What is your current activity level?
🧍‍♂️Sedentary
🚶 Moderately active
🏃 Very active
This will help us personalize your experience
Blog
>

Are Lectins Bad for Your Gut Health?

Published on
Updated on
Are Lectins Bad for Your Gut Health?

Table of Contents

Key Takeaways

Lectins are not bad for gut health if handled appropriately. Research has shown apparent benefits and some drawbacks for plant foods that contain ‘anti-nutrients’ like lectins, oxalates, phytates, and tannins.1 

Anti-nutrients from plants can be harder for the body to digest and may reduce the bioavailability of key nutrients. Consumption of large amounts of anti-nutrients can multiply this effect.1 Some diets discourage the eating of lectins in any amount. 

We will discuss the healthfulness of lectins, specifically in relation to gut health and function. 

A registered dietitian can help you heal your gut and learn more about your body. Book an appointment covered by insurance.

{{splash}}

What are Dietary Lectins?

Dietary lectins, or plant hemagglutinins (PHA), are proteins that bind to carbohydrates and are found in all plants. This protein-carbohydrate bond protects the plant in the wild but can cause more difficulty with digestion in humans. 

When eaten uncooked and raw, the lectins pass through the gastrointestinal tract unchanged. As lectins reach the small intestine, they can bind to receptors on the intestinal cell lining and cause damage.1

Larger amounts of lectins are found in certain plant foods like legumes, wheat, seeds, nuts, and some fruits and vegetables. Different cooking and preparation methods reduce the lectin content of these foods. 

Additionally, depending on the cultivation area, bean maturity, and plant variety, significant variations in lectin levels were found within the same bean (kidney bean).1 This makes it hard to predict the exact lectin content of plant foods accurately. 

Are Lectins in Food Good or Bad for You?

First, the bad, then the good. Lectins are harmful to you when eaten raw or undercooked. There are well-documented cases of food poisoning worldwide. PHA toxicity can occur after eating as few as 3 or 4 raw kidney beans. Symptoms include nausea and vomiting shortly after eating and then diarrhea. People typically recover within 3 to 4 hours. The PHA can cause red blood cells to clump together when eaten raw.1 No PHA toxin is present if the beans have been boiled for a minimum of 10 minutes. 

Animal studies have shown that after consuming raw beans or raw bean flours, intestinal alterations were seen, including reduced enzyme activity, microvilli changes, and intestinal damage from PHA toxicity.1 

However, these effects are not seen when the lectin-rich plant foods are cooked in specific ways! In human studies using cooked whole beans, there are no indications of intestinal changes, as seen with the raw lectin consumption in animal studies. 

Research shows actual benefits from the consumption of foods high in lectins. Animal studies using cooked legume lectins have demonstrated the anti-proliferative activity against various cancers.2 Additionally, diets high in legumes and whole grains are associated with reduced inflammation markers in animals and humans.1 

Beans and other lectin plant foods contain beneficial protein, carbohydrates, prebiotic fiber, vitamins, and minerals and are labeled as antioxidants.3 Consuming this nutrient mix helps to reduce insulin and blood glucose levels. Extensive human studies highlight the benefits of lectin-rich foods like whole grains, nuts, and legumes in managing type 2 diabetes, heart health, blood pressure, and inflammation.4 

{{local}}

Are Lectins Bad for Your Gut?

When eaten raw, lectins are harmful to your gut. These active lectins can cause intestinal damage. They may also interfere with the absorption of crucial minerals like zinc, calcium, phosphorus, and iron. Poor gut health and intestinal damage are often a precursor for autoimmune diseases.5 

In reality, the chance of a large active (raw) intake of lectin-rich foods is low. Lectins are heat sensitive and water-soluble. Food naturally high in lectin tastes terrible uncooked, which is a wonderful protective feature. 

Traditional cooking methods for dry beans call for several hours of soaking, followed by several hours of boiling. This process removes active lectins to negligible levels. Canned beans have already undergone this process and are low in lectins. Lectins are not harmful to most people when consumed properly. 

