cooking - this means you may be less likely to have an allergic reaction to cooked meat and other foods:

Ann Allergy. 1993 Jun;70(6):467-9. K. Kondo et al
Reduced responses of peripheral blood lymphocytes to heat-denatured food antigens in food-sensitive atopic dermatitis.

So can we conclude that raw meat is slightly less healthy, at least?

 

[pa5tabear]

'Humans have evolved to consume cooked foods' (E. O. Wilson 'The Social Conquest of Earth'). Meaning we derive nutrition more readlily from cooked than raw foods, as you noted.

The natural antigens in meat are denatured by cooking - this means you may be less likely to have an allergic reaction to cooked meat and other foods:

Ann Allergy. 1993 Jun;70(6):467-9. K. Kondo et al
Reduced responses of peripheral blood lymphocytes to heat-denatured food antigens in food-sensitive atopic dermatitis.

So can we conclude that raw meat is slightly less healthy, at least?

No doubt about the less healthy part. I'm just trying to understand why.

I know that the body reacts to the presence of antigens. I know that antigens are molecules (generally proteins) that cause antibody generation. These antigens could be surface proteins on microbes, or they could be protein molecules found in food.

It makes sense that cooking something might reduce an allergic response. In general, though, is your body going to pumping out antibodies in response to raw meat consumption?

I assume your body might harness less energy, but otherwise, are there still problems?

 

[Evo]

Cooking meat also increases the energy it provides.

In a first-of-its-kind study, Harvard researchers have shown that cooked meat provides more energy than raw meat, a finding that challenges the current food labeling system and suggests humans are evolutionarily adapted to take advantage of the benefits of cooking

http://news.harvard.edu/gazette/story/2011/11/why-cooking-counts/

 

[Monique]

I know that cooking meat kills most microbes that will make you sick if consumed.

Don't forget the parasites. I don't think research has been done to study the effects of uncooked meat in the human bowel.

 

[Darwin123]

I know that cooking meat kills most microbes that will make you sick if consumed. This is the main reason why eating raw meat is dangerous. Are there other reasons as well? I assume it's "okay" to eat raw meat, but that the body will not digest it as easily, due to more protein structure/bonding that must be broken down before the amino acids can be utilized for energy or synthesis of proteins for regeneration.

People do sometimes eat raw meat. I don’t know if we “evolved” to eat cooked meat. However, some people eat raw meat some of the time without apparent problem.
Steak tartare usually contains raw beef.
http://en.wikipedia.org/wiki/Steak_tartare
“Steak tartare is a meat dish made from finely chopped or minced raw beef or horse.[1][2] Tartare can also be made by thinly slicing a high grade of meat such as strip steak, marinating it in wine or other spirits, spicing it to taste, and then chilling it.[citation needed] This is often served with onions, capers and seasonings (the latter typically incorporating fresh ground pepper and Worcestershire sauce), sometimes with a raw egg yolk, and often on rye bread.
Although less common than the completely raw variety, there is a version served in France of steak tartare called tartare aller-retour. It is a mound of mostly raw steak tartare that is lightly seared on one side of the patty.”

Fish is meat. Sushi usually contains raw fish or crustacean.
http://en.wikipedia.org/wiki/Sushi
“Sushi is a Japanese food consisting of cooked vinegared rice (shari) combined with other ingredients (neta), usually raw fish or other seafood. Neta and forms of sushi presentation vary, but the ingredient which all sushi have in common is shari.”

 

[Monique]

People do sometimes eat raw meat. I don’t know if we “evolved” to eat cooked meat. However, some people eat raw meat some of the time without apparent problem.

Just because people don't get instantly sick, does not mean it is without problem..

Also, beware that raw products are often processed before consumption other than heating (freezing/brining):

Sashimi or other types of sushi containing raw fish present a risk of infection by three main types of parasites:
* Clonorchis sinensis a fluke which can cause clonorchiasis[34]
* Anisakis, a roundworm which can cause anisakiasis[35]
* Diphyllobothrium, a tapeworm which can cause diphyllobothriasis[36]

For the above reasons, the EU regulations forbids the use of fresh raw fish. It must be frozen at temperatures below −20 °C in all parts of the product for no less than 24 hours.

