Lectins Myths: Are They Harmful To Your Health?

Lectins are an “anti-nutrient” that have received a lot of media attention recently. Fad diet books cite this food component as one of the central causes of obesity, chronic inflammation, and autoimmune conditions.

I actually find this slightly ironic, because when we look at where lectins come from, they’re all from plant-based foods. But if we actually look at the statistics of how much Australian’s eat plant-based foods, 95% of adults aren’t actually meeting the fruit and vegetable recommendations.

So the claims that lectins are the cause of all of these diseases already isn’t making sense (1).

In this article we take a look at some of the lectins myths – are they harmful, should we avoid them and do they cause inflammation.

What are lectins?

Lectins are a protein found in plant foods that bind to carbohydrates. They resist being broken down in the gut and are stable in acidic environments (such as our stomach). This is actually a feature that helps to protect lectic-containing plants in nature (2).

What foods contain lectins?

Lectins are found in varying amounts in most plants. This includes beans, pulses, grains, fruits and vegetables, nuts, coffee, chocolate some herbs and spices. Pulses (think chickpeas, lentils, kidney beans) and grains (like rice and quinoa) contain the highest amount compared with other foods.


Why are they a problem?

When consumed, lectins can cause negative side effects. One of the most commonly reported reaction is found when eating raw or uncooked kidney beans. Kidney beans contain a type of lectic called phytohaemagglutinin. Ingestion of this can cause red blood cells to clump together as well as nausea, vomiting, stomach upset and diarrhea (3).

Lectins have also been shown to interfere with the absorption of minerals including iron, calcium, phosphorus, and zinc.

Some research has also indicated that they may bind to the cells lining the digestive tract. Over time, this may effect the intestinal flora and is theorized to play a role in inflammatory conditions such as type 1 diabetes and rheumatoid arthritis (3,4).


That sounds pretty bad, should I be worried?

Unsurprisingly, these theories have fuelled the profits of books and enzyme supplements from the anti-lectin movement. There is very limited research in humans about the number of active lectins consumed in the diet and their long term health effects.

Lectins in foods are most often studied in developing countries where there is high levels of malnutrition, limited cooking facilities and lack of dietary variety (5,6).

There are different forms of lectins found in different foods. The reactions people have to them vary significantly.

Some people with digestive conditions such as Irritable Bowel Syndrome may be more likely to experience some negative symptoms from lectins and other anti-nutrients. However, a reasonable suggestion is simply to eat less of the food causing the digestive problem (ps. see a dietitian to help you with this).


Do they have any benefits?

Lectins can also act as a powerful antioxidant. Antioxidants help to protect cells from damaging unpaired electrons known as free radicals. This antinutrient can also help slow down the digestion and absorption of carbohydrates. This helps to stabilise blood sugar levels and keeps you fuller for longer.

Emerging research has also looked into the beneficial effect low amounts of lectins on stimulating gut cell growth in patients who are unable to eat for long periods (3,7)

Researchers are also investigating the effects that lectins may have in the treatment of cancer and even could be used in antitumor drugs in the future (8).

In addition to this, research time and time again continues to show the benefits of eating whole grains and legumes. People who consume more whole grains have improved cardiovascular health outcomes. Eating legumes such as chickpeas, lentils and kidney beans are linked with supporting healthy body weight and reducing CRP inflammatory markers.


Preparing food to minimise lectins

It is quite rare to eat foods with a high amount of lectins. This is due to them being most potent in the raw state of foods and these foods not typically consumed raw.

When foods are cooked, especially at high heat using a liquid such as cooking, stewing, boiling or soaking, this inactivates most lectins. They are also water-soluble and found on the outer surface of the food. This means, when these foods are cooked, the exposure to water removes the lectins.

The body also has a fantastic ability to produce enzymes during digestion that helps to break them down.

When cooking beans in a crock pot, use canned beans or boil them for at least 30 minutes before putting in the crockpot.


The bottom line

Just don’t eat grains and legumes raw.

