Anti-Nutrients: The Hidden Danger In Your Green Smoothie

By Ali Wetherbee


“Eat Your Greens!”

We’ve been told for years that greens are packed with nutrition, that grains are a healthy part of a balanced diet, that beans are an ideal source of protein. But did you know that these foods are also full of anti-nutrients, substances that work against your efforts to get proper nutrition?

Plants’ Natural Defenses

Animals protect themselves with many different defenses. If a mouse encounters a predator, it will run, or if all else fails, scratch and bite. A zebra has black and white stripes to camouflage itself. Porcupines have sharp quills that will injure creatures that get too close. Wasps protect themselves with their poisonous sting. But how do plants defend themselves? They can’t exactly jump up and run away. Instead, plants have developed their own toxic substances to discourage animals — and people! — from eating them, and to protect them from plant pathogens and adverse environmental conditions. Many of these toxic substances have come to be known as anti-nutrients. They are present in varying quantities in many foods. Small amounts won’t do much damage but in larger amounts they can interfere with your body getting adequate nutrition, and in excessive amounts they can be fatal. Here’s a rundown of a few common anti-nutrients.


Found in: Grains, legumes

What it does: Bonds to minerals including calcium, magnesium, zinc, and iron, so that your body cannot use them


Found in: Cabbages, broccoli, kale, Brussels sprouts, collard greens, cauliflower, legumes

What it does: Depresses thyroid function


Found in: Legumes, wheat

What it does: Inhibits digestive enzymes, leading to indigestion, gas, and bloating and reducing the absorption of minerals


Found in: Leafy greens such as spinach, kale, chard, parsley, rhubarb leaves, and beet greens; blueberries, cocoa/chocolate, among others

What it does: Bonds with calcium, reducing the amount of calcium available to your body, and can lead to kidney stones. In the U.S., 80% of kidney stones are comprised of calcium oxalate.


Found in: Coffee, tea, wine, unripe fruits, grains, legumes

What it does: Inhibits digestive enzymes; binds to protein, reducing protein absorption; decreases mineral absorption

Can You Avoid Anti-Nutrients?

The anti-nutrients in many of these foods can be reduced or eliminated by proper preparation. Most anti-nutrient levels are highest when foods are in their raw form. Fermenting foods neutralizes the anti-nutrients. Steaming and lightly sautéing also cut down on the toxins while retaining most of the beneficial vitamins and minerals. Grains, nuts, and legumes should be soaked or sprouted to counteract anti-nutrients.

It’s Not All Bad News

Get your daily serving of greens without the anti-nutrients

Many of these anti-nutrients have beneficial effects, too. For example, phytates can prevent and fight cancer, and flavonoids are considered potent antioxidants. Still, some diets such as the Paleo diet recommend against ingesting many of these foods, particularly grains and legumes. On the other hand, traditional foods diets like the Weston A. Price Foundation (WAPF) diet take anti-nutrients into account and encourage followers to prepare foods properly. For example, the WAPF diet guidelines advise soaking or sprouting grains, nuts, and legumes, and consuming lacto-fermented fruits and vegetables regularly. Having a raw kale salad once a week probably won’t do much damage, but if you’re drinking green smoothies every day, you may be better off using fermented greens, like our Perfect Supplements Fermented Kale, instead. Cook foods that seem harder to eat raw, like cauliflower or beet greens – and imagine eating raw rice or raw Brussels sprouts! Unpalatable tastes and textures are warning signs that these foods need to be cooked to break down some of the anti-nutrients. Rotate and vary the foods in your diet to minimize the amount of any one anti-nutrient you ingest. And listen to your body. As these anti-nutrients build up in your system, you will stop craving the culprit foods. That means it’s time to stop eating them. Pay attention to these subtle signals, as they are your body’s natural protection.

3 thoughts on “Anti-Nutrients: The Hidden Danger In Your Green Smoothie

  1. Thank you. I’m pretty sure I read about the anti nutrients in greens before, but in an effort to add more beets into my life, I’ve been juicing the greens so as not to waste them. I have a special problems with my calcium uptake. I was in a severe trampoline accident that torque my shoulder, neck and jaw which in time cracked practically all my teeth as my jaw and teeth shifted. Now I know exactly why my the cracks in my teeth feels sharper every time I eat spinach and especially beet greens, even when they’re cooked. I hate to waste them. One of my favorite recipes is to cook them is a white clam sauce with lots of garlic, butter and frozen clams, but even with all that, I could still feel the beet greens stripping the enamel off my teeth. I’m going to try blanching them first and this time pour off the water before cooking them in butter, garlic and clams. If that doesn’t work, I’m only gonna get beets without the greens from now on. Thanks for your article. Have a wonderful, prosperous year.

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