Low Lectins Diet by Sue Kira

by sue

Low Lectins Diet

by Sue Kira, Naturopath & Clinical Nutritionist

What are lectins?

How to reduce lectins in food

Foods high in lectins to avoid

Low lectin foods to enjoy

What are lectins?

Lectins are certain types of proteins that can be found in abundance in foods such as raw legumes and grains, but they can also be found in many other foods like dairy products and some vegetables.

Protein lectins can be very difficult to digest, creating flatulence and other symptoms, especially for those with weaker digestive systems and other existing health conditions, as well as those with a genetic weakness for digesting certain lectins.

It is thought that lectins are the reason behind many of the top food intolerance reactions we get today. These reactive foods include wheat (gluten lectin), dairy, eggs (especially the whites), soymilk, peanuts, tree nuts, shellfish, and fish.

It is also thought that the genetic alteration of the plants we consume today has resulted in a far higher quantity of reactive lectins in these plants, compared to lectins in foods like grains and dairy of yesteryear. Crops have been modified to grow stronger and bigger to yield more crops per acre of land and to be more resistant to pests, diseases and the sprays used to control them.

What is the function of a lectin?

If we look at the function of lectins in a plant with seeds (e.g. wheat) we can see that lectins are there as a defence mechanism against invading insects and disease. Also, if an animal eats these seeds they pass intact through the animal’s digestive system so the seed can be dispersed and fertilised at the same time. Kind of neat for the plant’s survival, but not so good for us.

The lectin’s job is to ward off and attack offending pathogens in plants. But inside our body they act in a similar way when the lectins bind or stick together with certain molecules which can then create a chemical reaction between the food we ate (which contained lectins) and our blood, and the cells lining our digestive systems, creating agglutination (clumping).

The intact lectins clump cells together and then attack those clumps of cells as if they are foreign invaders. And to make it worse, our immune cells will also attack this clump, creating all sorts of issues and may even be implicated in conditions such as irritable bowel, and the more serious auto-immune problems, such as celiac disease.

Different lectins can affect various organs of the body, creating tissue reactions, such as in our gut, liver, kidneys, stomach or indeed any organ, tissue, or body system.

Lectins can even affect different blood types, and there has been a ‘blood type diet’ created for this purpose, but it’s complicated. So rather than have a diet for each blood type, the recommended foods in this article will cover the worst offenders that affect most people.

Signs & symptoms linked to lectin issues

  • Bloating and flatulence, especially after meals
  • IBS, cramps, spastic colon
  • Fatigue and tiredness, especially post meal fatigue
  • Brain fog, especially after meals, lack of concentration
  • Post-nasal drip, sinus, itchy nose, hay-fever, tonsillitis (recurrent)
  • Achy joints and muscles, random pains (inflammation)
  • Changes in bowel habits, diarrhoea, constipation (or alternation)
  • Skin problems (eczema, psoriasis, fungal etc)
  • Hormonal fluctuations
  • Intolerance to mould
  • Intolerance to cold
  • Low blood pressure
  • Immune imbalances – auto-immunity is common
  • Anxiety, perfectionism, OCD
  • Poor ability to handle carbs
  • Fluid retention – puffy eyes, legs, face
  • Migraines and headaches from inflammation and food reactions
  • Easy weight gain or stubborn weight loss
  • Needing to clear throat frequently, excess mucus
  • Hyperactivity in children
  • Recurrent UTI’s or cystitis

Many people are familiar with the reactions to the nightshade family of foods if they have problems with painful joints or arthritis; this is because these foods are high in lectins. Nightshades can be found in tomatoes and their products (sauces, paste etc), potatoes (not sweet potatoes as they are a different family), eggplants, capsicum/peppers, chilli, paprika and tobacco.

Lectins, the gastrointestinal and immune systems

It is quite normal for a certain amount of damage to occur to our intestinal cells as food passes through our digestive canal. These damaged cells will sloth off and quickly repair the lining with new cells. These are fast turn-over cells, just like the skin on our body. Slothing off old cells and replacing with new fresh cells is part of our natural regeneration process.

Lectins in foods also creates some of this damage, but they have a far greater capacity to destroy the cells of our intestinal wall at a much faster rate than the intestines can replace new cells to line the intestines and create an inflammatory process – which is the body’s way to speed up recovery.

Because the cell regeneration isn’t happening as fast as it should, our natural gut defences are compromised which can result in intestinal permeability (leaky gut). Our gut lining is there to allow certain molecules through and to shield and protect it from others by keeping them out.

