Anti-nutrients: What Are They And Do They Have Health Consequences?

What Are Anti-nutrients?

Anti-nutrients are a chemical compound found in plants that are somewhat toxic to animals. Anti-nutrients are plants’ defense mechanisms. Like animals, plants don’t want to get eaten, but they can’t run away or fight back so they produce plant toxins like anti-nutrients to harm the animals that eat them.

As plants’ defense system of anti-nutrients evolved so did animals (primarily herbivores) ability to handle these toxins. For example, “moose and other grazers have enzymes in their saliva as well as multiple stomachs which deactivate plant toxins such as tannins.” (1) That’s why herbivores can eat plants without dying or getting sick, or at least to some degree. (1, 2)

Herbivores can only handle so much of one plant toxin, therefore when able to, they rotate between eating different plants to avoid consuming too much of one plant toxin. If they aren’t able to rotate food sources, they have been found to get sick. (1, 2) Herbivores also avoid some plants especially those high in lectins, like grains, for the consumption of these foods causes them great pain. (4)

But what about humans?

Since humans are omnivores that got most of their Calories from animal foods for most of history, we have not evolved to handle plant toxins in the same way herbivores have. We can still handle some without health consequences, plants are part of an omnivore diet after all, but as you will see in this article we have to be careful and limit our intake of anti-nutrients to avoid health issues such as leaky gut, IBD, IBS, autoimmune diseases, nutrient deficiencies, kidney stones, and more. (1, 2, 3, 4)

One other key function of anti-nutrients is to store nutrients in plants by binding to them. While this mechanism helps plants, it’s not so great for humans. And this is where anti-nutrients get their name. They bind to nutrients in your GI track making the nutrients too bulky to be absorbed into your blood stream. These nutrients bound to anti-nutrients end up getting excreted in the feces. Therefore the more anti-nutrients you consume, the less nutrients your body absorbs and utilizes.

Different Types Of Anti-nutrients

There are many different types of anti-nutrients, but in this post I’m gonna share 4 of the most common ones.

Lectins

Lectins are a type of anti-nutrient and protein that are particularly harmful to the gut. Lectins bind to the epithelial cells lining your gut wall and puncture holes between the cells, a condition known as leaky gut or intestinal permeability. These holes in your gut lining allow microorganisms toxins, parasites, and food particles to slip through your gut lining and enter your blood stream. (2, 3, 4)

These are categorized as foreign by your body and trigger an immune response in the body, which is inflammatory by nature. The immune system goes on high alert and destroys anything resembling these foreign objects. Unfortunately the protein structure of lectins is very similar to several body tissues including the thyroid, myelin sheath (coating of nerves), synovial tissue (connective tissue), and more. (2, 4) Therefore your body accidentally attacks your own body. This is what an autoimmune disease is.

As you can probably imagine, high lectin consumption overtime leads to severe gut damage, leaky gut, chronic inflammation, and autoimmune disease.

(2, 4)

Oxalates

Oxalates (aka oxalic acid) are compounds found in certain plants that have a negative charge of -1 or -2, they are known as anions. This negative charge makes them like magnets searching for molecules with a possitive charge (cations). (4, 5)

When oxalates bind to minerals with a charge of +2 (like Sodium, Magnesium, Calcium, Copper, Zinc, or Iron) they form crystal-like substances that resemble glass or needles. (See picture below) (2, 4, 5)

These crystals are sharp and painful to tissues and can contribute to conditions like fibromyalgia (a condition characterized by chronic widespread pain) and arthritis. (4, 5) Under normal conditions, oxalates are excreted in urine or feces, however if too many oxalates are present the body moves to store them in tissues like the brain, GI system, endocrine glands like testicles and breasts, skin, joints, kidneys, thymus, blood vessels, eyes, thyroid, and muscles. This is known as oxalosis. (2, 4)

Oxalosis may lead to kidney stones, neurotoxicity, vulvar pain, menstrual disorders, hormone dysfunction, memory loss, mood disorders, Parkinsons, and Alzheimers. (2, 5)⠀⠀⠀⠀⠀⠀⠀

It’s also important to note that when oxalates bind to these minerals they are not able to be used by the body and therefore excessive oxalate consumption can lead to deficiencies in the previously mentioned minerals (Sodium, Magnesium, Calcium, Copper, Zinc, and Iron). (1, 2, 3, 4, 5)

