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Lectin is a type of glycoprotein found in many plant foods. Seeds of the grasses such as rice, rye, spelt and wheat have exceptionally high levels of this defensive glycoprotein. It is used as protection by the plants against the bacteria, fungi and insects which use N-Acetylglucosamine to build their cells walls. All animals, including birds, fish, humans and even worms, use N-Acetyglucosamine as a foundational substance for building the various tissues in their bodies, including cartilage, joints, bones and tendons.

The mucous known as the glycocalyx, or literally "sugar coat" is secreted in humans by the epithelial cells which line all the mucous membranes, from the layer of skin over the eyes and in the nasal cavities to the top to the bottom of the alimentary tube, as well as the protective and slippery lining of blood vessels. The glycocalyx is composed largely of N-Acetylglucosamine and N-Acetylneuraminic acid (also known as sialic acid) and lectin’s unique binding to these exact two glycoproteins is not accidental. Nature has designed lectin perfectly to attach to, disrupt and gain entry through these mucosal surfaces as a defence for the plants.

Viruses and lectins have many similarities. Both viral particles and lectin are very much smaller than the cells they enter and are taken into the cell through a process of endocytosis and both viruses and lectin gain entry through the sialic acid coatings of the mucous membranes (glycocalyx).

Because lectins are extremely small and resistant to decomposition by living systems they tend to accumulate and incorporate into tissues where they interfere with normal biological processes.

Most foods contain lectins in varying amounts and most do not cause any health issues however, common foods with known toxic lectins include all soya bean and wheat products including oils from these substances.

The most common sources of lectins

  • Beans: caster, cocoa, coffee, lentils, navy beans, peanuts and soya beans.

  • Dairy products (when cows are fed grains instead of grass).

  • Grains: brown rice, buckwheat, corn, millet, oats, quinoa, rye, spelt and wheat.

  • Nightshades: ashwaganda, aubergines, blueberries, goji berries, huckleberries, peppers, potatoes and tomatoes.


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Most people only react to one type of lectin in a certain food group and this is what is concerning when it comes to GM foods. GM (genetically modified) crops are modified by splicing 'lectins' from one plant family to another. This can cause a dilemma for those that know they can react to a particular plant family and not to another. When those plants are crossed genetically the person will react to the modified plant and probably not realise why.

If lectin has been established as causing health issues, then the following should be checked also as they too contain moderate levels of lectins:

  • Berries: blackberries, goji berries, raspberries and strawberries.

  • Fruit: apples, banana, cherries, currants, grapes, papaya, plums, pomegranates, quinces, raisins, rhubarb and watermelon.

  • Herbs and spices: caraway, garlic, marjoram, nutmeg and peppermint.

  • Nuts: coconut, hazelnuts and walnuts.

  • Seeds: sesame seeds and sunflower seeds.

  • Vegetables: asparagus, beetroot, carrots, courgettes, cucumbers, mushrooms, pumpkin, radishes, sweet potatoes and turnips.

Some believe that lectins may be inactivated by soaking, sprouting, cooking or fermenting. Soaking legumes overnight, draining the water, rinsing and draining again does seem to remove or inactivate many of the lectins. Heating seems to remove others in some foods but not all. There is little data to prove that any of these methods remove lectins completely as few foods have been tested and, of those that have lectins, many seem to remain after processing.

Lectins are hardy proteins that do not break down easily as they are resistant to stomach acid and digestive enzymes. They can bind to the gut wall and damage the gut lining which can alter gut permeability and then they can pass through the gut into general circulation. Lectins can cause alterations in gut function that can be responsible for and worsen the following conditions:

Lectin damage to the gut wall may allow other proteins to also cross undigested into general circulation and cause allergic reactions including anaphylaxis. Having gained access to general circulation various lectins may bind to surface cell membranes in arteries and vessels, organs and glands, including the thyroid, pancreas, kidney and adrenals, in susceptible animals and humans. This binding may begin antigen/antibody reactions leading to autoimmune disorders and degenerative diseases.

Is bread your worst enemy?

Because lectins are extremely small and resistant to decomposition by living systems they tend to accumulate and incorporate into tissues where they interfere with normal biological processes. It takes only 500 micrograms (about half a grain of sand) of ricin (a lectin extracted from castor bean casings) to kill a human. A single, one ounce slice of wheat bread contains approximately 500 micrograms of lectin but will usually only attack the mucosal lining of the gastrointestinal tract after constant accumulation in the diet. Unfortunately most bread also contains gluten which can cause similar issues and processed flour often has additives to help it flow freely, last longer and can be bleached white using chlorine.

The disruptive and damaging effects of wheat consumption are formidable in someone whose protective mucosal barrier has been compromised by non-steroidal anti-inflammatory drug (NSAID) use. Anti-inflammatory medications, such as ibuprofen and aspirin, increase intestinal permeability (as does gluten in grains and the glycoalkaloids found in plants from the nightshade family) and may cause absorption of even larger-than-normal quantities of pro-inflammatory lectins as well as undigested proteins.

Certain bacteria and viruses, including the influenza and herpes viruses, can also damage cells making them more susceptible to lectin and antibody/antigen reactions.
The type of lectin in wheat known as wheat germ agglutinin (WGA), like gluten, irritates and causes premature cell death in the gut and leads to a leaky gut condition with all the detrimental effects that will follow. It also disrupts the mucus membrane in the gut which can cause bacterial overgrowth and leads to a host of digestive issues like gastro-oesophageal reflux disease (GERD), ulcers and nutrient deficiencies.

