What Are Antinutrients?

Antinutrients are found commonly in a range of our foods and can block our body’s ability to absorb the nutrients we need. In which foods can we find these antinutrients and should we really be avoiding them at all?

What are antinutrients?

Nutrients - like carbohydrates, fats, proteins, vitamins and minerals, or water - constantly provide our bodies with the fuel to survive and thrive. Antinutrients, on the other hand, are substances that prevent our bodies from absorbing nutrients during digestion. While antinutrients are found in almost all plant-based foods, there are a few foods that naturally contain higher than average levels of antinutrients, like whole grains, legumes, leafy vegetables, soy, nuts and seeds.

This inhibiting effect is due to the binding functions of antinutrients in plants. For example, phytates, a type of antinutrient found in plants, are used by the plants to bind and store minerals. Another group of antinutrients is oxalates, which plants use for regulating calcium levels and for defence from insects or grazing animals, as the calcium oxalates can form hard, undesirable crystal-like formations.¹ While this binding function of antinutrients is generally useful for plants, it can have the opposite effect on us when they bind to nutrients we want in our bodies, leaving us unable to access them. In human bodies, if oxalates bind to calcium and are absorbed in our gut, research suggests that they could eventually form kidney stones.² There are several other antinutrients used by plants, including lectins, goitrogens, phytoestrogens, and tannins. Even fibre, used for structure by plants, is an antinutrient because it also absorbs essential nutrients and water while hindering the absorption of other nutrients in our gut.

Should we avoid antinutrients?

In short, definitely not. While foods with higher antinutrient levels can impact the absorption of some nutrients, these foods are generally rich in other beneficial nutrients. The mere presence of antinutrients does not make food harmful because, in a normal healthy diet, more than enough nutrients are eaten to compensate for losses.

There are also no major studies indicating that a diet containing foods high in antinutrients is dangerous to human health - in fact, the opposite is usually true. For instance, some studies have shown that diets rich in foods containing oxalates can actually reduce the likelihood of kidney stones by 40-50%, because of the high level of healthy nutrients in those foods more than balancing out any potential risk associated with antinutrients.³ For example, while tannins can hinder your absorption of iron, they are found in nearly all fruit and vegetables - foods which you certainly shouldn’t be avoiding. Some studies even link foods rich in tannins to lower rates of inflammation and better cardiovascular health.⁴

Finding a balance

While nutrients are generally associated with a positive influence on our health, sugars and saturated fats are technically nutrients, too - and eating these in excess is far from healthy. The key lies in excess - a ‘bad’ diet could consist of eating too much of a nutrient just as easily as eating too much of an antinutrient.

But if you’re still worried about antinutrients, food preparation methods like soaking in water, fermenting and sprouting, or cooking, actually remove significant quantities of antinutrients.⁵ For example, you already unknowingly remove dangerously toxic levels of lectins in raw beans when you soak and boil them - a process necessary to make them edible.

At the end of the day, humans have been eating foods containing antinutrients since we first evolved. Plants contain thousands of phytochemicals, and singling out the harmful effects of a few would mean ignoring the complex benefits of many others. So, should a person who is eating a normal diet worry about antinutrients? The short answer is no.