Food High in Lectins

About one-third of our food contains lectins. These include legumes, wheat, seeds, nuts, and some fruits and vegetables. Many foods contain higher lectin levels in their raw, uncooked form. These lower to safe levels after cooking.

Red kidney beans contain the highest amount of lectins in their raw state at 20,000 to 70,000 hau (hemagglutinating unit). Once cooked, they have a safe level of 200-400 hau.6 

Research on 32 different lectin-containing plant foods showed no detectable levels of lectin after cooking, except for nigella seeds (26 hau), broad green beans (26 hau), and tomatoes (104 hau).7 These are within the safe level. 

This list entailed bell peppers, eggplant, green beans, peas, potatoes, sugar peas, sugar snaps, tomatoes, barley, 20 different beans/legumes/lentils, four varieties of quinoa, various seeds, and wheat. Each lentil or legume was soaked for 10 to 12 hours, followed by 30 to 60 minutes of boiling. Different cooking times are listed within the study for the other plant foods.7 

Of note, 18 food items were within the safe level before cooking. Those containing high lectins before cooking included beans, lentils, and potatoes. These plant foods are within safe lectin levels once cooked. 

Lectins and Leaky Gut

Our gut (or intestinal cells) are made to absorb water and nutrients from our food and transfer these vital components to the bloodstream and body systems.  A leaky (or more permeable) gut allows more water, nutrients, and possibly toxins to pass through.8 

Combining a genetic predisposition with a leaky gut may allow for the trigger of the start and development of autoimmune diseases like type 1 diabetes, rheumatoid arthritis, and lupus.8 

Research indicates adequate vitamin D protects the intestinal wall, while stress can induce leaky guts. Some types of stress listed are burns, chronic alcohol consumption, and infections. This can all lead to increased intestinal permeability and the transfer of bacteria inside the cell wall. This transfer can trigger an abnormal immune response, leading to inflammation, tissue damage, and the activation or progression of autoimmune disorders.8

Research on lectins and their role in a leaky gut is not conclusive and limited. Some research indicates that the undigested lectins from plant-based foods can travel into some individuals' blood, trigger an immune response, and cause problems like autoimmune disorders.9 

Per the study results, lectins may be problematic for 8 to 15% of the population but are usually in conjunction with noted intolerance to eating foods with lectin.9 Therefore, it is recommended that if you show signs of intolerance (bloating, gas, physical discomfort), to consider eliminating or reducing lectin-rich foods. You may be part of the population whose immune system responds to lectin negatively.

{{splash}}

Takeaways

  • The consumption of raw or undercooked lectins (most commonly found in legumes) is dangerous for all people leading to food poisoning and intestinal cell damage. 
  • Cooking lectin-rich foods reduces the lectin to a low or non-existent level, making them safe for most of the population. 
  • Consuming foods containing lectins has been associated with preventing cancer progression2 and managing type 2 diabetes, heart health, blood pressure, and inflammation.4 
  • Lectins are present in foods that provide many proven health benefits and are a good source of nutrients. The benefits of foods containing lectins currently outweigh the risks.
  • If you show signs of intolerance after eating foods high in lectins, consider eliminating or reducing your intake with the help of a registered dietitian. You may need to eliminate certain types instead of all food containing lectins.

How a Dietitian Can Help

Navigating nutrition can be challenging, and diet can play a key role in quality of life, but it differs from person to person. That’s why it’s important to work with a gut health nutritionist who can tailor a nutrition plan that’s as unique as you are. 

Frequently Asked Questions

References

View all references
Nourish has strict sourcing policies and prioritizes primary sources, including medical organizations, governmental agencies, academic institutions, and peer-reviewed scientific journals. Learn more about our medical review process and editorial guidelines.

See a Registered Dietitian with Nourish

  • Covered by insurance
  • Virtual sessions
  • Personalized care
Schedule an appointment

Frequently asked questions

No items found.

Find a virtual dietitian in {State}

Find a dietitian near you

Covered by insurance.
Question 1

Are you more thirsty than usual?