With this breakdown in defence, we can get molecules into our blood stream that shouldn’t be there and at the same time, other important vitamins, minerals, and amino acids are let in before they are fully broken down, which means we can become deficient in certain nutrients as a result.

Also, the lining of the intestines is normally covered by tiny projections called microvilli which create a larger surface area for the absorption of nutrients. But when the gut wall is damaged, there is less microvilli which means less surface area to absorb digested nutrients.

The irritation on the intestinal wall can cause the body to try to evacuate the contents of the colon, which can result in cramps, vomiting and diarrhoea in some severe cases. It has been suggested that many people who thought they had food poisoning, actually had a lectin reaction or overdose.

The generalised inflammation that has been created can also cause symptoms of joint pain, skin rashes and even behavioural changes. Researchers have seen a common correlation of children with autism with high rates of leaky gut or other inflammatory bowel conditions often relative to lectin consumption.

Not everyone has these severe reactions – they may just get some discomfort in their bowel, bloating and flatulence and maybe the added headache or body ache. Sometimes the symptoms can be less gut orientated and may create damage in the background that goes unnoticed until something more severe comes up (but is not usually linked to lectins in the diet).

Earlier I referred to the agglutination (clotting) factor of lectins. This can occur anywhere in the body, specific to the type of lectin or the person it is affecting. It can affect the liver, kidneys or indeed any organ or body system. So how do we know? We possibly don’t, but there are some blood tests that can be done, and a gene test can show potential sensitivity.

Blood markers that will often show with lectin sensitivity

  • High Adiponectin: over 16
  • High TNF-alpha: over 3
  • High IL-6: over 3
  • Low white blood cells: under 5. Indicates white blood cells are being caught in the gut, spleen or elsewhere.
  • Low free and total T3: under 3 for free T3 and often higher TSH (thyroid-stimulating hormone) above 3. Low T3 from inflammation and oxidative stress.
  • Low Ferritin: under 70 for men and under 50 for women. Lectins can create inflammation in the gut that reduces iron absorption.
  • Low Insulin: under 4 – in the lectin sensitive who are not also leptin resistant.

Genetic markers that may lead to lectin sensitivity

Gene SNPs that increase risk for inflammation and intestinal permeability can increase your risk, but it is your epigenetics (how you live, what you eat and what happens to you) that create the biggest risk. In other words, if you eat lots of grains, legumes and pulses or even just bread plus have stress, infections, and a driven personality, this can be enough to set the ball rolling in the direction of lectin sensitivity.

The most common genes that can create weakness towards lectins are Cannabanoids-CNR1 and MTHFR. Folate (from methylene tetra-hydro FOLATE i.e. MTHFR) is necessary for healthy gut function and the MTHFR SNPs require higher methyl-folate intake, or loads of green veggies to keep this pathway and hence the gut healthy.

Methylation breaks down histamine in our gut, histamine increases gut issues, and therefore undermethylation can increase the likelihood of leaky gut and lectin sensitivity. For more information on Methylation, go to the article about the MTHFR/Methylation Diet

Risk factors for developing lectin sensitivity

  • Stress of any kind, psychological/emotional and physical i.e. excessive exercise
  • Vegetarian or vegan diet with high grain, pulses, legumes
  • Low vitamin D levels – needed for the immune system
  • Infections and toxin exposure/antibiotic use – disruption of gut flora
  • Low fish consumption as DHA is needed for good immune system balance
  • High electro-magnetic field (EMF) exposure can affect the immune system
  • Over activation of nervous system – anxiety, raciness, type A personality
  • Disrupted hormone system pathways – thyroid, adrenal, sex hormones, increased cortisol, menopause
  • Alcohol abuse, morphine, or codeine use
  • Sleep loss or insomnia – affects stress hormones

How to reduce lectins in food

Many foods contain lectins, but we can reduce the amount of lectin content in foods by soaking, sprouting, cooking or fermenting foods.

In most cases, the longer something is soaked or sprouted, the less lectins. But in the case of alfalfa sprouts, the lectin activity is actually increased by sprouting.

In other foods, the lectin is found in the seed coating, but as the seed germinates it loses its coating along with the lectins. Therefore it’s best to soak seeds, grains and some nuts, rinse them and sprout, ferment, or boil foods like beans and grains. This explains why traditional sour-dough recipes for bread used to be easier to digest than the breads commonly consumed today.