Lectins are certainly harmful when consumed. However, given that they are denatured during cooking and the evidence against limiting these foods from our diet is very weak, it is definitely not something to be concerned about. Just make sure to cook your food!

There is strong evidence supporting the health benefits of pulses, grains, nuts, fruits and vegetables (i.e even in foods where lectins are found). If removed in a “lectin-free” diet, this could potentially lead to nutritional deficiencies.

If you’re following a plant-based or vegan diet and experiencing digestive upset, take control and apply to work with one of our expert plant-based dietitians. .



1. 4364.0.55.001 – National Health Survey: First Results, 2014-15. (2020). Retrieved 3 February 2020, from https://www.abs.gov.au/ausstats/abs@.nsf/Lookup/by%20Subject/4364.0.55.001~2014-15~Main%20Features~Daily%20intake%20of%20fruit%20and%20vegetables~28

2. Peumans, W., & Van Damme, E. (1995). Lectins as Plant Defense Proteins. Plant Physiology, 109(2), 347-352. doi: 10.1104/pp.109.2.347

3.Vasconcelos, I., & Oliveira, J. (2004). Antinutritional properties of plant lectins. Toxicon, 44(4), 385-403. doi: 10.1016/j.toxicon.2004.05.005

4. Freed, D. (1999). Do dietary lectins cause disease?. BMJ, 318(7190), 1023-1024. doi: 10.1136/bmj.318.7190.1023

5. Gibson, R., Bailey, K., Gibbs, M., & Ferguson, E. (2010). A Review of Phytate, Iron, Zinc, and Calcium Concentrations in Plant-Based Complementary Foods Used in Low-Income Countries and Implications for Bioavailability. Food And Nutrition Bulletin, 31(2_suppl2), S134-S146. doi: 10.1177/15648265100312s206

6. Roos, N., Sørensen, J., Sørensen, H., Rasmussen, S., Briend, A., Yang, Z., & Huffman, S. (2012). Screening for anti-nutritional compounds in complementary foods and food aid products for infants and young children. Maternal & Child Nutrition, 9, 47-71. doi: 10.1111/j.1740-8709.2012.00449.x

7. Liu, Z., Luo, Y., Zhou, T., & Zhang, W. (2013). Could plant lectins become promising anti-tumour drugs for causing autophagic cell death?. Cell Proliferation, n/a-n/a. doi: 10.1111/cpr.12054

8.Sarup Singh, R., Preet Kaur, H., & Rakesh Kanwar, J. (2016). Mushroom Lectins as Promising Anticancer Substances. Current Protein & Peptide Science, 17(8), 797-807. doi: 10.2174/1389203717666160226144741

Vegan Low FODMAP Diet – Foods To Avoid, Recipes, Symptoms

Low FODMAP Diet For Vegans

The low FODMAP diet is a dietary approach developed by Monash University to improve the symptoms of people suffering from irritable bowel syndrome (IBS).

The diet limits foods that have been shown to aggravate the gut and cause IBS symptoms including intestinal bloating, gas and pain. These gut-aggravating foods are a high in a group of sugars called FODMAPs.

Following the low FODMAP diet has been shown to improve the symptoms of 3 in 4 individuals suffering from IBS symptoms.

In this article we take a deep dive into a Vegan Low FODMAP diet and what foods you should include and avoid.


What are FODMAPS?

FODMAP is an acronym describing a group of short-chain carbohydrates (or sugars). These are found both in food and as food additives.

FODMAPs are quickly fermented by healthy bacteria that reside within your intestines.

When these are fermented, they pull more water into your gut, which cause gas (hydrogen and methane) to be produced. This can also cause bloating and distention and impact the way muscles in your gut contract.

As a result, you can experience symptoms of wind, abdominal bloating, diarrhoea and constipation.

What does FODMAP stand for?

F – Fermentable

Process through which gut bacteria ferment undigested carbohydrate to produce gases

O – Oligosaccharides

Fructans & GOS – found in foods such as wheat, shallots, barley, inulin, rye, onions, garlic and legumes/pulses (chickpeas, lentils, kidney beans).