Question 1

Are you urinating more than usual?

Question 1

Is your blood sugar level consistently high?

Question 1

Do you experience extreme hunger or fatigue?

Question 1

Do you have blurry vision or numbness and tingling in your hands and feet?

Question 1

Do you experience frequent infections or slow-healing wounds?

Question 1

Do you have a family history of diabetes?

Your Result

Your results are in!

While you don’t seem to be at risk for prediabetes or type 2 diabetes based on this quiz, please contact your healthcare provider with any concerns. If you want to learn more about diet and lifestyle changes with diabetes, find a registered dietitian covered by insurance with Nourish.

Your Result

Your results are in!

You should seek guidance from your healthcare provider about the possibility of prediabetes or type 2 diabetes.

If you want to learn more about diet and lifestyle changes with diabetes, find a registered dietitian covered by insurance with Nourish.

Thank you! Your submission has been received!
Oops! Something went wrong while submitting the form.
Charleston
SC
South Carolina
32.7884363, -79.9399309
Paterson
NJ
New Jersey
40.916611, -74.172188
Palmdale
CA
California
34.576469, -118.116096
Lancaster
CA
California
34.697472, -118.144524
Murfreesboro
TN
Tennessee
35.845619, -86.390266
Santa Rosa
CA
California
38.547134, -122.816383
Eugene
OR
Oregon
44.052151, -123.091187
Shreveport
LA
Louisiana
32.523659, -93.763504
Clarksville
TN
Tennessee
36.527279, -87.360336
Cary
NC
North Carolina
35.7882893, -78.7812081
Salem
OR
Oregon
44.944099, -123.040283
Newport News
VA
Virginia
37.087082, -76.473015
Chattanooga
TN
Tennessee
35.0457219, -85.3094883
Akron
OH
Ohio
41.0842496, -81.6777863
Providence
RI
Rhode Island
41.823990, -71.412834
Tallahassee
FL
Florida
30.438255, -84.280731
Peoria
AZ
Arizona
33.7528919, -112.4902079
Sioux Falls
SD
South Dakota
43.536388, -96.731667
Yonkers
NY
New York
40.930790, -73.898293
Fayetteville
NC
North Carolina
35.052666, -78.878357
Rochester
NY
New York
43.156578, -77.608849
McKinney
TX
Texas
33.214561, -96.614456
Moreno Valley
CA
California
33.920891, -117.261162
Fremont
CA
California
37.548271, -121.988571
Frisco
TX
Texas
33.150673, -96.823608
Spokane
WA
Washington
47.658779, -117.426048
Boise
ID
Idaho
43.6008183, -116.2421086
Port St. Lucie
FL
Florida
27.273270, -80.342148
Irving
TX
Texas
32.814018, -96.948891
Winston-Salem
NC
North Carolina
36.096260, -80.243736
St. Petersburg
FL
Florida
27.773056, -82.639999
Laredo
TX
Texas
27.507130, -99.507500
Jersey City
NJ
New Jersey
,
Buffalo
NY
New York
42.8867166, -78.8783922
St. Louis
MO
Missouri
38.627003, -90.199402
Chandler
AZ
Arizona
33.3062031, -111.841185
Durham
NC
North Carolina
35.994034, -78.898621
Lincoln
NE
Nebraska
40.806862, -96.681679
Pittsburgh
PA
Pennsylvania
40.440624, -79.995888
Greensboro
NC
North Carolina
36.072701, -79.793900
St. Paul
MN
Minnesota
44.954445, -93.091301
Newark
NJ
New Jersey
40.735657, -74.172363
Lexington
KY
Kentucky
38.040585, -84.503716
Stockton
CA
California
