What You Need to Know About Plant Antinutrients

Have you seen the headlines about the dire need to avoid lectins and oxalates and wondered what all the fuss was about?

Some people have food sensitivities, but the key – as with all my advice – is determining the foods that are best for you and the foods you should avoid. It makes no sense to wipe out entire classes of extremely healthy foods simply because of a few misguided posts about them.

Please do not fear eating plants, which we have been doing as humans since time immemorial when we were hunters and gatherers. Do plants have defense mechanisms to protect themselves? Yes. We have a name for them: antinutrients, including lectins, oxalates, phytates, and goitrogens.

For the most of the population, eating these foods in moderation (as most of us do) is not harmful in any way – and, in fact, can be extremely beneficial in terms of the nutrients found in them. For a smaller subset of the population, eating too much of certain plants can cause some health issues, but the key is not discounting entire collections of foods on the chance that you might be affected.

The best test of ANY food you eat is how your body, gut, and brain respond after consumption. If you feel great after eating the food, then keep eating it. If you get sore joints, stomach troubles, brain fog, kidney stones, or thyroid issues, then please do dig deeper into foods containing these antinutrients.

Why are they called antinutrients? Because some people can’t digest and absorb the nutrients bound up in them very well. The key to remember is that almost all edible plants offer both antioxidant benefits and gut health benefits (because of the fiber).

Plant Antinutrients

1. Lectins. These are a type of protein in plants that can bind to sugar and reduce nutrient absorption. We are unable to digest lectins, and there is some concern that lectins – in large amounts – can damage the thin gut lining that prevents particulates (bacteria, undigested food particles) from our gut leaking into our bloodstream.

The highest concentrations of lectins are found in legumes, grains, and nightshade vegetables (tomatoes, eggplant, potatoes, and peppers), but all of these also offer valuable nutrients. That said, one option you have to keep enjoying these foods if you have issues with lectins is by cooking, sprouting, or fermenting; eating them in this manner reduces the lectin content to negligible amounts.

Lectins have antioxidant properties, protecting cells from damage caused by free radicals. They also appear to slow down digestion and the absorption of carbohydrates, which may help keep blood sugar and insulin levels stable.

2. Oxalates. Also known as oxalic acid, they are naturally occurring compounds in plants that can bind to minerals to form compounds, including calcium oxalate and iron oxalate, and have been connected to some types of kidney stones, as well as blocking some absorption of minerals. More typically, these pass easily through the body via urine or stool.

The highest concentrations of oxalates are found in leafy greens (especially spinach), vegetables (potatoes, beets), fruits (raspberries, dates), cocoa, nuts, and seeds. Excess oxalate can interfere with the absorption of essential minerals like calcium and magnesium, but, again, if you are not experiencing any issues, then you should focus on the many nutritional benefits of eating these foods, many of which are high in antioxidants. If you do have an issue with oxalates, consider cooking the food, which greatly reduces the oxalate content.

Oxalates have immune-boosting and antioxidant properties that help protect the body against oxidative stress and damage caused by free radicals; it’s also been shown that oxalates can help protect kidney health. They also contribute to bone health by promoting the absorption and utilization of calcium in the body.

3. Phytates. Similar to lectins and oxalates, phytic acid, which is found in plant seeds, can block the absorption of certain minerals, including iron, calcium, and zinc, but only when consumed at very high levels.

All edible seeds, nuts, beans, grains, lentils, legumes, and whole grains contain phytic acid, as do some roots and tubers, in varying quantities. Similar to lectins, sprouting, cooking, baking, processing, soaking, and fermenting, all help to destroy phytic acid and allow for increased mineral availability.

Phytates also have many benefits, including: antioxidant properties; anti-cancer, inhibiting the growth and spread of cancer cells; may prevent heavy metal toxicity; may protect against kidney stones; and may help to lower blood triglyceride levels, blood pressure, and blood sugar.

4. Goitrogens. These are naturally-occurring chemicals found in many plant-based foods that for some people can affect thyroid health by inhibiting the thyroid’s ability to use iodine.

Goitrogens are found in cruciferous vegetables -- bok choy, broccoli, Brussels sprouts, cauliflower, cabbage – but also in kale, strawberries, peaches, radishes, and spinach. Again, the advice to reduce the impact of the goitrogens is to use steaming, cooking, or fermenting.

Final Thoughts About Plant Antinutrients

For most people, the benefits from the healthy nutrients found in edible plants, seeds, and nuts far outweigh any negative effects of trace amounts of lectins, oxalates, phytates, or goitrogens. If you have some concerns when eating these foods raw, follow the advice and cook or ferment them.

As long as you are buying the healthiest versions of these foods, ideally grown in healthy soils and free of pesticides and herbicides, they offer multiple benefits, including:

• Vitamins, which are crucial for healthy metabolism, growth, vision, immunity, brain function, central nervous system, and bone health.

• Minerals, which are vital for strong bones, healthy muscles, heart and brain, nerve function, and oxygen transport. Minerals are also important for making enzymes and hormones.

• Fiber, which promotes a healthy gut microbiome, aids digestion, regulates blood sugar, reduces appetite, and can reduce inflammation and bloating.

• Antioxidants, which combat cellular damage from too many free radicals (a by-product of normal metabolism) and support healthy aging by reducing the risk of chronic diseases caused from too many free radicals.

Finally, get in touch with your body. Be mindful about your eating and observe how your body, gut, and brain react to the foods you consume. Experiment. Food can and should be your medicine, but you may need to customize what you eat based on how you react to the foods.

Additional Healthy Diet/Living Resources

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