D – Disaccharides

Lactose – found in dairy products like milk, soft cheeses and yogurts.

M – Monosacchardines

Fructose – found in honey, apples, high fructose corn syrups, mango, pear and watermelon.

P – Polyols

Sorbitol & Mannitol – Found in apples, apricots, nectarines, pears, plums, prunes, mushrooms, sorbitol (420), mannitol (421), xylitol (967), maltitol (965) and isomalt (953).


How does the diet work?

The low FODMAP diet is recommended to be followed under the supervision of a qualified dietitian who has experience in the specialised area. The diet has three main phases:

Phase 1: Elimination Phase

The diet begins with an “elimination phase” – a two to six week period of high restriction where FODMAP-containing foods are reduced and eliminated in the diet.

Phase 2: Challenge Phase

The “challenge phase” is where FODMAPs are gradually reintroduced and challenged whilst the baseline low FODMAP diet is maintained. This helps to identify which FODMAPs you have a reaction to. 

Phase 3: Liberation Phase

Using your results from the challenge phase, a gut health specialist dietitian will help to design your new diet. This would include a mixture of low and high fodmap foods and provide you with recommendations of what to do with foods you had a negative reaction to. The dietitian may also prescribe specific prebiotics or probiotics for you to take.

I don’t have IBS, should I do the low FODMAP diet?

It is important to seek out a definitive diagnosis of Irritable Bowel Syndrome. This can be done through your General Practitioner or Gastroenterologist. .

This helps to rule out functional gut disorders such as Coeliac Disease, Ulcerative Colitis and Chrons Disease. These conditions may also present with similar symptoms as IBS.

This process may require you to have a series of blood and/or stool test.

It is essential to rule out other conditions as undiagnosed, there may be serious, long term health consequences.

Consequences of the LOW FODMAP Diet

There can be negative consequences of following a vegan low FODMAP diet.

Firstly, the low FODMAP diet is very restrictive in nature. This is accentuated on vegan diets as almost all vegan foods contain fodmaps.

Legumes, a popular vegan protein source is very high in FODMAPs. Legumes are found in chickpeas, lentils, kidney beans, black beans and canellini beans.

Per meal, vegans should aim for 1 cup of legumes to meet their protein needs. Unfortunately a portion of FODMAP is only 1/4 cup of legumes, or 1/2 cup of canned lentils.

Vegans need to be additionally aware of meeting their protein needs when following a low FODMAP diet and opt for low FODMAP vegan protein sources such as tofu, tempeh, walnuts, peanuts and protein powder.

Following a low FODMAP vegan diet may place you at increased risk of nutritional deficiencies. Particular nutrients to be aware of include iron, zinc and calcium.

It is important to work 1:1 with a specialised vegan gut health dietitian if you are planning to follow the low fodmap diet. 

My Symptoms Are Improving, Should I Stay On The Diet?

No. It is important to complete the three phases of the diet and reintroduce FODMAPs.

FODMAPs are essential for good gut health They contain prebiotics, a fuel source for our good gut bacteria. This  helps to produce short-chain fatty acids which have a wealth of health benefits.

Recent research has shown that following a strict low FODMAP diet for a long period of time can reduce levels of certain beneficial bacteria in the gut.

The goal of the low FODMAP diet is to improve the health your gut by giving your gut time to rest, then, to reintroduce certain foods back into your diet over a controlled period of time. We only recommend the diet to be followed for 2 – 6 weeks due to it’s restrictive nature. It is especially important to complete the diet (elimination and challenge phases) as a vegan, as the diet cuts out a lot of food if you are following both dietary patterns. This may put you at risk for deficiencies of certain nutrients (it also gets very boring).

Can I follow the low FODMAP diet as a vegan?

As FODMAPs are only found in plant-based food (besides lactose), this can make the low FODMAP diet particularly difficult to complete whilst also following vegan diet. Yes it can definitely be done, but be warned that the it will reduce the variety of foods you are eating and you may find yourself getting bored quite easily. This reinforces the importance of completing the reintroduction challenge phase of the diet.

