> -----Original Message-----
> From: Paleolithic Eating Support List
> [mailto:[log in to unmask]] On Behalf Of Geoffrey Purcell
> Sent: Saturday, August 16, 2008 2:56 PM
> To: [log in to unmask]
> Subject: Re: food combining
>
> I'd be most interested in any scientific studies re this notion re
> proteins some plants having molecular structures very similar to
> those of the surface proteins in bacteria and influenza viruses.
From "Cereal Grains: Humanity's Double-Edged Sword," by Loren Cordain PhD
(www.thepaleodiet.com/articles/Cereal%20article.pdf):
<<There is now a substantial body of evidence indicating that the breaking
of tolerance to self antigens can occur when invading foreign proteins
contain amino acid homologies similar to a protein in the host [233, 242].
This similarity in structure shared by products of dissimilar genes (dubbed
molecular mimicry) causes cross-reactive immune responses which are directed
not only at the invading foreign protein but also at any cells displaying
amino acid sequences similar to those of the foreign protein. The main body
of evidence implicates viral and bacterial pathogens as initiators of cross
reactivity and autoimmunity [233, 242]; however there is an emerging body of
literature supporting the view that dietary antigens [243, 244], including
cereal grains [245, 246], may also induce cross-reactivity and hence
autoimmunity by virtue of peptide structures homologous to those in the
host. ....
It is probable that the process of molecular mimicry is involved in the
development of celiac disease [232]. Kagnoff et al. [260] have shown that
wheat alpha-gliadin shares an amino acid sequence homology with the E1B
protein of human adenovirus 12 (Ad-12) and that antibodies directed against
E1B cross-react with alpha-gliadin. Since 89% of patients with celiac
disease, versus 17% of controls, showed evidence of Ad-12 infection [260],
it is possible that Ad-12 infection in individuals genetically predisposed
to celiac disease (HLADQ2) may facilitate development of the disease by
virtue of cross-reactivity, perhaps by three-way mimicry among the two
foreign antigens (Ad-12, gliadin), the target tissue and even HLA proteins,
themselves [261].>>
According to Cordain, gliadin peptide fragments in partially digested wheat
have amino acid sequences homologous to those of the endogenous protein
(calreticulin) that is artificially expressed upon the surface of intestinal
epithelial cells in response to cereal grain lectin stimulation. To
summarize, the research has indicated a three-way molecular mimicry
between...
1) surface proteins on adenoviruses and bacteria
2) plant proteins in such foods as wheat
3) epithelial surface proteins in the human GI tract and other areas of the
body
> I do disagree re the notion re antnutrients in vegetables. In tiny
> amounts, such antinutrients could be more accurately labelled
> "phytonutrients" and have been shown to produce beneficial effects on
> the human body, via hormesis. But I agree that veg in large quantities,
> via veggie-juice etc., can be very harmful.
To clarify, I said "plants" (which includes legumes and grains) rather than
"vegetables," which might be interpreted to exclude legumes or grains.
Plants do contain antinutrients and some of them might also be classified as
phytonutrients--it is theoretically possible for a molecular component to be
both an antinutrient (mineral binder) and a phytonutrient (antioxidant). For
example, cereal grains contain such antinutrients as phytates,
alkylresorcinols, protease inhibitors, and lectins. Taking the phytate
example; phytates bind with iron, zinc, magnesium and other nutrients,
depleting them from the human body (which is a major reason why breads must
be fortified). Recent research indicates that phytate may also function as
an antioxidant, but whatever benefits this may have appear from the total
weight of the evidence to be overwhelmed by the negative effects of wheat
consumption (such as antinutrient effects, inflammatory effects, molecular
mimicry effects and/or insulin spikes). Some plants have higher levels of
antinutrients than others and antinutrients can be offset by sufficient
quantities of offsetting foods (for example, iodine from seafood and certain
leafy greens offsets the antinutriative effects of glucosinolates in
cruciferous vegetables) and by adaptive mechanisms in the human body that
were naturally selected during eons of eating those foods.
From "The Late Role of Grains and Legumes in the Human Diet, and Biochemical
Evidence of their Evolutionary Discordance," by Loren Cordain, Ph.D.,
www.beyondveg.com/cordain-l/grains-leg/grains-legumes-1a.shtml:
<<As touched upon previously, the issue of antinutrients in raw cereal
grains is a very real issue. There are components in raw cereal grains which
wreak absolute havoc with human health and well-being. The primary storage
form of phosphorous in cereal grains is phytate, and phytates bind virtually
all divalent ions, i.e., minerals for our purposes. Excessive consumption of
whole-grain unleavened breads (50-60% of total calories) commonly results in
rickets [Robertson 1981; Ewer 1950; Sly 1984; Ford 1972, 1977; MacAuliffe
1976; Hidiroglou 1980; Dagnelie 1990], retarded skeletal growth [Reinhold
1971; Halsted 1972; Sandstrom 1987; Golub 1996] including hypogonadal
dwarfism, and iron-deficiency anemia (will provide the references upon
request). The main lectin in wheat (wheat germ agglutinin) has catastrophic
effects upon the gastrointestinal tract [Pusztai 1993a]. Additionally, the
alkylrescorcinols of cereals influence prostanoid tone and induce a more
inflammatory profile [Hengtrakul 1991], as well as depressing growth [Sedlet
1984].>>
|
