Putrefaction product neurine in yolks

[dime]

Going through [1] (note that the book is 50 years old) I came across this:

The yolk of the egg is highly acid-forming, and though it contains lecithin, the latter quickly decomposes to form choline and finally neurine, a nerve poison.

Googling I couldn't find anything more than a short definition of neurine [2]:

Neurine is an alkaloid found in egg yolk, brain, bile and in cadavers. It is formed during putrefaction of biological tissues by the dehydration of choline. It is a poisonous, syrupy liquid with a fishy odor.

Neurine is a quaternary ammonium salt with three methyl groups and one vinyl group attached to the nitrogen atom. Synthetically, neurine can be prepared by the reaction of acetylene with trimethylamine. Neurine is unstable and decomposes readily to form trimethylamine.

I found one study which involves neurine [3], and that's all about it on the internet. It's interesting how there's so little information, given that pretty much everyone eats eggs. Maybe it's not so toxic.

I'm not sure whether this is relevant when eating raw egg yolks. I wouldn't stop eating them, but I wouldn't go and eat 20 per day, as e.g. this neurine might have some bad effects long term.

1. http://books.google.ca/books?id=6GLPJzr ... #v=onepage
2. http://en.wikipedia.org/wiki/Neurine
3. http://www.ncbi.nlm.nih.gov/pubmed/16988475

[djkvan]

Nice catch dime. I don't know how you found that, but it's priceless, IMO. I'll bet someone is going to argue: but if you eat the yolk fresh the lecithin will never degenerate into choline and neurine in the human digestive system. Food never degenerates in the human digestive system. Riiiight.

[Oscar]

All dead/lifeless organic matter will be subject to decomposition.

It is formed during putrefaction of biological tissues by the dehydration of choline.

Putrefaction is the decomposition of animal proteins, especially by anaerobic microorganisms, described as putrefying bacteria. Decomposition is a more general process.

Obviously fresh eggs will deteriorate and decompose the longer one waits.

Neurine is unstable and decomposes readily to form trimethylamine.

Trimethylamine [...] has a strong "fishy" odor in low concentrations and an ammonia-like odor at higher concentrations. It is a gas at room temperature...

This means that by the time neurine forms, you will smell it.

Neurine (vinyl-trimethyl-ammonium hydroxide) is a breakdown product of ACh, consequent to autolysis and is an organic poison found in cadavre brain.

This research isn't about eggs, but it does show that destruction of acetyl-choline (by beta-carbolines??) might have something to do with Alzheimers.

[dime]

Yes, so be careful how you eat egg yolks. And any protein food for that matter, protein putrefaction seems to produce quite a lot of toxins, not just neurine.
I'm guessing safest would be to eat protein foods alone on empty stomach, small quantities at a time.
I just hope neurine is not formed during normal processes in the body, becayse it says it's formed "by the dehydration of choline".

[djkvan]

The information says that neurine is found in egg yolks. Not decomposed egg yolks. Egg yolks. Period. An 1884 study found this substance in fresh yolk:

On experimentation with fresh substances (yolk included among them) Zuco in 1884 was able to extract a base which exhibited all the usual reactions of the alkaloids. It was found to be identical in composition to neurine and originated not due to sudden alterations of the proteids, but from the splitting up of the lecithins under the influence of acids or alkalies (e.g. Hcl in stomach). Furthermore, neurine hydrochloride isn't decomposed by sodium bicarbonate (so no duodenal alteration via gall bladder). The author was able to determine the toxicological question in cases of the extraction of alkaloids from substances in which putrefaction has not yet commenced.

From: http://books.google.ca/books?id=PNIAAAA ... lk&f=false

See section on pg. 109 which is titled The Nature of Ptomaines

Do you honestly think that the egg industry is going to promote this info?

[djkvan]

I just hope neurine is not formed during normal processes in the body

That is precisely how it is formed.

from the splitting up of the lecithins under the influence of acids or alkalies

...as in HCl in the stomach.

[RRM]

Neurine is formed during putrefaction....
...with a fishy odor.

Ok, thats clear.
Of course one should not eat putreficated proteinaceous food.
If an egg smells a bit weird; dont eat it, naturally.
Neurine is found in the brains of cadavers and in Alzheimer's patients because here its formed as a result of cholinergic neuron death.

...An 1884 study found this substance...

That is precisely how it is formed. ...from the splitting up of the lecithins under the influence of acids or alkalies
...as in HCl in the stomach.

So, in your view, consuming lecithin is dangerous...

Lecithin can be totally metabolized by humans, so is well tolerated by humans and non-toxic when ingested...
The non-toxicity of lecithin leads to its use with food, as an additive or in food preparation. It is used commercially in foods...
It is approved by the United States Food and Drug Administration for human consumption with the status "Generally Recognized As Safe."

[djkvan]

The study speaks for itself. The findings were made and seemingly buried for some 126 years. I have nothing to say but read it or believe whatever you want to.

[RRM]

The study speaks for itself.

...spoke...

The findings were made and seemingly buried for some 126 years.

wooow,... an ancient conspiracy...
Damn, they should have destroyed all the evidence...

...An 1884 study found...

[Oscar]

Don't eat rotten eggs sounds like wise advice.
Btw djkvan, your 'information' seemed unavailable.

[dime]

I just hope neurine is not formed during normal processes in the body

That is precisely how it is formed.

The newer sources say it's as a result of putrefaction, and putrefaction in the digestive system does not normally occur unless you stuff yourself with food and the protein gets properly absorbed (as far as I know).

Here's an interesting read (another old book, 1912): http://chestofbooks.com/health/nutritio ... otein.html

[djkvan]

Btw djkvan, your 'information' seemed unavailable.

I just linked to it by clicking on the exact link I provided.
I will walk you through the process, Oscar.
1. Click on the link.
2. Read the information (the article entitled The Nature of Ptomaines at the bottom of middle column of American Druggist pg 109 )
3. Stop you're done

BTW, nice edit on my last post, RRM.

The newer sources say it's as a result of putrefaction, and putrefaction in the digestive system does not normally occur unless you stuff yourself with food and the protein gets properly absorbed (as far as I know).

The original evidence says neurine results from the splitting up of the lecithins under the influence of acids or alkalies. I see nothing in the link you have provided that contradicts these findings which were made using fresh matter.

[RRM]

BTW, nice edit on my last post, RRM.

I moved your osteoporosis comment to here: viewtopic.php?f=17&t=490

The original evidence says neurine results from the splitting up of the lecithins under the influence of acids or alkalies.

That was in 1884.
Today we know that its a putrefaction product.
And that lecithine digestion does not yield any toxin.

these findings which were made using fresh matter.

And how did they, in 1884 determine that this egg was actually fresh,
and the yolk not contaminated due to poor lab conditions?

[djkvan]

Again, I just relayed the info. I don't have any further answers. I doubt that there were many fresh foodstuffs back in the late 19th century. Everything was preserved and stored in warehouses, with nobody able to walk to a local farm (there were very few farms back in the 19th century) and get a freshly laid egg. You appear to believe that a date is what determines a study's scientific validity. Such is a prejudice that may preclude objectivity, IMO.

[RRM]

That you appear to believe that a date is what determines a study's scientific validity is a prejudice that may preclude objectivity, IMO.

Science has come a long way since 1884...
The validity of a study is very much influenced by to what extend the possibility of cross-contamination has been excluded.
Nowadays protocols are very strict, and for a very good reason.
1884 was a whole different ballgame....