If grains give you gas and beans make you bloat, you’re not alone. Many people experience uncomfortable digestive symptoms, including gas, swelling, cramping, and pain, after eating legumes, grains, beans, and many seeds and nuts. The common denominator? These foods are all relatively high in natural compounds called antinutrients.
As the name suggests, antinutrients can interfere with the body’s ability to absorb vitamins and minerals. They may also cause damage to the intestinal lining and trigger an inflammatory response elsewhere in the body.
With this in mind, you may be inclined to give up the offending foods altogether. After all, abstaining from antinutrient-laden fare is a cornerstone of many elimination diets, which are designed to help people identify nutritional triggers for sensitivities, allergies, or digestive ailments. Some people suffering from seemingly unrelated symptoms — migraines, joint pain, or asthma, for instance — experience a reduction in symptoms when they steer clear of these foods.
Avoiding antinutrients is also part of the popular paleo philosophy, which eschews relatively modern (think postagricultural revolution) foods such as dairy, sugar, refined oils — and cultivated legumes and grains.
But there’s more to antinutrients than their malevolent name and digestive crimes suggest. Think of antinutrients as the unexpected hero of the ancestral-diets world: oft-misunderstood villains that may play a greater role in our well-being than they’re given credit for.
Learning more about antinutrients, including how to work with them, can offer much-needed relief and allow you to enjoy a wider variety of foods.
The first step toward establishing a better relationship with grains, legumes, seeds, and nuts is to see them in their evolutionary context.
“Every living thing has a defense mechanism,” says Diane Sanfilippo, certified holistic-nutrition consultant and author of Practical Paleo.
For animals, it’s the ability to fight or flee. Plants, however, can’t run away or put up their dukes. Some plants have thorns or hard outer shells that help protect them from being eaten; others guard themselves via antinutrient compounds that are difficult for animals — including humans — to digest.
Antinutrients behave in different ways in the human body. Some bind up important minerals like calcium, iron, and zinc, interfering with the body’s ability to use them. Others have been found to cause gut inflammation and irritate the digestive lining, says Maggie Ward, MS, RDN, LDN, nutrition director of the UltraWellness Center in Lenox, Mass.
But antinutrients also offer some important health benefits.
“Most things in the natural world have a risk–benefit ratio,” explains Ward. “Many of these compounds are phytochemicals that have a supportive effect on our immune systems, or serve as antioxidants to protect our cells from oxidative stress.”
The antinutrient phytate, for instance, has been shown to neutralize free-radical formation, according to research published in The Journal of Nutrition. As for broader health benefits, other studies suggest consumption of phytates can prevent osteoporosis and promote better blood-sugar control.
In the Nurses’ Health Study 3, a long-term epidemiological study of women’s health, women who ate the most phytate-rich diet had the lowest risk of developing kidney stones compared with those who ate the least.
Lectins are another example of antinutrients that can be beneficial. While some can spur inflammation, others have an anti-inflammatory impact on the body, according to research published in the journal Molecules. The defense role that lectins play in nature may also make them especially well suited to help fight off cancer cells. Researchers are investigating various types of carbohydrate-binding lectins for their antitumor properties.
Another reason to choose antinutrient-containing foods — unless you’re sensitive or allergic to them, of course — is that they’re important sources of healthy plant-based fats, proteins, and carbohydrates. And they provide bacterial diversity for your microbiome, which is increasingly understood as critical to overall health.
In one study published in Applied and Environmental Microbiology, extreme low-carb dieters (24 grams per day, roughly the amount in one small banana) experienced disproportionate decreases in fecal butyrate, the short-chain fatty acid produced by bacteria in the colon that can protect against colon cancer and inflammation.
Other research finds that people using the low-FODMAP diet, a plan that limits foods like beans and wheat to manage irritable bowel syndrome, experience decreases in beneficial gut bacteria.
If you have a condition related to inflammation or gut health, antinutrients may indeed be playing a problematic role, say experts. In many cases, taking a hardline approach and permanently exiling the offending foods is the only way to help the condition. (People with celiac disease should avoid all gluten, for example.) In other cases, a moderated approach to antinutrients may be more appropriate.
“The terrain is everything,” says Sanfilippo, who recommends that the paleo diet be considered more of a short-term elimination diet than a lifelong exercise in bread-shunning. It is more beneficial, she says, to figure out what your body can tolerate and reap the benefits of a more varied diet.
For instance, both Ward and Sanfilippo advise clients with compromised digestion or signs of increased inflammation to eliminate beans. They may eventually suggest reintroducing beans that have been soaked and cooked to find out what the clients can tolerate and, ideally, expand their eating options. (For more traditional methods for reducing problematic antinutrient activity in food, see “Make the Most of Antinutrients,” below.)
If you don’t have a diagnosis but feel “off” whenever you eat certain foods, carefully experiment with eliminating and then reintroducing the offending fare. You may find, for instance, that while super-refined grocery-store bread makes you uncomfortable, traditionally baked sourdough doesn’t bother you at all.
For most people, the impact of antinutrients on their bodies is best discovered through some dietary detective work, rather than by subscribing to one nutritional approach. Relying on your own judgment — perhaps with a little guidance from a registered dietitian nutritionist, or practitioner trained in holistic health — can help you discover the foods that best suit you right now.
Illustration by Stuart Bradford