Of all the nutritional recommendations that are passed around, eating more fruits and vegetables seems like a tip that should be universally good for everyone. Like every guideline, even this one has caveats.
Many plant foods contain compounds that are irritating to our digestive system, immune system, and even nervous system. These compounds can cause certain plant foods to do more harm than good. In some cases, proper preparation of the foods can mitigate the ill effects of the compounds, but in other cases, the foods should be avoided in their entirety.
Lectins are sugar-binding proteins found in all plant foods in varying amounts. They are also in dairy. The functions of lectins are wide-ranging, but some of them – particularly those found in grains, legumes, nuts, and seeds – can have damaging effects. While some lectins mainly provide information communication, others contribute to a plant’s defense mechanism.
Unripened fruit, for example, contains immature seeds. These seeds are too fragile to survive an animal’s digestive tract. Fruit consumption at this point in development is bad news for the next generation of fruit-bearing plants. Higher lectin content – which can cause digestive consequences such as bloating and diarrhea – would generally deter an animal from over-consuming the fruit, thus increasing the plant’s chances at passing on its genes to a new generation.
While acute cases of adverse lectin reactions may seem few and far between, it is likely that most people are actually experiencing a low-grade, chronic case. Unless you are paying a premium price for pre-soaked grains, legumes, and nuts, if you are not properly preparing them yourself, no one is doing it for you. Grain-based bread and baked goods, prepackaged nut mixes and nut butter, bean salads and canned beans can all wreak havoc on the delicate lining of the digestive tract. Have you ever wondered what makes beans – usually from a can – the “magical fruit?” It’s the lectin content.
So what’s actually happening deep within the digestive tract to cause this distress?
The lectins target the tight junctions – the links between the individual cells lining the small intestine – and open them up, cause the condition known as leaky gut. Without this “seal” between cells, large particles – and the lectins themselves – are then able to pass directly into the bloodstream. This causes inflammation and an immune response which can trigger both food allergies and autoimmune conditions like Hashimoto’s and lupus.
There are several strategies for reducing the harmful lectin content of certain foods. For grains, legumes, nuts, and seeds, soaking, sprouting and fermenting is extremely helpful. This may look like making traditional sourdough bread out of wheat, fermenting soy into miso or natto, soaking dried beans overnight before cooking or soaking and drying raw nuts and seeds. The skins of potatoes are also very high in lectins. Avoiding the skin or cooking them in a pressure cooker are two ways to avoid those lectins. The lectin content in dairy can be reduced by fermenting milk and butter into yogurt or cultured butter, respectively. If vine- or tree-ripened fruits are available, they are the best choice.
Another problematic plant compound is phytate. Phytates bind to minerals, such as calcium, iron, zinc, copper, and magnesium. This is very good for the plants involved since the phytates allow them to save and store minerals until they are needed. This isn’t so great for animals trying to eat the plants. With minerals tightly bound to phytates, they are not able to be absorbed in the digestive tract. Even if the food consumed is high in minerals, they will pass through undigested, leading to mineral deficiencies.
Grains contain high levels of phytates. Soaking and thoroughly cooking grains is a strategy for neutralizing phytates and increasing the availability of the rich minerals found in them.
Similar to phytates, oxalates also bind to minerals, particularly calcium and magnesium. Some individuals are sensitive to oxalates, and they can contribute to the formation of kidney stones. Oxalates are found in spinach, chard and beet greens. Gentle cooking can help, but for those who are sensitive, they may need to be avoided.
It may seem that plants are out to get you, but they are only attempting to maximize their reproductive success. With proper preparation of these foods, you will be better able to maximize your health.
Fallon, S. (2001.) Nourishing Traditions. New Trends Publishing: Brandywine.
Haas, E. M. (2006.) Staying Healthy with Nutrition. Celestial Press: Berkeley.
Wolf, R. (2010.) The Paleo Solution: The Original Human Diet. Victory Belt Publishing.
Greenfield, B. (2017.) The Plant Paradox: Are Lectins Really That Harmful or Is Dr. Steven Gundry Wrong? Ben Greenfield Fitness Podcast with Dr. Steven Gundry, September 2, 2017.
This is for informational purposes only and should not be interpreted as medical advice.
Sara Kennedy is a certified Nutritional Therapy Consultant. She lives fitness, nutrition and wellness – and wants to help save lives and change the world’s view on health and nutrition. Learn more about Sara and her plans at thriveak.com To reach her, email firstname.lastname@example.org