Hetero Cyclic Amines

[djkvan]

As per wiki:

Research has shown that an olive oil, lemon juice and garlic marinade cut HCA levels in chicken by as much as 90%. Six hours of marinating in beer or red wine cut levels of two types of HCA in beef steak by up to 90% compared with unmarinated steak. However, researchers say that "It may seem appetising to marinate steak in beer or wine, but this will have a minimal impact on the effect of the meat on your cancer risk and the best way to reduce your risk of cancer from eating red and processed meat is to eat less of it overall".[2]

High-temp cooking is the culprit here, no? Boil or rarely cook your meat or eat it raw if safe.
The research on chicken vs. red meat reflects the greater tendency of people to grill/overcook red meat I think. Still if eating the animal raw and as is is the best way to go there are many pieces of the beast that are being ignored by Wai that are revered by other diets e.g offal. Seems like a huge waste personally.

[RRM]

Boil or rarely cook your meat or eat it raw if safe.

What makes you think that boiling is safe?
Red meat consumption is also associated with endogenous N-nitroso compound formation.

[djkvan]

An important proviso to be kept in mind is that cancers in laboratory rats and mice are induced by doses (per unit of body weight) several orders of magnitude higher than what are usually ingested in normal meals by humans. (Typically, the amounts of HCAs are over a million times higher, based on calculations from data furnished in Augustsson [1999].) In fact, by itself, the ingested daily amount of heterocyclic amines is very probably too small to explain the development of human cancers, and the same is true for numerous other carcinogens. Thus, the simultaneous presence of heterocyclic amines with other genotoxic [i.e., inducing DNA damage] carcinogens and with tumor-promoting agents or tumor-promoting conditions makes it very difficult to make a numerical calculation for risk estimation.

re...

the latter study by Augustsson et al.

Heterocyclic amines have been shown to be carcinogenic in animals. This carcinogenic effect is induced by high doses, such as 10-400 mg/kg of body weight. The lack of carcinogenic effect of heterocyclic amines in our study may be due to the much lower intake in the study population (median 1 ng/kg of body weight).

In other words, doses required to induce cancer in laboratory animals are typically 10 million times higher (or even more) than those obtained by ordinary cooking.

[RRM]

In fact, by itself, the ingested daily amount of heterocyclic amines is very probably too small to explain the development of human cancers

Test animals are kept alive for a restricted period of time.
Humans usually eat foods containing carcinogenics for several decades prior to development of cancer.
Most cancers originate later in life.
Carcinogenics are carcinogenics.
If you are extremely unlucky, a single carcinogenic may already cause cancer.
Imagine what a lifetime intake can do.
Furthermore, from Nauwelaers G et al, DNA adduct formation of 4-aminobiphenyl and heterocyclic aromatic amines in human hepatocytes.

These DNA binding data demonstrate that the rat, an animal model that is used for carcinogenesis bioassays, significantly underestimates the potential hepatic genotoxicity of HAAs in humans.

Free full text of the quoted article.

...very difficult to make a numerical calculation for risk estimation.

Of course it is.
Some people smoke 2 packs of cigarettes a day and never get cancer, which is partly due to individual differences in the activating and detoxifying enzymes.
That does not mean that smoking cannot cause cancer, even though the risks have been downplayed for decades.

[djkvan]

Doses required to induce cancer in laboratory animals are typically 10 million times higher (or even more) than those obtained by ordinary cooking.

[panacea]

I just want to emphasize again that, according to djkvan this whole thing is based on:
"based on calculations from data furnished in Augustsson [1999].) In fact, by itself, the ingested daily amount of heterocyclic amines is very probably too small to explain the development of human cancers"

Which he thinks that since it came from a study, it's meaningful, when in reality, they didn't test this. They ASSUMED that since animal testing hca doses are millions times higher than daily human intake, that it's the required dose to cause cancer in these animals. It's not, it's the dose they use for ease and speedily induction of cancer. Then they made another assumption, that small intake of HCA over time in humans works in ratio perfectly proportional to this overblown dose, and that by copy-pasting the numbers of millions to very few in dose, they ASSUMED they could get an accurate picture of the low risk daily HCA intake has in humans. This was not tested, this was a series of systematic assumptions and not real science. For readers following this discussion, this is what djkvan views as good evidence low (but higher than natural) HCA intake being too small to matter in terms of cancer risk, not what any scientific minded person worth their salt views as good evidence for low (but higher than natural) HCA intake being too small to matter in terms of cancer risk.