37.957703, -121.290779
Honolulu
HI
Hawaii
21.306944, -157.858337
Cleveland
OH
Ohio
41.499321, -81.694359
Arlington
TX
Texas
32.7355816, -97.1071186
Oakland
CA
California
37.804363, -122.271111
Long Beach
CA
California
33.770050, -118.193741
Raleigh
NC
North Carolina
35.779591, -78.638176
Omaha
NE
Nebraska
41.256538, -95.934502
Colorado Springs
CO
Colorado
38.833881, -104.821365
Fresno
CA
California
36.737797, -119.787125
Albuquerque
NM
New Mexico
35.084385, -106.650421
Memphis
TN
Tennessee
35.117500, -89.971107
Washington DC
WA DC
Washington, DC
38.889805, -77.009056
Las Vegas
NV
Nevada
36.169941, -115.139832
Seattle
WA
Washington
47.606209, -122.332069
Charlotte
NC
North Carolina
35.2272086, -80.8430827
Sacramento
CA
California
38.590576, -121.489906
Richmond
VA
Virginia
37.540726, -77.436050
Surprise
AZ
Arizona
33.629002, -112.330170
Mesa
AZ
Arizona
33.415184, -111.831474
Louisville
KY
Kentucky
38.252666, -85.758453
Des Moines
IA
Iowa
41.586834, -93.624962
Lakewood
CO
Colorado
39.704708, -105.081375
Kansas City
KS
Kansas
39.112701, -94.626801
Reno
NV
Nevada
39.529633, -119.813805
Tacoma
WA
Washington
47.258728, -122.465973
Aurora
CO
Colorado
39.7405111, -104.830994
Oxnard
CA
California
34.197659, -119.175949
Amarillo
TX
Texas
35.221996, -101.831299
Henderson
NV
Nevada
36.039524, -114.981720
Vancouver
WA
Washington
45.633331, -122.599998
Gilbert
AZ
Arizona
33.352825, -111.789024
San Bernardino
CA
California
34.115784, -117.302399
Columbus
GA
Georgia
27.800583, -97.396378
Hayward
CA
California
37.668819, -122.080795
Milwaukee
WI
Wisconsin
43.038902, -87.906471
Lubbock
TX
Texas
33.576698, -101.855072
Norfolk
VA
Virginia
36.850769, -76.285873
Tulsa
OK
Oklahoma
36.153980, -95.992775
Garland
TX
Texas
32.914341, -96.636559
Fort Lauderdale
FL
Florida
26.124161, -80.143593
Tucson
AZ
Arizona
32.248814, -110.987419
Salt Lake City
UT
Utah
40.760780, -111.891045
Corona
CA
California
33.875670, -117.568840
Madison
WI
Wisconsin
43.073051, -89.401230
Huntsville
AL
Alabama
34.7014286, -86.6597495
Kansas City
MO
Missouri
39.099728, -94.578568
Irvine
CA
California
33.684566, -117.826508
Chula Vista
CA
California
32.640072, -117.084038
Denton
TX
Texas
33.215530, -97.132446
Aurora
IL
Illinois
41.7571701, -88.3147539
Baton Rouge
LA
Louisiana
30.4494155, -91.1869659
Columbus
OH
Ohio
39.961178, -82.998795
Baltimore
MD
Maryland
39.2908816, -76.610759
Detroit
MI
Michigan
42.331429, -83.045753
Chesapeake
VA
Virginia
36.7183708, -76.2466798
Atlanta
GA
Georgia
33.7489924, -84.3902644
Birmingham
AL
Alabama
33.5206824, -86.8024326
Scottsdale
AZ
Arizona
33.501324, -111.925278
Cincinnati
OH
Ohio
39.103700, -84.513610
North Las Vegas
NV
Nevada
36.201946, -115.120216
Riverside
CA
California
33.980602, -117.375496
Plano
TX
Texas
33.019844, -96.698883
Minneapolis
MN
Minnesota
44.977753, -93.265015
Salinas
CA
California
,
Anaheim
CA
California
33.836594, -117.914299
Springfield
MO
Missouri
37.208958, -93.292297
Fort Wayne
IN
Indiana
41.077469, -85.137489
Phoenix
AZ
Arizona
33.448376, -112.074036
Bakersfield
CA
California
35.3738712, -119.0194639