 

[pa5tabear]

Cooking meat also increases the energy it provides.



http://news.harvard.edu/gazette/story/2011/11/why-cooking-counts/

Yes, this makes sense, because the body breaks down proteins in order to use the amino acids in the kreb's cycle for energy, or anabolysm.

When meat is cooked, it is mostly denatured, so there are fewer bonds that must be broken.

 

[Darwin123]

Just because people don't get instantly sick, does not mean it is without problem..

Also, beware that raw products are often processed before consumption other than heating (freezing/brining):

The OP specifically asked if raw meat was bad without microbes. Although parasites are not always microbes, I think that he meant without parasites as well. His implication is that raw meat may not be digested properly, even if microbes and parasites are not present.
Examples were provided where raw meat was ingested as a delicacy. If raw meat produced digestive problems, then the eater would have immediate discomfort or pain. Then, raw meat would not be a delicacy. We would be hearing complaints from the tartare and sushi eaters. Also from Eskimos and other aboriginal peoples who occasionally eat uncooked food.
Pathogens may be the main reason that humans cook their food. However, reading these posts have raised doubt.
Other replies have pointed out that cooked meat is digested more completely than raw meat. Their hypothesis is that the greater benefit in calorie terms is from cooked meat. Further, maybe uncooked meat produces more flatulence. If food is undigested in the gut, then gas could be produced.
So maybe their are other reasons than pathogens for cooking food. There may be multiple reasons for cooking meat.
Tools seem necessary for comfortable eating of meat. The delicacies involving raw meat are made by chopping the meat into very small pieces. Chopping into small pieces helps the gut digest food by increasing the surface to volume ratio. I don't think that even a carnivore's teeth can slice the muscle into such small pieces. Certainly, our teeth aren't suited for fine chopping muscle.
Therefore, eating raw meat seems to involve good tools. If you cook the food, then you are using fire as a tool. If you chop the meat into small pieces, then you are using a good chopper. Neither method would be available to a primate without tools.
Either way, it seems that meat is probably a late addition to human diets. Most primates don't eat large amounts of meat. All primates eat some meat. However, the big staple in the diet of nonhuman primates seems to be vegetable matter. Humans are the only primate to make meat a staple of their diet. This may be one advantage of tools (choppers and fire).

 

[pa5tabear]

The OP specifically asked if raw meat was bad without microbes. Although parasites are not always microbes, I think that he meant without parasites as well. His implication is that raw meat may not be digested properly, even if microbes and parasites are not present.
Examples were provided where raw meat was ingested as a delicacy. If raw meat produced digestive problems, then the eater would have immediate discomfort or pain. Then, raw meat would not be a delicacy. We would be hearing complaints from the tartare and sushi eaters. Also from Eskimos and other aboriginal peoples who occasionally eat uncooked food.
Pathogens may be the main reason that humans cook their food. However, reading these posts have raised doubt.
Other replies have pointed out that cooked meat is digested more completely than raw meat. Their hypothesis is that the greater benefit in calorie terms is from cooked meat. Further, maybe uncooked meat produces more flatulence. If food is undigested in the gut, then gas could be produced.
So maybe their are other reasons than pathogens for cooking food. There may be multiple reasons for cooking meat.
Tools seem necessary for comfortable eating of meat. The delicacies involving raw meat are made by chopping the meat into very small pieces. Chopping into small pieces helps the gut digest food by increasing the surface to volume ratio. I don't think that even a carnivore's teeth can slice the muscle into such small pieces. Certainly, our teeth aren't suited for fine chopping muscle.
Therefore, eating raw meat seems to involve good tools. If you cook the food, then you are using fire as a tool. If you chop the meat into small pieces, then you are using a good chopper. Neither method would be available to a primate without tools.
Either way, it seems that meat is probably a late addition to human diets. Most primates don't eat large amounts of meat. All primates eat some meat. However, the big staple in the diet of nonhuman primates seems to be vegetable matter. Humans are the only primate to make meat a staple of their diet. This may be one advantage of tools (choppers and fire).

Yes, I was wondering about harm not due to microbes/parasites.

