Should I Worry About Antinutrients in Foods?

Learn how to include antinutrients from whole plant foods in your diet in a healthy way as Sharon answers your top questions on whether antinutrients are dangerous or not.

You might have heard about the buzzy term “antinutrients” in the media in recent years, as it’s the latest in certain fad diet guru’s advice warning against plant-based eating. The idea is that these antinutrient compounds can latch onto vitamins and minerals, thus preventing you from absorbing certain micronutrients. Although some plants naturally have antinutrient compounds, the real question we should be asking ourselves is if these compounds are harmful to our health, are there ways to remove antinutrients, and is there enough scientific evidence claiming these compounds are harmful? Keep reading as I answer your top questions on antinutrients in foods so you can get the latest juicy scoop on antinutrients!

Beans, such as this recipe for Heirloom Bean Cassoulet with Root Vegetables, contain antinutrients that are reduced by soaking and cooking

Should I worry about antinutrients in food?

Antinutrients—naturally occurring compounds in plant foods—seem to be the latest buzzword, often decried by advocates of meat-heavy diets who condemn eating pulses, soy, and whole grains. It’s true that antinutrients interfere with the availability of nutrients in the human body, but there is more to antinutrients than meets the eye. Many antinutrients can be reduced by soaking, cooking, sprouting, or fermentation. And research suggests that some antinutrients may actually be good for us. After all, a body of science shows that people who consume lots of whole plant foods live longer and have less disease.

What are antinutrients?

You might have heard the term “antinutrient” in a nutrition course or even media headline, when you learned that these chemically active substances found in a variety of edible plants act in ways to combat the nutrients found in the plant, either by reducing their nutrient availability or providing some sort of adverse effect. Scientists identified antinutrients decades ago, discovering that some specific antinutrients bind nutrients, thereby preventing their digestion and utilization by the body, while other antinutrients appear to be toxic at high levels. Antinutrients are a normal part of the plant structure, often found in leaves, roots and seeds of the plant.

Whole grains, such as in this recipe for Mason Jar Kale Barley Salad with Turmeric Vinaigrette, contain antinutrients that are reduced by cooking.

What’s nature’s purpose for antinutrients? 

Scientists suspect that they help ensure the survival and propagation of the plant species. Scientists believe that plants synthesize antinutrients as a defense mechanism against insects, parasites and other bacterial and fungal infestations. For example, fruits contain seeds for the purpose of propagation of their species. However, if birds and animals were to eat the fruits containing the seeds and digest them to obtain additional nutrients and calories, then there will be no seeds left for the continuation of the plant species. So, they make compounds that are so bitter that birds and animals discard them while consuming the fruits. Some of these compounds may also prevent the activity of the digestive enzymes, so that even if the seeds are consumed, they are excreted without altering their physiology. Thus, antinutrients are part of the plant’s chemical defense system against invaders in order to ensure its survival.

Where are antinutrients found?

A wide range of plant foods contain antinutrients, but they are found in particularly significant amounts in cereals and legumes, such as wheat and beans. There are dozens of different antinutrients, including enzyme inhibitors, flatus factors, saponins, and phytates. Look at phytates found in grains as an example—these antinutrients act to reduce the bioavailability of minerals and the digestibility of proteins and carbohydrates found in the grain. Phytate can make the minerals calcium and zinc unavailable, resulting in the classical “Dwarf” syndrome known in Egypt—a country in which unleavened bread is consumed that allows high levels of phytates to exist in the grain, leading to severe zinc deficiencies and growth impairment in children.

The negative effect of antinutrients is mainly due to their effect on the absorption and utilization of nutrients. For example, legumes contain compounds called enzyme inhibitors. In particular, an enzyme inhibitor called trypsin inhibitor, present in soybean. These enzyme inhibitors prevent digestion of dietary proteins and make then unavailable as nutrients, leading to protein deficiencies and related health disorders.

Fortunately, processing, such as cooking, soaking, germination and fermentation of particular plant foods, decreases the content of antinutrients like phytate. Perhaps that’s why so many early cultures figured out long ago that they were better off soaking and cooking certain foods like grains and legumes rather than eating them raw.

This recipe for Southwestern Stuffed Peppers with Black Beans and Quinoa contains whole grains and beans, but cooking reduces antinutrients.

What’s the latest take on antinutrients?

Food scientists have known about the existence of many antinutrients, yet they are just scratching the surface when it comes to their overall function in human health. A theory is beginning to immerge that suggests low levels of antinutrients may contain beneficial properties for the body. This shouldn’t come as a surprise, since a body of evidence links consumption of whole plant foods with a range of health benefits.

There are some misconceptions with regards to what antinutrients are and their impact on human health. By definition, antinutrients are compounds, either natural or synthetic, that prevent the utilization of nutrients. As a result of this concept, antinutrients were considered by nutritionists as being undesirable and compounds that needed to be removed from our foods by processing or genetics. However, recent research has shown that what we consider as antinutrients may in fact be beneficial to our health.

Dietary fiber is a good example of how antinutrients may actually be beneficial. There was no known nutritional role for dietary fiber; in fact, it was believed that dietary fiber could bind to minerals and some other nutrients and make them unavailable. As a result, cereal process technology was developed to remove or reduce dietary fiber from cereals and flours. Now we know that dietary fiber serves a very important role in our health; fiber benefits include action as a laxative, function as substrates for fermentation in the colon and the production of volatile fatty acids, action in slowing the rate of nutrient transit through the gastrointestinal tract, absorption and thereby prevention of nutrient surges, and perturbation in the entire metabolic responses. Fiber is now considered to play a beneficial role in the prevention of cancer, cardiovascular diseases, diabetes and many other chronic human diseases.  So, dietary fiber, once thought to be an antinutrient, is now considered beneficial.

The viewpoint on antinutrients has changed to such an extent in the scientific community that scientists are increasingly referring to the them as “biologically active compounds” in food. Early research with dietary fiber contributed considerably to this change in thinking. Following on the dietary fiber work, extensive research on several other so-called antinutrients, such as saponins, trypsin inhibitors, and lectins, showed that they may play a role in the prevention of human chronic diseases such as cancer, cardiovascular diseases, diabetes and several other human health disorders.  The question seems to be one of concentrations in terms of their effects, going from nutritional to pharmacological to toxic. Scientists now have a fairly good understanding of the mechanisms of action of antinutrients, but more research is needed to better understand their role in human health. Ironically, some of compounds that fall on the list of antinutrients are now referred to as “nutraceuticals” or “functional foods”, because of their demonstrated beneficial effects on human health. Maybe in the near future, the chapter on antinutrients in nutrition textbooks will bear another name.

About Ask Sharon:

As part of my program “Ask Sharon”, I am answering the top questions of the month submitted through my blog, Facebook, Twitter or Instagram to answer here. You can even win a prize! Don’t forget to submit your burning nutrition questions this month via my blog, or other social media

Check out the other nutrition questions I’m answering at The Plant-Powered Dietitian:

How to Prepare Dried Beans to Avoid Antinutrients
Does Roasting Veggies Ruin Nutrients?
Is “Clean Eating” a Healthy Lifestyle?

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