In recent years there seems to be an increasing epidemic of people suffering from chronic digestive and autoimmune diseases. Food intolerances or sensitivities can be at the root of the problem. Most people, including doctors, have little idea how the foods they eat can contribute to their chronic illness, fatigue, and digestive symptoms.
However, there is much evidence in the medical literature and in the lay public about how foods are causing and/or contributing to the current epidemic of chronic and autoimmune diseases. There are several diets that are used by many people to improve their health with varying degrees of success, despite a general lack of hard scientific evidence of their effectiveness. One of the clues to the cause and mitigation of diet-related diseases may lie in proteins known as lectins, found in all foods.
Both animal and plant food sources contain complex proteins known as lectins. These proteins typically have the ability to attach to sugars or carbohydrates on the surface of human cells. Some of these proteins can cause human red blood cells to clump together, a process called agglutination. The process of agglutination occurs when someone receives the wrong type of blood during a blood transfusion. In fact, red blood cell agglutination, which is specific to each person or group of people, is the basis of blood group testing. There is some data that blood types can affect how people respond to certain foods, although blood type specific diets seem to have been disproved. The attachment or binding of certain food lectins can trigger a variety of cell-specific effects. These reactions can mimic hormones or cause changes in cells. This is called molecular mimicry.
Most plants contain lectins, some of which are toxic, flammable, or both. Many of these plant and milk lectins are resistant to cooking and digestive enzymes. Grain lectins, for example, are fairly resistant to human digestion, but are well suited to ruminants such as cattle that have multi-chambered stomachs. Therefore, lectins are present in our diet and are often resistant to our digestion, and some have been scientifically proven to have significant GI toxicity in humans. Others have been shown to be beneficial and perhaps even protective against cancer. Either way, plant and animal proteins are non-body proteins and are processed positively or negatively by the digestive system and our immune system.
The human digestive system was designed to process a variety of plant and animal proteins through the process of digestion and elimination. Some plant and animal proteins or lectins are highly toxic to humans and cannot be eaten without causing death, as can castor beans and some mushrooms. Other foods must be prepared before they are safe to eat. Preparations can include peeling, prolonged soaking, and cooking like kidney beans. Other foods may be poorly tolerated due to genetics or an underlying pre-existing food allergy or intolerance. Others are tolerated to some degree or amount, but not in large amounts or on a frequent basis. People who are intolerant to the milk sugar lactose due to a congenital or acquired deficiency of the lactase enzyme can tolerate small amounts but may experience severe gas, bloating, abdominal pain, and cramping with explosive diarrhea when large amounts of lactose-containing foods are consumed. Food can become unbearable for some people after their immune system changes or the gut has been damaged from some other cause.
Of the food lectins, grain lectins; milk lectins; and legume lectins (particularly peanut lectin and soybean lectin) are the most common, associated with reports of aggravation of inflammatory and digestive diseases in the body and improvement in those diseases and/or symptoms when avoided. Recent research by Loren Cordain PhD. suggest that these lectins can effectively serve as a “Trojan horse,” allowing intact or near-intact foreign proteins to penetrate our natural gut defenses and get behind the lines to cause damage well beyond the gut, commonly in Joints, brain and skin of affected individuals. Once the gut is damaged and the defense system breached, the result is what some refer to as “leaky gut.” Additionally, many people who develop “leaky gut” have not only gut symptoms, such as bloating, bloating, diarrhea, and abdominal pain, but also other symptoms outside of the gut, or extraintestinal symptoms. Commonly affected areas are the brain or peripheral nerves, skin, joints, and various body glands. Continued exposure of the gut to these toxic food lectins results in sustained stimulation of the body’s defense mechanisms in a dysfunctional manner, ie autoimmune disease.
Incorrect types or amounts of good and bad bacteria in the gut, or gut dysbiosis, can contribute to this process of abnormally stimulating the immune system. Research supports the strong possibility that such stimulation may be enhanced by the bacteria’s interaction with food lectins. Some believe this can further aggravate gut injuries and autoimmune diseases. This latter concept is accepted and recognized by physicians in some form as hygiene theory. It is speculated that our gut bacteria have changed due to increased hygiene and overuse of antibiotics and that this phenomenon may play a significant role in the increasing prevalence of autoimmune diseases such as diabetes, arthritis and chronic gut conditions such as Crohn’s disease and irritable bowel syndrome.
However, lectins as a cause are largely ignored in the US, although the field of lectinology and the role of lectins in disease is becoming more accepted internationally. Avoiding certain food lectins can be helpful in achieving health and healing chronic gut injuries. Curing a “leaky gut” and avoiding ongoing abnormal stimulation of the immune system by toxic lectins and bacteria in the gut is the basis for ongoing research and the likely success of several popular diets such as the Paleo diet, the carbohydrate-specific diet, and gluten-free /casein-free diet. More research is needed in this exciting but often neglected area. The Food Doc, LLC has a website which will provide physician-authored information on food intolerances, sensitivities and allergies such as lectin, gluten, casein and lactose intolerance with dietary advice that will soon include an online symptom assessment and food diary.
Copyright 2006, The FoodDoc, LLC. All rights reserved.
Thanks to Dr. Scot Lewey