While a diet too high in oxalates (see picture of foods high in oxalates below) is the main cause of oxalosis; It can also be worsened by toxic metals; overgrowth of bacteria, fungus, candida, or parasites; mold exposure; vitamin B6 deficency; excessive consumption of vitamin C; and genetic conditions such as hyperoxaluria (a condition that inhibits the processing of oxalates). (4) Although very uncommon, death has been reported from consuming 5000 mg of oxalates in a day. (1, 2)

It should be noted that humans actually produce 10-30 mg of oxalates a day when breaking down the amino acids glycine and hydroxyproline and a molecule called glycoxalate. (1, 2) So we are able to tolerate some level of oxalates. However foods high in oxalates (like those listed below) typically have about 40-755 mg of oxalates per 100g serving, therefore it’s easy to overdo the oxalates if you’re not carefully about your food choices. (2)

Green smoothies are the worst culprit of excessive oxalate consumption. I know they feel healthy, but they’re really not! The foods highest in oxalates typically get thrown into a blender for green smoothies, things like spinach, kale, or other leafy greens, almond milk, almond butter, and turmeric. (2, 4, 5) Other high oxalate foods are listed below:

(2, 4)

Polyphenols

Polyphenols are a large group of molecules found in plants that serve as plant pigments and phytoalexins (a type of plant toxin used to fend off predators). (1, 2) There are many types of polyphenols including resveratrol, quercetin, flavinoids, tannins, stilbenes, lignans, curcumin, capsaisin, and many more. (1, 2)

Mainstream nutrition claims these molecules are magical anti-inflammatory, anti-oxidant, cancer fighting, heart disease preventing molecules, however the science just doesn’t support these claims. Most studies done on polyphenols are epidemiology studies (studies where a large group of people is observed, but there is no intervention). These studies do not account for many variables and are unreliable. Therefore they are typically used to make correlations which serve as the hypothesis in interventional (or experimental) studies which can lead to causative theories.

Like I said many of the studies behind the health claims of polyphenols are epidemiology studies. In these studies an increase in polyphenol consumption often correlates with the health benefits listed above. However there are so many variables that are unaccounted for so we can’t accurately make a causative statement from this data. (2)

There are however a few interventional studies on polyphenols. However many of these studies failed to show benefits in terms of inflammation, DNA damage, or immunological markers. (2, 6) And in one study a 10-week period without dietary fruits and vegetables lead to a decrease in oxidative damage to DNA, blood proteins, and plasma lipids, concomitantly with marked changes in antioxidative defence. (7) Since this was an exclusion of fruits and vegetables as a whole, which have many compounds, we can’t say for sure that the lack of polyphenols is what lead to these benefits, however the evidence for polyphenols improving inflammation, DNA damage, immunological markers, oxidative stress, cancer risk, heart disease risk, and so on doesn’t seem to be there!

Now that we got that cleared up, lets look at some of the specific types of polyphenols. A major family of molecules that falls under the classification of polyphenols is flavinoids. Flavinoids includes anthocyanins (found in the skin of berries), isoflavones (found in soy), catechins (found in tea), flavan-3-ols (found in cacao), and more. (2)

Flavanoids (primarily isoflavones, genistein, and quercetin) are endocrine disruptors. They disrupt normal hormone function by mimicking the hormone estrogen which can lead to decreased fertility and reproductive health, hormone imbalances, reproductive abnormalities, and tumors. (2) Flavanoids have also been shown to negatively impact the thyroid. (2)

Tannins (a type of flavanoid) are designed to inhibit digestive enzymes of animals trying to eat them. This leads to poor digestion and less nutrient absorption (especially vitamin C, iron, and protein). (2, 3)

Overall, the purposed benefits of polyphenols are not backed by quality science and there are a few concerns with the consumption of too many polyphenols potentically disrupting hormones, reproductive health, digestion, nutrient absorption, and thyroid health. Polyphenols role in inflammation is inconclusive (it’s possible that this may vary between the types of polyphenols as well). Polyphenols don’t appear to have as many consequences as lectins and oxalates, however I would advice avoiding soy which is high in multiple endocrine disrupting polyphenols. The negative effects of these have been better studied and proven. (8)

(9, 10)

