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20. Nobody Wants to be Eaten, Including Vegetables -- Part I: How Lectins Impact Our Health

In this video, Dr. Paul Mason from Sydney talks about a protein that's found in plants called lectins and how they can have a massive impact on our health, from obesity, Parkinson's disease, to autoimmune diseases. Understanding lectins he believe fills in a massive chasm in conventional medicine when it comes to treating a myriad of chronic diseases.

The story begins in 1976 in England when nine school boys ate some kidney beans that had been soaked but not boiled. Within one and a half hours, all nine of them ended up with profuse diarrhea and vomiting. Some of them had only consumed four kidney beans. And further study shows that a diet containing only 1% kidney beans will kill a rat in two weeks. This is how toxic kidney beans can be. Why is that?


Although a kidney plant looks very defenseless, it can actually engages in some very potent chemical warfare and one of the weapons is called lectins. The particular lectin contained in kidney beans is called phyto hemagglutinin. In fact, there's over a hundred known sources of lectins (see list below), and many of these are toxic to humans. Each lectin is a protein with a unique structure and has the ability to bind to carbohydrates. All of our cells in the body have glycoproteins which protrude up from the cell membrane and they contain a carbohydrate moiety on the end of it and lectins can bind to that carbohydrate moiety and that means lectins can therefore bind to our human cells.


Lectins are resistant to cooking. In the case of red kidney beans it's recommended that you should soak them for five hours and then boil them for at least 10 minutes to reduce the lectins to a less dangerous level. Besides being heat stable, lectins are often very resistant to the normal digestive enzymes that we have lining our gut. It's to the point where a lot of lectins provide no nutritional value at all, they often excrete it completely unchanged. Often on the way through the intestinal tract, some of these unchanged lectins bind to the walls of our intestine and do significant damage including killing the cells.

Our intestinal tract ideally should only allow absorption of nutrients across the wall while not allowing entry of any toxins. Its basic structure has three layers. Firstly there's a mucus layer on top indicated in green. Then beneath are the epithelial cells which had joined together side by side by what are called tight junctions. And on top of the epithelial cells is the little frill layer which is called micro villi. On the very tip of these micro villi, there are something called a glycocalyx, which has a carbohydrate component. This means that lectins can actually bind to this part of the intestinal membrane. If we take something like wheat germ agglutinin and that will actually bind to the internal lining of our gut and damage it and that causes something called leaky gut.


Leaky gut or intestinal permeability allows the toxins to enter the body. The graph below demonstrates the potential of these toxins, i.e. lectins, to enter our body. Seven participants consumed 200 grams of peanuts and this test measured the amount of peanut lectin within their blood. You can see that within half an hour the level started to rise and within an hour there was a significant amount of lectin seen in the circulation.

Remember these lectins have the ability to bind to the surface of cells. It means that after entering our circulation, they can actually bind ourselves in many different organs, depending on what particular affinity the lectin has for a particular kind of cell. There was a study that was done on females with unexplained infertility. They've captured in pictures that soybean agglutinin electon bound to some endometrial tissue which is the lining of the uterus.

Unfortunately the consumption of lectins in our diet is actually increasing significantly so in part this is due to natural selection, selective breeding and genetic modification of crops which tends to select for species that are natural resistant to pesticides and that natural resistance comes from lectins. The specific health consequences that these lectins can have include obesity, reflux, Parkinson's disease, and autoimmune diseases.

For obesity, many people have noticed that when they cut plant foods out of their diets they lost weight as much as ten kilograms, even if they're already on a low carbohydrate diet. So why is that? It's because insulin is a hormone that stimulates fat storage and lectins can stimulate the insulin receptors. This graph below is from a 1983 study and it compared active fat storage between lectin and insulin, including the cases when insulin alone was given, when insulin plus a lectin in the form of wheat germ agglutinin was given, and when lectin was given alone. The point is that lectin stimulates the insulin receptor in a far more prolonged fashion than even does insulin.


Lectin can also impact on another hormone critical to fat storage which is leptin. The hormone leptin is essential in regulating appetite satiety and energy balance. Take a look at the two mice below. The one on the left with no leptin demonstrates the importance of leptin functioning effectively. Lectins can actually bind to the leptin receptor and interfere with it causing resist. In animal studies using isocaloric diets that simply eliminate lectins that leads to significant weight loss in the animals.


In terms of reflux, it happens when you have stomach acid in the stomach that ascends up the esophagus. It's often called heartburn. You might be surprised to learn that lectins can also cause this. There is one study which showed a dramatic reduction in the acid levels in the esophagus within six days of starting a low carbohydrate diet.

For Parkinson's disease, there's evidence now that this can be caused by lectins. It can actually ascend up to the brain by traveling along nerves. The nerve in particular is called the vagus nerve. So theoretically if that was true if you just simply cut the nerve you would interrupt the highway which the lectins are sent to the brain and you should be able to reduce the risk of Parkinson's disease. In one study published in 2015 they compared every patient in Denmark who had this procedure between 1977 and 1995 and this is what they found they found that by cutting the vagus nerves, the risk of developing Parkinson's disease dropped by 47%. There is a more recent study that was able to actually confirm the mechanism. it was able to demonstrate that lectins were actually able to travel to the neurons in the brain which are affected in Parkinson's disease and this graphic here shows the ingested P-type lectin (where the arrows pointed) sitting on top of a neuron in the brain that makes dopamine.


In autoimmune disease the body attacks its own tissues and the particular tissues attacked determine what specific autoimmune disease it is. Different examples of them might include different types of inflammatory arthritis, pernicious anemia, multiple sclerosis, type 1 diabetes, inflammatory bowel disease, lupus and so on. The list goes on but the point is that all autoimmune diseases are characterized by the body's immune system attacking itself and one of the defining features is called Auto antibodies. Normally antibodies are used to defend against foreign invaders pathogens. If you have a bacteria the antibody will have a strong affinity for the bacteria. When it attaches to it, then stimulates or initiates an immune response that will lead to the eventual destruction of that bacteria. If this was a healthy cell here, hopefully that has no affinity for it. In the case of autoimmune diseases antibodies have receptors that can actually bind to healthy cells and then that can lead to healthy tissue starting to be destroyed. The presence of these antibodies is actually one of the major things that is used to diagnose autoimmune diseases. And leaky gut that allows lectins to enter into the circulation is a key contributor to autoimmune disease.

What can cause leaky gut? Will continue in Part II.


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