Low FODMAP Vegan Foods

Egg alternatives: flax-egg, chia-egg.

Milk alternative: soy milk (made from soy protein e.g. santarium), macadamia milk, almond milk, rice milk

Fruit: rockmelon, grapes, green banana, strawberries, orange, kiwi fruit, mandarin, pineapple, honeydew melon, passionfruit, raspberries.

Vegetables: eggplant, green beans, bok choy, capsicum, carrot, cucumber, lettuce, potato, tomato, zucchini, kale, spinach, choy sum, lettuce, chinese cabbage, Jap (kent) pumpkin.

Grains: corn flakes, oats, quinoa flakes, quinoa, rice, corn pasta, rice cakes, sourdough spelt bread, wheat/rye/barley free breads, millet, bean thread noodle, polenta, buckwheat pasta, gluten-free pasta (made from rice, potato, corn)

Proteins: firm tofu, tempeh, red kidney beans (up to 1/2 cup), brown lentils (up to 1/2 cup).

Nuts & seeds: sunflower seeds, chia seed, flax seed, pumpkin seed, brazil nuts, macadamia, peanuts, walnuts.

Condiments: dark chocolate, maple syrup, table sugar, rice malt syrup, soy sauce, vinegar, coconut milk, lemon juice, fresh herbs, dried spices.

Drinks: cacao powder hot chocolate, peppermint tea, white or black or green tea, water.


Low FODMAP Vegan Meal Plan


2 slices of gluten free toast with peanut butter + 1/3 of a banana, sliced

Smoothie: 1 cup of sanitarium so good soy milk or almond milk + 40g brown rice protein + 1 cup frozen strawberries + 1 tbsp flaxseed + 1 tbsp chia seed + 1 drizzle maple syrup


30g macadamias + 1 orange


6 rice paper rolls made with tofu, alfafa, cucumber, capsicum, carrot and rice noodles


2 ice cakes with 1/8 of avocado + 1/2 tomato, sliced

2 rice cakes with peanut butter + 1/3 banana


Brown rice and tofu stirfry made with 1/2 cup brown canned lentils, 1/2 cup broccoli (heads only), 1/2 cup green beans, 1/4 sliced capsicum, 1/2 bok choy, handful of spinach and soy sauce and sesame oil to dress


Coconut yoghurt with carmens fruit free muesli and 1 kiwi fruit, diced

Low FODMAP tumeric mushroom soup
Low FODMAP Tumeric Mushroom Soup

Top mistakes to avoid:

1. Check your soy milks

Milks made from soy beans are high FODMAP whilst those from soy proteins are low FODMAP.

2. Don’t start a probiotic at the same time

Probiotics are live microorganisms that can lead to health benefits in the gut. There is some evidence that probiotics can help with IBS symptoms, but this may vary depending on which probiotic preparation is used. We recommend that you try one management strategy at a time; commence the low FODMAP diet first. If you have not achieved good symptom control after two to six weeks, consult with your dietitian. At this review-stage, you can discuss other management strategies and the possibility of introducing probiotics.

3. Be ware of meat-alternatives

Vegan meats made with gluten are low in fodmaps (e.g. seitan) , but not those made from soy!

4. Be careful of canned beans!

In canned legumes (lentils and chickpeas) the water-soluble FODMAPs (GOS) leach out of the legume into the brine mixture. So, if you’re eating a low FODMAP diet, make sure that you discard the brine and wash your legumes before use.


What if nothing works?

Not everyone find that the low FODMAP diet improve their symptoms. If you are one of the one in four individuals with IBS that don’t experience any benefit, there are a few other alternative therapies that may be of assistance. This includes probiotics, medication, clinically-trialed herbal preparations (e.g. Iberogast) or gut-directed hypnotherapy.


Recommended resources:


Following a low FODMAP diet as a vegan is tricky, we get it. Get 1:1 help with the digestive experts on plant-based nutrition at PNW Clinic. Meet our team here.