Lectins are glycoproteins of 60,000-100,000 MW. They are carbohydrate-binding proteins, macromolecules that are highly specific for sugar moieties and are known for their ability to agglutinate (clump) erythrocytes in vitro.
Lectins play numerous roles in biological recognition phenomena involving cells, carbohydrates, and proteins. Lectins also mediate attachment and binding of bacteria and viruses to their intended targets. The molecular properties of lectins offer a way for molecules to stick together which can influence cell-cell interaction much like the lock-and-key binding found with enzyme and substrate. Lectins are found in both plants and animals. Lectins found in plants are known to be toxic to animals.
Why do plants have toxic lectins ?
Plant lectins are toxic to all animals so basically these so called -Anit-nutrients- Gluten, Lectins and Phytates—are plants’ way of protecting themselves against being eaten.
Shown below is the structure of the most common animal lectin. The upper left shows how protein presents a tight fit with the sugar galactose.
SOURCE: 1W6M X-RAY CRYSTAL STRUCTURE OF C2S HUMAN GALECTIN-1 COMPLEXED WITH GALACTOSE
Foods with high concentrations of lectins, consist of: beans, cereal grains, seeds, nuts, and potatoes. If consumed in excess, they may be harmful when uncooked or improperly-cooked. Adverse effects may include nutritional deficiencies, and immune (allergic) reactions. Most effects of lectins are due to gastrointestinal distress through interaction of the lectins with the epithelial cells of the gut by binding.
Plant Lectins cannot be fully digested by humans and can they enter the bloodstream. Our immune system then recognizes them as foreign, attacks them causing an inflammatory response. Because fo their affinity to sugar moeties, lectins can bind to our intestinal lining. There they can damage our intestines in a way that creates openings large enough to allow large undigested proteins to enter our bloodstream. This sets off and immune response against these unfamiliar invaders, which causes the body to have a systemic inflammatory response. Beans have a very high concentration of lectins. So much that just five raw Kidney Beans can kill a human. This will happen because the lectins will bind to the sugar molecules on the surface of our red blood cells and cause them to clump together and coagulate the blood. But food poisoning contracted from raw or undercooked beans is completely preventable by properly cooking them.
Grains, beans, nuts, and seeds in their natural form were never consumed in ancient times without being soaked or fermented first. Soaking releases some of the lectins which can be drained off. Adding baking soda or vinegar increases the Perhaps one of the safest methods of cooking beans is in a pressure cooker where the temperatures are much higher. Pressure cooking seems to be particularly effective at inactivating lectins.Supplements and Diet
Foods such as seaweeds and ground up shrimp shells bind Lectins. Also MSM or Glucosamine tablets used by many for joints works against lectins. The most effective form of glucosamine for binding lectin from wheat is N-Acetyl-D-glucosamine. Below is shown the crystal structure of the lectin, wheat germ aglutinin, bound to glucosamine. When glucosamine is bound to lectins is prevents binding to cell surface sugar moeities.
SOURCE: 2UVO HIGH RESOLUTION CRYSTAL STRUCTURE OF WHEAT GERM AGGLUTININ IN COMPLEX WITH N-ACETYL-D-GLUCOSAMINE- (N-acetyl-d-glucosamine shown in CPK model, image created using Jsmol)
What is a Paleo Style Diet?
READINGS AND REFERENCES
3-Do dietary lectins cause disease?- The evidence is suggestive—and raises interesting possibilities for treatment
Gluten is a protein found in wheat. What part of the wheat grain is it located? How can you identify foods that contain gluten? ... read more.What are the genes in the Human Genome responsible for Celiac Disease?
There are two genes that are responsible for Celiac disease although other genes and environmental factors play a role in those that get the disease, since as many as 30-40% of the population may have the gene(s) but not show symptoms... read more.Why is an immune response triggered against gluten in some individuals?
How does gluten cause celiac disease?... read moreWhat is the difference between celiac disease and gluten sensitivity?
Only 1% percent of the population has true Celiac disease. Many more have what is know as gluten sensitivity What is the difference between the two, and how to know which one you have... read more. Is gluten the only substance in wheat people are sensitive to? ... read more.What are the ongoing Clinical Trials for Celiac Disease
There is still a lot that is not understood about how gluten's affect humans... many clinical trials are underway... read moreWhat are lectins -why are they toxic and cause illness?
Both plants and animals contain lectins. What are they and why can they be very toxic to our bodies. Why do beans have to be soaked and properly cooked? What is the role of lectins in autoimmune disease? ...read moreRole of Lectins in Inflammation
Although gluten has been in the limelight for sometime, many people may not realize that other lectins may be causing digestive issues... read more