So I was reading some stuff today, when I came across this:

--
Lectins–found in cereals, potatoes, and beans–have effects throughout the body as widespread and significant as our own hormones, but originating from outside our bodies, they react with our physiology in ways that are often quite harmful. They can strip off protective mucous tissues, damage the small intestine, form blood clots, make cells react as if stimulated by a random hormone, stimulate cells to secrete random hormones, make cells divide at improper times, cause lymphatic tissues to grow or shrink, enlarge the pancreas, or even induce apoptosis. In an editorial for the British Medical Journal titled “Do dietary lectins cause disease?” David L J Freed answers the question affirmatively, writing:

Until recently their main use was as histology and blood transfusion reagents, but in the past two decades we have realised that many lectins are (a) toxic, inflammatory, or both; (b) resistant to cooking and digestive enzymes; and (c) present in much of our food. It is thus no surprise that they sometimes cause “food poisoning.” But the really disturbing finding came with the discovery in 1989 that some food lectins get past the gut wall and deposit themselves in distant organs.

The question of whether or not the lectins in grain causes cancer is still open, but there is certanly a good deal to suggest it. Lectins are well-known to cause cancer-like reactions in colon cells in a test tube. Franceschi, et.al; “Intake of macronutrients and risk of breast cancer” (Lancet 1996;347(9012):1351-6) showed that while risk of breast cancer went down with total fat intake, it rose with carbohydrate intake, but the original study on a correlative “cause” of cancer remains the most compelling: Stanislaw Tanchou’s 1843 study that found a nearly perfect correlation between cancer in major European cities, and grain consumption. Tanchou predcted that no forager would ever be found with cancer, initiating a frenzied search to find the counterproof. Though no such forager was ever found, cancer often became commonplace among those same populations once they were settled into an agricultural lifestyle. Between the effects of grain and more recent environmental factors, it seems evident that the natural occurence of cancer among our foraging ancestors must have been negligible. In the modern United States, some 50% of men and 33% of women will suffer from some kind of cancer. Among foragers, we have significant difficulty producing even a single example.

--

I found this at this site: [anthropik.com]

I was wondering if anyone had any more information about lectins? A lot of the nutritional/evolutionary information in these articles is incorrect/incomplete, and the site is pro-Paleo diet (the author says somewhere, something to the effect of how grains provide way more protein than leafy greens... har har).

I still haven't quit steaming potatoes, entirely. But if they ARE that bad... I should.

Interesting article!

Here is a site with a pretty thorough scientific description:
[www.dadamo.com]

"Lectins are proteins of non-immune origin that specifically interact with sugar molecules (carbohydrates) without modifying them. Lectins are found in a variety of species from plants to insects to man. They serve many different biological functions from the regulation of cell adhesion to glycoprotein synthesis and the control of protein levels in the blood. Lectins are also known to play important roles in the immune system by recognising carbohydrates that are found exclusively on pathogens, or that are inaccessible on host cells.

Lectins are often found in common foods, and many of them are blood type specific. Because cancer cells often manufacture copious amounts of antigens on their surface, many lectins will agglutinate them in preference to normal cells."

Thanks for the info, I've got to get everyone I know, who won't give up these foods to at least consider soaking/sprouting/fermenting these foods! I

[wholehealthsource.blogspot.com]
"Another thing I have to mention about lectins is they can be broken down by certain food processing techniques. Remember all those old-fashioned things our grandparents used to do to grains and beans before eating them, like soaking beans overnight, sourdough-fermenting bread dough and nixtamalizing corn? All those things we've abandoned in favor of modern convenience foods? You guessed it, those reduce lectins dramatically, along with a long list of other toxins like phytic acid and protease inhibitors."

Cousens has a big chapter on lectins in his book Concious Eating, explaining how it reacts with various blood types.
[books.google.com]

I have read that lectins in plants are rarely blood-type specific.

ref is here, it's from 1980, only a couple of the tested ones showed specificity.
[www.ajcn.org]

Anyway, they can't be all that bad if sweet potato makes up over 50% of the Okinawan Centenarian diet. And another 5-10% from cereal grains, and not necessarily refined ones, either.

Also there are lectins in fruits and vegetables.

I don't we need to be worrying about killer lectins.

These little buggers are interesting....

You're right arugula,

Their in lots of fruits and vegetables, and from what I'm reading, lectins serve a biological purpose, like most protein chains.

For the article to tie them to the cause of cancer is misleading. Lectins don't cause cancer, but bind cancerous cells together much the same way they bind carbohydrates.

Also We seem have natural human antibodies to dietary lectins.
[www.dadamo.com].



Edited 1 time(s). Last edit at 09/04/2008 01:01AM by swimmer.

Maybe this is interesting for You too:
[www.krispin.com]

Ricin is lectin:
[en.wikipedia.org]
"Ricin is a protein toxin that is extracted from the castor bean (Ricinus communis).