Soybeans can be one of the hardest to digest, even after soaking and sprouting or cooking, but by adding the technique of fermentation, the humble soybean can be used as tempeh, natto, tamari and miso with less chance of creating health issues.

Not all lectins can be destroyed by the above methods, and some people simply cannot tolerate these foods anyway, so they are best avoided.

Foods high in lectins to avoid

Pretty much all foods contain some lectins but some are worse than others. Here are those that contain the highest amounts of detrimental lectins…

  • All grains, including bulgur, buckwheat, millet, quinoa, kamut, spelt, rice (brown and white), oats and especially the grains with gluten such as wheat, spelt, rye and barley plus their germs and brans, such as wheat germ or wheat bran and rice bran.
  • Nightshade fruits, vegetables and spices including tomato and tomato products, peppers, including chilli, paprika, potato and eggplant. Tobacco is also a nightshade plant.
  • Legumes, beans and pulses – soybeans, chickpeas (garbanzo), kidney, navy, pinto, lentils, mung beans, lima, fava, string beans, field beans, peanuts and cashews. Unfortunately for many, this also includes cacao beans (chocolate)!
  • Nuts and seeds – especially almonds, pine nuts and hazelnuts, chia seeds, pumpkin seeds, and sunflower seeds.
  • Dairy including all milk and milk products such as cheese, yogurt and kefir.
  • Yeast (except ‘nutritional’ yeast).
  • Certain fruits and vegetables such as all melons, mangos, corn, cucumber, pumpkin, squash of any kind including zucchini and the nightshades mentioned above.
  • Sweeteners such as agave, sugar, sucralose, and any artificial sweetener.
  • Oils to avoid include cotton seed oil, canola, corn oil, grapeseed, peanut oil, safflower and sunflower oil.
  • Extra things to avoid include coffee, some spices such as nutmeg, caraway, peppermint and marjoram, and garlic in high amounts (small amounts of garlic can be fine).

Low lectin foods to enjoy

  • Grains that are acceptable in small amounts are amaranth and wild rice
  • Pasture raised/grass-fed, free-range animals incl their organs (beef, pork, lamb, rabbit)
  • Fresh sausages from any animal without smoking or nitrates/nitrites
  • Pasture raised/grass-fed, free-range poultry (chicken, turkey, duck, quail etc)
  • Wild caught seafood (most farm raised fish and seafood are fed grains), salmon, sardines, oysters, prawns/shrimp, anchovies, trout, mussels
  • Egg yolks from grass fed omega rich poultry. Whites are high in lectins
  • Nuts – macadamia, coconut, chestnuts, pistachios, pecans and walnuts
  • Mylks from the above nuts such as macadamia and coconut mylk
  • Seeds – flax (linseeds) and sesame seeds or tahini (sesame paste), carob
  • Oils – sesame, olive, coconut and macadamia oil, lard, chicken fat, duck fat, bone marrow, tallow
  • Small amounts of these fruits – apples, blueberries, cherries, bananas, papaya, strawberries, raspberries, pomegranate, plums, peaches, nectarines, kiwi and citrus fruits. Unlimited amounts of other fruits.
  • Vegetables include lettuce, broccoli, kale, mustard leaf, celery, beet greens, spinach, cauliflower, Brussel sprouts, sweet potato, yams, taro, radish, turnips, and sprouts of other vegies except alfalfa. Do not include vegies included in the above list of foods to avoid.
  • Sweeteners of monk fruit, raw honey, stevia and yacon.
  • Spices and herbs of non-seed type including oregano, rosemary, basil, ginger, onions, chives and garlic (small amounts), thyme, bay, parsley, dill, coriander/cilantro, cinnamon, wasabi, turmeric, tarragon, saffron, orange and lemon peel/zest, sage, lavender.
  • Condiments such as sea salt, kelp, nori, apple-cider vinegar, coconut aminos, coconut teriyaki, baking soda (not baking powder), nutritional yeast with no additives (but not other yeasts), bone broth, gelatine and collagen


Before you commence your diet, see your medical or health care professional for qualified guidance about what foods and supplements are best for your body. While on the diet do not stop any medications or supplements previously prescribed unless advised otherwise by your medical or health care professional.

During the early stages of a new diet, you may experience symptoms such as fatigue, headaches, or body aches, which may occur because your body is detoxifying. However, if you are unsure about a symptom at any time, check immediately with your medical or health care professional.


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