It wouldn't have to induce immediate pain/discomfort though. Just because people do it doesn't mean that there aren't minor adverse effects that wouldn't be present with cooked meat.

I don't think the "digested more completely" claim is necessarily true. Evo posted a link saying that more energy is gained. This could be due to more complete digestion, but it could also be due to less energy required to break it down. You could still digest it completely (break down all component amino acids), but spend more energy doing so.

Why would raw meat produce more flatulence? I'd expect the opposite.

I agree with the rest of your post about tools, surface area, and late addition to the diet.

 

[Monique]

I think that he meant without parasites as well.

As said, there is no research on the non-microbe/parasite effects of raw meat on the human gut. Even for pets there are very few studies and the ones that are published are small scale/ short term.

It could be that the decomposition of raw meat in the gut is different from cooked meat with a differential effect on disease risk in the long run, but that would require large-scale longitudinal studies.

 

[Darwin123]

Yes, I was wondering about harm not due to microbes/parasites.

It wouldn't have to induce immediate pain/discomfort though. Just because people do it doesn't mean that there aren't minor adverse effects that wouldn't be present with cooked meat.

I don't think the "digested more completely" claim is necessarily true. Evo posted a link saying that more energy is gained. This could be due to more complete digestion, but it could also be due to less energy required to break it down. You could still digest it completely (break down all component amino acids), but spend more energy doing so.

Why would raw meat produce more flatulence? I'd expect the opposite.

I agree with the rest of your post about tools, surface area, and late addition to the diet.

If energy is expended to break it down, then that energy has to be taken from the food itself. The minimum calorie intake has to include the energy required to break it down.
If energy is needed to break raw meat down, then more raw meat would be necessary to satisfy the minimum calorie intake than cooked meat. A person living on a small amount of cooked meat would starve less rapidly than a person living on the same amount of cooked meat. In times when the supply of food is low, this could make a big difference in the chances of survival.
Microbes in our gut do most of the digestion. Most of what our metabolisms used is first digested by the microbes. Aerobic microbes do a more efficient job of digesting food then anaerobic microbes. Aerobic bacteria work faster than anaerobic bacteria. Anaerobic microbes generally leave a lot of "half digested" food in the form of gases. So it is the anaerobic bacteria that leave the gas that smells.
High protein foods like meat have a lot of nitrogen compounds and sulphur compounds in them. What is left over from half digested meat is mostly carbon disulphide and ammonia. Both of them are smelly gases.
Suppose that the body doesn't expend energy to break down the raw meat. Supposing that more raw meat remains undigested than cooked meat. Or that the cooked meat is digested faster than the raw meat. The anaerobic bacteria have time to work on the proteins of the meat.
If you don't believe it, then smell the breath of a cat or dog. Dogs and cats eat a lot of meat. Furthermore, they don't use tools. They can't cut their meat into small pieces. So their ability to digest meat is somewhat compromised. Their breaths smell bad. "Doggy breath" is rather legendary. They don't care, of course.
This is from the meat. I don't know if cooking the meat would make a difference. I conjecture that it may.
Lactose intolerant people have a problem with flatulence and bloating. Undigested dairy products cause this extra gas. One of the remedies for lactose intolerance is probiotic foods and pills. Probiotic means having large amounts of aerobic bacteria. Another way to reduce gas is to take the dairy products in the form of hard cheeses. Hard cheeses have been worked on for a long time by microbes. So hard cheeses are easier to digest than milk or soft cheeses. Also, lactaid is an enzyme that breaks down lactose in milk products.
I conjecture that the lactaid and aerobic microbes that make hard cheese are doing the same job to the milk as cooking does to the meat. It breaks the material down.
This may answer the question as to why people think of hard cheese as a delicacy rather than drink milk. Most adults can't extract calories from unprocessed milk. Most adults have lost most of their ability to digest milk while growing up. Even adults that are lactose tolerant have difficulty digesting milk.. However, the calories from hard cheese can be digested even by adults.
So way back, those adults that ate hard cheese would have been at an advantage in lean times. This is why Brian said, "The cheese makers will inherit the earth" !-)
So I conjecture that raw meat causes flatulence, bloating, bad breath and starvation in lean times. Even without parasites !-)