The wheat germ agglutinin and another unknown factor in wheat also cause vitamin D stores to deplete abnormally fast and can therefore lead to vitamin D deficiency, with all its accompanying issues like weakening of the bones, a weakened immune system and a vulnerability to infectious diseases and bacterial attacks.

Because wheat has so many potential adverse effects on so many people, nutritionists often recommend removing wheat from the diet first when investigating the root cause of someone's health issues. It can take anywhere from one week to three months to see improvement to health after wheat is removed from the diet but it is worth considering because, if it is the culprit, as long as wheat continues to be consumed the health issues will never be resolved.

NOTE: Dairy products may be potentially more harmful when pasteurised and processed because of the reduction of SIgA, an immunoglobulin that binds to and eliminates dangerous lectins.

Lectin and its affect on the leptin hormone

The lectin from wheat also often ends up circulating in the body and in the brain, where it can cause leptin-resistance which causes effects similar to insulin-resistance. Those two factors could be a cause or promoter of obesity as leptin and insulin are the two most important hormones to properly regulate in order to maintain a normal weight and energy balance.

Leptin is a hormone that is produced by the body’s fat cells and is often referred to as the “satiety hormone” or the “starvation hormone.” The level of leptin in the blood, that reaches the hypothalamus in the brain, indicates to the brain the level of fat stored and available energy and, when there is enough fat stored, there is no need to eat and that calories can be burned at the normal rate. It also has many other functions related to brain function, fertility, immunity and others.

When the brain does not receive the leptin signal it believes that the body is starving even though it has more than enough energy stored. This makes the brain change the physiology and behaviour in order to regain the fat that the brain believes is missing.

Most people try to exert cognitive inhibition (willpower) over the leptin-driven starvation signal but this is often futile as the hormone signal telling the brain that the body is starving and must eat and conserve energy by becoming sluggish is far stronger than a person’s determination not to eat and to exercise more.

A sign of leptin-resistance is a large amount of body fat particularly around the waistline.

While leptin reduces the appetite ghrelin increases it. Ghrelin is a hormone secreted primarily in the lining of the stomach when it is empty and causes the appetite to increase. Like leptin, ghrelin goes into the blood, crosses the blood-brain barrier and ends up at the hypothalamus where it tells the brain it is hungry for food. Too much production of ghrelin can then lead to weight gain. Then too much fat storage will cause disruption to the leptin signals which, under normal circumstances, reduce the appetite for food.

Ghrelin is a hormone that the stomach produces when it is empty which, like leptin, travels to the hypothalamus in the brain and tells it that the body needs to eat food. Consuming a high carbohydrate diet produces more ghrelin because some carbohydrates are digested very quickly unlike protein and fat. If too much lectin is ingested so that the leptin hormone is disrupted from telling the brain it has enough fat deposits and the stomach is empty too often so that there is an increase in the ghrelin hormone, meaning the brain thinks it is starving, weight gain and obesity can be the result.

Other possible symptoms of lectin intolerance

Inflammation associated with rheumatoid arthritis is aggravated by lectin.

The sensation of extremities falling asleep could be due to a lack of nutrients like vitamin B12 that are passed through the digestive system rather than being absorbed due to lectin intolerance. Muscle weakness can also be experienced due to lack of vitamin B12.

Lectin may also worsen the symptoms of schizophrenia.

Six ways to correct the levels of ghrelin and leptin

  1. Avoid all wheat products.

  2. Avoid all foods that contain lectins, especially bread made from grain flours, for three months. When symptoms have improved gradually introduce them back again until one causes a reaction then eliminate that completely from the diet.

  3. Consume foods that take longer to digest as this will reduce ghrelin levels. As a general rule, carbohydrates move quickly through the stomach, protein takes a little longer and fats spend the longest time to work their way through the digestive system.

  4. Consume omega-3 fatty acids from fish oil daily as this can help to correct imbalances of both ghrelin and leptin.

  5. Too much fructose seems to increase leptin-resistance. Fructose is a monosaccharide known as fruit sugar and is found in ripe fruits and honey. Fructose prevents leptin and insulin from elevating to normal levels after a meal, while increasing ghrelin and triglycerides. Having high blood triglycerides can prevent the transport of leptin into the brain. The best way to lower triglycerides is to reduce carbohydrate intake and, to rebalance the hormones, reduce intake of ripe fruits and honey.

  6. Lack of sleep leads to more ghrelin and less leptin being secreted, as well as disrupted glucose and insulin metabolism. See Insomnia for natural resolutions for sleep disorders.

To find out which of the lectin-containing food groups may be responsible for the disorders mentioned above try eliminating them from the diet for at least a month, one at a time, to see if pain and inflammation and belly fat is reduced and any of the above disorders improve. Rarely does a person have to eliminate more than one or two of the lectin food groups on a long-term basis.

Nutritious natural foods low in lectin and fructose

  • Algae such as chlorella and spirulina

  • Almonds

  • Apple cider vinegar

  • Asparagus

  • Avocado

  • Basil

  • Beef (grass fed only)

  • Bok choy

  • Broccoli

  • Brussel sprouts

  • Cauliflower

  • Chia seeds

  • Coriander

  • Dill

  • Flaxseeds

  • Game birds

  • Ginger

  • Hempseeds

  • Krill oil

  • Leafy greens

  • Millet

  • Octopus and squid

  • Oily fish

  • Olive oil

  • Onions

  • Organ meats

  • Pumpkin seeds

  • Rabbit

  • Rice (white and wild)

  • Shellfish

  • Spring onions

  • Squash

  • Swede

  • Turmeric

  • Venison

  • Watercress

If there is no improvement then check that the intolerance is not to the other food allergens listed here: Allergies

"Nature cures not the physician..." Hippocrates 460 BC


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