The U.S. Centers for Disease Control (CDC) gives a possible minimum figure of 500 micrograms (about the size of a grain of salt) for the lethal dose of ricin in humans if exposure is from injection or inhalation. . . .

Ricin B Chain is a lectin . . ."


So perhaps, even if lectins are in most foods, just like proteins are in most foods, there has to be different TYPES of lectins, just like there are different types of proteins. I.e. animal proteins are very acidic to the body and hard to digest while plant proteins are easier to digest. So there must be harmless lectins and also lectins you would rather avoid?



Edited 2 time(s). Last edit at 09/04/2008 04:35PM by Lillianswan.

Ani,

Lillianswan Wrote:
-------------------------------------------------------
> So perhaps, even if lectins are in most foods,
> just like proteins are in most foods, there has to
> be different TYPES of lectins, just like there are
> different types of proteins. I.e. animal proteins
> are very acidic to the body and hard to digest
> while plant proteins are easier to digest. So
> there must be harmless lectins and also lectins
> you would rather avoid?

Hmmm, that does seem logical, there are definitely many different types and configurations of the molecule.

The health based articles concentrate more on grains then other plants. But one research study linked major problems from lectins in tomatoes. (gotta find that link again) Perhaps it's like gluten, where a portion of the population have a predisposition intolerance (genetics), yet many people do produce the antibodies, and have no problems consuming them. The article ani posted alluded to that, siting a study on selective IgA deficient people. Some great info, but that author is pushing a low carb, high meat based diet.

Here is a cool site, it has 3d models of the various lectin molecules. cool looking, almost pretty. Click on the menu on the left and choose a category, a type, etc. Then click on the eye icon to see a model. Click the "medline" button to read a description.
[www.cermav.cnrs.fr]

I believe that in order to find out how something effects us, we need to know how it works. I have to admit, some of the sites I'm finding contain science that's over my head, and it's been a many years since my last biology class. Also, my shoulder is being a real PAIN the last couple of days, so it's a little hard to concentrate and learn. I'm having fun though...



Edited 1 time(s). Last edit at 09/04/2008 05:58PM by swimmer.

That site had tons of different types of lectins, it was very cool to see them in picture form! Thanks!

Since lectins are connectors between things on a cellular level (I think ?) it was like walking into a hardware shop and seeing lots of different types of fasteners: screws, nail, bolt, ect. They are all different, to connect different things together.

swimmer Wrote:
-------------------------------------------------------

>
> For the article to tie them to the cause of cancer
> is misleading. Lectins don't cause cancer, but
> bind cancerous cells together much the same way
> they bind carbohydrates.
>
Actually, this could explain why the body can't fight cancer. The immune systems can't destroy the aberrant cells because they are coated with Lectins
One characteristic of Cancer cells is thickened cell membranes. Could this be cause by a buildup of Lectins? Several successful alternative cancer treatments use proteolytic enzymes.

What about the issue of heat altered Lectins? In correct quantities, natural plant material isn't usually toxic. Many things are toxic if over consumed. Wild animals will nibble small amounts of many different plants that would be poison them if eaten in large quantities.
Grains have been heavily modified genetically to increase yields. We shouldn't be surprised if they are less than healthy. I remember that a high Lysine corn was developed many years ago. The result was a corn protein that would sustain life by itself. It didn't produce as much, so never caught on with farmers. How many other harmful trade-offs occurred on the road to higher yields?

TruthHunter

Thanks, everyone. =)

TruthHunter Wrote:
-------------------------------------------------------

> Actually, this could explain why the body can't
> fight cancer. The immune systems can't destroy the
> aberrant cells because they are coated with
> Lectins
> One characteristic of Cancer cells is thickened
> cell membranes. Could this be cause by a buildup
> of Lectins? Several successful alternative cancer
> treatments use proteolytic enzymes.
>
> What about the issue of heat altered Lectins? In
> correct quantities, natural plant material isn't
> usually toxic. Many things are toxic if over
> consumed. Wild animals will nibble small amounts
> of many different plants that would be poison them
> if eaten in large quantities.
> Grains have been heavily modified genetically to
> increase yields. We shouldn't be surprised if they
> are less than healthy. I remember that a high
> Lysine corn was developed many years ago. The
> result was a corn protein that would sustain life
> by itself. It didn't produce as much, so never
> caught on with farmers. How many other harmful
> trade-offs occurred on the road to higher yields?
>
> TruthHunter


Good idea, but not quite, lectins don't work like glue, our cells don't work like that. Here is the discussion section from the first link that I posted (quoted in blue):

WARNING this quote contains info an animal testing!
Carbohydrate Specificity

While it is relatively easy to describe what a lectin does, they represent such a large and diverse class of naturally occurring molecules that it would be impossible to come up with a description of any one lectin that would fit all others. In a simple sense, a lectin is a protein-based molecule with a ‘sweet tooth.’ By this we mean that most lectins are comprised at least in part by proteins synthesized by the living organism than made it. Lectins like to attach to carbohydrates, mainly sugars or glycoproteins. Many of these carbohydrates are found on the exterior walls or membranes of simple cells, where they constitute the outer markers, or antigens, of that living creature. The great majority of the plant lectins are present in seed cotyledons where they are found in the cytoplasm or in the protein bodies, although they have also been found in roots, stems and leaves. Not surprising, many of these seeds, stems and leaves are components of many common foodstuffs. Thus lectin ingestion as part of any normally balanced diet is virtually unavoidable.

