Some consider lectins to be a controversial food compound . While foods that contain lectins – primarily plant foods – provide a wide variety of health benefits, there is some preliminary research that lectins may promote inflammation in some people (1).
Lectins are considered to be anti-nutrients, which means they can block the absorption of nutrients, most commonly zinc or iron (2). However, there is a lack of human studies around this, so more research is necessary (3). There is also preliminary research to suggest that lectins could be used to reduce the negative side effects caused by some cancer treatments (4).
Summary: Foods that are high in lectins are mainly plant foods with many health benefits. Lectins are considered anti-nutrients, meaning they can block the absorption of other nutrients. However, soaking or cooking the foods with lectins has been found to reduce their potentially harmful effects.
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Foods High in Lectins
Check the list below to learn more about foods high in lectins and how they can affect your health.
Wheat, rye, barley, and oats are some of the most popular foods high in lectins. Wheat germ has the highest amounts of lectin, but cooked grains appear to have significantly less lectins (7). Whole wheat and other whole grains also are excellent sources of fiber, B vitamins and minerals (8).
There is some early research in test tube and animal studies to suggest that other compounds in grains may promote inflammation in the body, but there needs to be more research to confirm this (9). Chronic inflammation is thought to contribute to many common diseases, such as cardiovascular disease, diabetes, autoimmune disease, and more (10). However, many other factors besides diet can contribute to chronic inflammation, including smoking, aging and stress (11).
Some consider wheat, rye and barley to be a controversial food because of its gluten content. Those with celiac disease must avoid gluten completely (12). There is also some limited evidence to suggest that small numbers of people, besides those with celiac disease or wheat allergies, may have sensitivity to gluten (13). However, more research is needed to understand gluten sensitivity (14). If you are concerned that you may have issues with foods containing gluten, speak with a health care provider.
Summary: Many grains, including wheat, also contain lectins. Cooking appears to eliminate the lectin content in these grains. Whole grains also provide many healthful nutrients, including fiber, B vitamins and minerals.
Cereal is mainly another food that is high in lectins because it is primarily made of the grains (listed above) that are high in lectins. The amounts of lectins in cereals vary. The production and processing of commercially prepared cold breakfast cereals reduces much of the lectins (15). And cooking grains for hot breakfast cereals also reduces the lectin content (7).
Some varieties of cereal can also have added sugars (16). However, many other brands limit the amount of added sugar, and cereals can also contain beneficial fiber, vitamins and minerals, and it associates regular consumption of whole grain breakfast cereals with decreased risk of chronic disease, including heart disease (17).
Summary: Cereal contains some lectins because it is primarily made of grain. The lectins are reduced in the production of cold cereals, and cooking grains for hot cereals also helps to reduce some lectins. Cereal can also be an excellent source of beneficial nutrients. Check the nutrition label to find varieties that have lower amounts of added sugars.
Potatoes are a starchy vegetable that contain some lectins. They are also full of nutritious vitamins and minerals, including potassium, vitamin C and folate (18).
One study in mice found adverse reactions to the lectins in potatoes. However, there is no research on humans examining any potential effects of lectins in potatoes (19).
Potatoes can be a healthy part of your diet, so there is no need to cut them out completely. Moderation is key with this versatile starchy vegetable. Do not be afraid to get the nutritious health benefits from potatoes in your diet.
Summary: Potatoes contain some lectins, but they also contain many beneficial vitamins and minerals. Potatoes can be a nutritious addition to a balanced, healthy diet.
4. Beans and Lentils
Legumes such as lentils, peas, beans, and peanuts are foods high in lectins (20). However, dried beans are the best example of how lectins can be removed before they even get to your plate.
Dried beans typically need hours for soaking before cooking. At that point, almost all the lectins evaporate since lectins are water-soluble (21). Soaking also helps to eliminate the compounds in beans that contribute to bloating or gas (22). Cooking also helps to reduce the amount of lectins in beans (21).
Legumes are an excellent addition healthy part of a balanced diet. Studies show that legumes help to slow digestion, which can help with blood sugar spikes, and it can help lower blood cholesterol levels (22).
Summary: Legumes, including lentils, peas, peanuts, and beans are high in lectins. Cooking and soaking legumes can help eliminate most of the lectins in these foods. They provide many health benefits, including aiding digestion and helping to reduce cholesterol.
Soy products are everywhere. From tofu to soybeans and soy milk to tempeh, there are plenty of ways to get soy in your diet. But is soy right for you?
Soy has many health benefits and nutrients, such as plant compounds that may help reduce the risk of heart disease, breast and prostate cancer (23). There is also some evidence that soy compounds may to reduce the severity of hot flashes in postmenopausal women (24).