[Oscar]

Djkvan is correct that the Wai Diet hasn't been proven as such, which is where Occam's Razor comes in. Carcinogenic substances causing cancer. For instance it's is widely accepted that smoking is associated with, and can cause lung cancer. Does that happen overnight? No, it takes years. A small dose over the course of years can be as harmful as a big dose at one time. And with 1 gram of roasted beef roughly equaling 8 cigarets for certain tested carcinogenic substances, one can at least conclude there might be a correlation. Yes, it's easy to discredit scientific experiments, as there are discrepancies with real life circumstances. We are not the same as laboratory animals, doses are not the same, the time scale is different, etc. On the other hand it's equally easy to turn an idea into a belief without a scientific foundation and/or backing. In the end it's up to us to use discriminatory and logical thinking, common sense, and apply Occam's Razor. And since each of us has a different perspective, world view, and personal truth, conclusions may differ.

[RRM]

Doses required to induce cancer in laboratory animals are typically 10 million times higher (or even more) than those obtained by ordinary cooking.

Maybe in some study regarding a specific HCA, but the overall picture is very different.
These HCA have been shown to be carcinogenic when administered in the diet (for 1 to 2 years) at concentrations of 100-800 ng / gram (100-800 ppm) : IQ, MeIQ, MeIQx, PhIP, Trp-P-!, Trp-P-2, Glu-P-1, Glu-P-2, AalphaC and MeAalphaC.
A cooked diet may contain up to 45 ng MeIQx and 258 ng PhIP per gram cooked food,
and one study found 650 ng A alpha C and 63 ng MeA alpha C in 1 gram of grilled beef.Matsumoto T et al
and another one 1068 ng Glu-P-2 per 1 gram of grilled fish patty Wu J et al
Thats a whole different order than 10 million / 1.
In rats they cause cancer in 1 or 2 years.
Humans live much longer, so that the cancer risk is multiplied.
Also, carcinogenic effects of HCAs are additive or synergistic, and even very low doses of HCAs may cause cancer.
Hence the epidemiological associations between HCA intake and various cancer types.

Check out the WaiWiki page about HCA

[Emeira]

Marinades reduce heterocyclic amines from meat

Effect of oil marinades with garlic, onion, and lemon juice on the formation of heterocyclic aromatic amines in fried beef patties.
http://www.ncbi.nlm.nih.gov/pubmed/17988088

[RRM]

Yes, it is well documented that dry-heating yields more HCAs and AGEs/ALEs in general than heating with the use of water (/marinades).

[Emeira]

Are there any articles about how much HCAs can be formed within a certain period of time and temperature. For example: 5 min and 50-70 C or 20 min 50-70 C and so on.
I like to cook small pieces of chicken in water for max 5 min at 50-70 C or mackerel in oven for 20 min (max 30min) 50-70 C.
I like when color of meat/fish turns white, watery and soft.

Do you think is unhealthy to cook this way RRM?

[Aytundra]

The relationship between acrylamide and its precursors, namely free asparagine and reducing sugars, was studied in simple cakes made from potato flake, wholemeal wheat and wholemeal rye, cooked at 180 degrees C, from 5 to 60 min. Between 5 and 20 min, large losses of asparagine, water and total reducing sugars were accompanied by large increases in acrylamide, which maximized in all three products between 25 and 30 min, followed by a slow linear reduction. Acrylamide formation did not occur to any extent until the moisture contents of the cakes fell below 5%. A comparison of each type of cake with a commercial product, made from the same food material, showed that acrylamide levels in all three commercial products were well below the maximum levels in the cooked cakes.http://www.ncbi.nlm.nih.gov/pubmed/?ter ... at+and+rye.

Is slow cooking (long time of cooking) harmful? (i.e. 25-30min)
or is moisture, type of food, type of cooking method, type of cookware, type of heat waves (microwave) all part of the equations?

[RRM]

HCAs are formed at higher temperatures, but AGEs in general also form at lower temperatures.
AGEs are not healthy, as they accelerate ageing.
http://www.waiwiki.org/index.php?title= ... d_reaction
So, raw is better, and slow cooking is better than 'real' cooking.