Until recently, it was not recognized that nature could employ sugars for the synthesis of highly specific compounds that can act as carriers of biologic information. Monosaccharides can servo as "letters" vocabulary of biologic specificity, where the words are formed by variations In the nature of the sugars present, the type of linkage, and the presence or absence of branch points. The first proof that sugars could serve as specificity determinants came from the discovery that influenza virus could agglutinate red cells only in the presence of certain membrane-bound carbohydrates. It these were removed, the virus no longer could bind to the cell. Sugars on cell surfaces also seem to determine the distribution of the circulating cells within the body.

Radioactively treated rat lymphocytes will migrate to the spleen when re-injected into the animal. However if the sugar fucose is removed from the surface of the cells before reintroduction, the cells migrated to the liver instead, as if the fucose served as a ZIP code - directing the calls where to go. It was not until 1953 that we discovered that the specificity of the ABO blood group-system was determined by similar sugars. For example, the difference between blood types A and B lies in a simple sugar unit that sticks out from the end of a carbohydrate chain of a glycoprotein or glycolipid. In blood type A the determinant is N-acetylgalactosamine, in type O it is fucose, and in group B it is galactose.

When a lectin contains multiple binding sites, they can interconnect large numbers of cells, causing them to clump together or agglutinate. Each molecule of a lectin has two or more regions, perhaps clefts or grooves, each of which fits a complementary molecule of a sugar or several sugars. It is by means of these combining sites that the lectin attaches itself to the sugars on cell surfaces. Bacteria typically attach to prospective host cell membranes via receptors with lectin-like sugar specificity. This is of great importance, as the adherence of bacteria to host tissue surfaces is the initial event in a bacterial infection. Salmonella and Escherichia coli both carry several surface lectins with pronounced immunosuppressive ability. Both adhere to epithelial cells by attaching to the sugar mannose on the victim cell’s surface.

The attachment of lectins can often be blocked by the use of sugars specific to the lectin as a sort of ‘sacrificial molecule.’ For example, colonization of the urinary tract with E. Coli can markedly be reduced by the administration of mannose sugars, which is probably why cranberry juice works in preventing bladder infections, since it is an excellent source of mannose.

The binding of lectins to sugar is quite weak. It does not form a covalent bond, but is reversible, like enzyme-substrate or antigen-antibody reactions. Lectin-sugar reactions actually share many factors in common with antigen-antibody reactions, especially precipitation, which has prompted several investigators to suggest that lectins are plant antibodies. However this has been tempered by several major differences between the two. Antibodies are made by higher organisms which have specific immunologic organs. Lectins are present as constituent proteins. Second, antibodies are all structurally similar to one another, whereas lectins are structurally diverse; examination of the amino acid sequence, molecular size and other molecular properties show that lectins have little in common other than they are all proteins.

For example soybean agglutinin is a glycoprotein with no di-sulphide bond; its molecular weight is 120,000, It consists of four subunits and has two binding sites. Wheat germ agglutinin is not a glycoprotein and is rich in di-sulphide bonds with a molecular weight of 36,000, It has two identical subunits and four binding sites for sugars.

End quote.

Lectins are impervious to enzymatic activity, so protease based enzymes are not likely to have any effect. Apparently they must serve their purpose for us in their complete whole form. Lectins are not evil, they serve a very important role in nature, and in human biological functions.

At this point I don't believe there is any tie to the toughness of a cancerous cell wall and lectins. Even though lectins have been observed to cross link and this allows them "pool" and make a puddle or cap on a part of a cell. They can not coat a cell wall and that "cap" would not effect the molecular makeup of the cell membrane and make it tough.

I agree about modified grains. I believe that the fundamental problem for humans consuming grains is not the grains themselves, but all the modification that has occurred over several human generations. That said, I also know that our genetics plays a role because many people seem to lack the natural antigens needed for our bodies to tolerate certain proteins, like celiac disease. Apparently there is a similar genetically based intolerance to lectins for some people.

Some studies use various lectins to stop tumors from growing.

Yeah Arugula, I was reading an article on that today. Fascinating isn't it?

It seems they use specific lectins to activate specific antibodies against the tumors. One study was working with AIDS for a more broad activation.

It's just kinda tough for me to read about creating cancers in, and infecting rats and dogs with diseases for the research.

Swimmer, I work part time at the vet school.

Everyone there wants to "help" animals, "loves" animals.

Number of vegans aside from me: 0.

It's sickening.

One positive note, at this uni, there is a trend moving away from research on live animals to dead ones. The reasons why however have nothing to do with ethics. It's simply cheaper and less hassle for the researchers.