Garden Grove
CA
California
33.774269, -117.937996
Anchorage
AK
Alaska
61.2163129, -149.894852
Indianapolis
IN
Indiana
39.768402, -86.158066
Nashville
TN
Tennessee
36.162663, -86.781601
Tempe
AZ
Arizona
33.425522, -111.941254
Mobile
AL
Alabama
30.695366, -88.039894
New Orleans
LA
Louisiana
29.951065, -90.071533
Knoxville
TN
Tennessee
35.960636, -83.920738
Grand Rapids
MI
Michigan
42.963360, -85.668083
Fontana
CA
California
34.102890, -117.435760
Elk Grove
CA
California
38.418129, -121.393257
Cape Coral
FL
Florida
26.5625742, -81.9438802
Grand Prairie
TX
Texas
32.745499, -97.003532
Fort Collins
CO
Colorado
40.588970, -105.082458
Killeen
TX
Texas
31.117119, -97.727798
Modesto
CA
California
37.639095, -120.996880
Oklahoma City
OK
Oklahoma
35.468491, -97.521263
Santa Ana
CA
California
33.745571, -117.867836
Ontario
CA
California
34.063343, -117.650887
Brownsville
TX
Texas
25.9015688, -97.4984005
Montgomery
AL
Alabama
32.379223, -86.307739
Hialeah
FL
Florida
25.857595, -80.278107
Springfield
MA
Massachusetts
42.102051, -72.585762
Toledo
OH
Ohio
41.652805, -83.537865
Pembroke Pines
FL
Florida
26.007765, -80.296257
Overland Park
KS
Kansas
38.974819, -94.683601
Little Rock
AR
Arkansas
34.746483, -92.289597
Glendale
CA
California
34.142509, -118.255074
Roseville
CA
California
38.752125, -121.288010
Wichita
KS
Kansas
37.687176, -97.330055
Huntington Beach
CA
California
33.659485, -117.998802
Augusta
GA
Georgia
33.4709714, -81.9748429
Worcester
MA
Massachusetts
42.271389, -71.798889
Virginia Beach
VA
Virginia
36.852924, -75.977982
Oceanside
CA
California
33.1958696, -117.3794834
Santa Clarita
CA
California
34.456043, -118.571335
Philadelphia
PA
Pennsylvania
39.952583, -75.165222
Corpus Christi
TX
Texas
27.800583, -97.396378
Portland
OR
Oregon
45.512230, -122.658722
Denver
CO
Colorado
39.739235, -104.990250
Boston
MA
Massachusetts
42.3554334, -71.060511
Atlanta
GA
Georgia
33.7489924, -84.3902644
Chicago
IL
Illinois
41.8755616, -87.6244212
Orlando
FL
Florida
28.538336, -81.379234
Jacksonville
FL
Florida
30.332184, -81.655647
Tampa
FL
Florida
27.950575, -82.457176
Long Island
NY
New York
40.757801, -73.940033
Queens
NY
New York
40.728226, -73.794853
Bronx
NY
New York
40.8466508, -73.8785937
Staten Island
NY
New York
40.643501, -74.076202
Brooklyn
NY
New York
40.6526006, -73.9497211
New York
NY
New York
40.712776, -74.005974
San Jose
CA
California
37.342205, -121.851990
San Francisco
CA
California
37.774929, -122.419418
San Diego
CA
California
32.834686, -117.130775
Los Angeles
CA
California
34.052235, -118.243683
El Paso
TX
Texas
31.761877, -106.485023
San Antonio
TX
Texas
29.387428, -98.496574
Dallas
TX
Texas
32.776665, -96.796989
Fort Worth
TX
Texas
32.755489, -97.330765
Houston
TX
Texas
29.760427, -95.369804
Austin
TX
Texas
30.2711286, -97.7436995

Book an appointment with a {category} dietitian

Covered by insurance.

Book an appointment with an online dietitian

Covered by insurance.

Find a

dietitian covered by insurance

No items found.
Weight loss medication
Mental Health
Intuitive Eating