The loss of nutrients is irrelevant

For starters, antinutrients usually only act on the meal they have been eaten with and do not impact the next meal. So that would mean eating a breakfast high in antinutrients will not cause you to absorb less nutrients from your dinner. However, I’d argue that if I eat a meal I want to get the most nutrition possible out of it. That is the actual purpose of eating food in the first place. I eat to live, not live to eat.

This also assumes that one even has meals that are not high in antinutrients. Just a coarse look at what people eat nowadays, and I myself have eaten in the past, shows that pretty much every single meal will have some kind of antinutrient in it. Usually multiple different kinds actually, since most meals do consist of a bunch of ingredients. Let’s take a stereotypical sandwich for example:

• Bread: Phytates & Lectins, especially if it’s whole grain and non-fermented
• Salad leaves: Oxalates
• Tomatoes: Solanine and chaconine

Even if we assume you toss some butter, cheese and ham on top, a good chunk of the micronutrients in that sandwich will be inevitably lost. The actual amounts lost aren’t even known, but we have a few pointers.

One study assessed the amount of zinc lost due to antinutrients, by giving people oysters. Oysters are very high in zinc and when consumed on their own the body absorbs the zinc readily. But when oysters are eaten combined with beans, about 60% of the zinc is not absorbed. Even worse, in combination with tortillas, the amount of zinc absorbed drops to practically 0%.

Prevalence of nutrient deficiencies

The majority of people are not obviously nutrient deficient, but that doesn’t mean that a chronical, subclinical deficiency isn’t present. And what are the ideal ranges? The Recommended Daily Allowances (RDAs) are somewhat of a guide, though there is criticism to be had about how adequate the RDAs actually are. Anyway, do people reach their RDAs?

On a global scale it is estimated that one-third of the world suffers from at least one micronutrient deficiency. That’s a whole lot and certainly not all of it can be attributed to insufficient food availability. Although poorer countries have even worse numbers, this can also be observed in first-world countries where people regularly suffer from obesity. Let’s check some of these.

Iron deficiency anemia

Anemia is more prevalent in women, even more so if they are currently pregnant. Maybe if they’d just get their iron from red meat instead of high oxalate spinach, the numbers would be less dire.

• 30% of women (aged 15-49 years) suffer from anemia
• 40% of children (aged 6-59 months) suffer from anemia
• Half of it is attributed specifically to iron deficiency anemia
• Another cause of anemia is vitamin deficiency

Zinc deficiency

An estimated 17.3% of the general population are deficient in zinc.

Calcium deficiency

About 50% of the general population has inadequate intake of calcium.

Magnesium deficiency

48% of the general population has inadequate intake of magnesium putting them at risk of deficiency.

Iodine deficiency

38% of people were classified as iodine deficient, 5% had hypothyroidism due to severe deficiency.

To sum it up

• Iron absorption is decreased by oxalate, phytates, lectins and tannins.
• Calcium absorption is hampered by oxalate, phytates and lectins.
• Zinc absorption is decreased by phytates and lectins.
• Iodine absorption is impacted by glucosinolates and goitrogens.
• Magnesium absorption is decreased by phytates.

So, to me it seems pretty obvious that people are actually struggling to get adequate micronutrients from their food. You cannot convince me that antinutrients do not play a role in that.

You can just supplement that

Sure, supplementation may help the issue a little, but it’s a band aid solution. Nutrient deficiencies are not caused by supplement deficiencies. I’d argue they are quite directly caused by antinutrients and the continuous vilification of the most nutritious foods available. Your food should fulfill all your nutritional requirements, period.

Food preparation destroys antinutrients

This is a big argument and I largely agree with it. Traditional food preparation methods such as soaking, fermenting, sprouting, nixtamalization (bet you never heard that one) and especially cooking destroy antinutrients and toxins. These methods exist specifically to turn things that are inedible to humans into food, and it’s quite an amazing feat of human ingenuity. But this does not always apply, as phytate for example is heat stable below 150 °C, so boiling will have little to no effect on phytate content.

But cooking specifically is known to also destroy nutrients at the same time, so in the end nutrients are lost one way or the other. Even then, some trace amount of antinutrients will almost always be left in the food and can unfold their detrimental effects. Bloating and gas can be also caused by leftover lectins for example. There are also quite some foods that are generally consumed in their raw form, like salads, giving you the full broadside of their antinutrients.

Lastly, some of these food preparation methods are not popular or regularly used. Nixtamalization is particularly important for corn, but not all corn products are nixtamalized. Sprouting is basically only done by tryhard vegans, though it actually reduces some antinutrients by a lot. At least fermenting is still popular with foods like Sauerkraut, Kimchi and sourdough bread.

Some substances thwart antinutrients

To be fair, this is a little bit of a strawman but I have actually seen this argument once. It’s not even a bad argument because there are actually anti-antinutrients. However, I’ve only heard this in the context of oxalates, which can be counteracted with citric acid. This is absolutely correct. But at the same time, just because I have an antidote doesn’t mean I should just poison myself. I’m not aware of other anti-antinutrients, so this only applies to oxalate. Considering there are many more types of antinutrients, I’d consider this a weak argument still.

Antinutrients have benefits that outweigh the negatives

This is an argument that, in my opinion, really doesn’t bear out in reality. They are often ascribed antioxidant, anti-inflammatory or anticancer properties based on some weak epidemiology or in vitro studies. Not a single antinutrient has been confirmed to actually exert these benefits when consumed. I’m not denying the possibility that there are medicinal properties in these substances, but considering the whole host of “side effects” of the medicine I’ll err on the side of caution. If anything, these substances should be used in a targeted, medicinally indicated fashion.

For example: Lectins have been demonstrated to have anticancer properties. But the study that was referred to tested specific lectins found in mistletoe, which is not commonly consumed as a food (and is also somewhat poisonous). Further, it was an in vitro study, meaning the extracted lectins were directly applied to a cell culture in a petri dish. In no way should this result be interpreted as “eating mistletoe cures/prevents cancer”, and neither does it mean that all lectins have these effects.

The same study also investigated lectins in Jack Beans (which are mildly toxic and almost exclusively used as pig feed) as well as Solomon’s seal (“Polygonatum cyrtonema Hua”, a rather obscure plant from china that I could find very little info on regarding toxicity. It’s seems to be mainly used as decorative plant)

And in terms of epidemiology there is an association between consuming legumes and overall better health outcomes. But since it’s observational, that doesn’t actually mean that legumes are healthy.

Ignoring toxicity

Something that I feel like is often ignored is that antinutrients do not only prevent nutrient absorption. Many of them are straight up poisonous or mess with hormones, enzymes and metabolic processes. Some are implicated in causing autoimmune reactions by binding to cells for prolonged periods of time. And that’s just what we know about them so far, nobody knows what effects they could have beyond that.