Soybeans can cause some issues from the lectin content if eaten raw. But fermenting soy products typically lose their lectin contents (25). These include tempeh and tofu. Sprouting and cooking soy beans by boiling for at least 10 minutes also helps to deactivates most of the lectins (26).
Summary: Soy is another legume that also contains high amounts of lectins when raw. Fermenting, sprouting, and cooking soy helps to effectively reduce the lectin content. Soy also has many potential health benefits and nutrients.
Peanuts are technically a legume, as previously mentioned, but their high lectin content is worth mentioning twice.
However, there is limited research that the lectins in peanuts cause any harmful effects in humans (27).
In moderation, these nuts can be a healthy way to get more magnesium, protein, healthy fats, vitamin E, and manganese into your diet (28). Peanut consumption is also associated with reduced risk for many chronic diseases, including heart disease (29).
Some people claim to that nightshade vegetables may contribute to inflammation because of their alkaloid content (32). However, most of the research conducted on nightshades was conducted on animals, not humans, and the amounts of alkaloids used in these studies were far more concentrated than the amounts found in foods. There is not any research yet suggesting nightshade vegetables contribute to inflammation in humans (33).
Eggplants are a nutritious vegetable to add to your regular diet. Eggplant is rich in potassium, folate, vitamin K, manganese, and more (34).
Summary: Eggplants are nutritious vegetables, contain some lectins, and are also a nightshade vegetable, meaning they contain alkaloids. While some research suggests alkaloids contribute to inflammation in animals at large doses, there is no research yet suggesting negative effects in humans from the usual amounts found in foods.
Peppers are another food that contains some lectins, and they are also a nightshade vegetable (31).
However, no studies to date have found any negative effects of the alkaloids or lectins in peppers in humans (35), (36). Peppers also bring many nutrients to the table. They are high in vitamin C, fiber, potassium, and much more (37).
Some can have an aversion to peppers even beyond their high lectin content. Peppers can exacerbate symptoms that develop with acid reflux or heartburn, for example (38). If peppers are something you feel your body does not process well, speak with a health care provider for alternatives.
Summary: Peppers are another nightshade vegetable that contains some lectins. However, that does not mean that peppers should be avoided. There is no evidence that the lectins or alkaloids in peppers cause any adverse effects in humans. They are also rich sources of nutrients, including vitamin C, fiber and potassium.
Tomatoes are another vegetable high in lectins, as well. They are also high in many essential nutrients like fiber and vitamin C and E (39). Tomatoes also contain the antioxidant lycopene, which has been found to help reduce inflammation and are associated with reduced risk for heart disease and some cancers (40), (41).
This popular vegetable is also of the nightshade variety. Similar to the other nightshades, most of the research on lectins in tomatoes was conducted on mice, and there is no evidence that tomato lectins cause harm in humans (42).
Summary: Tomatoes are another nightshade that is high in lectins. However, there is no evidence that the lectins in tomatoes cause any issues in humans. Tomatoes are also rich in many beneficial nutrients, including fiber, vitamin C, and lycopene – a powerful antioxidant.
Corn is another common vegetable that contains some lectins (43). The lectins in corn help the plant fight off fungal infections while it is growing, but there is no research suggesting the lectins in corn are harmful when consumed (44).
It is high in many beneficial plant compounds. Corn is also rich in B vitamins, vitamin C, potassium, and magnesium. It is also full of fiber, so it can be a part of a healthy balanced diet (45). Try to eat corn fresh, frozen or canned with no added salt to avoid excess sodium.
Summary: Corn also contains some lectins, but it is a highly nutritious food containing fiber, B vitamins and minerals. There is no evidence suggesting the lectins in corn is harmful.
Foods high in lectins can be a part of a healthy, balanced diet. Most people consume very few lectins in their diet because soaking and cooking these is adequate to reduce the amounts of lectins in these foods (21). While some people may have a slight intolerance to lectins, most research on these compounds finds that the many health benefits of consuming foods that contain lectins outweighs the very limited risks (3).
Remember that it is best to vary your diet as much as possible with a wide variety of foods.
If you find a certain food bothers you, it might be helpful to speak with your health care provider about any concerns that you may have. Before considering eliminating lectin-containing foods from your diet, speak with a health care professional.
Summary: Many healthful foods contain lectins. However, the cooking process destroys most of the lectins in these foods. They also contain many beneficial nutrients, including fiber, vitamins, minerals, and antioxidants. Current research does not support avoiding lectins from your diet.