Grains Part III – Lectin

Part III: Are Grains Healthy for You?

Caveman Doctor recently received several questions regarding grains and if they were healthy. One person even referred to quinoa as a “superfood.”  Caveman doctor was really confused as to what a grain was since he never ate them during his time on Earth.  He was also really confused by the term superfood and remembered that the last time he ate a superfood, he got supersick and was in his cave bathroom for an entire day. After he asked around, he got his hands on some oats and wheat and figured he would give them a try. At first, he didn’t believe they were food as they were lacking the bold color, smell, and feel of foods he was used to eating. He tasted the oats and wheat, but immediately spit them out due to their bland taste. Caveman Doctor is used to colorful, flavorful foods and was very confused as to why anyone would eat these things known as grains.

Does Caveman Doctor even recognize this as food?

In the last post we discussed phytic acid. This week we move along to lectins and discuss their health effects, and how they may potentially lead to cancer, weight gain, and several other major health issues.

2. Lectins


 “We should think twice about consuming foods that contain a large amount of lectins, especially on a routine basis.”

We already discussed the potential reasons why people eat grains. When you are told your entire life by the media, your doctors, and everyone else under the sun how healthy something is, you assume it is actually healthy. Unfortunately, grains are not the only unhealthy “health food” that has been recommended to us for years by our health professionals.
While we talked extensively about phytic acid in the last post, this one is shifting gears to the other dangerous player in grains – lectin.  Beans, seeds, some nuts, and of course, grains, are foods that contain large amounts of lectin, a complex protein that causes many physiologic reactions when eaten. First off, lectins cause immune and antigenic reactions (much like pollens or other allergens). The immune response triggered by lectins can lead to autoimmune diseases, which are basically the immune system on overdrive, as seen in diseases like rheumatoid arthritis or lupus1.  Lectins have been also shown to interact with our GI cells, damage them, and then inhibit their ability to repair themselves.2
This triple threat causes a “leaky gut” and allows bacteria, infectious elements, and toxins easy access to our system through our gut, which is normally our body’s fortress wall. Plan and simple, any food that causes distress to our cells (GI in this case) and then does not allow them to fix themselves should not be considered a healthy food, but rather a quite harmful one.
Interestingly, these lectins were likely a defense mechanism for the plants that contained them, as they deterred predators from eating those plants. Much like a toxin from poisonous mushrooms, lectins are unhealthy toxins to humans, insects, and other predators causing unhealthy reactions when eaten. We should think twice about consuming foods that contain a large amount of lectins, especially on a routine basis.
Just as when we consume large amounts of the sugar fructose, lectins have been shown to cause leptin resistance.  Leptin (deceivingly similar word to lectin) is the chemical within our body that affects many physiologic functions, including suppressing appetite. Leptin resistance results in increased appetite, and has been shown to lead to obesity as well.3
Lectins (again, the bad chemical found in plants like grains and legumes, not the hormone within our body) can bind to our kidney cells and have been responsible for kidney damage, which results in excess protein in the urine.4 They act as antigens and bind to receptors on pancreatic cells and may induce diabetes.5
Finally and most importantly, lectins have been shown to travel throughout the body, bind to receptors on cells that are potentially harmful, and activate them. These receptors include the insulin receptor and Epidermal Growth Factor Receptor (EGFR)6, both of which have been heavily implicated in cancer and are a recent target of many novel therapeutic cancer drugs.7, 8 They have also been shown to initiate mitogenesis,9 which is basically the process when our cells divide. Over-stimulation of mitogenesis is a potential cause of cancer.
To add insult to injury, lectins are actually used in biochemical warfare. Now I may be a doctor and not a rocket scientist, but when something is used in biochemical warfare, it’s usually not on my healthy food list. A part of ricin (a highly toxic poison) is a lectin, which binds to our cell surfaces and allows it to enter our cells, inhibiting function and causing death, similar to when it binds to the receptors discussed above.
Also, please keep in mind lectins are in beans, peanuts, and other legumes, not just cereals and grains. Dairy from cows fed grains (the lectins are passed from their feed) also has higher amounts. For more questions on legumes, search my website for other posts.

In review, lectins are plentiful in grains, are toxic and inflammatory to the human body,5 and can potentially lead to:


1. Autoimmune diseases
2. GI distress
3. Inability of GI cells to heal, thereby allowing toxins and infections to seep into our bodies
4. Induction of the cancer-promoting pathways EGFR and Insulin
5. Mitogenesis (cells dividing, which can lead to cancer)
6. Obesity
7. Diabetes

Be informed and be healthy!


1. Cordain L, Toohey L, Smith MJ, Hickey MS. Modulation of immune function by dietary lectins in rheumatoid arthritis. The British journal of nutrition 2000;83(3): 207-17.

2. Miyake K, Tanaka T, McNeil PL. Lectin-based food poisoning: a new mechanism of protein toxicity. PloS one 2007;2(8): e687.

3. Friedman JM, Halaas JL. Leptin and the regulation of body weight in mammals. Nature 1998;395(6704): 763-70.

4. Coppo R, Amore A, Roccatello D. Dietary antigens and primary immunoglobulin A nephropathy. Journal of the American Society of Nephrology : JASN 1992;2(10 Suppl): S173-80.

5. Freed DL. Do dietary lectins cause disease? BMJ 1999;318(7190): 1023-4.

6. Jonsson T, Olsson S, Ahren B, Bog-Hansen TC, Dole A, Lindeberg S. Agrarian diet and diseases of affluence–do evolutionary novel dietary lectins cause leptin resistance? BMC endocrine disorders 2005;5: 10.

7. Ciardiello F, Tortora G. EGFR Antagonists in Cancer Treatment. New England Journal of Medicine 2008;358(11): 1160-74.

8. Rubin R, Baserga R. Insulin-like growth factor-I receptor. Its role in cell proliferation, apoptosis, and tumorigenicity. Laboratory investigation; a journal of technical methods and pathology 1995;73(3): 311-31.

9. Kilpatrick DC. Mechanisms and assessment of lectin-mediated mitogenesis. Molecular biotechnology 1999;11(1): 55-65.
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