Antinutrients — What Are They and Why Should You Care?

For some people, quinoa, spinach, and peanut butter are considered anything but health food. 

Sounds far-fetched, huh? These are some of the healthiest foods on the planet… right?

It may be surprising, but the answer isn’t black and white. And that’s because of antinutrients, which are found to some degree in all plant foods.

Let’s take a dive into this weird world of antinutrients and learn more about what they are, where they’re found, and how they may affect our health.

What Are Antinutrients?

Antinutrients are compounds found in some foods that may interfere with your body’s ability to absorb nutrients.[*]

They are thought to be part of a plant’s built-in defense systems, like thorns. But while thorns poke you, antinutrients don’t affect you until after you’ve eaten the plant and your body starts breaking it down.

Antinutrients are mostly found in foods that would otherwise be considered healthy to most people, like beans and legumes, grains, nuts, seeds, and vegetables. 

Key Types of Antinutrients

There are countless types of antinutrients, but some that you’re likely to hear about most often include[*][*]:

• Phytates: bind to minerals like iron and calcium, preventing their absorption; found in most beans, nuts, seeds, and grains
• Tannins: interfere with the absorption of plant-based iron, may inhibit digestive enzymes; found in tea, coffee, chocolate, and wine[*]
• Lectins: prevent proper nutrient absorption and may damage intestinal lining; found in wheat, tomatoes, eggplants, and peppers
• Oxalates: bind with calcium to prevent its absorption; found in dark green leafy vegetables
• Saponins: may damage intestinal lining and inhibit digestive enzymes; found in chickpeas, soybeans, alfalfa sprouts, and some beans
• Solanine: may cause intestinal damage by damaging the cells, but more research is needed; found in tomatoes, eggplants, white potatoes, and peppers[*]

There are many other types of antinutrients too, but these are the most common. For the most part, these antinutrients are found in nuts, seeds, and grains, along with some green leafy vegetables.

Are Antinutrients Harmful?

If you were to ask the average person, they’d probably say that they don’t have issues with most foods that contain antinutrients. After all, many of these foods seem healthy.

However, there’s a significant portion of the population that is sensitive to one or more types of antinutrients — and they may not even be aware of it.

The effects of antinutrients — like potential nutrient deficiencies — can take a while to manifest. They’re also not always traceable to antinutrients. For instance, someone with a low iron level may not necessarily see the connection between their iron level and their intake of foods high in tannins (which inhibit iron absorption). Someone with mild, occasional heartburn may not immediately realize that it usually occurs after they eat nightshade vegetables.

Not to mention, gluten is a lectin — and people can run the gamut from mildly intolerant of gluten, to full-blown Celiac disease (which requires strict gluten avoidance).

Antinutrients may contribute to a number of conditions, including:

• Nutrient deficiencies
• Chronic inflammation
• Digestive problems 

Damage to the digestive tract from antinutrients may also cause leaky gut or intestinal permeability. This allows digestive material to escape from your digestive tract and into other parts of your body, which can cause an immune response that might lead to inflammation, autoimmune disease, and symptoms that may not seem related to digestive health.[*]

Top 10 Foods Highest in Antinutrients

So, which foods have antinutrients? All plant foods contain some, but here are a few to watch out for: 

1. Kidney beans: Kidney beans are the most stark example of an antinutrient food. They contain high levels of a lectin called phytohemagglutinin, which is toxic in large amounts. This lectin is neutralized by cooking, but eating raw or undercooked kidney beans can cause severe digestive illness.[*]
2. Wheat: Wheat contains the lectin gluten, which can cause nutrient absorption issues and digestive problems in people who are sensitive to it — an estimated 7% of the population.[*]
3. Soybeans: Soybeans contain antinutrient phytates, saponins, and tannins, but traditional preparation methods neutralize many of these antinutrients via fermentation. Fermented soy products include soy sauce, natto, and tempeh.[*]
4. Spinach: Oxalates found in raw spinach and other vegetables can interfere with calcium uptake. The oxalates bind with calcium to prevent it from being absorbed and may also increase your risk of forming calcium oxalate kidney stones.[*]
5. Swiss chard: Like spinach, swiss chard is also high in oxalates.[*]
6. Peanuts: Peanuts are particularly high in phytate, which affects iron and zinc absorption. Peanuts are technically a legume, so they are also excluded from most low-lectin diets.
7. Chickpeas: Chickpeas contain several different antinutrients, including lectins, tannins, phytates and saponins. Like other legumes, chickpeas can be soaked, sprouted, or boiled to neutralize these antinutrients.[*]
8. Coffee, tea, and wine: Tannins — found in coffee, tea, and wine — can interfere with iron absorption, which can contribute to low iron stores. Iron deficiency is fairly common, and tannin intake may be an important consideration if you have low iron levels.[*][*]
9. Chocolate: Cacao is also high in tannins. However, milk chocolate products that contain lower amounts of cocoa have a lower antinutrient content than dark chocolate or baking chocolate.[*]
10. Seed oils: Seed oils — like corn oil, soybean oil, and canola oil — have gone through extensive processing. However, they may still contain traces of natural antinutrients. Additionally, heating and reheating of oil (for example, in a restaurant fryer) can cause other antinutrient compounds to form. For this reason, it’s a good idea to avoid deep fried restaurant foods.[*][*]

