As the Paleo Diet concept increasingly gains traction worldwide, it has spawned an explosion of copy cat books over the past 3-4 years. Look no further than Amazon.com to literally see the hundreds of diet and cookbooks that manage to shoehorn the word “Paleo” into their titles. In a way, all of these books are a good thing because they tend to get more and more people involved in a lifetime way of eating that may improve health and well being, while reducing the risk for chronic diseases. The downside of this situation is that many authors are poorly informed and frequently provide misleading information about food, recipes and meals that are not “Paleo” by any stretch of the imagination.
We have recently written a number of comprehensive articles about some of these items including sea salt, dairy foods, honey and nut flours. I even understand that a popular Paleo influencer now added beans and legumes to his list of foods which are acceptable in contemporary Paleo diets. Apparently he has not read my lengthy article on the topic, nor is he aware of the notion that almost all beans and legumes are either inedible, poorly digestible or toxic in their raw state. Hence until humanity acquired the technology to create fire at will, legumes were not on the original menu that helped to shape our present day genome.
As I have previously explained, legumes both in their raw and cooked state contain a number of antinutrients (lectins, saponins, protease inhibitors, phytate, thaumatin like proteins among others) which can impair nutrition/health, adversely affect gut function, increase intestinal permeability and promote autoimmune disease. Increasingly, scientists studying autoimmune disease now recognize that a leaky gut represents a key environmental factor in triggering autoimmune disease in genetically susceptible individuals.1-3 Although the link between autoimmunity and legumes is poorly documented in humans, at least one legume is known to cause an autoimmune disease. Except for gluten containing grains (wheat, rye and barley), only alfalfa sprouts, seeds and supplements are known to elicit an autoimmune disease.
A long line of intriguing research in humans, primates and rodents4-33 demonstrates that alfalfa sprouts, seeds and supplements may cause an autoimmune disease known as systemic lupus erythematosus (SLE), particularly when consumed in excessive quantity. The classical explanation is that alfalfa contains an amino acid called L-canavanine which is thought to cause SLE via dysregulation of T and B lymphocytes in the immune system.6, 13, 14, 16, 18, 19, 30, 31, 33
However, this explanation may not fully explain why alfalfa sprouts, seeds and supplements cause autoimmunity.20 With the increasing realization that a leaky gut represents a fundamental environmental factor that underlies autoimmunity,1-3 then any food which has the potential to increase intestinal permeability may be suspect in autoimmune diseases.
Below is a table showing the saponin content of various foods. Note alfalfa sprouts tops the list.
One of the few raw legumes that we eat in the typical western diet are alfalfa sprouts. In vegetarian diets, they are standards in meatless sandwiches and vegetable salads. Alfalfa sprouts, seeds and supplements are potent sources of saponins23-28 which increase intestinal permeability. Most people eat alfalfa sprouts irregularly, so the potential adverse health effects of sporadic alfalfa consumption are probably of minor consequence, except for people suffering from autoimmune disease.
As a contemporary Paleo dieter, we should learn from the wisdom of our ancestral diet: a diet that rarely or never consisted of legumes.
Loren Cordain, Ph.D., Professor Emeritus
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