Antinutrients—compounds found in otherwise healthy foods that can inhibit your body’s ability to use good-for-you nutrients—have been generating buzz in the health and wellness world since Steven Gundry, MD, an American cardiac surgeon, came out with his book, The Plant Paradox, last year. In it, he claims that lectin, an antinutrient found in vegetables like tomatoes and peppers, is a major cause of everything from autoimmune disorders to heart disease and diabetes. Antinutrients, Gundry claims, could be “the hidden danger lurking in your salad bowl.” Since then, the frenzy has led wellness warriors to abandon once-loved tomatoes and switch from brown to white rice.
While antinutrients do play a role in the body, the research to support most of these claims is thin (if not nonexistent). If you’re eating a balanced, varied diet, antinutrients likely aren’t affecting your health—but understanding the science behind the hype will help you make informed decisions about your nutrition.
What Are Antinutrients?
Antinutrients are naturally occurring compounds in plant foods that limit the bioavailability of vitamins, minerals, and other nutrients during digestion, says Lauren Minchen, a nutritionist based in New York City. Common antinutrients include phytates and lectics (found in grains, beans, legumes, and nuts) and polyphenols (coffee, tea, and wine). Some vegetables, including eggplant, tomatoes, and peppers, also contain antinutrients. In living plants, the compounds act as a natural defense system against disease by bonding to molecules in the cell walls of invading fungi, bacteria, and pests. When we consume them, instead of binding to molecules in the cell walls, antinutrients bind to micronutrients. For example, phytates bond to carbohydrates, and lectins bond to minerals. When that happens in the gut, the body is unable to absorb those nutrients efficiently.
The Antinutrient Paradox
Despite the name, these compounds aren’t all bad. Some antinutrients function as antioxidants, which can have a positive effect on the body, preventing damage from free radicals in the environment. You can’t focus only on the disadvantages, stresses nutritionist Sharon Palmer, because other compounds in the food offer numerous benefits.
For instance, tomatoes contain high levels of lectins, which can cause stomach issues and block absorption of nutrients in the gut. Despite that, tomatoes are healthy. “Studies show people who eat more tomatoes have lower inflammation and oxidative stress levels and lower disease risks. We also know that eating tomatoes in a single meal decreases the inflammatory and oxidative stress levels immediately,” Palmer says. Similarly, an overload of phytates from grains can inhibit the availability of calcium and zinc, yet hundreds of studies show the benefits of eating whole grains. In some cases, the antinutrients themselves could actually be beneficial—polyphenols in tea, coffee, and wine, for instance, fight inflammation and support a healthy immune system.
When to Be Concerned
While antinutrients can block nutrient absorption, it would take a very specific, homogenous diet to create a real nutrient deficiency. “Athletes and active people naturally require higher levels of vitamins, minerals, and phytonutrients than the average person, because their bodies need more fuel to support their activity level,” Minchen says. So, while carbo-loading is an effective way to fuel up for long days, for instance, it could actually contribute to mineral depletion if you’re doing it, say, several times a week.
This can lead to nutrient deficiencies and the associated health conditions that can come along with them, Minchen explains. Lectins have been tied to zinc deficiency, which “can lead to a decreased immune system, a greater incidence of colds and flu, and a breakdown of skin barrier,” she says. If you have nutrient deficiencies that show up in lab testing, you might consider the role of antinutrients, and people who eat a vegan or raw-food diet may be at greater risk for overconsumption.
Beyond nutrient absorption, most studies on antinutrients are done on raw foods in a laboratory setting, not within the context of a diet pattern, so we need more science to put their role in the body into perspective, Palmer says.
How to Avoid Antinutrient Overload
If you’re already eating a diverse diet, you’re likely off the hook here. If you eat mostly or entirely plant foods, it’s easy to ensure that you’re not getting too many antinutrients. Sprouted or soaked grains, beans, nuts, and seeds can help reduce phytate content. You can buy these at the store, but it’s easy to sprout and soak at home, Minchen says. (If you buy dried beans, you’re probably already doing this.)
For veggies with high antinutrient content, lightly steaming or sautéing can reduce antinutrient content, allowing for greater absorption, Minchen says. Cooking veggies can lower some nutrients, like vitamin C, so Minchen recommends a 50/50 approach: Half of your veggies should be raw, the other half cooked. Overall, if you’re eating a balanced, varied diet, you shouldn’t worry about antinutrients.