How to Reduce Antinutrients in Food

Our ancestors (and even our parents and grandparents) were pros at minimizing antinutrients in food, using methods like soaking, sprouting, boiling, and fermenting. There’s been a resurgence in these methods too, and a huge demand for fermented and sprouted foods.[*][*][*][*]

Sprouting and fermenting are two very satisfying hobbies that are really easy to get started with. You can find fermenting and sprouting starter kits online, and it’s also becoming easier to find fermented and sprouted foods on supermarket shelves. We recommend Cleveland Kitchen for fermented foods and One Degree Organic Foods for sprouted grain products.

And if you are feeling adventurous, why not get started with one of these homemade Keto-friendly ferment recipes:

Fermented Garlic 

Keto Beet Kvass 

Keto Kimchi 

Additionally, you can soak or boil most legumes and grains before cooking them. Make sure to rinse them after the soak or boil, before starting the rest of the cooking process.

Cooking neutralizes many antinutrients, too. While a huge pile of raw spinach in a salad may not agree with you, some steamed spinach in scrambled eggs may be a better choice because cooking destroys some of the oxalates.

Top 5 Diets Lowest in Antinutrients

Interested in avoiding antinutrients? There are several eating patterns that can help you with that. Here are the best 5 diets for keeping your antinutrient intake low:

1. Carnivore: Carnivore is a ketogenic diet that includes only animal foods like meat, bone broth, and some full-fat dairy products. Because it contains no plant foods, it’s free of antinutrients.
2. Animal-Based: The Animal-Based Diet, developed by Dr. Paul Saladino, is based on the Carnivore diet, but allows for the inclusion of certain plant foods low in antinutrients — like olive oil, zucchini, and certain fruits.
3. Autoimmune Protocol: The Autoimmune Protocol (AIP) is an elimination-style diet designed to help people identify food intolerances. At the start of the diet, you’ll eliminate some potentially inflammatory plant foods, but you can slowly re-introduce them and continue eating the foods that don’t affect you negatively.
4. Gut and Psychology Syndrome (GAPS) Diet: The GAPS diet is similar to the AIP. It’s an elimination diet that’s designed to address leaky gut and brain-related disorders. Vegetables are allowed on GAPS, but grains and legumes are off-limits until the reintroduction phase.
5. Paleo: Finally, the Paleo diet can also help you reduce your antinutrient intake because it restricts soy, legumes, peanuts, and grains. However, Paleo does allow for many other vegetables and plant foods, so it’s not as low in antinutrients as other diets on this list. 

The entire idea of antinutrients is really surprising, especially considering the “health halo” that exists around plant-based foods. While plant foods like fruits, vegetables, and grains are full of nutrients and antioxidants, they may not be worth it for everyone — especially people who are profoundly sensitive to antinutrients.

Many people who follow the Carnivore diet say that they’ve never felt better. A lot of these people were dealing with autoimmune conditions and digestive disorders that never seemed to fully improve, until they decided to give up plant foods.

That’s not to say that Carnivore is right for everyone, though. Some of us love our veggies, and many of us don’t seem to be bothered by antinutrients. Still, it might be a good idea to consider if they could be affecting your health.

At Carb Manager, we’re here to support you in your health journey. We’ve got recipes for Carnivore, Animal-Based, AIP, and Paleo, and meal planning tools to help you be successful. And if you’re not anti-antinutrient, we also offer support for many other low carb, whole food-based diets.