Mystery of the meat-eaters' molecule

[talitha]

There's a really interesting article in the Daily Torygraph today about a sugar - sialic acid - that occurs in animals. Apparently the human version is one molecule different to the version found in other animals and this is well recognised as causing immune system problems when people are given serums, tissue etc derived from animals.

Now a scientist at the University of California has proposed that humans absorb this sugar when they eat red meat and milk products. He suggests that the body recognises it as an invader and that it therefore causes inflammation which in the long term could cause heart disease, some cancers and auto immune illnesses.

If anyone's interested you can read the article at http://www.telegraph.co.uk/earth/mai...olecule108.xml


More grist to the vegan mill

[Korn]

He suggests that the body recognises it as an invader and that it therefore causes inflammation which in the long term...

The article is interesting, but actually says that "Eating these foods could trigger inflammation and, over the long term, heart disease, certain cancers and auto-immune illnesses. Prof Varki stresses, however, that "we have not proven any link to disease, just suggested that it is something to explore"."


Some interesting quotes from the article:

Chronic inflammation is also linked with cancer; intriguingly, the team found that Neu5Gc [the animal sugar] was concentrated in tumours, particularly those that spread throughout the body. This could aid detection of such diseases, by getting scientists to look for the animal acid rather than the tumours themselves.

They found that we are the only primates whose bodies do not produce Neu5Gc - although further research established that our Neanderthal cousins were missing this version of the sugar acid, too.

Instead, human (and Neanderthal) cells bristle with a sugar called Neu5Ac. The two molecules are identical, apart from one little detail: the ape molecule has a single extra oxygen atom. Because of the many different jobs this sugar does throughout the body, this one atom was the first example found of a fundamental genetic and biochemical difference between humans and our closest relatives.

Profs Muchmore and Varki then found out why this oxygen atom is missing: our molecule is the precursor of the animal version. Unlike chimpanzees and other great apes, humans lack a particular version of an enzyme that converts Neu5Ac (or, to give it its full name, N-acetylneuraminic acid) into Neu5Gc. This tiny change could potentially explain some of the more unusual differences between humans and apes.

Chimpanzees do not seem to suffer from heart disease, cancers, rheumatoid arthritis or bronchial asthma - common conditions in humans. Nor do they get sick from the human malaria parasite, which uses sialic acid to latch on to our blood cells.

It is ironic that what may have protected our ancestors then could be responsible for much of the pain of their long-lived descendants.

[mariannetheresa]

i was just about to post this and i am glad to see you have.

[gogirlanime]

Very interesting, I kind of knew this already, that eating red meat and dairy puts a toll on you immune system but I didn't know specifically why. Thank you for this article!

[BonnieS]

Thank you for the very interesting link!

[Korn]

The Daily Telegraph link is dead, so here's another link to the same article.

Mystery of the meat-eaters' molecule

Another excerpt:

Some of this might sound familiar: several previous studies have linked ingestion of red meat to cancer and heart disease. But these focused mostly on the role of saturated fats, and on products that arise from cooking. Prof Varki, however, believes that his little molecular difference could also be to blame: Neu5Gc elicits an immune reaction that might contribute to a whole spectrum of human diseases.

[Korn]

Here's a new report, discussing the effect of a very specific animal ingredient: animal protein.

Animal Protein Bad for Bones

Animal protein is associated with decreased bone health, according to a study in this month's British Journal of Nutrition. In Beijing, China, 757 girls with an average age of 10 years were randomly assigned to a group consuming cow's milk fortified with calcium, one consuming cow’s milk fortified with calcium and vitamin D, or a third group that served as controls and made no changes. Bone mass was measured at the beginning of the study and at 12, 24, 48, and 60 months. While calcium intake was positively associated with bone health, animal protein, especially from meat and eggs, was negatively associated with bone mineral density and content.

Zhang Q, Ma G, Greenfield H, et al. The association between dietary protein intake and bone mass accretion in pubertal girls with low calcium intakes. Br J Nutr. 2010;103:714-723.