Phytates

Phytates (aka phtyic acid) are naturally occurring substances plants use to store phosphorus. Similar to oxalates, phytates have an affinity for minerals with a charge of +2 like magnesium, manganese, calcium, iron, copper, selenium, potassium and zinc. Therefore phytates bind to these minerals and block their absorption into the blood stream. Consequently, consuming too many phytates too frequently could lead to deficiency of these minerals. (3, 4, 5) Phytates have also been shown to reduce the activity of digestive enzymes such as trypsin and pepsin. (5)

However phytates do have some benefits as well. Since they bind to minerals with +2 charges, they also bind to heavy metals like mercury and lead (which also have +2 charges). This prevents absorption of heavy metals and helps eliminate them. (4, 5) Phytates can also help remove biofilms (a mucus like matrix that hides pathogens from being detected by your body). (5)

Phytates can be broken down pretty well through soaking, sprouting, and fermenting your food. However if you have leaky gut or mineral deficiencies it’s probably best to avoid phytates at least until those are resolved. (3, 4, 5) Another thing to mention is that foods high in phytates tend to be high in lectins, oxalates, and other anti-nutrients which may cause problems.

Overall Thoughts On Anti-nutrients:

I think to achieve optimal health it’s best to limit your anti-nutrient intake, particularly that of lectins and oxalates. Notice I didn’t say eliminate, that’s because most people can tolerate a small amount of anti-nutrients and there are still benefits to consuming some fruits and vegetables. The real problem lies with excessive anti-nutrient and plant consumption.

Also if you have leaky gut, an autoimmune disease, IBS, and/or IBD, I would suggest being extra strick about reducing anti-nutrients (especially lectins), you may even choose to eliminate all of them. This is key to healing your gut which will inturn help heal these conditions.

To reduce anti-nutrient consumption:

• Really limit grains, beans, nuts, seeds, and leafy greens
• Soak any grains or legumes overnight and rinse before consuming
• Roast or soak nuts and seeds before consuming
• Ferment or cook vegetables before consuming
• Have most of your plant intake be from fruits and vegetables

It’s also important to experiment and see what works for you. Everybody is so different and will react differently to anti-nutrients. Tune into your body. If you start to get or already have digestive issues, skin issues, food sensitivities, mood disorders such as depression or anxiety, frequent yeast infections or UTIs, autoimmunity, SIBO, candida over growth, IBD, IBS, hashimotos, fibromyalgia, or chronic fatigue, then I would suggest decreasing your anti-nutrient consumption. This will help heal your gut and support gut health which plays a major role in the previously mentioned symptoms and conditions.

Works Cited

1. Eriksson, Keenan. “Your Vegetables Want To Kill You.” Medium. 1 June 2020. https://medium.com/the-carnivore-curation/your-vegetables-want-to-kill-you-c863763d02cd

2. Sladino, Paul. The Carnivore Code. New York: Houghton Mifflin Harcourt. 2020. Print.

3. Kummer, Michael. “What Are Antinutrients? – A Science-Based Review.” Michaelkummer.com. 9 April 2019. https://michaelkummer.com/health/antinutrients-food/

4. Bucko, Alexandra. “Ill-Digestion, Leaky Gut, and Deteriorating Effects of Anti-nutrients.” 5 August 2019. https://www.throughhealthandback.com/blog/2019/8/5/ill-digestion-leaky-gut-and-deteriorating-effects-of-antinutrients

5. Bucko, Alexandra.Through Health and Back. Accessed 12 May 2021. https://www.instagram.com/throughhealthandback/

6. Peluso, Ilaria et al. “Effects of High Consumption of Vegetables on Clinical, Immunological, and Antioxidant Markers in Subjects at Risk of Cardiovascular Diseases.” Oxidative medicine and cellular longevity vol. 2018 5417165. 8 Oct. 2018, doi:10.1155/2018/5417165

7. Young, J F et al. “Green tea extract only affects markers of oxidative status postprandially: lasting antioxidant effect of flavonoid-free diet.” The British journal of nutrition vol. 87,4 (2002): 343-55. doi:10.1079/bjnbjn2002523

8. O’Brien, Kayley. “Health Consequences Of Xenostrogens.” Heart to Kitchen. 19 February 2021. https://www.hearttokitchen.com/health-consequences-of-xenoestrogens/

9. Gotter, Ana. “Top Foods with Polyphenols.” Healthline. 8 March 2019. https://www.healthline.com/health/polyphenols-foods#TOC_TITLE_HDR_1

10. Staughton, John. “Top 11 Foods High in Polyphenols.” Organic Facts. 28 July 2020. https://www.organicfacts.net/foods-polyphenols.html